NIGEL WILLIAMS v RETURN TO WORK CORPORATION (SA) [2023] SASCA 125

On Appeal from SOUTH AUSTRALIAN EMPLOYMENT TRIBUNAL (DOLPHIN PJ, CLAYTON AJ AND COLE DP) ET-20-04340; ET-21-03187 Applicant/Respondent: RETURN TO WORK CORPORATION (SA) Counsel: MR B ROBERTS KC WITH MR D O’LEARY SC - Solicitor: MINTER ELLISON / SPARKE HELMORE LAWYERS Respondent: BRENTON ENGLISH Counsel: MR S MCDONALD SC WITH MR P SALU - Solicitor: MAHONY’S LAWYERS Applicant: NIGEL WILLIAMS Counsel: MR MARK ROBERTS SC - Solicitor: TINDALL GASK BENTLEY Hearing Date/s: 24/02/2023 File No/s: CIV-22-006862; CIV-22-004654 A SUPREME COURT OF SOUTH AUSTRALIA (Court of Appeal: Civil) DISCLAIMER - Every effort has been made to comply with suppression orders or statutory provisions prohibiting publication that may apply to this judgment. The onus remains on any person using material in the judgment to ensure that the intended use of that material does not breach any such order or provision. Further enquiries may be directed to the Registry of the Court in which it was generated. RETURN TO WORK CORPORATION (SA) v ENGLISH; WILLIAMS v RETURN TO WORK CORPORATION (SA) [2023] SASCA 125 Judgment of the Court of Appeal (The Honourable Chief Justice Kourakis, the Honourable Justice Doyle and the Honourable Justice Bleby) 23 November 2023 WORKERS' COMPENSATION - ASSESSMENT AND AMOUNT OF COMPENSATION - AMOUNT OF COMPENSATION DURING INCAPACITY - LUMP SUM PAYMENTS - SPECIFIC INJURIES WORKERS' COMPENSATION - ENTITLEMENT TO COMPENSATION - INJURY, DISEASE OR DISABILITY - AGGRAVATION OF INJURY WORKERS' COMPENSATION - ENTITLEMENT TO COMPENSATION - CAUSAL RELATION BETWEEN INJURY AND INCAPACITY OR DEATH - GENERALLY These reasons address two matters: the first involves a question of law reserved by the Full Bench of the South Australian Employment Tribunal (the English matter), and the second involves an appeal from a decision of the Full Bench (the Williams matter). Return to Work Corporation (SA) (the Corporation) is the moving party in the English matter, and the respondent in the Williams matter. The two matters raise issues concerning the construction of ss 22(8)(c) and 58(6) of the Return to Work Act 2014 (SA) (the RTW Act). In particular, they raise issues concerning the proper construction of the references to injuries “from the same trauma” (s 58(6)) and impairments “from the same injury or cause” (s 22(8)(c)) in the context of determining when injuries and impairments respectively may be combined for the purposes of assessing an injured worker’s entitlements under the RTW Act. -- 1 of 56 -- The English Matter: Mr English suffered a work injury to his neck on 4 March 2019 in the course of his employment as an arborist. On 10 May 2019, he suffered a further work-related injury when he fell and injured his right quadriceps. On the findings of the primary judge, the fall occurred as a result of lightheadedness brought on by prescribed pain medication that Mr English had been taking for his neck injury. The primary judge was satisfied that the impairment from the second injury should be combined with the impairment from the first injury, because both impairments were "from the same cause" for the purposes of s 22(8)(c). The Corporation appealed to the Full Bench of the Tribunal, which referred the following question of law to the Court of Appeal, pursuant to s 70 of the South Australian Employment Tribunal Act 2014 (SA): On the facts as found by [the primary judge], does s 28(8)(c) of the [RTW Act] apply so as to require or permit the impairments to Mr English’s neck and to his right quadriceps to be assessed together or combined to determine the degree of impairment of Mr English? Held (per Doyle JA, Bleby JA agreeing), answering the question in the affirmative: 1. Determination of whether a later or consequential impairment qualifies for combination under s 22(8)(c) of the RTW Act requires an evaluative assessment of the causal explanations for the impairments, having particular regard to any differences between them. It requires consideration of the nature and significance of any additional events or integers in those causal explanations. 2. Whilst a physiological link between the consequential impairment and an earlier injury or cause may inform the analysis or evaluation, it is not a necessary feature of the impairment to be combined. 3. It is appropriate to characterise both impairments as arising “from the same injury or cause” for the purposes of s 22(8)(c). 4. Whilst the causal explanation for the second impairment involves additional events or integers (the ingestion of pain medication resulting in lightheadedness and a fall), there was a direct and straightforward relationship, or causal chain, between the two injuries and hence the two impairments. Kourakis CJ (in dissent), answering the question in the negative: 1. Combination under s 22(8)(c) requires that both impairments have their origin in, and progress from (in the sense of being aetiologically linked to), the same cause. The Williams Matter: Mr Williams worked as an electrician. In May 2013, while climbing scaffolding at work, he experienced a sharp sudden pain to his right knee. Subsequent investigations revealed a tear of the medial meniscus in the context of severe osteoarthritis within the right knee. He underwent an arthroscopy and subsequent surgery. In September 2014, Mr Williams resumed work as an electrician with a new employer. Between September 2014 and May 2015, Mr Williams performed primarily sedentary tasks. From early May 2015, Mr Williams was required to perform more physically demanding work including work that required him to repeatedly climb up both ladders and stairs, as well as regularly working in a crouched position with bent knees or kneeling down. Mr Williams began to experience increased pain in his right knee, and also noticed pain in his left knee. He could not recall a particular incident that caused the pain to start, rather he noticed that it came on gradually and worsened over time. -- 2 of 56 -- After consultations with various doctors, Mr Williams received a total knee replacement of his right knee on 27 October 2015, and an arthroscopy of his left knee on 11 March 2016. He underwent a total knee replacement of the left knee on 20 March 2017. Mr Williams received lump sum payments under s 58 of the RTW Act, however, he disputed the determination of these payments in the Tribunal, arguing that the injuries or impairments to his right knee and left knee should be combined under ss 58(6) or 22(8)(c) of the RTW Act. The primary judge found that Mr Williams’ work activity from early May 2015 caused an injury to the right knee by way of aggravation and acceleration of the pre-existing degenerative changes. In relation to the left knee, his Honour found that the same work activity over the same period from early May 2015 caused an aggravation and acceleration of pre-existing degenerative changes of the left knee. Having made those findings, the primary judge held that the injuries to the right and left knee arose from the same trauma and should be combined. The Corporation appealed, arguing that the judge’s findings that both knee injuries arouse out of the same “work activity” was not sufficient to meet the statutory requirement that the injuries arose from the “same event or series of events” and hence the “same trauma” for the purposes of s 58(6), or to establish that the impairments arose from the “same cause” for the purposes of s 22(8)(c). The Full Bench held that the primary judge misapplied s 58(6) because his Honour’s findings did not support a conclusion that all of the events comprising that work activity were the exclusive causes of each knee injury. The majority also held that the primary judge erred in combining the impairments resulting from both the right knee injury and the left knee injury under s 22(8)(c). As such, the Full Bench allowed the appeal. Mr Williams appealed, and the Corporation filed a notice of alternative contentions. The appeal and notice of contention raised three matters. The first two concerned whether, on the facts as found by the primary judge, the injuries or impairments to Mr Williams’ right knee and left knee were permitted or required to be combined as arising from “the same trauma” (s 58(6)) or from “the same … cause” (s 22(8)(c)) respectively. The third concerned the adequacy of Rossi DPJ’s reasons for concluding that the only cause of the right knee and left knee injuries was “the same work activity” over “the same period”. Held (per Kourakis CJ, Doyle and Bleby JJA), allowing the appeal, setting aside the orders of the Full Bench on 18 March 2022 and restoring the orders made by the primary judge on 24 September 2020: 1. The findings made by the primary judge were sufficient to permit combination under s 22(8)(c) of the RTW Act. 2. The findings made by the primary judge were sufficient to permit combination under s 58(6) of the RTW Act (per Doyle JA, Bleby JA agreeing, Kourakis CJ disagreeing). 3. The primary judge’s reasons were not inadequate. Return to Work Act 2014 (SA) ss 3, 4, 21, 22, 33, 39, 41 56, 58; Return to Work (Scheme Sustainability) Amendment Act 2022 (SA); Workers Rehabilitation and Compensation Act 1986 (SA) ss 3, 43, referred to. Comcare v Martin (2016) 258 CLR 467; English v Return to Work Corporation (SA) [2021] SAET 103; Marrone v Employers Mutual Limited (2013) 116 SASR 501; Martin v Return to Work (SA) [2016] SAET 95; Military Rehabilitation and Compensation Commission v May (2016) 257 CLR 468; Return to Work Corporation (SA) v English [2022] SAET 86; Return to Work Corporation (SA) v Mitchell (2019) 135 SASR 315; Return to Work Corporation (SA) v Preedy (2018) 131 SASR 86; Return to Work Corporation (SA) v Summerfield (2021) 138 SASR 175; Summerfield v Return to Work Corporation (SA) [2019] SAET 106; Travel Compensation Fund & Tambree (2005) 224 CLR 627; Wagenfeller v Return to Work Corporation (SA) [2021] SAET 199; Williams v Return to Work Corporation (SA) [2020] SAET 187, considered. -- 3 of 56 -- -- 4 of 56 -- RETURN TO WORK CORPORATION (SA) v ENGLISH; WILLIAMS v RETURN TO WORK CORPORATION (SA) [2023] SASCA 125 Court of Appeal – Civil: Kourakis CJ, Doyle and Bleby JJA 1 KOURAKIS CJ: I am grateful to Doyle JA for his Honour’s helpful summary of the factual circumstances, and litigation history, of the question of law reserved in Return to Work Corporation (SA) v English (the English matter) and of the appeal in Williams v Return to Work Corporation (SA) (the Williams matter). I agree with his Honour’s analysis of the applicable authorities. 2 Respectfully, I take a different view of the proper construction of s 22(8)(c) of the Return to Work Act 2014 (SA) (the RTW Act). Nonetheless, the construction I favour leads to the same conclusion in the Williams matter despite that difference. I would therefore allow the appeal brought by Mr Williams. However, the application of s 22(8)(c) of the RTW Act, on the construction I would give it, to the facts of the English matter results in a different conclusion. I would answer the question of law reserved ‘No’. My reasons follow. Construction of s 22(8)(c) of the Return to Work Act 2014 (SA) 3 Section 22(8)(c) of the RTW provides: 22 – Assessment of permanent impairment (8) An assessment must take into account the following principles: … (c) impairments from the same injury or cause are to be assessed together or combined to determine the degree of impairment of the worker (using any principle set out in the Impairment Assessment Guidelines); … 4 Section 22 of the RTW Act is part of a scheme for assessing the degree of whole person impairment resulting from a compensable injury or injuries. A compensable injury is an adverse pathological change consequent upon a physiological insult to a worker’s body arising out of, or in the course of, his or her employment (the workplace activity). A workplace activity, in that sense, is a compensable cause. 5 If different impairments from the same injury or cause are assessed separately, eligibility thresholds imposed by the RTW Act for the payments of particular forms of compensation might not be met. Section 22(8)(c) of the RTW Act allows impairments to be combined but only if they are ‘from’ the same injury or cause. Neither in Williams nor English was it contended that the impairments were from the same injury. Therefore, the particular question which arises in both matters is whether the adjectival clause ‘from the same cause’ in s 22(8)(c) of the RTW Act must be read down having regard to statutory and broader context of -- 5 of 56 -- [2023] SASCA 125 Kourakis CJ 6 that subparagraph. There are four reasons for limiting the meaning of the term ‘same cause’ to the same workplace activity. 6 The first is semantic. The preposition ‘from’ is used to specify the starting point of chronological, spatial or causal progression. In the case of s 22(8)(c) of the RTW Act, the progression is of two or more impairments which must share, therefore, the same origin and source, being either a workplace activity or an injury caused by a workplace activity. Importantly, s 22(8)(c) of the RTW Act does not require impairments to be assessed together merely because they have in common one or more of their compensable causes or contributing factors. That is a necessary, but not a sufficient condition, for combination. To satisfy the requirements of s 22(8)(c) of the RTW Act the different impairments must be from ‘the same injury or cause’. 7 A pathological process originating in a compensable injury may over time produce impairments in parts of the body extending beyond the initial injury site because of the physiological interdependence and adaptability of the body. In such a case, the injury is the source and origin of both the primary and secondary impairments because the pathological process resulting in the secondary impairment commenced with physiological adaptations which are responsive to the primary impairment flowing from a compensable injury. 8 A primary impairment in the leg, or a side-effect of medication taken to alleviate the pain of that primary impairment, may cause or contribute to a fall and a consequential secondary impairment in the other leg in the common law sense. However, it is a strained use of language to say that the primary impairment and the secondary impairment, so caused, are from the initial compensable injury when the secondary impairment did not originate in it. The aetiology of the secondary impairment so caused commences with the subsequent chance event, without any prodromal sequence leading from the initial injury to the secondary impairment. Moreover, strictly, the secondary impairment is not from the compensable injury but from the primary impairments the compensable injury produced, or the medications taken for it. 9 The second reason is contextual, having regard to the purpose of s 22(8)(c) of the RTW Act. The most obvious reason for the use of the term ‘injury or cause’, instead of injury alone, or cause alone, is that an injury is circumscribed by that part of the anatomy on which the physiological insult operates. If both a lower limb and upper limb injuries arise out of the same workplace activity the result cannot be described as a single injury to the ‘arm-leg’. The accepted use of the word ‘injury’ properly results in a statement that there have been two injuries, one to an arm and another to the leg. It would be capricious to deny a worker who well exceeds the threshold for seriously injured worker status if the leg and arm injuries were combined, but to grant that status to a worker who injures only one limb and surpasses the threshold by no more than a narrow margin. To achieve the legislative purpose, ‘cause’ must include a single workplace activity which results in multiple injuries. I acknowledge that an evaluative judgment will often be -- 6 of 56 -- [2023] SASCA 125 Kourakis CJ 7 required as to the metes and bounds of the causal workplace activity. But practical resolutions of those issues is not difficult and intuitively ascertainable by judicial officers with experience in workplace injury litigation. 10 The use of both the words ‘injury’ and ‘cause’ is significant. Impairments which are from the same injury must also be from the same cause, but impairments may be from the same cause even though they are not from the same injury. The inclusion of the word ‘injury’, unless it is mere surplusage, can only serve to limit the scope of the word ‘cause’. The linking of two words in a statutory provision indicates that they should be understood in the same sense; a word which stands with another word must mean something analogous to it.1 The disjunctive use of the words ‘injury’ or ‘cause’ suggest a narrowing of the meaning of the latter restricting it to those causes which are the origin and source of both impairments. There is a common law causal chain between the initial compensable injury and the fall which causes the secondary impairment in the case postulated in [8] above. However, s 22(8)(c) of the RTW Act requires that the secondary impairment itself be traced back to the cause of the primary impairment; it is not sufficient that the cause of the secondary impairment can be traced back to the workplace activity which caused the primary impairment. It is the lawyer’s familiarity with common law causal chains and contributing factors which leads to conflation of the adjectival clause ‘from the same cause’ in s 22(8)(c) of the RTW Act with the common law causation chain, but not with the adjectival clause ‘from the same injury’. 11 Counsel for Mr Williams accepted that for an injury or cause to be the starting point of an impairment, that injury or cause must be capable of producing in the sense of initiating, an impairment of that kind. I accept that proposition as a necessary, but not sufficient condition. An impairment can only be said to be from the same cause if the impairment is, aetiologically, linked to the same cause. 12 Thirdly, a wider construction of the word ‘cause’ will bring more workers within s 22(8)(c) of the RTW Act, based on events which have only an indirect connection with the causal workplace activity. That construction therefore weakens the policy rationales for not allowing the combination of all work-related impairments. 13 It is of course open to Parliament to distinguish between impairments as it sees fit, but when the proper construction of a critical provision of a statutory scheme is in doubt, a construction which is of more certain application and supported by a more obvious policy position should be preferred. An evaluative assessment based on the protean concept of sameness of causes alone is permissive of conclusions which differ widely and even irreconcilably. The outcome of litigation would be difficult to predict, settlements will be less achievable and hearing times extended. However, a requirement that both impairments have their origin in, and progress from, the same workplace activity will provide a clearer 1 Lend Lease Real Estate Investments Ltd v GPT RE Ltd [2006] NSWCA 207 at [30] per Spigelman CJ. -- 7 of 56 -- [2023] SASCA 125 Kourakis CJ 8 delineation between those impairments which can, and those which cannot, be combined. Disposition of the English matter 14 In the English matter the relevant impairments were first an impairment to Mr English’s neck for which he took pain medication, and secondly an impairment to his right quadriceps caused when he fell because of pharmacologically induced light-headedness. 15 It can be accepted that in the broadest sense, there is a causal connection between the neck and quadriceps impairments. However, the quadriceps impairment is neither ‘from’ the workplace event which caused the neck injury, nor from the neck impairment itself, in the sense of originating in the reactive physiological adaptations initiated by the neck injury or the workplace activity. It is a strained use of language to say that an impairment is from, has its origin in, a cause with which it has no prodromal connection, and which is no more than the setting for the engenderment of the secondary impairment. Nor can it be said that the quadriceps impairment is from, in the sense of originating in the workplace activity, the blow to the neck, when there was no quadriceps impairment until much later following a chance fall. 16 By contrast, and in order to illustrate my constructional choice, if the same workplace event resulted in trauma to both the neck and quadriceps, both impairments are from the same cause. Similarly, if the blow to the neck caused light-headedness which resulted in a fall which could be characterised as part of the same workplace activity, or its aftermath, the secondary quadriceps impairment can be said to have proceeded from the same cause. By aftermath, I would include the rescue and first aid response to the workplace activity which caused the initial injury. Disposition of the Williams matter 17 In the Williams matter the initial impairment was to his right knee consequent upon a tear to the medial meniscus and the two surgical procedures he underwent to treat it. Several years after the last intervention, and whilst engaged in employment which required repeated climbing up and down stairs and ladders and working from a crouched position, his right knee impairment was exacerbated and the left knee impairment came on gradually. The impairments required replacement of both knees. 