1. It is undisputed the applicant suffered workplace injury to his left and right knees that were treated with arthroscopic surgery that was accepted as reasonably necessary.
2. The issue identified by the parties that requires determination is whether the effect of the applicant's injuries continued after arthroscopic surgery and made a material contribution to the need for the later replacement surgeries of the left and right knees.

1. The following documents were in evidence before the Commission at the arbitration hearing, without objection, and considered in making this determination:

(a) ARD and attached documents of 229 pages;

(b) Reply and attached documents of 168 pages (Reply), and

(c) Application to Lodge Additional Documents made by the applicant on

9 September 2025 with attached documents of 63 pages (ALAD-A).

1. There was no application to call oral evidence or cross-examine any witness at the hearing.

1. The applicant provided statement evidence in relation to the dispute dated 18 December 2024 and 29 August 2025. He commenced as a plant operator with the respondent on

18 April 2004. Injuries to his left knee, on 27 November 2014, and his right on, 28 May 2015, occurred and he then underwent arthroscopic medial meniscectomy surgery for those on

27 April 2015 and 9 November 2015 respectively. Dr Johan Le Roux was the orthopaedic surgeon who conducted the procedures. In relation to the left knee, the applicant said his:[1]

"... injury did improve post-surgery, however, I continued to have ongoing difficulties with squatting and walking for prolonged periods of time. I was able to continue working, and manage the pain with medication."

1. He was "able to return to pre-injury duties" after the right knee surgery but "continued to experience problems with both ... knees" where there was said to be "ongoing and increasing pain" and, despite that, he continued to work. The applicant said he "... was walking awkwardly due to the pain, and began to develop stiffness in [his] right hip and the lower part of [his] right leg".[2] He "felt unstable and like [he] might slip and fall at any point" and "did have a fall in 2021 as a result of instability in both knees".[3]
2. According to his statement:[4]

"21. By mid-2022, the pain became so bad that I returned back to the care of my General Practitioner and got another referral to Dr Le Roux.

22. In particular, I complained of ongoing problems with both knees, particularly with the left knee, with pain down the left ankle.

23. I had a further fall on 27 July 2022 as a result of instability in both knees, which caused pain into my right hip and my right ankle."

1. The applicant then underwent knee replacement surgery (arthroplasty), performed by Dr Le Roux, on 5 June 2023 for the left and then the right on 19 August 2024. He was apparently unable to "wait for the insurance company to overturn their denial" given he was "in so much pain" wanting to "continue working and return to some sort of normalcy in life".[5] The applicant was absent from work for around three months following each operation when he received physiotherapy with "strengthening and conditioning" programs. He considered there was a "favourable outcome" from each surgery and a reduction in pain. Various examples of daily living were given by the applicant (including squatting and walking down hills) about how, despite some persisting "minor aches and pains", he has a "lot more freedom in [his] movement" and feels "more confident" after the arthroplasties.[6] The applicant acknowledged the existence of arthritis in both knees prior to the workplace injuries in 2014 and 2015, and that he had experienced "very minor aches and pains" prior to those years,[7] but there had been no "significant problems with [his] knees prior to those two incidents".[8]

1. The applicant received specialist treatment at all relevant times from Dr Johan Le Roux, orthopaedic surgeon, who performed the arthroscopic medial meniscectomies and later arthroplasties.
2. At the time of a consultation with the applicant on 16 October 2015 regarding his right knee injury, Dr Le Roux recorded there having not been "much relief" from the left knee injury, which by that time was six months after the arthroscopic surgery.[9] It was reported following a post-operative consultation for the right knee on 20 November 2015 that there was "very little pain at all" and his knee was "moving freely", which the applicant felt was "much better than the previous arthroscopy" for the left knee.[10] On 8 January 2016 Dr Le Roux further reported on the applicant's right knee which was said to be "a bit sensitive over his medial port site when he is walking" but otherwise he was "feeling quite well" and pain medication was not required with a return to work due the following week.[11]
3. The applicant next consulted Dr Le Roux on 6 July 2022 when he was reported to be "struggling with both knees, but especially his left" which was "giving him a lot of pain and discomfort". He was having "trouble with day-to-day activities" and "trouble sleeping at night". The specialist identified the applicant with bilateral varus knees (bowing outwards), effusion in both knees with tenderness over the medial joint lines and "significant pain down into his left ankle" that the applicant thought was due to the way he was walking.[12] Arthroplasty surgery was identified as appropriate by Dr Le Roux.
4. In a report to the respondent's insurer dated 20 October 2022 (which was apparently in response to a letter seeking further information following a request for surgery submitted around 6 July 2022 after the consultation on that date), Dr Le Roux explained that he did not know whether the applicant would have required arthroplasty surgery at "some time in his life had he not sustained his accepted injury". The (at that time) proposed joint replacement surgery was for "pain management" and that it was hoped the applicant's "discomfort with activities of daily living and working would be alleviated".[13] Dr Le Roux considered the applicant would be "unfit for his usual duties for the first twelve weeks following surgery" and there would then be a "graded return to work based on his recovery and rehabilitation milestones".[14]
5. A left knee arthroplasty was performed on the applicant on 5 June 2023 by Dr Le Roux,[15] and on 7 December 2023 he was reported to be "doing very well" and "quite happy" albeit with "a bit of swelling on occasion".[16] The left knee was also reported to be "doing well" on