18 The facts in the Williams matter illustrate well the purpose served by the dual alternative conditions of sameness of cause or injury. Injuries which develop gradually because of repetitive conduct have long been the subject of either broad factual findings or statutory deeming provisions in workers compensation schemes. In that context there is no difficulty in identifying the cause of the impairments in both, the exacerbation of the right knee impairments and the development for the first time of the left knee impairment, as the single workplace -- 8 of 56 -- [2023] SASCA 125 Kourakis CJ 9 activity of repeatedly climbing stairs and ladders over the period May 2015 to 18 August 2015. I would therefore allow the appeal brought by Mr Williams, the Williams matter. 19 On the other hand, for the injuries to be combined pursuant to s 58(6) of the RTW Act, the knee impairments must arise from the same trauma. Trauma is defined as an event, or series of events, out of which a work injury arises.2 An ‘event’ in that context, like the word trauma, is the physiological insult which causes injury. The series is thereby defined by reference to the resulting disability caused by a series of physiological insults which in Mr William’s case is an impairment to each knee. A series so defined does not allow for the broad approach to workplace activities employed to identify a compensable cause for the purposes of s 28(8)(c) of the RTW Act. 20 The question therefore is whether the same series of physiological insults caused both knee impairments. 21 The climbing over a period of time was plainly not a single event. If one is to rely on the extended definition of trauma, namely a series of events, it is necessary to identify the integers of that series. The evidence failed to establish that a single series of events did so. Indeed, it is most unlikely that the same series of events caused both knee impairments because climbing usually involves weight bearing on one knee at a time. The physiological insults to the right knee, therefore, cannot be integers in the series of events out of which the left knee impairment arose. Similarly, those insults to the left knee cannot be integers in the series of events out of which the right knee impairment arose. It follows that the left and right knee impairments were not caused by the same series of events. 2 Return to Work Act 2014 (SA) s 4(1). -- 9 of 56 -- [2023] SASCA 125 Doyle JA 10 22 DOYLE JA: These reasons address two matters that have come before the Court of Appeal: the first involves a question of law reserved by the Full Bench of the South Australian Employment Tribunal (the English matter), and the second involves an appeal from a decision of the Full Bench of the Tribunal (the Williams matter). Return to Work Corporation (SA) (the Corporation) is the moving party in the English matter, and the respondent in the Williams matter. 23 The two matters raise issues concerning the construction of ss 22(8)(c) and 58(6) of the Return to Work Act 2014 (SA) (the RTW Act). In particular, they raise issues concerning the proper construction of the references to injuries “from the same trauma” (s 58(6)) and impairments “from the same injury or cause” (s 22(8)(c)) in the context of determining when injuries and impairments respectively may be combined for the purposes of assessing an injured worker’s entitlements under the RTW Act. 24 I propose to commence by identifying the relevant legislative context, before then summarising four decisions of the Full Court bearing upon the issues raised; namely, the decisions in Marrone v Employers Mutual Limited3 (Marrone) and Return to Work Corporation (SA) v Mitchell4 (Mitchell) in relation to the predecessor provision to s 58(6), and the decisions in Return to Work Corporation (SA) v Preedy5 (Preedy) and Return to Work Corporation (SA) v Summerfield6 (Summerfield) in relation to s 22(8)(c). I will then undertake an analysis of the meaning of the contested provisions, and how they are to be applied in resolving the two matters before this Court. The legislative context 25 Immediately prior to the enactment of the RTW Act (that is, under the Workers Rehabilitation and Compensation Act 1986 (SA) (the WRC Act)), a person injured at work was eligible to receive weekly payments while incapacitated. 26 If a worker had no work capacity, he or she was entitled to weekly payments equal to 100 per cent of the worker’s notional weekly earnings for the first 13 weeks (the first entitlement period), 90 per cent for the next 13 weeks (the second entitlement period) and 80 per cent for a further 104 weeks (the third entitlement period). At the end of the third entitlement period, a worker who had no work capacity was entitled to on-going payments at 80 per cent of their notional weekly earnings. Subject to continuing assessments of work capacity, that entitlement would continue until retirement age. 27 A similar regime applied to workers who had partial incapacity. A worker with some work capacity, but not full work capacity, was entitled to weekly 3 Marrone v Employers Mutual Limited (2013) 116 SASR 501. 4 Return to Work Corporation (SA) v Mitchell (2019) 135 SASR 315. 5 Return to Work Corporation (SA) v Preedy (2018) 131 SASR 86. 6 Return to Work Corporation (SA) v Summerfield (2021) 138 SASR 175. -- 10 of 56 -- [2023] SASCA 125 Doyle JA 11 payments equal to the difference between the worker’s notional weekly earnings and the worker’s designated weekly earnings for the first entitlement period. The worker was thereafter entitled to 90 per cent of the difference for the second entitlement period, and 80 per cent of the difference for the third entitlement period. At the end of the third entitlement period, the worker was eligible for ongoing income maintenance subject to assessment by a Medical Panel that the relevant disability was likely to continue indefinitely. 28 There were also provisions of the WRC Act governing lump sum payments for non-economic loss, the payment of medical expenses and the redemption of an injured worker’s ongoing entitlement to weekly payments and medical expenses. 29 The enactment of the RTW Act brought about significant changes to injured workers’ entitlements. 30 The RTW Act introduced the concept of a “seriously injured worker”. Under s 21 of the RTW Act, a seriously injured worker is a worker whose work injury has resulted in permanent impairment and the degree of whole person impairment (WPI) has been assessed under s 22 to be 30 per cent or more. Classification as a seriously injured worker entitles the worker to increased benefits by way of weekly payments of income maintenance and medical expenses. 31 In the case of a non-seriously injured worker, the worker’s entitlement to income maintenance payments ceases after two years (s 39(3)). And subject to s 33(21), the worker’s entitlement to medical expenses comes to an end if the worker has not had an entitlement to receive weekly payments for a continuous period of 12 months, or has not had an entitlement to receive weekly payments and a period of 12 months has expired (s 33(20)). However, the worker is entitled to a lump sum payment for future economic loss if their WPI is 5 per cent or more (ss 56(1) and (2)). 32 In the case of a seriously injured worker, the worker is entitled to ongoing income maintenance (s 41) and medical expenses (s 33(21)(a)) until retirement age. The entitlement to income maintenance reduces from 100 per cent to 80 per cent of the worker’s notional weekly earnings after 52 weeks (ss 41(1)(a)(i) and 41(1)(b)(i)). 33 In the case of both seriously injured workers and non-seriously injured workers (with a WPI of 5 per cent or more), the worker is also entitled to a lump sum payment for non-economic loss (s 58), calculated by reference to a prescribed amount (being an indexed figure prescribed by regulation). 34 Importantly, in determining a worker’s entitlement to a lump sum payment under ss 56 (economic loss) and 58 (non-economic loss), the RTW Act permits two or more injuries arising “from the same trauma” to be treated as one injury (to the extent set out in the relevant Guidelines) (ss 56(5) and 58(6)). But it also provides that only one claim may be made in respect of any impairment or -- 11 of 56 -- [2023] SASCA 125 Doyle JA 12 impairments that result from injuries (including consequential injuries) arising “from the same trauma” (ss 56(8) and 58(9)). In s 4(1), “trauma” is defined to mean “an event, or series of events, out of which a work injury arises”. 35 The predecessor WRC Act contained the same definition of “trauma” and, by s 43(6), provided that in determining a worker’s entitlement to a lump sum payment for non-economic loss, two or more compensable injuries arising “from the same trauma” were to be treated as the one injury to the extent set out in the relevant Guidelines. Section 43(6) of the WRC Act was thus similar to ss 56(5) and 58(6) of the RTW Act in providing that injuries were to be combined for assessment purposes if they arose “from the same trauma”. 36 As elaborated upon below, the Full Court in Marrone held that s 43(6) only permitted the combination of injuries in circumstances where the events forming the series of events out of which they arose were the exclusive cause of all of the injuries sought to be combined (Kourakis CJ);7 or where one and the same event, or series of events, caused multiple compensable injuries (White J).8 Thus, while injuries sharing a common cause were, in some circumstances, able to be combined, the operation of s 43(6) was confined to a narrow category of cases. It did not permit the combination of injuries merely because they shared a common cause. 37 An issue has arisen in the Williams matter as to the application of the equivalent entitlement to combine injuries under s 58(6) of the RTW Act. It relates primarily to the specificity with which the series of events giving rise to an injury must be identified when determining whether it may be combined under that section as arising from “the same trauma”. However, it also involves consideration of the relevance of an earlier injury to the ability to combine a later injury constituting an aggravation or acceleration of the earlier injury. 38 While the language of “from the same trauma” that appeared in s 43(6) of the WRC Act was replicated in ss 56 and 58 of the RTW Act, the “leading and dominant”9 provision in undertaking assessments of whole of person impairments arising from work injuries (s 22) uses different language. 39 Under s 22, the assessment must be made by an accredited medical practitioner in accordance with the Guidelines published by the Minister (ss 22(2) and (3)). Certain requirements for the Guidelines are prescribed (s 22(4)). The Minister is required to consult the professional associations of accredited medical practitioners before publishing or amending the Guidelines (s 22(5)). An assessment must not be made until there is evidence that the injury has stabilised, and must be based on the worker’s current impairment, including any changes in 7 Marrone at [3]-[4], [28]. 8 Marrone at [86]; Sulan J agreeing at [30]. 9 Preedy at [60] (Stanley J, Kourakis CJ and Parker J agreeing). -- 12 of 56 -- [2023] SASCA 125 Doyle JA 13 the signs and symptoms following any medical or surgical treatment undergone by the worker in respect of the injury (s 22(7)). 40 Relevantly for present purposes, s 22(8) sets out several principles that must be followed in undertaking the assessment: (8) An assessment must take into account the following principles: (a) if a worker presents for assessment in relation to injuries which occurred on different dates, the impairments are to be assessed chronologically by date of injury; (b) impairments from unrelated injuries or causes are to be disregarded in making an assessment; (c) impairments from the same injury or cause are to be assessed together or combined to determine the degree of impairment of the worker (using any principle set out in the Impairment Assessment Guidelines); (d) impairment resulting from physical injury is to be assessed separately from impairment resulting from psychiatric injury; (e) in assessing impairment resulting from physical injury or psychiatric injury, no regard is to be had to impairment that results from consequential mental harm; (f) in assessing the degree of permanent impairment resulting from physical injury, no regard is to be had to impairment that results from a psychiatric injury or consequential mental harm; (g) any portion of an impairment that is due to a previous injury (whether or not a work injury or whether because of a pre-existing condition) that caused the worker to suffer an impairment before the relevant work injury is to be deducted for the purposes of an assessment, subject to any provision to the contrary made by the Impairment Assessment Guidelines; (h) assessments are to comply with any other requirements specified by the Impairment Assessment Guidelines. 41 Under s 22(10), only one assessment may be made of the degree of permanent impairment of a worker from injuries (including consequential injuries) arising from the same trauma; any injury that may develop or manifest itself after the assessment of the impairment is made will not be assessed. 42 It can be seen from the list of principles governing WPI assessments set out above that s 22(8)(c) of the RTW Act permits the combination of impairments “from the same injury or cause”. An issue that arose in both Preedy and Summerfield was the nature of the causal connection underpinning the entitlement to combine impairments under s 22(8)(c). Whilst the decisions of the Full Court in Preedy and Summerfield establish that s 22(8)(c) is to be construed more broadly than the reference to “from the same trauma” in s 43(6) of the WRC Act, and hence -- 13 of 56 -- [2023] SASCA 125 Doyle JA 14 ss 56 and 58 of the RTW Act, the parties in the present matters are in dispute as to how far it extends. 43 In short, the Corporation submits that the operation of s 22(8)(c), while permitting the combination of impairments from consequential injuries, is confined to the combination of impairments from consequential injuries of a particular and limited type. It is confined to the combination of impairments from consequential injuries that represent a physiological response to the earlier injury, and that do not involve any additional or external cause other than matters such as the ordinary activities of life. Mr English, on the other hand, submits that there is no basis in the text, context or purpose of s 22(8)(c) for confining its operation in this way. He contends for a broader operation of s 22(8)(c) that extends to impairments that are linked by a causal chain to the earlier injury, at least in the circumstances of what he contends is the relatively straightforward causal chain upon which he relies. 44 In the Williams matter, equivalent issues to the ones that have arisen in relation to the operation of s 58(6) have arisen in relation to s 22(8)(c). 45 Before addressing in more detail the context in which the issues have arisen in the English and Williams matters, it is helpful to review the reasoning of the Full Court in each of Marrone, Mitchell, Preedy and Summerfield. The decision in Marrone 46 Mr Marrone suffered compensable disabilities10 to his right elbow, right forearm and right shoulder as a result of repetitive lifting activities. These disabilities were treated as having been suffered on 8 June 2006. As a result of increased used of his left arm in compensation for these disabilities, he suffered a compensable disability to his left shoulder on about 2 April 2009. In determining Mr Marrone’s entitlement to lump sum compensation for non-economic loss, the Workers Compensation Tribunal considered whether the left shoulder disability could be said, for the purposes of s 43(6) of the WRC Act, to have arisen “from the same trauma” as the disabilities to his right elbow, forearm and shoulder. 47 The Full Bench of the Tribunal referred a question of law to the Full Court of the Supreme Court concerning the proper construction of the phrase “arising from the same trauma” under s 43(6) of the WRC Act. The question was in the following terms: Did [the primary judge] err in law in his interpretation of the expression “2 or more compensable injuries arising from the same trauma” for the purposes of s 43(6) when he 10 Noting that the legislation at the relevant time referred to “compensable disability” but was amended with effect from 1 July 2012 to refer to “compensable injury”. The Court in Marrone proceeded on the basis that this amendment made no difference: Marrone at [32] (White J, Sulan J agreeing). See also Mitchell at [30], [58] (Stanley J, Kourakis CJ and Hinton J agreeing). -- 14 of 56 -- [2023] SASCA 125 Doyle JA 15 concluded that the worker’s disability to his right shoulder/elbow and the worker’s disability to his left shoulder arose from the same trauma? 48 It is to be recalled that “trauma” was defined to mean an event, or series of events, out of which a compensable disability arises.11 49 In contending that the question should be answered “no”, Mr Marrone argued that if the event, or events, which cause a compensable disability are integers in a series, which series also includes events which caused another compensable injury, then both injuries could be said to arise out of the same series of events, and hence are to be combined for the purposes of s 43(6). The compensating authority, on the other hand, in contending that the questions should be answered “yes”, argued that two compensable disabilities do not arise out of the same series of events unless all of the events forming the series are the exclusive causes of both disabilities. 50 The Full Court (Kourakis CJ, White and Sulan JJ) accepted the approach contended for by the compensating authority, and answered the question “yes”. 51 Kourakis CJ approached the issue on the basis that the connection between events which made them a series was causal, with all events which have operated as a cause of an injury constituting a series.12 Noting that causal chains in personal injury cases may extend over many years, and encompass a range of industrial and non-industrial events, his Honour commenced by explaining his view that a textual analysis favoured the compensating authority’s construction:13 If events A and B are the only causes of injury Y, and events A, B and C are the only causes of injury Z it can be accepted that each of the events A and B are causes of both injury Y and injury Z. Put in another way, injuries Y and Z have, as common causes, events A and B which form part of a series of events which includes the other cause of injury Z. However event C is not also a cause of injury Y. Injury Y arises out of a series of events A:B whereas injury Z arises out of the series of events A:B:C. The two series, self evidently, are not identical. The series which caused injury Y is a subset of the series which caused injury Z. To hold that it is sufficient if the injuries share one or more common, but not all, causes is to substitute for the phrase “arising out of the same [event or series of events]” the phrase “arising out of an event or events which are part of a series of events”. 52 Kourakis CJ then turned to address the industrial and legislative history and context in which s 43(6) of the WRC Act fell to be considered. In the course of this, his Honour noted that permitting the combination of disabilities under this section would, in some situations, increase the lump sum entitlement of a worker, but in other situations have the opposite effect.14 53 His Honour considered that the purpose of s 43(6) was to promote consistency between the entitlements of workers with comparable overall 11 WRC Act, s 3(1). 12 Marrone at [4]. 13 Marrone at [3]. 14 Marrone at [16]-[19]. -- 15 of 56 -- [2023] SASCA 125 Doyle JA 16 impairments caused by the same events, regardless of whether the whole of person impairment results from the loss of a single faculty or multiple faculties.15 In his view, if injuries arose out of a completely different event or events, or from additional events, it was less likely that their differential treatment would engender a sense of grievance.16 His Honour also considered that the primary purpose of the extended definition of the term “same trauma” was probably to cover injuries which were caused by a series of repetitive work duties or protracted exposures to injurious environments.17 54 Kourakis CJ reasoned that the practical operation and industrial context of s 43(6) suggested that the narrower, literal construction of the phrase “series of events” was legislatively intended:18 If impairments which share a common cause arise out of the same series of events for the purpose of s 43(6) of the Act, subsequent compensable impairments sustained many years after an initial compensable impairment and in very different circumstances will be combined to constitute a single whole of person impairment. That is the significance of the causal relationship between events which constitute a series for the purpose of s 43(6) of the Act to which I earlier referred. An impairment to one faculty in the first of a series of industrial events may be the cause of one or more industrial accidents in other workplaces over the course of the worker’s life which results in impairments to a number of other faculties. The making of an additional award of compensation based on a separate assessment of the subsequent impairment suffered in those circumstances would not raise concerns or grievances of the kind to which I have earlier referred. Indeed, if the impairments were combined, some difficult questions would arise as to whether the scale of awards extant at the time that the earlier or subsequent impairments were sustained should be engaged. 55 After explaining that his construction of the phrase “same trauma” was consistent with authority, Kourakis CJ concluded that the text and context of s 43(6) combined to support the construction proposed by the compensating authority, and required that the question posed be answered “yes”.19 His Honour summarised his conclusion:20 The series must include all of the events out of which the injury arose; it must be a comprehensive series. Questions may arise as to whether a step in the progression of an impairment is part of the internal physiological pathogenesis of the injury or whether it is caused by an external event, but any two impairments do not arise out of the same series unless all of the events in the series have operated as a cause of both impairments. 56 White J (with whom Sulan J agreed) commenced with an analysis of the relevant provisions of the WRC Act. Focusing upon the reference to a “series of events” in the definition of “trauma”, White J said that an “event” connoted a 15 Marrone at [20]-[21]. 16 Marrone at [22]. 17 Marrone at [23]. 18 Marrone at [24]-[25]. 19 Marrone at [27]-[29]. 20 Marrone at [28]. -- 16 of 56 -- [2023] SASCA 125 Doyle JA 17 physical happening or occurrence of some kind, and that the extension of the definition to a “series of events” connoted a number of events, connected to one another in a relevant way.21 His Honour added that the reference to a “series of events” was apt to encompass a sequence of events from which a disability develops gradually:22 The manner of expression of the definition indicates that the matters giving rise to the requisite connection between the events must go beyond the mere fact that a compensable disability has arisen from them. It implies that there must be some relationship between the events, perhaps temporal or sequential, or of some other quality, such as the nature of the events, which establishes a degree of “connectedness”. In practical terms, the expression seems apt to encompass the kinds of sequence of events from which a disability develops gradually. 57 In then addressing the relevant industrial and legislative history and context more generally, his Honour made reference to significance of the inclusion of reference to a “series of events” in broadening the reach of s 43(6):23 The exception [to the immaterial nature of several other differences between the WRC Act and its predecessors] is the phrase “series of events” in the definition of “trauma”. The 1932 and 1971 Acts did not have any counterpart to this phrase. The inclusion of the phrase in the definition of “trauma” in the WRC Act appears to be a legislative recognition that a compensable disability may arise form a single incident or from a series of incidents. It has the effect, in any event, of broadening the disabilities to which s 43(6) will apply. For the reasons given earlier, that broadening seems confined to disabilities arising from a succession of traumas connected in some way by time, sequence or character and not just from the circumstance that, in combination, they have given rise to a compensable disability. 58 White J ultimately concluded that the operation of s 43(6) was “confined to the circumstance in which one and the same event, or series of events, causes multiple compensable disabilities. With the exception of disabilities arising from a series of events, it has no application to traumas suffered successively.”24 His Honour answered the question posed “yes”.25 59 The effect of the decision in Marrone was thus that Mr Marrone’s overuse disability of his left arm did not arise out of the same trauma as, and could not be combined with, his right arm disability for which Mr Marrone had overcompensated by making greater use of his left arm. The decision in Mitchell 60 Mr Mitchell suffered a compensable lower back injury in late 2008 or early 2009. In January 2011 his injury was treated by lumbar spinal fusion. In July 2013, his injury was assessed for the purposes of the WRC Act as involving a WPI 21 Marrone at [46]-[47]. 22 Marrone at [48]. 23 Marrone at [62]. 24 Marrone at [86]. 25 Marrone at [92]. -- 17 of 56 -- [2023] SASCA 125 Doyle JA 18 of 26 per cent. Mr Mitchell later made claims for lump sum compensation under s 43 of the WRC Act in respect of several subsequent impairments or injuries resulting from the medication he had been taking for pain control after his January 2011 surgery. 61 The issue in Mitchell was whether the subsequent injuries could be combined with the lumbar spine injury as having arisen “from the same trauma” for the purposes of s 43(6) of the WRC Act. 62 The primary judge and Full Bench of the South Australian Employment Tribunal permitted the injuries to be combined under s 43(6). Whilst recognising the potential difficulty with this flowing from Marrone, their Honours did so by applying the decision of the Full Bench in Martin v Return to Work (SA)26 (Martin) to the effect that complications from surgery and medical treatment are not to be treated as produced by separate traumas. 63 The Full Court allowed the appeal. Stanley J (with whom Kourakis CJ and Hinton J agreed) commenced by observing that the Court had held in Marrone that for compensable injuries to be combined pursuant to s 43(6) of the WRC Act it was not sufficient that they share a common cause or causes; to be combined the injuries must arise out of the same event or series of events.27 64 Stanley J next turned to consider the ordinary sense in which the word “injury” is used in the context of workers compensation legislation. He referred in this respect to what Gageler J said in Military Rehabilitation and Compensation Commission v May:28 An injury, it has long been repeatedly explained, is some definite or distinct “physiological change” or “physiological disturbance” for the worse which, if not “sudden” is at least “identifiable”. The universality of that explanation has been questioned, and the comment has fairly been made that “a distinct physiological change is not itself an expression of clear and definite meaning.” The expression has nevertheless been shown by repeated usage to have utility as an exposition of the particular sense in which injury has been used, and continues to be used, in the particular legislative context. 65 Stanley J reasoned that the Full Bench in both Martin and Mitchell had fallen into error in relying upon decisions that related to the compensability of injuries in circumstances where s 43(6) addressed the different issue of whether injuries may be combined for the purposes of assessing a person’s WPI and consequential entitlement to lump sum compensation for their non-economic loss.29 26 Martin v Return to Work (SA) [2016] SAET 95. 27 Mitchell at [24]. 28 Military Rehabilitation and Compensation Commission v May (2016) 257 CLR 468 at [75] (citations omitted). 29 Mitchell at [42]; noting that his Honour referred in this respect to his reasons in Preedy at [31], with which Kourakis CJ and Parker J agreed. -- 18 of 56 -- [2023] SASCA 125 Doyle JA 19 66 Stanley J held that the latter issue was governed by the decision of the Full Court in Marrone,30 which was binding and should be followed.31 His Honour explained the limiting effect of the requirement that injuries arise “from the same trauma” before they may be combined under s 43(6):32 The work to be performed by the opening words of s 43(6) is to prescribe the condition for combining two or more compensable injuries in assessing an entitlement to lump sum compensation for non-economic loss. That condition is that the compensable injuries must arise from the same trauma. That is a condition of limitation. It restricts the circumstances in which combination is to occur for the purposes of assessing the entitlement to lump sum compensation. That is its statutory purpose. That purpose would be frustrated if the Act is construed in a way which treats distinct physiological changes which do not arise from the same event or events as being one injury, and thereby circumventing the limitation the legislature has imposed. In effect, it would permit combination to occur without statutory authorisation and by eliminating the condition precedent for combination adopted by the legislature. 67 Stanley J acknowledged the possibility that there may be circumstances where changes in symptoms after medical or surgical treatment resulting from compensable injury might properly be characterised as part of the same injury. He gave as an example a back injury where the level of pain and restriction in movement changed as a result of medical or surgical treatment. But he said that was not this case. In Mr Mitchell’s case, the later complications were separate physiological changes constituting a distinct, subsequent compensable injury.33 68 Stanley J rejected Mr Mitchell’s argument that these subsequent injuries might be combined under s 43(6) as having arisen “from the same trauma”:34 Marrone requires that before combination can occur the compensable injuries must arise from the same trauma. That is to say the injuries must arise from one and the same event or series of events. As White J explains in Marrone the legislature in enacting s 43(6) uses the expression “disability” in the sense of “impairment”.35 For the reasons set out above the amendment substituting “injury” for “disability” does not alter that construction. Plainly, the impairments that arose as a complication of the respondent’s ingestion of opioid medication to relieve the symptoms of his lumbar spine injury following surgery arose not from the injury to his lumbar spine, but from his ingestion of opioid medication. While those impairments were causally related to his lumbar spine injury, the crucial and necessary event for the development of those impairments was the ingestion of the opioid medication. As that event occurred subsequent to the events which resulted in the injury to his lumbar spine, it was not the case that those injuries arose from the same trauma as the lumbar spine injury. Accordingly, the condition for combination prescribed by s 43(6) was not made out. 30 Noting that the correctness of Mitchell had been affirmed in Preedy, albeit while at the same time distinguishing it in the context of construing the different terminology in s 22(8)(c) of the RTW Act. 31 Mitchell at [46]. 32 Mitchell at [47]. 33 Mitchell at [54]. 34 Mitchell at [58]-[59]. 35 [2013] SASCFC 67 at [90], (2013) 116 SASR 501 at 521. -- 19 of 56 -- [2023] SASCA 125 Doyle JA 20 69 The appeal was allowed, the award of compensation pursuant to s 43 set aside, and the matter remitted for further hearing in accordance with the Court’s reasons. The decision in Preedy 70 Mr Preedy injured his left shoulder in the course of his employment. While receiving physiotherapy for this injury he sustained a neck injury, being a fracture of his C5 vertebrae. There was medical evidence to the effect that Mr Preedy was suffering from undiagnosed multiple myeloma (a cancer of blood cells in the bone marrow) that was likely to have eventually resulted in a fracture of his vertebrae. The physiotherapy nevertheless contributed to his neck injury. 71 In determining Mr Preedy’s WPI for the purposes of assessing his entitlement to a lump sum for non-economic loss under s 58(6) of the RTW Act, the Corporation proceeded on the basis that the neck and shoulder injuries had not arisen “from the same trauma” and so could not be combined. On appeal, the Tribunal rejected an argument that both the neck and shoulder impairments could nevertheless be combined under s 22(8)(c) as arising “from the same injury or cause”. However, the Full Bench of the Tribunal allowed Mr Preedy’s appeal, holding that his injuries should be assessed together to determine his WPI for the purposes of his entitlement to a lump sum for his non-economic loss. The Corporation appealed to the Full Court. 72 Stanley J (with whom Kourakis CJ and Parker J agreed) delivered the leading judgment. His Honour explained that there were two aspects to the Full Bench’s reasoning in permitting the combination of Mr Preedy’s injuries for the purposes of s 58(6) of the RTW Act.36 The first involved reasoning, based on the Full Bench’s decision in Martin to the effect that adverse consequences from surgical or medical treatment (short of situations involving gross negligence that might break the chain of causation) should be regarded as forming part of the original compensable injury. Stanley J held that the reasoning in Martin was flawed as it relied upon authorities addressing the compensability of later injuries resulting from medical or surgical treatment, and not the separate issue of whether they may be combined for the purposes of assessing a worker’s WPI under s 58(6) or s 22(8)(c) of the RTW Act.37 73 The second involved reasoning that, while s 58(6) is subordinate to s 22(8)(c), with the latter being the “leading and dominant” provision, the former nevertheless governs the ability to combine injuries when assessing a worker’s WPI for the purposes of determining their entitlement to a lump sum for non- economic loss.38 But because (on the Full Bench’s reasoning) Mr Preedy’s neck 36 Preedy at [29]. 37 Preedy at [30]-[31]. 38 Preedy at [32]. -- 20 of 56 -- [2023] SASCA 125 Doyle JA 21 and shoulder injuries arose from the same trauma, they were able to be combined under s 58(6). 74 Stanley J, while agreeing that s 22 is the leading and dominant provision, held that this meant that impairments might be combined under that section for the purposes of assessing a worker’s WPI even when the combination of the underlying injuries was not required or permitted by s 58(6).39 75 In arriving at this conclusion, Stanley J undertook a review of the structure and provisions of the RTW Act. He noted the distinction between the concepts of “injury” and “impairment” under the RTW Act, describing them as “related but distinct” concepts, with the latter being a condition that relates from the former. Whilst s 58(6) was addressed to the combination of injuries for the purposes of assessing a worker’s entitlement to a lump sum for non-economic loss, s 22(8)(c) was addressed to assessing a worker’s degree of impairment when determining their WPI.40 76 Noting the potential for confusion as a result of the definition of “injury” including reference to “impairment”, Stanley J said:41 I accept that on its face there appears to be some blurring of the distinction between “injury” and “impairment” given that the definition of “injury” in the Act includes reference to “impairment”. But that definition is conditioned by the opening words of s 4(1) of the Act, namely, “Unless the contrary intention appears”. I consider there is a contrary intention to be found in ss 22 and 58. In the case of ss 22 and 58, I consider it is clear that “injury” and “impairment” are used in the different sense I have explained. To construe these provisions by reference to the definition of injury would be circular. In these provisions there is a distinction between causes and consequences. That construction is reinforced by the reference in s 22(8)(c) to “the same injury or cause”. That expression should be construed ejusdem generis. The words “injury” and “cause” convey a related concept which is concerned with the thing or event from which an impairment results, but they are not necessarily identical otherwise there would have been no need for the Parliament to refer to a “cause”. The relevant “cause” is the cause of the impairments. This construction is also reinforced by consideration of the terms of s 22(8)(d), (e) and (f) all of which refer to “impairment” resulting from physical or psychiatric injury. It is unnecessary for the purposes of the disposition of this appeal to consider the full extent of the meaning of this term. 77 In elaborating upon the operation of the reference in s 22(8)(c) to impairments arising “from the same injury or cause”, his Honour said:42 However, the causal test propounded in s 22(8)(c) can be demonstrated by way of illustration where a worker suffers an injury to her right knee at work which causes her to favour that leg with the result that the added pressure on the left knee causes injury to that knee. The worker suffers two separate impairments: one to each leg. Those impairments can be said to be from the same injury or cause, namely, the injury to the right knee. But 39 Preedy at [60]-[61]. 40 Preedy at [50]-[51]. 41 Preedy at [54]. 42 Preedy at [55]. -- 21 of 56 -- [2023] SASCA 125 Doyle JA 22 even if the impairment to the left leg is not from the injury to the right knee, the impairment of the left leg can be said to have been caused by the injury to the right knee. 78 In explaining the separate operation of s 58(6) and s 22(8)(c), Stanley J said:43 For the purposes of undertaking a lump sum assessment pursuant to s 58, if a worker suffers two or more work injuries which arise from the same event or series of events, those injuries may be treated as a single injury to the extent set out in the Guidelines. In addition, in undertaking an assessment of the degree of WPI pursuant to s 58, impairments from the same injury or cause are to be assessed together or combined to determine the degree of impairment using any principle set out in the Guidelines. That is the clear statutory injunction in [s 22(8)(c)]. 79 In allowing the appeal, Stanley J held that the Full Bench had erred in concluding that Mr Preedy had suffered two work injuries “from the same trauma” under s 58(6), and in then failing to consider the separate issue of whether his impairments had nonetheless arisen “from the same injury or cause”.44 80 The appeal was allowed and the matter remitted for determination of the factual question inherent in the application of s 22(8)(c).45 81 In addition to agreeing with Stanley J, Kourakis CJ made some additional observations in which he emphasised the critical role of s 22(8)(c) in determining the entitlements of workers (including their right to be treated as seriously injured workers with the greater entitlements that this entails); and that the words “from the same injury or cause” in s 22(8)(c) were not to be read down by reference to the notion of injuries “from the same trauma” in s 58(6).46 The decision in Summerfield 82 In 2016, Mr Summerfield fractured his left femur and injured his left hip when he was assaulted and fell onto concrete in the course of his employment. He underwent a total left hip replacement and subsequent revision surgery. His claim for weekly payments of compensation for the fracture and hip replacement pursuant to the RTW Act was accepted. 