20 June 2024.[17] 6. Dr Le Roux conducted right knee replacement surgery on 19 August 2024[18] and the applicant was said to be "doing well" by the time of a 19 September 2024 post-operative consultation when pain was "under control" and there was "no obvious excessive swelling".[19]

1. The applicant qualified Associate Professor Leon Kleinman, orthopaedic surgeon, to conduct an independent medical examination. In his 11 October 2023 report, Associate Professor Kleinman considered the original workplace injuries aggravated and accelerated underlying osteoarthritis but despite the treatment by way of arthroscopic medial meniscectomies, both knees "continued to deteriorate".[20] The applicant "did not recover in full from the events on the 27 November 2014 and 28 May 2015" and he had "ongoing, increasing pain in his knees following the incidents" according to Associate Professor Kleinman.[21] He opined that the aggravation and acceleration of the applicant's underlying osteoarthritis caused by the workplace injuries resulted in continued and increasing pain in his knees.[22]
2. It was Associate Professor Kleinman's assessment that the applicant's established osteoarthritis:[23]

"... would have ultimately come to bilateral knee replacement surgery but the falls at work accelerated the rate of deterioration of the pre-existing osteoarthritis in his knees and as a result the need for knee replacement surgery has arisen earlier than otherwise would have been expected.

... I note that there is no mention of any knee problems contained in the clinical notes prior to the falls. Therefore the falls at work caused the need for the knee replacement surgery to arise earlier than expected."

1. The respondent qualified Associate Professor Paul Miniter, orthopaedic surgeon, to conduct an independent medical examination of the applicant. In his report of 26 September 2022 following a consultation, Associate Professor Miniter, commenting on the applicant's left knee condition for which arthroplasty surgery was at the time proposed, considered that it was "a more than reasonable way of handling the situation". It was "also reasonable to consider bilateral total knee replacement",[24] and he commented:[25]

"The available evidence would suggest that, at presentation, [the applicant] had osteoarthritic disease and one would be constructively critical of arthroscopy in the situation such as that. It is most unlikely that it would be beneficial and this has proven to be the case.

The current situation is simply progression of the original presentation. I do not relate this specifically to the nature of his work. As a plant mechanic, one would not expect him to be particularly associated with knee degenerative change."

1. Associate Professor "could see no evidence of injury" and considered the applicant "simply has osteoarthritic disease" that affected both knees.[26] He accepted total knee replacement surgery would be appropriate and a return-to-work period of "6-8 weeks after ... surgical treatment" would be required.[27]
2. In his next report of 19 December 2022, Associate Professor Miniter believed the applicant "would have required total knee replacement at or around the same time in his life" even had he not been working for the respondent,[28] although he did not explain the basis for that opinion where the applicant had no recorded history of knee problems other than the workplace injuries. It was that specialist's view the applicant had no "work-related injury of significance" but accepted there may have been an aggravating "twisting episode of the left" side that was "not likely to have altered the natural history of the matter". He believed that if there was an injury "it has long since resolved" with explanation of his reasoning.[29]
3. A further report was prepared by Associate Professor Miniter on 10 March 2025, following a consultation some weeks earlier, wherein he cited the applicant with "osteoarthritic disease of both knees".[30] He reiterated his view that the applicant's bilateral knee condition was unrelated to work and expressed a belief the arthroscopic surgeries did not materially contribute to the need for the applicant to have knee replacement surgery. The applicant told Associate Professor Miniter that he was "happy with the outcome" of the knee replacement surgeries and did not "have any significant ongoing knee pain".[31]
4. In commenting on the reporting of Associate Professor Kleinman regarding the applicant being asymptomatic prior to the 2014 and 2015 injuries, Associate Professor Miniter did "not believe that this is correct for the reasons" said to have been given earlier in the report. There was however no consideration of that issue in the report, that is, he did not engage in any detail with the applicant being asymptomatic prior to workplace injury, and there being no prior reporting by the applicant of having knee problems. That relevant matter, raised and addressed by Associate Professor Kleinman, was arbitrarily dismissed without explanation.