83 By late 2017, Mr Summerfield had an obvious limp favouring his left leg and was suffering pain in his left hip region with tenderness in his mid-back extending his left buttock. He also had a shortening of his left leg. Mr Summerfield made a further claim for compensation for his left hip, left leg, lumbar spine, scarring and altered gait. Following a dispute, consent orders were made in the Tribunal, with the Corporation accepting the claim in respect of Mr Summerfield’s lumbar spine injury, and his altered gait as a consequence of his earlier compensable injuries. 43 Preedy at [67]. 44 Preedy at [68], [71]. 45 Preedy at [72]. 46 Preedy at [4]; Stanley J agreeing at [73]. -- 22 of 56 -- [2023] SASCA 125 Doyle JA 23 84 Mr Summerfield made a claim for lump sum compensation pursuant to s 58 of the RTW Act. The Corporation determined the claim on the basis of a WPI of 31 per cent for the left femur, left hip and surgical scarring for the injury in May 2016, and a WPI of 8 per cent for the subsequent lumbar spine injury. 85 On appeal to the Tribunal, Mr Summerfield argued that the impairment from his lumbar spine injury (resulting from his altered gait) should be combined with the impairment from his earlier hip injury. 86 Cole DP found that there was an unbroken causal chain of events linking Mr Summerfield’s lumbar spine impairment back to his earlier hip injury (by reason of the hip injury and surgery leading to an altered gait, which led to the lumbar spine injury).47 His Honour held that while Mr Summerfield’s lumbar spine impairment did not arise “from the same trauma” as his earlier hip impairment for the purposes of s 58(6) of the RTW Act, those two impairments were – on an application of the reasoning of the Full Court in Preedy – nevertheless “from the same injury or cause” and able to be combined under s 22(8)(c). The Full Bench dismissed the Corporation’s appeal from this decision. 87 On a further appeal to the Full Court, the Corporation accepted that the Full Court’s earlier decision in Preedy was correct, but nevertheless argued that the illustration given in paragraph [55] of Stanley J’s reasons did not form part of – and, indeed, was inconsistent with – the ratio of that case. The Corporation argued that whilst the lumbar spine impairment and left hip impairment shared a “common cause”, in that the latter could be linked back to the former (via Mr Summerfield’s altered gait as a result of his hip injury and surgery), this did not mean they arose from “the same injury or cause”. The notion of impairments arising from “the same injury or cause” under s 22(8)(c) should be construed narrowly as requiring a greater connectedness than was inherent in the impairments sharing a common law cause. And as the impairments here arose from quite separate injuries which occurred a year apart, it could not be said they arose “from the same injury or cause”. 88 The Full Court dismissed the Corporation’s appeal. The leading judgment was delivered by Stanley J, with whom Kourakis CJ and I agreed. Stanley J began his analysis by rejecting the Corporation’s submissions directed towards paragraph [55] of his reasons in Preedy:48 In my view, the appeal must be dismissed. The reasons in para [55] of Preedy are consistent with the reasons in the preceding paragraph and form part of the ratio of the decision. It is not plainly wrong. As I said in Preedy at para [54] the relevant “cause” is the cause of the impairments. This construction is reinforced by consideration of the terms of s 22(8)(d), (e) and (f) all of which refer to “impairment” resulting from physical or psychiatric injury. These provisions maintain the distinction between injury and impairment which is critical to the operation of s 22(8)(c). The implication in s 22(8)(b) is that impairments from related 47 Summerfield v Return to Work Corporation (SA) [2019] SAET 106 at [22]. 48 Summerfield at [19]. -- 23 of 56 -- [2023] SASCA 125 Doyle JA 24 injuries or causes are not to be disregarded in making an assessment of permanent impairment. Injury and cause form part of a class of a thing or an event from which an impairment results. Section 22(8)(c) is to be construed disjunctively and distributively. Plainly, injury and cause are distinct concepts, albeit they are, in the context of s 22(8), related. The adjective “same” applies to both injury and cause. Impairments from the same cause are to be assessed together or combined. But that does not mean there is any warrant for construing the concept of “cause” in s 22(8)(c) to mean “trauma”. If the Parliament had intended to convey the same concept it could have used the same term. The use of a different expression in this particular context, where s 22(10) uses the expression “trauma”, clearly conveys a different meaning. 89 Stanley J reasoned that there was no warrant for construing “cause” in s 22(8)(c) narrowly to mean a single cause. Rather, the notion of impairments from the same cause included an impairment from a consequential injury where, as a matter of common sense, the impairments were so connected as to permit a finding that they were from the same cause:49 The causal test permits an impairment from a consequential injury to be combined with an impairment from another injury where, as a matter of common sense, the impairments are so connected that the trier of fact is satisfied that the impairments are from the “same cause”. 90 At the same time, his Honour eschewed reliance upon a common law test of causation, resting on a description of the appropriate approach as involving an evaluative assessment that is informed by common sense, and that recognises that more than one event might have been the “cause” of the impairment to be combined:50 The appellant’s submission that the example in para [55] invokes the common law test of causation is neither accurate nor helpful in construing s 22(8)(c). To characterise the test of causation in s 22(8)(c) as a common law test is inaccurate and does not assist in construing its meaning. Section 22(8)(c) posits a statutory test of “cause”. It is to be construed in accordance with its text, context and purpose. It is an evaluative test. That evaluative test is to be applied adopting a common sense approach that recognises that more than one event might have been the “cause” of the impairment.51 91 Stanley J explained that the attempt to confine the words “from the same injury or cause” in s 22(8)(c) by reference to the construction of the words “same trauma” in Marrone had been rejected in Preedy and was misconceived. There was no reason to depart from the construction of s 22(8)(c) in Preedy, including the illustration in paragraph [55].52 92 It followed that the Corporation’s appeal was dismissed. 49 Summerfield at [20]. 50 Summerfield at [21]. 51 See the discussion by Lander J, with whom Bollen and Nyland JJ agreed, of the concept of causation in the different statutory context of the Workers Rehabilitation and Compensation Act 1986 (SA) in Workcover Corporation v Sherriff (unreported, Supreme Court, SA, 1 October 1996). 52 Summerfield at [22]. -- 24 of 56 -- [2023] SASCA 125 Doyle JA 25 Amendments to the RTW Act 93 Following the High Court’s refusal of the Corporation’s application for special leave to appeal in Summerfield, Parliament made various amendments to the RTW Act through the Return to Work (Scheme Sustainability) Amendment Act 2022 (SA) (the Amendment Act). 94 The Amendment Act added the following legislative note after s 22(8): Note— The Parliament confirms that this subsection is to be interpreted and applied in accordance with the principles enunciated in the reasons of the Full Court of the Supreme Court in Return to Work Corporation of South Australia v Summerfield [2021] SASCFC 17. 95 Each of ss 22(10), 56(5), 56(8), 58(6) and 58(9) were amended to remove references to the combination of injuries arising “from the same trauma” and replace them with provisions permitting or requiring the combination of impairments “from the same injury or cause” in conformity with s 22(8)(c). 96 The Amendment Act also amended the definition of a “seriously injured worker” to increase the qualifying percentage WPI from 30 per cent to 35 per cent. 97 The present matters relate to events pre-dating the Amendment Act, and so fall to be determined according to the terms of the RTW Act prior to the above amendments. Whilst Mr English contends that the Court should “take into account” the effect of the amendments when construing s 22(8)(c), I am not persuaded that any proper basis for doing so has been identified. In any event, the issue is of no practical significance because it is not suggested that the amendments provided any particular guidance as to the meaning of s 22(8)(c), other than confirming the applicability of the reasoning of the Full Court in Summerfield (which the parties already accept is applicable to the resolution of the present matters). Consideration 98 The two matters before this Court concern the meaning of the references to injuries arising “from the same trauma” in s 58(6), and impairments “from the same injury or cause” in s 22(8)(c) of the RTW Act. 99 The task of construing these provisions requires a consideration of the text, context and purpose of the relevant provisions.53 Of course, the task must also be approached having regard to the earlier decisions of the Full Court in Marrone, 53 As to the importance of focusing upon the statutory text, context and purpose when addressing matters involving statutory notions of causation, see Comcare v Martin (2016) 258 CLR 467 at [42] (the Court) and Travel Compensation Fund & Tambree (2005) 224 CLR 627 at [28]-[30] (Gleeson CJ), [45], [49] (Gummow and Hayne JJ), [79] (Callinan J). -- 25 of 56 -- [2023] SASCA 125 Doyle JA 26 Mitchell, Preedy and Summerfield. There is no challenge to the correctness of, or reasoning in, any of these decisions. 100 The starting point is that both s 58(6) and s 22(8)(c) form part of a legislative scheme for the assessment of compensation for work injuries. Both are addressed to the assessment of an injured worker’s WPI and, in particular, to the circumstances in which a worker’s injuries or impairments may be combined for the purposes of that assessment. 101 These provisions are to be approached on the basis that s 22 is the leading and dominant provision when undertaking assessments of an injured worker’s WPI under the RTW Act.54 That said, when determining a claim for a lump sum payment under ss 56 or 58, the combination provisions in those sections and in s 22 operate in a complementary way. In other words, when assessing an injured worker’s WPI for the purposes of a claim under ss 56 or 58, injuries may be combined if they arise from the same trauma (under ss 56(5) or 58(6)) and, in addition, impairments may be combined if they arise from the same injury or cause (under s 22(8)(c)).55 102 Whilst the ability to combine injuries or impairments will generally favour the worker (for example, by assisting them to qualify as a seriously injured worker, or by otherwise entitling them to a greater benefit), this may not always be so.56 But even if it might be said that a purpose of the combination provisions is to assist injured workers, this provides little guidance in construing ss 22(8)(c) and 58(6) in circumstances where the very issue is the extent of this assistance. It must also be borne in mind that the objects of the RTW Act include achieving a reasonable balance between the interests of workers and the interests of employers (s 3(2)(c)). 103 Speaking generally, it may also be said that a purpose of the combination provisions is to promote consistency between the entitlements of workers with comparable overall impairments caused by the same events, regardless of whether the WPI results from a single injury or impairment, or multiple injuries or impairments.57 104 Ultimately, I do not consider that there is anything in these broader purposes of the combination provisions that provides much assistance in determining their precise meaning or reach. Certainly there seems to be no reason to approach the construction of the combination provisions of the RTW Act on the basis that a purposive approach requires a narrow construction of these provisions.58 It seems to me that the focus must be very much upon the text of the provisions. 54 Preedy at [60] (Stanley J, Kourakis CJ and Parker J agreeing). 55 Preedy at [67] (Stanley J, Kourakis CJ and Parker J agreeing). 56 As Kourakis CJ observed in Marrone at [16]-[19] in the context of lump sum compensation under s 43 of the WRC Act. 57 Marrone at [20]-[21] (Kourakis CJ). 58 Summerfield at [24] (Stanley J, Kourakis CJ and Doyle J agreeing). -- 26 of 56 -- [2023] SASCA 125 Doyle JA 27 Injuries arising from the same trauma under s 58(6) of the RTW Act 105 An injured worker may seek a lump sum payment for non-economic loss under s 58 of the RTW Act. For the purposes of determining the worker’s entitlement under that section, s 58(6) permits the combination of work injuries “arising from the same trauma”. “Trauma” is defined in s 4(1) to mean “an event, or series of events, out of which a work injury arises”. An “event” in this context may be understood to mean an incident, occurrence or happening. 106 There is no reason to think that s 58(6) of the RTW Act should be approached any differently from the materially identical s 43(6) of the WRC Act. As the parties in the present matters accept, s 58(6) should therefore be approached in accordance with the reasoning of the Full Court in Marrone, as affirmed in Mitchell. 107 As the parties in the present matter also accept, there is no material distinction between the reasoning of Kourakis CJ and White J (with whom Sulan J agreed) in Marrone. 108 On the reasoning of Kourakis CJ, injuries may only be combined where the events forming the series of events out of which each of those injuries arose are the exclusive and comprehensive cause of each of the injuries sought to be combined.59 In other words, the requirement that the injuries arose from the same trauma contemplates that there be an identity, or ‘sameness’, between the event or series of events out of which each of the injuries sought to be combined arose. It is not enough that there is an overlap or similarity between the event or series of events out of which the injuries arose. 109 White J held that injuries may only be combined where they arose out of the same event or same series of events.60 Whilst not as explicit or prescriptive as to the requirement that the injuries arise out of the same series of events, there is no reason to think that White J had in mind anything less than what Kourakis CJ required. 110 Similarly, in applying Marrone in Mitchell, the Full Court may be taken to have endorsed the approach indicated by Kourakis CJ’s reasoning in Marrone. The outcome in Mitchell – namely, that the involvement of an additional event (the ingestion of pain medication) prevented a finding that later injuries arose from the same trauma as the earlier injury61 – is consistent with this approach. 111 It is thus to be accepted that the requirement that the injuries arose from the same trauma, and therefore the same event or series of events, is an important limitation upon the ability to combine injuries under s 58(6). 59 Marrone at [3]-[4], [28] (Kourakis CJ). 60 Marrone at [86] (White J, Sulan J agreeing). 61 Mitchell at [58]-[59] (Stanley J, Kourakis CJ and Hinton J agreeing). -- 27 of 56 -- [2023] SASCA 125 Doyle JA 28 112 At the same time, the inclusion of the reference to a “series of events” in the definition of “trauma” – which did not appear in the earlier (that is, the 1932 and 1971) incarnations of the WRC Act – is a legislative recognition that injuries may arise out of more than one event, and in that sense a recognition of the breadth of the circumstances in which injuries may be said to have arisen out of the same trauma and hence be combined.62 It is a recognition that injuries may arise from “a succession of traumas connected in some way by time, sequence or character”;63 or “a series of repetitive work duties or protracted exposures to injurious environments”;64 and that there will be circumstances in which such injuries may be combined. 113 In the Williams matter, the injuries to Mr Williams’ right and left knees that were sought to be combined both arose from a series or succession of events, being work activities involving climbing and crouching movements. It will be necessary to return later in these reasons to the precision required before it can be concluded that the series of events giving rise to each of those injuries possessed the identity or sameness required by s 58(6). Impairments arising from the same injury or cause under s 22(8)(c) of the RTW Act 114 Whereas s 58(6) is concerned with the combination of injuries, s 22(8)(c) is concerned with the combination of impairments. In assessing the WPI for an injured worker seeking a lump sum payment under s 58 of the RTW Act, multiple impairments may be combined under s 22(8)(c) if they are “from the same injury or cause”. As Stanley J explained in Preedy, impairment and injury in this context are related but distinct concepts. The distinction is between a consequence and a cause, with the former being a condition resulting from the latter.65 115 Like s 58(6), s 22(8)(c) uses the preposition “from” to introduce the criterion for combination. In its ordinary usage, “from” indicates the starting point, origin or source of the relevant thing. It may also indicate the cause of, or explanation for, that thing. Its use in s 22(8)(c) may be described as requiring consideration of the causal explanations for the impairments sought to be combined, perhaps with a focus upon the start or origin of those explanations. More particularly, and with some risk of tautology, it requires consideration of the “injury or cause” that provides the causal explanation for each of the impairments sought to be combined. 116 Whilst the reference in s 22(8)(c) to “injury or cause” is disjunctive, these words are also to be construed ejusdem generis, with the words “injury” and 62 Marrone at [62] (White J, Sulan J agreeing). 63 Marrone at [62] (White J, Sulan J agreeing). 64 Marrone at [23] (Kourakis CJ). 65 Preedy at [51], [54] (Stanley J, Kourakis CJ and Parker J agreeing). -- 28 of 56 -- [2023] SASCA 125 Doyle JA 29 “cause” conveying a related concept which is concerned with the thing or event from which the impairment arose.66 117 At the same time, the concepts of injury and cause are not identical. The latter is undoubtedly broader than the former; it extends to things or events which are not injuries. Indeed, it seems to me that “cause” in this context may be understood to encompass “injury”, in the sense that an injury from which an impairment arises is a thing or event that might equally be described as a cause from which the impairment arises. Accordingly, if two impairments are from the same injury then it would seem that they are also from the same cause, in the sense that both impairments are from the event or events that caused that injury. However, two impairments may also be combined where they are from different injuries but nevertheless the same cause (such as the same work accident). 118 To illustrate the point, assume a worker suffers two impairments as a result of a work accident (being hit by a falling object) in which the worker suffers two injuries (an arm injury and a leg injury). If both impairments can be said to be from the arm injury, then they may be combined, either on the basis that they are from the same injury (the arm injury) or on the basis that they are from the same cause (being the work accident). However, even if they are from different injuries (one from the arm injury and the other from the leg injury) then they may still be combined as being from the same cause (the work accident). 119 Given that “cause” encompasses “injury” in this context, it may be that the inclusion of the reference to “injury” in the criterion for combination under s 22(8)(c) has no work to do beyond emphasising or confirming that impairments from the same injury may be combined, without needing to consider the potentially more vexed issue of whether they can also be said to be from the same cause. Whether the ejusdem generis construction of the phrase “injury or cause” provides a basis for using the reference to “injury” to confine the meaning of “cause” in this context is a matter to which I shall return. 120 The requirement that the impairments be from “the same injury or cause” is to be construed not only disjunctively but also distributively, with the adjective “same”, and hence the requirement of “sameness”, applying to both “injury” and “cause”.67 121 It was established in Preedy, and confirmed in Summerfield, that the construction of the reference to impairments arising from “the same injury or cause” in s 22(8)(c) is not to be confined, or read down, by reference to the notion of injuries arising from “the same trauma” under s 58(6) of the RTW Act.68 Whilst both subsections share a requirement of sameness, the notion of impairments 66 Preedy at [54] (Stanley J, Kourakis CJ and Parker J agreeing); Summerfield at [19] (Stanley J, Kourakis CJ and Doyle J agreeing). 67 Summerifield at [19] (Stanley J, Kourakis CJ and Doyle J agreeing). 68 Preedy at [4] (Kourakis CJ, Stanley J agreeing); Summerfield at [19], [22] (Stanley J, Kourakis CJ and Doyle J agreeing). -- 29 of 56 -- [2023] SASCA 125 Doyle JA 30 arising from “the same injury or cause” is to be understood more broadly than injuries arising from the same trauma. It would seem that this is a consequence of the inherent flexibility in the notion of the cause of an impairment, relative to the fairly prescriptive definition of trauma under the RTW Act. 122 As Stanley J emphasised in Summerfield, there is no warrant for construing “cause” in s 22(8)(c) narrowly as confined to a single cause.69 Impairments may arise from the same cause even though they each arise from multiple causes, in the sense that they may be causally explained by multiple events. 123 It is also apparent from the reasoning in both Preedy and Summerfield that impairments may arise from the same cause even though there is not a complete identity or correspondence between the events providing the causal explanation for the impairments sought to be combined. Put another way, the involvement of an additional event or events in the causal explanation for one impairment does not necessarily prevent it being described as arising from the same cause as another impairment, and hence being combined under s 22(8)(c). 124 That this is so is apparent from both the illustration given in paragraph [55] of Stanley J’s reasons in Preedy (as endorsed in Summerfield70), and in the application of s 22(8)(c) to the facts in Summerfield. 125 In the hypothetical illustration appearing in paragraph [55] of Stanley J’s reasons in Preedy, the worker suffered a right knee work injury which caused her to favour that leg, with the result that the added pressure on her left knee caused injury to that left knee. The two resulting impairments, to the right knee and the left knee, were able to be combined under s 22(8)(c) because they both arose from the same injury (the right knee injury) and, indeed, from the same cause (the right knee injury, or the events giving rise to that injury). It did not matter that the causal explanation for the later impairment (the left knee impairment) included an additional event or integer (the added pressure or overcompensation affecting the left knee) that was not part of the causal explanation for the earlier impairment (the right knee impairment). The involvement of this additional causally relevant event did not undermine or defeat the “sameness” of the causal explanations for the two impairments required by s 22(8)(c). 126 On the facts of Preedy itself, there was plainly an additional causally relevant event, given that the later neck injury was sustained while receiving physiotherapy for an earlier shoulder injury sustained by Mr Preedy during the course of his employment. Because the trial judge had not addressed the factual question inherent in the application of s 22(8)(c), the matter was remitted for determination. Whilst the Full Court did not determine the question of whether the two impairments in that case arose from the same injury or cause, there was no suggestion that the involvement of an additional cause or event (the physiotherapy 69 Summerfield at [20] (Stanley J, Kourakis CJ and Doyle J agreeing). 70 Summerfield at [22]-[24] (Stanley J, Kourakis CJ and Doyle J agreeing). -- 30 of 56 -- [2023] SASCA 125 Doyle JA 31 treatment) necessarily precluded that conclusion; otherwise the remitter would have been pointless. 127 More significantly, on the facts of Summerfield, there was an additional event or events in the causal explanation for the later impairment, and yet both impairments (the earlier left hip impairment and the later lumbar spine injury) were held to have arisen from the same injury or cause for the purposes of s 22(8)(c). The causal explanation for the later impairment included surgery and an altered gait that did not form part of the causal explanation for the earlier impairment. Yet once again, this did not undermine or defeat the causal sameness between the two impairments required for their combination under s 22(8)(c). 128 In contemplating the involvement of additional or different events in the causal explanation for an impairment which may nevertheless possess the requisite sameness to permit combination under s 22(8)(c), Stanley J referred to combining an impairment from a “consequential injury … where, as a matter of common sense, the impairments are so connected that the trier of fact is satisfied that the impairments are from the ‘same cause’”.71 His Honour later said that application of the common law test of causation was “neither accurate nor helpful” in construing s 22(8)(c); that the section had to be construed having regard to its text, context and purpose; and that it required an “evaluative test … to be applied adopting a common sense approach that recognises that more than one event might have been the ‘cause’ of the impairment”.72 129 At one end of the spectrum of possible approaches, it is to be accepted that the requirement of causal sameness for the purposes of combining impairments under s 22(8)(c) does not require an identity between the causal explanations for those impairments. Fidelity to the requirement of causal sameness can accommodate the presence of an additional causally relevant event or events in the causal explanation for one of the impairments. 130 At the other end of the spectrum, it is also to be accepted that the mere fact that two impairments share what may qualify as a common law cause – or may be linked by what might be described as a common law causal chain – will not suffice for combination. This would be to overlook the work to be done by the requirement of causal sameness in s 22(8)(c). 131 The difficulty lies in attempting to identify where, between these two ends of the spectrum of possible approaches, the line should be drawn. 132 Fastening upon Stanley J’s reference to “consequential injuries” qualifying for combination under s 22(8)(c), the Corporation seeks to confine the operation of that section to consequential injuries of a particular type – being essentially consequential injuries conforming to the fact patterns in the Preedy hypothetical 71 Summerfield at [20] (Stanley J, Kourakis CJ and Doyle J agreeing). 72 Summerfield at [21] (Stanley J, Kourakis CJ and Doyle J agreeing). -- 31 of 56 -- [2023] SASCA 125 Doyle JA 32 and in Summerfield. The Corporation articulated the particular type of consequential impairment which might qualify for combination under s 22(8)(c) as an impairment which arises as a direct physiological consequence or product of the first injury (such as the overcompensation injury in the Preedy hypothetical) or as an inevitable consequence of the first injury (such as the lumbar spine injury as a result of an altered gait following a hip injury in Summerfield). 133 The Corporation accepts that these consequential injuries could be said to involve additional or external causal events, but contends that they were not such as to undermine or defeat the requirement of causal sameness. For example, the fact that the overcompensation or altered gait might have involved the worker walking did not matter because this was merely an ordinary activity of life. 134 Further, in order to accommodate the result in Summerfield, where the altered gait was a product of both the original hip injury and the surgery that followed, the Corporation contended that the involvement of surgery as an additional integer in the causal explanation for the later impairment did not matter because there was a finding at first instance that the altered gait resulted from the hip injury and surgery.73 As such, the hip injury remained, on the Corporation’s argument, “a continuing operative cause of the second impairment, albeit in combination with another cause (eg, surgery for the original injury).” 135 To my mind, the Corporation’s attempts to prescribe or define the particular circumstances in which a later impairment might be said to arise from the same cause as an earlier impairment are unconvincing. The particular limits or categories articulated by the Corporation are unclear and unstable. More fundamentally, I do not consider that they have any sound basis in the text, context or purpose of the legislation. 136 The legislative text requires that the impairments be “from the same injury or cause”. Whilst the requirement that the impairments be “from the same … cause” must have some limits, I see no basis in any of these words for confining the combination of impairments to circumstances where the later impairment involves a direct physiological consequence of an earlier injury without the involvement of any additional event(s) other than what might be regarded as the ordinary activities of life.74 The words “from” and “cause” are inherently broader, and more flexible, than this. Even bearing in mind the ejusdem generis approach to construction of “injury” and “cause”, I do not think there is a secure basis for the Corporation’s articulation of the limits upon the circumstances in which impairments arising from consequential injuries may be combined. 137 Similar observations apply in relation to the relevant statutory context and purpose. I have described the assessment context in which s 22(8)(c) operates, and the significance and apparent purpose of the potential for a worker to combine 73 Referring to Summerfield v Return to Work Corporation (SA) [2019] SAET 106 at [45] (Cole DP). 74 Even putting to one side the involvement of the surgery in Summerfield. -- 32 of 56 -- [2023] SASCA 125 Doyle JA 33 impairments. Whilst these considerations are consistent with there being limits to the circumstances in which combination should occur, they do not suggest a narrow view of those limits, let alone provide a sound basis for the particular articulation of those limits urged upon this Court by the Corporation. 138 I accept that the requirement that the impairments arise from the same cause (that is, the requirement of causal sameness) requires a consideration of the nature and significance of any additional or different events in the causal explanations for the impairments sought to be combined. I also accept that, in determining whether the presence of those additional or different events are incompatible with the impairments being said to arise from the same causal explanation, it may be relevant to consider whether they might be described as merely physiological or inevitable consequences of the earlier injury, or as involving no more than the ordinary activities of life, or indeed as not interfering with the earlier injury’s role as a continuing operative cause. But I do not accept that these concepts, or the particular fact patterns in the Preedy hypothetical and in Summerfield, can be taken to define the outer limit of the circumstances in which consequential injuries may qualify for combination under s 22(8)(c). At most these concepts are helpful in an analytical, rather than definitional, sense. 139 In my view, it is neither possible nor appropriate to be any more prescriptive than Stanley J was in Summerfield. In determining whether impairments are to be combined under s 22(8)(c) in assessing an injured worker’s WPI, the issue is whether the impairments are “from the same injury or cause”. In considering whether a later impairment qualifies for combination, it is necessary to consider the causal explanation for each of the impairments, in order to determine whether those explanations possess the requisite sameness. This requires an evaluative assessment of the causal explanations, and in particular any differences between them. It requires an evaluative assessment of whether any additional events or integers in the causal explanations are of a nature or significance that means the impairments cannot be said to arise from the same injury or cause. 140 I see no difficulty in adding that the evaluative assessment will be informed by common sense, as long as it is understood that this is not to suggest that common sense is the criterion or touchstone by which the requisite causal sameness is to be determined.75 Equally, I would add that the evaluative assessment is to be approached in a practical manner, focusing upon the substance of the causal explanations for the relevant impairments. It is not to be approached in a manner that is overly technical or artificial. 141 However, I do not think it is appropriate to attempt to be any more prescriptive than the above. This is hardly a surprising conclusion; it would leave the evaluative task required by s 22(8)(c) in no different position from numerous 75 Comcare v Martin (2016) 258 CLR 467 at [42] (the Court); Travel Compensation Fund v Tambree (2005) 224 CLR 627 at [45] (Gummow and Hayne JJ) (but see also at [81] (Callinan J) as to the use that might nevertheless be made of common sense in a causal enquiry). -- 33 of 56 -- [2023] SASCA 125 Doyle JA 34 other statutory causation tests where the courts have eschewed any attempt to prescribe or define their intended reach. In the case of s 22(8)(c), any more precise identification of either (i) the type of additional causally relevant events that might be inconsistent with the requirement that the impairments have the same causal explanation, or (ii) the appropriate level of abstraction or generality at which the evaluative assessment should be approached, is better addressed through the application of that subsection to the facts of particular cases. As it happens, the English matter requires consideration of the former, and the Williams matter requires consideration of the latter. The English matter 142 Mr English worked as an arborist in a business known as All Trees All Stumps. He suffered a work-related injury to his neck on 4 March 2019. The injury occurred when Mr English cut a rope line which he had attached to a heavy branch. The rope swung and collided with the back of his neck, forcing him forward and pinning his head and neck against a cherry picker. 143 On 10 May 2019, Mr English suffered a further work-related injury when he was on-site endeavouring to quote for a job and fell, injuring his right quadriceps. On the findings of the primary judge (Crawley DPJ), the fall occurred as a result of lightheadedness brought on by prescribed pain medication (Lyrica) that Mr English had been taking for his neck injury.76 144 By way of elaboration upon the above, Mr English’s evidence77 was to the effect that, immediately before the fall, he felt dizzy and disorientated. He described falling backwards unexpectedly, and ending up with his right leg folded underneath him. He attributed his dizziness and disorientation to his medication. 145 This claimed link between Mr English’s medication and fall was supported by a report from Dr Milan,78 the general practitioner who had prescribed the Lyrica (pregabalin) as pain relief medication for the neuropathic pain Mr English was suffering due to his earlier neck injury. Dr Milan explained that lightheadedness was a well-recognised adverse effect of Lyrica, and that it was reasonable to suppose that the medication could have resulted in a fall. He expressed the opinion that Mr English’s fall could be linked to his medication, and said that he subsequently reduced Mr English’s dosage in order to lower the risk of him falling. The evidence of Dr Milan was not challenged. 146 Crawley DPJ accepted the above evidence, and made the following factual findings:79 The effect of the evidence that I heard from the Applicant in particular was that the fall occasioning the second injury occurred in circumstances where he suffered a loss of 76 English v Return to Work Corporation (SA) [2021] SAET 103 at [66]. 77 English v Return to Work Corporation (SA) [2021] SAET 103 at [19], [23]. 78 English v Return to Work Corporation (SA) [2021] SAET 103 at [25]. 79 English v Return to Work Corporation (SA) [2021] SAET 103 at [66]. -- 34 of 56 -- [2023] SASCA 125 Doyle JA 35 balance as a consequence of at least lightheadedness. The lightheadedness is consistent with having consumed the high dosages of Lyrica prescribed and said by the Applicant to have been taken by him. In the absence of any other explanation for such lightheadedness, I am prepared to find that the second injury arose as a result of the fall which in turn arose out of the consumption of Lyrica which was only undertaken because of and in response to the pain of the first injury. 147 In assessing Mr English’s claims for lump sum compensation under ss 56 and 58 of the RTW Act, the Corporation had declined to combine the two impairments suffered by Mr English. However, based upon his findings in paragraph [66] of his reasons, Crawley DPJ set aside the Corporation’s determinations under ss 56 and 58, holding that, “in keeping with the terms of the test proposed in Summerfield, I am satisfied that the impairment from the second injury should be combined with the impairment from the first injury, because the impairments are from the same cause.”80 148 The Corporation appealed to the Full Bench of the Tribunal. The Full Bench (Dolphin PJ, Gilchrist and Calligeros DPJJ), with the agreement of both parties, referred a question of law to the Court of Appeal pursuant to s 70 of the South Australian Employment Tribunal Act 2014 (SA).81 The question referred is: On the facts as found by Crawley DPJ, does s 22(8)(c) of the [RTW Act] apply so as to require or permit the impairments to Mr English’s neck and to his right quadriceps to be assessed together or combined to determine the degree of impairment of Mr English? Determination of the English matter 149 The question of law referred to this Court requires determination of whether, on the facts found by the primary judge (Crawley DPJ), s 22(8)(c) applies to require or permit the impairments to Mr English’s neck and to his right quadriceps to be combined and assessed together in determining his WPI. 150 The key factual findings made by Crawley DPJ are those in paragraph [66] of his reasons, set out above. On the basis of those findings, Mr English relies upon what he contends is a fairly straightforward causal chain between the event causing the earlier neck impairment and the occurrence of the later right quadriceps impairment: 1. Mr English suffered a neck injury on 4 March 2019, as a result of a falling rope line hitting and pinning him, causing an impairment of his neck. 2. He was prescribed, and ingested, high doses of the drug Lyrica in order to treat neuropathic pain caused by his neck injury. 80 English v Return to Work Corporation (SA) [2021] SAET 103 at [67]. 81 Return to Work Corporation (SA) v English [2022] SAET 86. -- 35 of 56 -- [2023] SASCA 125 Doyle JA 36 3. His ingestion of Lyrica on 10 May 2019 caused him to feel lightheaded and to fall over. 4. The fall resulted in the injury to his right quadriceps, and hence the impairment to his right quadriceps. 