1. The clinical records evidence discloses the applicant attended a consultation with Dr David Healey, general practitioner (GP), on 3 January 2017 when problems with his right knee were reported.[32] Dr Healey referred the applicant to Dr Le Roux for specialist attention following that consultation.[33] The applicant later consulted Dr Furat Jajo, GP, on 17 June 2022 for bilateral knee pain that was "worse with walking" where there had been no "recent trauma". A referral was made to Dr Le Roux.[34]

1. It is undisputed the applicant injured his knees at work during 2014 and 2015. He underwent arthroscopic medial meniscectomy surgery for each knee. The respondent contends the effects of the injuries resolved thereafter and that the need for the later arthroplasty surgeries was attributable to the applicant's degenerative osteoarthritis condition. Once the applicant recovered after arthroscopic surgery, the respondent contends it was not thereafter liable for the degenerative change. That is the best explanation for the requirement for surgery according to the respondent, which is demonstrated by the intervening period of several years when the applicant was able to work and function.
2. Although there may have been degenerative factors present, the applicant argues the effect of the workplace injuries persisted and materially contributed to his need for knee replacement surgery.
3. Section 60 of the Workers Compensation Act 1987 (the 1987 Act) provides for the reasonably necessary treatment of workplace injury. The applicant has the onus to establish, on the balance of probabilities, the provision of the knee replacement surgery was reasonably necessary as a result of workplace injury. I must have a "a sense of actual persuasion" that the reasonable necessity exists and that it results from the injury as claimed: Nguyen v Cosmopolitan Homes Pty Ltd [2008] NSWCA 246 and Yucel v AAES Pty Ltd t/as Roadtrack [2015] NSWWCCPD 51. There is no dispute the applicant required that surgery and that it was reasonably necessary. The issue to be resolved relates to the nexus with the workplace injuries.
4. Citing various authority, in Murphy v Allity Management Services Pty Ltd [2015] NSWWCCPD 49 (Murphy), Roche DP identified that in order to satisfy the test of causation implied by the expression "result of", it is not necessary to establish the work injury was the only, or even a substantial, contributing factor to the need for medical treatment. It is sufficient to establish only that the injury "materially contributed".
5. A commonsense examination of the causal chain is required to determine whether the need for the claimed treatment arises as a result of the work-related injury: Kooragang Cement Pty Ltd v Bates (Kooragang).[35]
6. The independent medical examiner evidence is not significantly divergent on most matters, the fundamental difference is on the issue of whether the arthroplasty surgeries are attributable to degenerative osteoarthritis alone or whether an aggravation and acceleration brought on by workplace injury continued. Associate Professor Miniter considers that workplace injury played no part. Associate Professor Kleinman's opinion was of injury and aggravation to osteoarthritis that never resolved and worsened over time.
7. Although Associate Professor Miniter accepts the knee replacement surgery as reasonable treatment for applicant's condition, he insists there was no workplace injury or connection to the requirement for the surgery. This is despite the injuries and subsequent arthroscopic surgeries being accepted by the respondent as have been work-related. Associate Professor Miniter considers that degenerative osteoarthritis is the cause of the applicant's problems and the need for surgery. He does not however provide an explanation for that condition being asymptomatic until the applicant was injured in circumstances where there had been no history of any knee problems reported prior to the injuries at work.
8. Associate Professor Miniter attributes any worsening in the applicant's condition to the degenerative nature of osteoarthritis, but without engaging with how that may have been affected by the injuries received by the applicant at work, as has been accepted by the respondent. There is also no consideration of why knee replacement surgery is a reasonably necessary treatment for the applicant's degenerative osteoarthritis but not where that condition may have been aggravated or accelerated by workplace injury (which he rejects as a proposition, again contrary to it being accepted by the respondent). He did though identify that arthroscopic medial meniscectomy was unlikely to be successful, which was evidently correct, and considered those procedures would not have contributed to the need for total knee replacement surgery.
9. Associated Professor Kleinman accepted the applicant's osteoarthritis was a relevant factor, he considered the knee replacement surgery was necessary, at the time it was proposed, to treat the ongoing issues associated with workplace injury. It was his view, consistent with that expressed by Associate Professor Miniter, that those were not resolved by arthroscopies. Associate Professor Kleinman considered the applicant never recovered from the workplace injuries and the effects from them continued to worsen over time. He accepted the applicant would have at some stage required knee replacement surgery due to osteoarthritis, but that the injuries accelerated the condition, thereby bringing forward the need for the surgery. It was therefore attributable to the injuries causing aggravation and acceleration rather than the natural degenerative process alone.
10. On that basis, the injuries can only have made a material contribution factor to the applicant's need for surgery at the time it arose. That is, other than for the workplace injuries, the knee replacement surgeries would not have been required as early in the applicant's life as they otherwise would have been. I accept Associate Professor Kleinman's opinion as the most cogent and likely on the undisputed history, it is preferred to that of Associate Professor Miniter in circumstances where the latter did not engage with several key issues relevant for consideration.
11. The applicant's evidence is that although he returned to work after arthroscopic surgeries, he did so with ongoing and worsening pain. He concedes there was some improvement after the arthroscopies but that did not last. It apparently reached a point during 2022 that he was no longer able to continue without intervention.
12. The respondent submitted the lengthy period where the applicant did not seek any treatment between 2015 and 2022 is indicative of the workplace injury resolving and degenerative factors then being responsible for deterioration. There was however at least one occasion when the applicant attended his GP for medical assistance, on 3 January 2017 regarding his right knee, when a referral back to Dr Le Roux was made. It is unclear what then transpired because there is no evidence of consultation with that specialist at the time.
13. In any case, that the applicant may not have otherwise attended for medical treatment between those years is not evidence that he did not have relevant symptoms and experience pain. The effect of his evidence is that he managed and tolerated the problems, that included "walking awkwardly" and feeling instability to the extent he thought he may fall (and ultimately did), for as long as he could before it became necessary to seek further medical intervention.
14. The post operative reporting of Dr Le Roux following the arthroscopies is generally consistent with the applicant's ongoing problem, especially with respect to the left knee. Although Dr Le Roux considered the applicant was sufficiently recovered to return to work following the two arthroscopies, his reports fall short of being evidence the applicant ever fully recovered from the workplace injuries after having those procedures.
15. The respondent referred to the decision of Parker DP in Palasty v Lendlease Building Pty Limited[36] regarding the absence of an alternative explanation not proving that causation must therefore lie with employment:[37]