151 In contending that the two impairments arose from the same injury or cause for the purposes of s 22(8)(c), Mr English emphasises that each event in the chain was caused by, and was a natural and foreseeable consequence of, the preceding event in the chain. The ingestion of pain medication was an obvious and natural consequence of the first injury that caused Mr English to suffer pain. The suffering of a common side effect of that medication – lightheadedness – was a natural consequence of taking a high dose of the medication. Falling over was a natural consequence of the lightheadedness. And injuring another body part, such as by way of a tear of his right quadriceps, was a natural consequence of Mr English falling over. 152 Having regard to the direct and straightforward nature of the causal chain relied upon, Mr English contends that both impairments can be said to have arisen from the same injury (the initial neck injury), or from the same cause (the event that caused the initial neck injury or, indeed, the neck injury itself). Put another way, Mr English contends that the involvement of the additional events (the ingestion of Lyrica, lightheadedness and fall) in the causal chain leading to the subsequent impairment was not such as to prevent characterisation of the two impairments as arising from the same cause. He observes that his pain was a physiological response to the neck injury; his ingestion of Lyrica was by way of treatment of that pain; his lightheadedness was a physiological response to the Lyrica; and his fall occurred when engaging in an ordinary activity of living (that is, walking). In other words, assuming some significance in the concepts relied upon by the Corporation in its attempts to articulate the limits of causal sameness for the purposes of s 22(8)(c), they encompassed the essential features relied upon by Mr English. 153 Mr English acknowledged that if additional events of a different type had been involved, then the position might be otherwise. He gave, as an example, circumstances corresponding to his case, but where the lightheadedness that resulted in his fall occurred as a result of the combination of the ingestion of pain medication and the voluntary ingestion of alcohol by the worker. He gave, as a further example, circumstances in which a worker, knowing that he was lightheaded as a result of ingesting Lyrica, nevertheless took the risk of operating heavy machinery or driving a vehicle, resulting in an accident that caused a second injury and impairment. Mr English emphasised that it was not necessary for this Court to determine whether – in the context of a “no fault” scheme in which such additional causes would not preclude an injury from being compensable – such additional causes would necessarily prevent a finding of causal sameness so as to permit combination for the purposes of assessing the worker’s WPI. The point -- 36 of 56 -- [2023] SASCA 125 Doyle JA 37 sought to be made through these examples was to contrast them with what Mr English contended was the more straightforward nature of the causal chain in his case. 154 One might hypothesise any number of additional causally relevant events or circumstances that might alter the analysis. Ultimately, however, the disposition of the English matter can only be resolved by addressing the particular facts of that case. 155 I accept the central thrust of the submissions by Mr English, and the result he contends for. In my view, while the causal explanation for the second impairment involves additional events or integers (the ingestion of pain medication resulting in lightheadedness and a fall), there is a direct and straightforward relationship, or causal chain, between the two injuries and hence the two impairments. The additional events are each the natural and foreseeable consequence of the preceding event. The causal chain does not involve, let alone depend upon, any additional event which can be said, as a matter of common sense, to have undermined the directness of the causal chain between the events causing the first injury and the occurrence of the second injury and impairment. In my view, it is appropriate to characterise both impairments as sharing the same causal explanation, and hence arising “from the same injury or cause” for the purposes of s 22(8)(c). Mr English’s right quadriceps impairment can properly be characterised as arising from his earlier neck injury, or indeed the events which caused that injury. 156 I do not think that it matters that the causal chain between Mr English’s two injuries may not consist entirely of events which can be characterised as a single physiological process commencing with his earlier injury, with the addition only of ordinary activities of life. As explained earlier, I do not consider that these labels, or the precise fact patterns in the Preedy hypothetical or in Summerfield, are determinative of the circumstances in which consequential or successive impairments may qualify for combination under s 22(8)(c). That said, as I have endeavoured to explain, I consider that the nature of the causal chain inherent in Mr English’s later impairment is similar in its nature and directness to the causal chains inherent in the later impairments in both the Preedy hypothetical and in Summerfield. Mr English was prescribed and ingested Lyrica so as to address pain that was a physiological response to his neck injury; his lightheadedness was a common physiological response to the Lyrica; and he was not engaged in any activity other than walking when he became lightheaded and fell. 157 For the reasons given, I would answer the question reserved “Yes”. -- 37 of 56 -- [2023] SASCA 125 Doyle JA 38 The Williams matter 158 At first instance in the Williams matter,82 Rossi DPJ held that Mr Williams’ impairments to his left and right knees could be combined under ss 58(6) and 22(8)(c) of the RTW Act because both arose out of work activity undertaken by Mr Williams between May and August 2015. 159 The Full Bench of the Tribunal allowed the Corporation’s appeal.83 The majority (Clayton AJ and Cole DP) held that the impairments were not able to be combined under either s 58(6) or s 22(8)(c). Dolphin PJ, on the other hand, agreed that they were not able to be combined under s 58(6), but upheld Rossi DPJ’s decision that they were able to be combined under s 22(8)(c). 160 Mr Williams has appealed to this Court. Before setting out his grounds of appeal, and the issues raised by the Corporation’s notice of contention, it is necessary to address in more detail the factual background to this matter, and the reasoning of the Tribunal at first instance and on appeal. Factual Background 161 Mr Williams worked as an electrician. In November 2012, he commenced working with PJ Corporate Electrical Pty Ltd. 162 In May 2013, while climbing scaffolding at work, Mr Williams experienced a sudden sharp pain to his right knee. Subsequent investigations revealed a tear of the medial meniscus in the context of severe osteoarthritis within the right knee. He was referred to an orthopaedic surgeon (Dr Wallace) who treated the tear arthroscopically on 29 May 2013. Whilst the arthroscopic surgery resulted in some improvement, further surgery was performed on the right knee in February 2014, this time by another orthopaedic surgeon, Dr Pourgiezis. 163 In June 2014, Mr Williams was made redundant by PJ Corporate Electrical Pty Ltd. 164 In September 2014, Mr Williams commenced employment as an electrician with Chandler McLeod, a labour hire company supplying labour to the Australian Submarine Corporation. Between September 2014 and the commencement of May 2015, Mr Williams performed primarily sedentary tasks in relation to circuit boards. 165 From early May 2015, Mr Williams was required to perform more physically demanding work, including work that required that he repeatedly climb up and down both fixed ladders and stairs, and A-frame ladders, in order to access the different levels of the ships he was working on and to access overhead cable ducts. He would often be required to climb ladders as many as 20 times a day, and when working on overhead cables he would be up and down a ladder every few minutes. 82 Williams v Return to Work Corporation (SA) [2020] SAET 187. 83 Return to Work Corporation (SA) v Williams [2022] SAET 34. -- 38 of 56 -- [2023] SASCA 125 Doyle JA 39 He was also regularly required to work in a crouched position with bent knees or kneeling down, and at times crawling on his hands and knees, while installing under-floor cables and working in awkward places. He worked full-time on Monday to Friday with regular additional Saturday shifts. 166 Mr Williams gave evidence as to the onset and progression of his 2015 knee injuries. After describing the change in his work activities at the Australian Submarine Corporation from early May 2015, he said that the pain in his right knee soon began to increase, causing him to limp. However, while “going up and down ladders and working on [his] hands and knees” he also noticed pain in his left knee. He said that he could not recall any particular incident that caused the pain to start, adding that “it came on gradually”, and then “grew” and “got worse” as time went on. 167 On 19 May 2015, Mr Williams consulted Dr Groves, primarily because of pain in his left knee, although he was also experiencing pain in his right knee. An x-ray of Mr Williams’ left knee taken on 21 May 2015 showed degenerative changes in that knee. Mr Williams was referred back to Dr Pourgiezis for his consideration of both of Mr Williams’ knees. 168 On 1 July 2015, Mr Williams saw Dr Pourgiezis and was complaining of pain in both knees. Dr Pourgiezis recommended a total knee replacement of the right knee and an arthroscopy of the left knee. 169 On 18 August 2015, Mr Williams saw Dr Groves again. By this time his right knee pain had increased and was “quite bad”. He had been continuing to climb ladders and work in awkward places, but “felt [he] could not keep doing it”. He did not return to work after this date. 170 On 27 October 2015, Dr Pourgiezis performed a total knee replacement of Mr Williams’ right knee. 171 On 11 March 2016, Dr Pourgiezis performed an arthroscopy of Mr Williams’ left knee. It was not successful in treating the left knee and a total knee replacement of the left knee was performed by Dr Pourgiezis on 20 March 2017. 172 In 2018, Mr Williams’ WPI was assessed by Dr Jezukaitis. The assessor was advised of a pre-existing injury to the right knee sustained in May 2013, and was asked to deduct any impairment attributable to the 2013 injury. He was also asked to deduct any impairment attributable to pre-existing degenerative changes to the left knee. 173 Dr Jezukaitis assessed the impairment to the right knee at 21 per cent (having deducted one per cent for the 2013 injury), and the left knee at 22 per cent (having deducted eight per cent for the pre-existing impairment to the left knee). -- 39 of 56 -- [2023] SASCA 125 Doyle JA 40 174 Both injuries were given a date of injury of 18 August 2015, noting that s 188 of the RTW Act provides that injuries which develop gradually are taken to have occurred when the worker first becomes totally or partially incapacitated for work. Mr Williams did not return to work after 18 August 2018. 175 On 14 September 2018, the Corporation determined that Mr Williams was entitled to lump sum payments under s 58 of the RTW Act in the amounts of $49,149 (on an assessed WPI of 21 per cent) for his right knee, and $53,609 (on an assessed WPI of 22 per cent) for his left knee. 176 Mr Williams disputed this determination in the Tribunal, arguing that the injuries or impairments to his right knee and left knee should be combined under ss 58(6) or 22(8)(c) of the RTW Act. Reasons of the trial judge 177 The only issue at trial was whether the injuries to the right knee and left knee were to be combined under ss 58(6) or 22(8)(c) of the RTW Act.84 178 Mr Williams submitted that the injury to his right knee in 2015 was a separate injury to the one he sustained to that knee in 2013, and it was caused by his repetitive climbing of ladders and working in a crouched position. As the left knee injury arose from the same work activity, the two impairments or injuries could be combined.85 179 The Corporation submitted that the only basis upon which combination was permitted under either s 58(6) or s 22(8)(c) was if the two injuries (for s 58(6)) or two impairments (for s 22(8)(c)) arose from the same trauma; that the proper characterisation of the injury to the right knee was a single injury which commenced with a specific traumatic event in 2013 (the sharp pain experienced in May 2013); and that the injury to the left knee was a separate injury which commenced while undertaking different work with a different employer and was of gradual onset.86 180 The Corporation accepts that its submissions at trial with respect to s 22(8)(c) were dependent upon a form of argument that was unsuccessful before the Full Court in Summerfield. As noted below, before the Full Bench, the Corporation adjusted its submissions with a view to confining and distinguishing Preedy and Summerfield. 181 In relation to the right knee, Rossi DPJ first addressed the pre-existing 2013 right knee injury, finding that Mr Williams suffered a “significant injury” to that knee on 4 May 2013 by way of a meniscal tear in the context of compartmental osteoarthritis. His Honour found that although “there was some level of ongoing 84 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [1]. 85 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [24]-[28]. 86 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [31]-[32]. -- 40 of 56 -- [2023] SASCA 125 Doyle JA 41 impairment of function of the right knee and some ongoing symptoms, the condition of the right knee was relatively stable until early May 2015.”87 182 Rossi DPJ also addressed the change in Mr Williams’ work activities from early May 2015, and in particular the requirement that he repeatedly climb ladders and work in a crouching position.88 He summarised his findings in relation to Mr Williams’ changed work activities between early May 2015 and 18 August 2015, stating his satisfaction that “from the beginning of May 2015 he was engaged in arduous repetitive work which put substantial strain upon both of his knees, on an ongoing basis, whilst at work.”89 183 Rossi DPJ ultimately found, based upon the evidence of Mr Williams, and “the consistent expert medical opinion of Dr Pourgiezis and Dr Groves” that Mr Williams’ “work activity [from early May 2015] caused an injury to the right knee by way of aggravation and acceleration of the pre-existing degenerative changes which rendered the condition of the right knee much more symptomatic and the level of impairment much greater.”90 184 In relation to the left knee, his Honour found that the “same work activity over the same period from early May 2015 caused an aggravation and acceleration of pre-existing degenerative changes of the left knee and this too has been productive of ongoing symptoms and impairment.”91 185 Having made these factual findings, Rossi DPJ acknowledged the reasoning of the Full Court in Marrone and Mitchell to the effect that in determining the WPI for the purposes of the predecessor to s 58(6), it was not sufficient to permit combination that two injuries have a common cause or causes. To be combined, they must arise from the same trauma, and hence the same event or series of events. And the series of events must include all of the events out of which the injury arose; it must be comprehensive.92 However, his Honour held that the injuries to the right knee and left knee arose from the same trauma and should be combined:93 The only trauma giving rise to the impairment concerning the left knee injury and the impairment concerning the right knee injury is the work activity referred to in these reasons from early May 2015. It is a single event of a period of work activity or, alternatively, the same series of events of repeated work activity constituting the same trauma. 186 In so holding, his Honour rejected the Corporation’s argument that the 2013 right knee injury should be treated as part of the 2015 right knee injury, or as 87 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [44]. 88 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [11]. 89 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [12]. 90 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [46] 91 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [46]. 92 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [37]-[39]. 93 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [53]. -- 41 of 56 -- [2023] SASCA 125 Doyle JA 42 constituting a separate trauma, injury or cause from which the 2015 right knee injury arose.94 187 Rossi DPJ also held, in the alternative, that the impairments from the right knee injury and left knee injury could be combined under s 22(8)(c) on the basis that the work activity from early May 2015 was the sole cause of both impairments:95 In this matter, the sole cause of the impairments of both the aggravation and acceleration injury to the left knee and the aggravation and acceleration injury to the right knee is the work activity involving the climbing of ladders and steps and the working in a crouched position from early May 2015 until 18 August 2015. There is no relevant external causal event. 188 The effect of combining the impairments was to produce a WPI of 38 per cent, entitling Mr Williams to be treated as a seriously injured worker. 189 The Corporation appealed, arguing that the judge’s findings that both knee injuries arose out of the same “work activity” was not sufficient to meet the statutory requirement that the injuries arose from the “same event or series of events” and hence the “same trauma” for the purposes of s 58(6), or to establish that the impairments arose from the “same cause” for the purposes of s 22(8)(c). The appeal was framed as raising issues of law as to the sufficiency of the judge’s findings, and not a challenge to the judge’s findings of fact themselves. Reasons of the Full Bench 190 Commencing with the operation of s 58(6) of the RTW Act, the Full Bench were unanimous in their view that Rossi DPJ misapplied it to the facts as found. 191 In their joint reasons, Clayton AJ and Cole DP accepted the Corporation’s argument that Rossi DPJ erred in characterising Mr Williams’ work activity over a period of three to four months (from May to August 2015) as “the same trauma” without identifying more specifically what work activity caused what injury.96 Their Honours explained that the application of a common date for the right knee and left knee injuries of 18 August 2015 was a legal fiction resulting from s 188 of the RTW Act, and “does not assist to identify what activity caused or contributed to each injury or when.”97 Their Honours described the difficulty with this task:98 The difficulty in making such findings in this case can be illustrated by the following. The respondent saw his GP Dr Groves on 19 May 2015 complaining primarily of left knee symptoms worse than his right knee symptoms. The respondent was then referred to orthopaedic surgeon Dr Pourgiezis who saw the respondent on 1 July 2015. By that time the respondent’s right knee symptoms had worsened such that a right total knee 94 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [54]. 95 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [59]. 96 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [96]-[98]. 97 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [99]. 98 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [100]. -- 42 of 56 -- [2023] SASCA 125 Doyle JA 43 replacement was recommended. Left knee arthroscopy was also recommended. The respondent had continued to work after 19 May 2015 with worsening effects on his right knee compared with his left, but what activity specifically caused or contributed to that worsening in the right knee is not the subject of findings, because the medical evidence did not address that. 192 After referring to the reasons of the Full Court in Marrone, Clayton AJ and Cole DP held that Rossi DPJ misapplied s 58(6) because his Honour’s findings in relation to Mr Williams’ work activity did not support a conclusion that all of the events comprising that work activity were the exclusive causes of each knee injury:99 It can be accepted that some aspects of the respondent’s work activity between early May 2015 and 18 August 2015 were causes of his right knee and left knee injuries. So much is consistent with each injury being compensable by reference to that work activity. However, it does not follow that the two injuries arise from the same trauma. The findings made in relation to the work activity do not lead to the conclusion that all of the events comprising the work activity over the relevant three to four months are the exclusive causes of each knee injury. The judge did not reach that conclusion because the evidence before the judge was not sufficient to allow it. On [Mr Williams’] case, any multiple injuries from the same style of work activities over any period of employment would be injuries from the same trauma. We consider that is not the correct meaning and application of s 58(6) of the RTW Act. 193 In addition to the lack of specificity about the events constituting the work activity, their Honours also identified a second reason why the right knee and left knee injury could not be said to have arisen from the same trauma for the purposes of s 58(6). 194 Their Honours referred to the decision of the Full Bench of the Tribunal in Wagenfeller v Return to Work Corporation (SA)100 (Wagenfeller), relying upon it as authority for the proposition that multiple injuries occurring as a result of a single event could not be combined in circumstances where one of those injuries (but not the others) was partly attributable to an earlier injury in that it comprised an aggravation, acceleration, exacerbation, deterioration or recurrence of an earlier injury. Applying Marrone and Mitchell, the Full Bench in Wagenfeller reasoned that multiple injuries did not arise from the same trauma in circumstances where one of those injuries was partly attributable to an earlier trauma.101 195 Relying upon this reasoning in Wagenfeller, Clayton AJ and Cole DP held that the second reason why s 58(6) could not apply to combine the right knee injury and the left knee injury was that the former was partly attributable to the May 2013 right knee injury, being an aggravation or acceleration of that earlier injury:102 99 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [106]-[107]. 100 Wagenfeller v Return to Work Corporation (SA) [2021] SAET 199. 101 Wagenfeller v Return to Work Corporation (SA) [2021] SAET 199 at [50]-[51]. 102 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [115]. -- 43 of 56 -- [2023] SASCA 125 Doyle JA 44 In this case, the right knee injury was partly attributable to the May 2013 injury and partly attributable to the work activity between May and August 2015, because it was an aggravation/acceleration of the earlier injury. Applying the reasoning in Wagenfeller, the right knee injury did not arise from the same trauma, and s 58(6) of the RTW Act will not apply to combine the impairments. 196 Dolphin PJ agreed with Clayton AJ and Cole DP that s 58(6) did not permit combination of Mr Williams’ knee injuries. In particular, his Honour agreed that “on the facts of this case the level of abstraction is too great to say that the impairments to Mr Williams’ knees were caused by exactly the same trauma(s) as each other.”103 197 Turning to the combination of impairments under s 22(8)(c), Clayton AJ and Cole DP held that Rossi DPJ’s finding that the impairment from the right knee injury and the impairment from the left knee injury were from the “same injury or cause” faced the same difficulty as the finding that the injuries were from the “same trauma”, namely that “work activity over a period of three to four months leading to injury in each knee does not identify the specific cause of each impairment from the knee injuries.”104 Their Honours reasoned that, unlike the impairments sought to be combined in Preedy and Summerfield, and the impairments in the illustration contained in paragraph [55] of Stanley J’s reasons in Preedy, there was no causal relationship between Mr Williams’ two knee injuries and the impairments resulting from them.105 Noting Stanley J’s reference in Preedy to “injury” and “cause” in s 22(8)(c) being related concepts concerned with the thing or event from which the impairment results, their Honours said:106 The notion of “work activity”, even limited to certain actions over a three to four month period, is too wide and nebulous [and] does not in our view fall within the concept of the thing or event from which an impairment results. That is particularly so when there is no causal relationship between the two injuries and the impairments which have resulted. 198 Dolphin PJ dissented on this issue, holding that s 22(8)(c) did permit combination of Mr Williams’ two knee injuries. In so holding, his Honour emphasised the potential breadth of Stanley J’s articulation in Preedy and Summerfield of the causal connection required for impairments to be from the same cause for the purposes of combination under s 22(8)(c):107 In my opinion, his Honour’s careful explanation of s 22(8)(c) in both Preedy and Summerfield allows sufficient latitude for factual situations, not limited to just consequential injuries, to be considered as being sufficiently connected to the original injury, such that the impairments from both may be combined under s 22(8)(c). In that regard, the touch stone will be the common sense evaluative judgment by the judicial officer as to the connectedness of the impairments. 103 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [9]. 104 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [116]. 105 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [122]-[123]. 106 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [126]. 107 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [32]. -- 44 of 56 -- [2023] SASCA 125 Doyle JA 45 199 Applying this approach to the facts, Dolphin PJ emphasised the trial judge’s finding that, from the beginning of May 2015, Mr Williams was engaged in arduous repetitive work which put substantial ongoing strain on both his knees, until he cased that work on or about 18 August 2015.108 After also referring to Rossi DPJ’s findings that this work involved repeatedly climbing up and down ladders, and working in a crouched position with bent knees or kneeling down, his Honour explained why he considered that this was sufficient to permit combination under s 22(8)(c):109 In my opinion, those findings are able to support the common sense conclusion that the impairments to Mr Williams’ knees are from the “same cause”. That being as emphasised by Stanley J in Summerfield, that s 22(8)(c) posits a statutory test of “cause”, which is an evaluative test “to be applied adopting a common sense approach that recognises that more than one event might have been the ‘cause’ of the impairment.”110 Common sense dictates that on the facts of this case the impairments to Mr Williams’ knees arose from the “same cause” of the repetitive climbing of ladders/steps and working in a crouched/kneeling position during his employment from May 2015 to August 2015. 200 In reaching this conclusion, Dolphin PJ rejected the Corporation’s argument that a finding that the two knee injuries arose from the same cause required findings at a greater level of specificity: for example, findings to the effect that every time Mr Williams climbed or crouched he suffered micro-strains, or micro- traumas, to each of his knees; or findings to the effect that the same instances of climbing or crouching otherwise led to both knee injuries; and not merely findings which left open the possibility that the knee injuries arose from different events on different days within the period of the work activity.111 Appeal and notice of contention 201 Mr Williams’ notice of appeal to this Court contains three grounds, namely that the Full Bench erred in holding: 1. that Rossi DPJ misapplied s 58(6) of the RTW Act to the facts as found by him; 2. that Mr Williams’ injuries are not from the same trauma; and 3. that the work activity resulting in impairment to each knee as found by Rossi DPJ does not establish that the knee impairments are from the same cause within the meaning of s 22(8)(c) of the RTW Act. 202 Mr Williams requires leave to appeal, but this is not opposed. 108 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [33]. 109 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [34]-[35]. 110 Summerfield at [21]. 111 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [15], [16], [20], [25], [29], [36]. -- 45 of 56 -- [2023] SASCA 125 Doyle JA 46 203 The Corporation filed a notice of alternative contention in which it sought to sustain the Full Bench’s judgment on the basis of three broad contentions:112 1. the Full Court’s decisions in Preedy and Summerfield do not, in terms, apply to the present case because those decisions are concerned with a particular and limited species of consequential injuries, and the present case does not concern consequential injuries; 2. the “evaluative test” identified in Summerfield, which speaks of an assessment of the cause of the impairments, is directed to an assessment of whether the cause of the impairment arising from the first injury and the cause of the impairment arising from the second injury are “the same”, not whether the events are of the same nature, character or type by reference to the ordinary activities of work undertaken over a period of time (eg climbing ladders and crouching); and 3. the trial judge’s reasons for concluding that the only cause of the relevant work injuries to the left knee and right knee was “the same work activity” over “the same period” are inadequate, because there must be a trauma (or event) for each injury before there can be a conclusion under s 58(6) that the traumas are “the same”, and there was no such finding here. Determination of the Williams matter 204 Broadly speaking, there are three questions of law to be considered in the Williams matter. The first two concern whether, on the facts as found by Rossi DPJ, the injuries or impairments to Mr Williams’ right knee and left knee were permitted or required to be combined as arising from “the same trauma” (s 58(6)) or from “the same … cause” (s 22(8)(c)) respectively. The third concerns the adequacy of Rossi DPJ’s reasons for concluding that the only cause of the right knee and left knee injuries was “the same work activity” over “the same period”. Combination under s 58(6): injuries arising from the same trauma 205 The starting point for consideration of whether Mr Williams’ two knee injuries arose from “the same trauma” under s 58(6) is to identify, on the findings of Rossi DPJ, the series of events out of which each of those injuries arose. It is then necessary to consider whether those two series are the same, in the sense that there is an identity between them, as opposed to a mere overlap or similarity between them. 206 Mr Williams initially suffered a right knee injury in May 2013 while in the employment of PJ Corporate Electrical Pty Ltd and climbing scaffolding. He experienced a sudden sharp pain in his right knee, with subsequent investigation revealing a tear of his medial meniscus. After surgical intervention during 2013 112 As summarised and refined in the Corporation’s written submissions. -- 46 of 56 -- [2023] SASCA 125 Doyle JA 47 and 2014, he was made redundant in June 2014. On the findings of Rossi DPJ, Mr Williams continued to experience some level of ongoing impairment of his right knee as a result of his 2013 injury to that knee (the meniscal tear); however, the condition of his right knee was relatively stable until early May 2015.113 207 Having commenced work with the Australian Submarine Corporation in September 2014, there was a change in Mr Williams’ work duties from early May 2015. From that date he was required to perform more physically demanding work, including work that required that he repeatedly climb up and down ladders, and regularly worked in a crouched position with bent knees or kneeling down. Importantly, Rossi DPJ found that this change in work responsibilities required that Mr Williams engage in “arduous repetitive work which put substantial strain upon both of his knees, on an ongoing basis”.114 208 It is apparent from the findings of Rossi DPJ that the 2015 injuries to Mr Williams’ knees were of gradual onset and progression. Unlike Mr Williams’ 2013 right knee injury, his 2015 knee injuries were not referrable to a particular incident or occasion. This was consistent with Mr Williams’ evidence, mentioned earlier, to the effect that he did not recall any particular incident that precipitated his 2015 knee injuries, describing the pain as coming on gradually and then worsening over time. 209 Rossi DPJ described both of the 2015 knee injuries as involving aggravation and acceleration of pre-existing degenerative changes. Importantly, he described the injury to the right knee as being caused by Mr Williams’ “work activity” from early May 2015, and the injury to his left knee as caused by the “same work activity over the same period from early May 2015”.115 These references to “work activity” must be understood as references to the particular activities (involving climbing and crouching movements) that he had described earlier. 210 As recounted earlier, Rossi DPJ accurately summarised the approach required by the decisions of the Full Court in Marrone and Mitchell in determining whether injuries can be said to have arisen from “the same trauma” for the purposes of combination under s 58(6) of the RTW Act.116 Having done so, his Honour first rejected the Corporation’s argument that the 2013 right knee injury should be treated as part of the 2015 right knee injury, or as constituting a separate trauma, injury or cause from which the 2015 right knee injury arose.117 His Honour then held that both of the 2015 knee injuries arose from the same trauma for the purposes of s 58(6) of the RTW Act because the “only trauma” giving rise to those injuries was “the work activity” from early May 2015 described above.118 Subsequently, in the context of his findings for the purposes of combination under 113 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [44]. 114 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [12]. 115 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [46]. 116 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [37]-[39]. 117 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [54]. 118 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [53]. -- 47 of 56 -- [2023] SASCA 125 Doyle JA 48 s 22(8)(c), his Honour found that “the sole cause” of both of the 2015 knee injuries was “the work activity involving the climbing of ladders and steps and the working in a crouched position from early May 2015 until August 2015. There is no “relevant external causal event.”119 211 The issue for this Court is whether, in the face of these factual findings, the Full Bench erred in overturning Rossi DPJ’s conclusion that Mr Williams’ 2015 knee injuries should be combined under s 58(6) as having arisen from the same trauma. 212 The first reason Clayton AJ and Cole DP gave for overturning this conclusion was the lack of specificity in Rossi DPJ’s findings as to the series of events from which the two injuries arose. In their Honours’ view, it was not sufficient to proceed on the basis that both injuries arose from “work activity” over a three or four month period. The notion of “work activity”, even limited to certain activities over a three to four month period, was too wide and nebulous. A finding at this level of generality or abstraction did not enable a conclusion that the same series of events caused both injuries. Such a conclusion required identification of the specific activity or activities that caused each knee injury, and a finding that all of the events giving rise to the one injury were also the exclusive and comprehensive causal explanation for the other injury. But no such finding could be made in respect of Mr Williams’ knee injuries, because the evidence did not permit it to be made.120 213 Dolphin PJ agreed with Clayton AJ and Cole DP on this issue, reasoning that “on the facts of this case the level of abstraction is too great to say that the impairments to Mr Williams’ knees were caused by exactly the same trauma(s) as each other.”121 That said, when later addressing whether Mr Williams’ impairments arose from the same cause for the purposes of s 22(8)(c), his Honour took a different view. In that context, his Honour accepted that findings at a greater level of specificity were not required. It was not necessary, for example, to find that each and every time Mr Williams climbed or crouched he suffered micro-strains, or micro-traumas, to each of his knees, or to find that precisely the same instances of climbing or crouching otherwise led to both knee injuries. A finding that both knee impairments arose from the same cause could accommodate the possibility that they might have arisen from different events on different days within the period of the work activity.122 214 In my view, the Full Bench erred in this first reason it gave for overturning Rossi DPJ’s conclusion that both knee injuries arose from the same trauma for the purposes of s 58(6). As outlined earlier, it is to be accepted that the approach dictated by Marrone and Mitchell requires that there be an identity between, or 119 Williams v Return to Work Corporation (SA) [2020] SAET 187 at [59]. 120 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [96]-[100], [106]-[107], [116], [126]. 121 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [9]. 122 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [15], [16], [20], [25], [29], [33]-[36]. -- 48 of 56 -- [2023] SASCA 125 Doyle JA 49 sameness of, the series of events giving rise to both injuries before those injuries can be combined under s 58(6). However, the issue in this case is the degree of specificity that is required before such a conclusion can be reached. 215 It will be recalled from my earlier consideration of the Full Court’s reasoning in Marrone that both Kourakis CJ and White J accepted that the inclusion of a series of events in the definition of “trauma” involved a legislative recognition that injuries may arise out of more than one event; that they may arise from “a succession of traumas connected in some way by time, sequence or character”,123 or from “a series of repetitive work duties or protracted exposure to injurious environments”.124 216 Unlike his sudden 2013 knee injury, both of Mr Williams’ 2015 knee injuries were, on the findings of Rossi DPJ, of gradual onset and progression, being in the nature of repetitive strain injuries; they were, on the findings of Rossi DPJ, caused by the ongoing strain upon Mr Williams’ knees by reason of the climbing and crouching movements he was required to undertake between early May and 18 August 2015. 217 By reason of the inclusion of reference to a “series of events” in the definition of “trauma”, and hence in the criterion for combination under s 58(6), it can be accepted that s 58(6) contemplates the potential for injuries of this nature to be combined. With this in mind, I do not think that in considering whether, in a particular case, such injuries may be combined, too technical or artificial an approach should be taken in determining whether there is an identity between the series of events giving rise to each injury. Depending upon the nature of the injuries, and the events giving rise to them, a more practical and realistic approach may be called for. 218 A finding that two injuries arose out of a worker’s “work activities” would not, without more, suffice for the purpose of combination under s 58(6). It would not be a sufficiently precise description of either an event or series of events. However, Rossi DPJ’s findings went further than this. His Honour’s findings related to work activities of a particular type during a particular period of time. His Honour’s findings were directed to the period from early May 2015, when Mr Williams’ tasks changed from the previously sedentary tasks he had been undertaking, to work of a more arduous type. His findings were directed to a closed period of three to four months (early May 2015 to 18 August 2015), and to a particular type of physical activity (regular climbing and crouching movements) during that period. Importantly, his Honour also found that this arduous repetitive work put substantial strain upon both of his knees “on an ongoing basis”. It is of some significance in this respect that the two impairments sought to be combined are equivalent impairments from equivalent injuries to equivalent body parts (the 123 Marrone at [62] (White J, Sulan J agreeing). 124 Marrone at [23] (Kourakis CJ). -- 49 of 56 -- [2023] SASCA 125 Doyle JA 50 left and right knees). Rossi DPJ later expressly excluded the involvement of any cause of either knee injury outside of the work activity that he had described. 