"The point is not whether there was evidence of an alternative cause. The point is did the appellant prove that the employment was a material contributing factor to this aggravation?..."

1. It provides useful guidance and is relevant to follow. Although there is no onus for it to do so, the respondent has provided an alternative possible cause for the requirement for surgery, the applicant's underlying osteoarthritis condition. That condition is undisputedly relevant, but so too is the aggravation or acceleration of that condition caused by the workplace injury that Associate Professor Kleinman identified as the reason for the persisting and worsening symptoms experienced by the applicant. He provided a coherent explanation of contribution while Associate Professor Miniter failed to engage fully with pertinent considerations.
2. The relevant inquiry is whether the effect of the applicant's workplace injury continued after arthroscopy. He was asymptomatic prior to the injuries but his unchallenged evidence is thereafter that it never abated prior to the knee replacement surgeries. Associate Professor Kleinman considered it was the workplace injuries that set into motion the sequence of events, the aggravation and acceleration of the applicant's underlying arthritis that was caused by those injuries, he then experienced symptoms including pain that nonetheless continued after the arthroscopies. It was the injuries that were the reason for the ongoing pain and the ultimate requirement for knee replacement surgery earlier than would otherwise have been required for osteoarthritis alone. The causal chain was not broken by the arthroscopies as the applicant did not fully recover after those were performed. The applicant's evidence is unambiguous, his symptoms, pain and restrictions did not cease and continued after the arthroscopies. In those circumstances, the workplace injuries did make a material contribution to the need for the applicant to undergo the knee replacement surgeries.
3. I am reasonably satisfied that the applicant's employment has materially contributed to the need for surgery: Murphy. It is undisputed the bilateral knee replacement surgery was reasonably necessary. The evidence establishes the applicant's workplace injuries did not fully resolve after the arthroscopic procedures undertaken during 2015. His problems persisted and worsened over time. There was undoubtedly underlying a degenerative osteoarthritis condition, however that was aggravated and accelerated by the workplace injuries where that aggravation and acceleration did not resolve. This is confirmed by the applicant's evidence along with the findings and opinion of Associate Professor Kleinman.
4. Accordingly, the respondent is liable for the reasonable, and related, costs of the bilateral total knee replacement surgeries performed on the applicant on 5 June 2023 and

19 August 2024. He is also entitled to weekly compensation associated with the period of recovery from that surgery due to incapacity. The periods claimed by the applicant from

5 June 2023 to 8 September 2023 and then from 19 August 2024 to 4 November 2024 are consistent with the recovery and rehabilitation periods identified by Dr Le Roux. It is accepted the applicant was incapacitated for work during those periods for the purposes of s 33 of the 1987 Act. I note also that Associate Professor Miniter considered a recovery period would be required following surgery.

1. It is undisputed the applicant injured his knees at work and received treatment by way of arthroscopic medial meniscectomies during 2015. Despite that surgical treatment, the applicant's symptoms and pain from the injuries persisted and worsened over time. He later underwent total knee replacement surgeries during 2023 and 2024. The need for those was due to a material contribution made by the workplace injuries. The respondent is liable to compensate the applicant for the cost of the knee replacement surgery and for the time spent away from work recuperating.

[35] Kooragang Cement Pty Ltd v Bates (1994) 10 NSW CCR 796.

[36] [2021] NSWPICPD 19.