219 In summary, Rossi DPJ was plainly alive to the requirements of the statutory test of injuries “from the same trauma” – in particular the requirement that the same series of events be the exclusive and comprehensive cause of the injuries sough to be combined – and made findings to the effect that the test was made out. 220 I do not think the conclusion that Mr Williams’ 2015 knee injuries arose from the same trauma necessarily required any greater level of specificity. In making findings of fact, it is appropriate for a judge to have regard to the nature of the issue and the evidence in determining the degree of specificity or precision required before a finding may be made. To require greater specificity in the present case would, in my view, be to demand an approach to the requirement of “sameness” in s 58(6) which is too technical or artificial. Such an approach would make it very difficult to combine injuries which arise from repetitive work duties despite this being contemplated by the breadth of the notion of trauma included in s 58(6). 221 The position in the present case would have been different had either or both of the 2015 knee injuries been in the nature of sudden injuries potentially attributable to one particular movement. Whilst the 2013 knee injury was of this nature, the 2015 knee injuries were not. It is plain on the evidence and findings at first instance that the 2015 injuries arose from the cumulative effect of the repeated strain placed upon both knees by the regular climbing and crouching movements that Mr Williams was required to undertake in the period from early May 2015 to 18 August 2015. 222 I do not think that a conclusion that the 2015 knee injuries arose from the same trauma required a finding that each and every such movement had some tangible effect upon each knee, or that precisely the same movements on the same occasions were the only events contributing to each injury. Taking a requirement of precision to its logical conclusion, of course there were some differences in the events giving rise to each injury; even if every instance of climbing contributed to both injuries, it could still be said that there was a difference between the events causing each injury because only the steps placing weight on the right knee contributed to the injury to that knee and only the steps placing weight on the left knee contributed to the injury to that knee. This is an illustration of the reason why a more practical and common sense approach may be appropriate, depending upon the evidence, and the nature of the events and injuries in question. -- 50 of 56 -- [2023] SASCA 125 Doyle JA 51 223 It is also relevant to have regard to the manner in which the trial was conducted. Perhaps because Mr Williams initially pitched his case in a different way,125 there was not as much attention as one might otherwise have expected, in both the lay and expert evidence, to the precise mechanism, and series of events, contributing to Mr Williams’ 2015 knee injuries. There was no attempt, through cross-examination of Mr Williams or Dr Pourgiezis, to suggest that one or other of the knee injuries arose in a materially different way, or on a different occasion, from the other. There was no challenge to the relatively general terms in which they described the onset and progression of Mr Williams’ knee injuries. This was not an area of any significant forensic contest at trial. 224 Related to the above, had the case been run differently, with a greater forensic focus upon the issues now sought to be agitated, it may be that more detailed or specific findings as to the series of events from which Mr Williams’ 2015 knee injuries arose could have been made. However, that does not mean that the findings in fact made were not available on the evidence, and sufficient to sustain a conclusion that both injuries arose from the same series of events, and hence the same trauma. In my view, those findings were available, and sufficient for the purpose described. 225 It may be accepted, as Clayton AJ and Cole DP emphasised, that Mr Williams’ symptoms from his two 2015 knee injuries commenced and progressed with slightly differing timing. It would appear that he first experienced pain in his right knee, before then becoming more concerned with his left knee, and then ultimately needing surgery for both knees. However, I do not think that this undermines the basis for Rossi DPJ’s conclusion that both of the 2015 knee injuries arose from the same series of events. It does not stand in the way of a conclusion that, as a matter of common sense and practical reality, both of Mr Williams’ 2015 knee injuries arose out of the series of events constituted by his repeated climbing and crouching movements during the relevant period. Whilst the precise movements on each occasion he attended work may have operated slightly differently upon each of his knees, this is not a case in which it can be said that one of the injuries might have occurred on a particular day, or even during a particular week, with the other injury occurring on a different day, or during a different week. Plainly, on the findings of Rossi DPJ, the climbing and crouching movements during the relevant period operated on an ongoing basis on both knees throughout the relevant period. 226 Bearing in mind the nature of the knee injuries sustained, and the events giving rise to those injuries, I consider that that Rossi DPJ’s factual findings were an appropriate and sufficient basis for his Honour’s conclusion that both of 125 Involving an argument that an alteration in his gait from his right knee contributed to the injury to his left knee. To the extent that this might otherwise have been relevant, it is significant that this case was ultimately abandoned, and there was no finding by Rossi DPJ that altered gait was a relevant cause of the left knee injury. -- 51 of 56 -- [2023] SASCA 125 Doyle JA 52 Mr Williams’ 2015 knee injuries arose from “the same trauma” for the purposes of s 58(6). No greater level of precision or specificity was required. 227 For the reasons given, I consider that the Full Bench erred in the first reason given for overturning Rossi DPJ’s conclusion that Mr Williams’ 2015 knee injuries could be combined under s 58(6). 228 Turning to the second reason that Clayton AJ and Cole DP gave for rejecting combination under s 58(6), as explained earlier, their Honours relied upon Wagenfeller in holding that s 58(6) could not apply to permit the combination of Mr Williams’ 2015 injuries to his right and left knees because the former was partly attributable to his 2013 right knee injury, being an aggravation or acceleration of that earlier injury.126 229 I accept that there will be cases in which multiple injuries cannot be combined by reason of the fact that one of those injuries (but not the others) is an aggravation or acceleration of an earlier injury. But it seems to me that this conclusion must rest upon a finding that the earlier injury was an event (or formed one of a series of events) out of which one of those later injuries arose. Only then will there be an impediment to the requirement of sameness in the traumas giving rise to each of the later injuries. 230 On the evidence and findings before Rossi DPJ, the condition and impairment of Mr Williams’ right knee was relatively stable in the period leading up to his change of work activities in early May 2015. There was no finding to the effect that this pre-existing injury was an event which caused or contributed to the occurrence of the 2015 right knee injury. To the contrary, Rossi DPJ turned his mind to this issue and excluded the pre-existing injury as an event in the series of events from which the 2015 right knee injury arose. 231 It is true that there was a pre-existing level of impairment to Mr Williams’ right knee (as a result of degenerative changes related to, or contributed to by, the 2013 injury to that knee). But this does not mean that it was one of the events giving rise to his 2015 right knee injury. For the same reason, the pre-existing level of impairment to Mr Williams’ left knee (as a result of degenerative changes, unrelated to any particular injury) was not one of the events giving rise to his 2015 left knee injury. 232 Put another way, it may be accepted that there were other events or circumstances (the pre-existing injury to, and degeneration of, Mr Williams’ knees) that contributed to the overall condition, or level of impairment, of his knees following his 2015 injuries. But it does not follow from this that those other events or circumstances causally contributed to the occurrence of the 2015 injuries (for the purposes of s 58(6)) or, indeed, to the impairment from those injuries (for the purposes of s 22(8)(c)) as assessed by Dr Jezukaitis. It is to be recalled in this 126 Return to Work Corporation (SA) v Williams [2022] SAET 34 at [115]. -- 52 of 56 -- [2023] SASCA 125 Doyle JA 53 respect that the right knee impairment sought to be combined under s 22(8)(c) was the impairment referrable to the 2015 injury to that knee, with the earlier injury to that knee having been separately assessed and deducted. 233 For these reasons, I am also satisfied that the Full Bench’s second reason for overturning Rossi DPJ’s decision to combine Mr Williams’ 2015 knee injuries under s 58(6) of the RTW Act was erroneous. 234 I conclude by observing that there is a sense in which both of the reasons given by Clayton AJ and Cole DP for overturning Rossi DPJ’s conclusion in relation to the application of s 58(6) do not properly reflect the findings of fact made by Rossi DPJ, despite the appeal below and in this Court being directed to the proper operation of the combination provision on the facts as found by Rossi DPJ. The majority’s reasoning that only “some aspects” of Mr Williams’ work activities may have caused one or other of his 2015 knee injuries does not properly reflect Rossi DPJ’s findings to the effect that the relevant activities had an ongoing effect on his knees throughout the relevant period. And the majority’s reasoning to the effect that the 2015 right knee injury was “partly attributable to the May 2013 injury”, cannot be reconciled with Rossi DPJ’s rejection of this proposition. 235 The appeal fell to be determined on the basis of the facts as found by Rossi DPJ. On those findings, both 2015 knee injuries were explained by the cumulative effect of the climbing and crouching movements described earlier, and nothing else. Even if it were open to question the evidential basis for these findings, that is not to the point. These findings were made and were properly directed to, and sufficient to satisfy, the test for combination under s 58(6) of the RTW Act. 236 For the reasons set out, I consider that the Full Bench erred in overturning Rossi DPJ’s conclusion that Mr Williams’ 2015 knee injuries were to be combined under s 58(6) of the RTW Act. Combination under s 22(8)(c): impairments arising from the same injury or cause 237 Turning to the ability to combine impairments under s 22(8)(c) of the RTW Act, I commence by addressing the first alternative contention relied upon by the Corporation; namely, that Preedy and Summerfield do not, in terms, apply to the Williams matter because those decisions were concerned with a particular and limited species of consequential injuries, and the Williams matter does not involve consequential injuries. 238 I accept that the Williams matter does not involve consequential injuries and hence that Preedy and Summerfield do not, in terms, apply to the Williams matter. However, I do not accept that the combination of impairments under s 22(8)(c) is confined to such cases. 239 This might have been the case had combination under s 22(8)(c) been confined to impairments arising from the same injury. But it is not confined in this -- 53 of 56 -- [2023] SASCA 125 Doyle JA 54 way; it extends to the combination of impairments arising from the same cause. Accepting, as I explained earlier, that “cause” is a broader concept than “injury”, s 22(8)(c) must be understood as extending to the combination of impairments from multiple injuries which may not be linked other than by reason that they both arose out of the same incident or event. I refer in this respect to my earlier example of a worker who is hit by a falling object and suffers injuries to his arm and leg. As the impairments from both injuries arise from the same cause (the work accident involving the falling object), they may be combined under s 22(8)(c), despite them relating to simultaneous injuries rather than sequential or consequential injuries. 240 Accepting this to be so, the issue that remains in respect of the operation of s 22(8)(c) in the Williams matter is whether the facts as found by Rossi DPJ were sufficient to sustain his conclusion that Mr Williams’ 2015 knee injuries were from the same cause, in the sense of sharing the same causal explanation. This requires consideration of the level of specificity required to support a conclusion that two impairments are from the same cause; and whether the fact that one of the impairments is an aggravation or acceleration of an earlier injury necessarily stands in the way of such a conclusion. 241 It can thus be seen that, in the context of the Williams matter, similar issues arise in applying s 22(8)(c) to those that have been addressed in the context of applying s 58(6). Indeed, the reasons given by the majority of the Full Bench for overturning the conclusion of Rossi DPJ that the impairments to Mr Williams’ right and left knees could be combined under s 22(8)(c) were essentially the same as the first reason they gave for overturning the primary judge’s equivalent conclusion in relation to the combination of those injuries under s 58(6). In short, their reasons were that Rossi DPJ’s finding that both injuries, and hence both impairments, arose out of “the same work activity over the same period” was simply too general or abstract to permit a conclusion that those injuries arose out the same cause. 242 For essentially the reasons I have already given in the context of my consideration of the application of s 58(6), I consider that the majority of the Full Bench erred in reasoning this way. Bearing in mind the nature of the evaluative task required by a consideration of whether two impairments can be said to have arisen “from the same injury or cause” under s 22(8)(c), I do not think that it required the degree of precision or specificity contemplated by the reasoning of the majority of the Full Bench. I am satisfied that it can be said, on the findings of Rossi DPJ, that the impairments from each of Mr Williams’ 2015 knee injuries arose from the same cause (being his work activity in undertaking regular climbing and crouching movements between early May 2015 and 18 August 2015). To the extent that there were any differences, or additional events, in the causal explanations for the two injuries, they were not such as to prevent a conclusion that they arose from the same cause for the purposes of s 22(8)(c). -- 54 of 56 -- [2023] SASCA 125 Doyle JA 55 243 I am also satisfied that the Full Bench’s reasoning in Wagenfeller does not stand in the way of this conclusion. Indeed, even if, contrary to my earlier conclusion, Mr Williams’ 2013 right knee injury can be said to have been a causally relevant event in the occurrence of his 2015 right knee injury, I do not think this prevented a conclusion that both 2015 knee injuries were nevertheless from “the same cause” (being the work activities described above) for the purposes of s 22(8)(c). 244 For the reasons set out, I am persuaded that the majority of the Full Bench erred in overturning Rossi DPJ’s conclusion that his 2015 knee impairments were to be combined under s 22(8)(c) of the RTW Act. Inadequacy of reasons 245 The third of the Corporation’s alternative contentions involves a challenge to the adequacy of Rossi DPJ’s reasons for concluding that the only cause of each of Mr Williams’ 2015 knee injuries was the same work activity over the same period. The Corporation contends that his Honour’s reasons were inadequate because there must be an identification of the event, or series of events, before there can be a conclusion that both injuries arose from the same trauma under s 58(6), and there was no such finding here. 246 As counsel for the Corporation acknowledged in oral submissions, this contention does not advance the matter beyond the challenges otherwise made to the generality of Rossi DPJ’s findings. Having rejected the Corporation’s argument that Rossi DPJ’s conclusion that both injuries arose from the same trauma required more specific findings, there is no merit in the related complaint that his Honour’s reasons are inadequate for not making such findings. Assuming the correctness of my view as to what was required to sustain combination of Mr Williams’ injuries under s 58(6), Rossi DPJ’s reasoning and findings in support of that conclusion were adequate. Conclusion and orders 247 In the English matter, the question reserved is as follows: The question of law referred to this Court requires determination of whether, on the facts found by the primary judge (Crawley DPJ), s 22(8)(c) applies to require or permit the impairments to Mr English’s neck and to his right quadriceps to be combined and assessed together in determining his WPI. 248 I would answer that question “Yes”. 249 In the Williams matter, I would allow the appeal, set aside the orders made by the Full Bench on 18 March 2022, and restore the orders made by Rossi DPJ on 24 September 2020 (permitting the combination of his right and left knee impairments). -- 55 of 56 -- [2023] SASCA 125 Bleby JA 56 250 BLEBY JA: I gratefully adopt Doyle JA’s account of the factual circumstances of these matters and his Honour’s analysis of the authorities. 251 On the construction of s 22(8)(c) of the Return to Work Act 2014 (SA), I respectfully agree with and adopt the analysis of Doyle JA. In doing so, I only need to make a few observations. I take the observations of Stanley J in Summerfield127 as providing, for present purposes, a descriptive baseline of the causal test provided for by s 22(8)(c). Working from that starting point, I respectfully do not think that the precepts of statutory interpretation require that, in order for an impairment to be characterised as being from the same cause as another, it must be linked aetiologically to that same cause. 252 First, I agree with Doyle JA that the word ‘cause’ is inherently broader than this, as is the word ‘from’. I do not think that the phrase ‘injury or cause’ necessarily requires that ‘cause’ be read more narrowly in order to avoid ‘injury’ being rendered surplusage. To narrow the meaning of ‘cause’ so as not to overlap with ‘injury’, to the point where it is limited to causes that are the physiological origin and source of both impairments, would be a considerable strain. 253 That is not the end of the matter, of course. I note the emphasis that Kourakis CJ has placed on the policy rationales for not allowing the combination of all work-related impairments. It seems to me that these rationales are still met by the facility of allowing an evaluative judgment as described by Doyle JA. However, to stipulate the limit preferred by Kourakis CJ would, I think, press heavily against the legislative purpose of providing a reasonable balance between the interests of workers and employers.128 254 I would instead read the phrase as requiring, in Doyle JA’s words, an evaluative assessment of the causal explanations, and the differences between those explanations, having regard to any additional events or integers. To limit this, for example, to the same workplace activity together with its aftermath, in my view begs the question. If the aftermath includes the rescue and first aid response, it can be asked rhetorically why it would not then include an impairment consequent on the prescribed pain management response to the injury? Here, I think, both context and purpose require that the attractions of predictive clarity that would accompany the reading preferred by Kourakis CJ should give way to the fairness of an evaluative judgment of the sameness of the causal explanations. 255 It follows that for the reasons given by Doyle JA, I would join in the orders proposed by his Honour. 127 Return to Work Corporation of South Australia v Summerfield (2021) 138 SASR 175 at [20]-[21]. 128 Return to Work Act 2014 (SA), s 3(2)(c); see Return to Work Corporation of South Australia v Summerfield (2021) 138 SASR 175 at [24]. -- 56 of 56 --