1. On 4 February 2025 Raymond Jeffrey Byrne, the appellant lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Dr Rob Kuru, a Medical Assessor, who issued a Medical Assessment Certificate (MAC) on 7 January 2025.
2. The appellant relies on the following grounds of appeal under s 327(3) of the Workplace Injury Management and Workers Compensation Act 1998 (the 1998 Act):
   • the assessment was made on the basis of incorrect criteria, and
   • the MAC contains a demonstrable error.
3. The delegate is satisfied that, on the face of the application, at least one ground of appeal has been made out. The Appeal Panel has conducted a review of the original medical assessment but limited to the ground(s) of appeal on which the appeal is made.
4. Rule 128 of the Personal Injury Commission Rules 2021 (the PIC Rules) and Procedural Direction PIC7 - Appeals, reviews, reconsiderations and correction of obvious errors in medical disputes set out the practice and procedure in relation to the medical appeal process under s 328 of the 1998 Act. An Appeal Panel determines its own procedures in accordance with r 128(1) of the PIC Rules.
5. The assessment of permanent impairment is conducted in accordance with the SIRA NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4th ed

1 March 2021 (the Guides) and the American Medical Association Guides to the Evaluation of Permanent Impairment, 5th ed (AMA 5). "WPI" is reference to whole person impairment.

1. On 22 October 2024 this matter was referred to the Medical Assessor for an assessment of WPI caused by injury to the "left lower extremity, right lower extremity" on 3 June 2024.
2. The Medical Assessor noted that Mr Byrne attributed his problems in both knees to the nature and conditions of his employment as a Stevedore. He noted that there had been an arthroscopy in 2008 in the right knee and a further arthroscopy on the left knee in about 2010.
3. He noted that over the years the pain deteriorated and that Mr Byrne progressively was limping.
4. Mr Byrne came to bilateral knee replacements on 10 August 2023.
5. The Medical Assessor assessed 15% WPI as a baseline impairment for each knee but then deducted one half in relation to each knee leaving an entitlement of 8% for each knee giving a combined table value of 15%.

1. The Appeal Panel conducted a preliminary review of the original medical assessment in the absence of the parties and in accordance with the Procedural Direction PIC7.
2. As a result of that preliminary review, the Appeal Panel determined that it was not necessary for the worker to undergo a further medical examination because the appeal was concerned with whether the evidence before the Medical Assessor regarding Mr Byrne's pre-existing degenerative condition had been properly considered. A re-examination would not have assisted the Panel in that regard.

1. The Appeal Panel has before it all the documents that were sent to the Medical Assessor for the original medical assessment and has taken them into account in making this determination.

1. The parts of the medical certificate given by the Medical Assessor that are relevant to the appeal are set out, where relevant, in the body of this decision.

1. Both parties made written submissions which have been considered by the Appeal Panel.

1. The procedures on appeal are contained in s 328 of the 1998 Act. The appeal is to be by way of review of the original medical assessment but the review is limited to the grounds of appeal on which the appeal is made.
2. In Campbelltown City Council v Vegan [2006] NSWCA 284 the Court of Appeal held that the Appeal Panel is obliged to give reasons. Where there are disputes of fact it may be necessary to refer to evidence or other material on which findings are based, but the extent to which this is necessary will vary from case to case. Where more than one conclusion is open, it will be necessary to explain why one conclusion is preferred. On the other hand, the reasons need not be extensive or provide a detailed explanation of the criteria applied by the medical professionals in reaching a professional judgement.

1. At [4] of the MAC, the Medical Assessor noted that "Mr Byrne told me he had had an arthroscopy on one of his knees in 1990."
2. At [6], the Medical Assessor recorded that "I was able to review no imaging related to the injury today."
3. The Medical Assessor's summary at [7] was:

"Mr Byrne developed osteoarthritis in both of his knees and has subsequently undergone knee replacements. He has had a good result from his knee replacements. He attributes the arthritis in his knees to the nature and conditions of his employment."

1. In response to the templated title "The facts on which the assessment is based" at [9], the Medical Assessor said:

"A thorough history, a comprehensive physical examination, a review of the documentation made available by the Personal Injury Commission with reference to the SIRA Guidelines (2021) and AMA-5."

1. At [10c] the Medical Assessor noted his agreement with the baseline assessment found by both medico-legal experts of 15% WPI, and noted further the difference in the deductions made, Dr Millons making a 1/10th deduction and Dr Miniter a deduction of 50% "for pre-existing condition".
2. The Medical Assessor said at [11] that Mr Byrne suffered from pre-existing conditions of:

"Knee replacements were required to treat a constitutional condition rather than a work-related injury. In the absence of the constitutional injury, knee replacement surgery would not have been required and impairment would not be assessable.

Whilst the extent of the deduction is difficult or costly to determine the available evidence is that the deductible proportion is large and a deduction of one tenth is at odds with the available evidence. In my opinion the deductible proportion is one half for the following reasons.

As stated above, in the absence of the pre-existing constitutional condition, it is unlikely that any impairment would have been assessable subsequent to injury at

1. The error alleged by Mr Byrne was that the Medical Assessor had erred in law in assessing one half deduction for his assessment regarding each knee.
2. Mr Byrne submitted that the Medical Assessor did not explain how an underlying condition in his right knee had actually contributed to his current condition and degree of impairment.
3. Mr Byrne noted that the Medical Assessor purported to justify the definition on the basis that Mr Byrne had pre-existing osteoarthritis in his knees, that the pre-existing osteoarthritis was a constitutional condition and that if "the constitutional injury" had not occurred, no impairment would have been assessable.
4. Further error was alleged in the failure by the Medical Assessor to identify why it was that he found that the evidence was at odds with the statutory deduction of 1/10th.
5. Mr Byrne then turned to specific grounds.

Ground 1: Failing to properly refer to and accurately account for the extensive history of work-related injury to the appellant's knees, and the post-traumatic contribution of workplace injuries to the appellant's osteoarthritis

1. Mr Byrne submitted that the history of work related injuries sustained by him were ignored.
2. The Medical Assessor, whilst recording the history in terms of Mr Byrne "attributing problems" to his work duties, did not acknowledge what work Mr Byrne was referring to. The expression "attributes", Mr Byrne said, diminished the fact that his employment had contributed to the condition of his knees. It also failed to acknowledge that there was no dispute that the injury being assessed was an aggravation, acceleration, exacerbation or deterioration of the disease process.

Ground 2: Failing to conduct a proper enquiry into the pre-existing condition of each of the appellant's knees, to distinguish between the history pertaining to each knee, and to acknowledge the work-related circumstances prompting the surgery performed to the right knee in 2008 and the left knee in 2010

1. It was apparent, Mr Byrne submitted, that the Medical Assessor had attributed the effect of the osteoarthritis equally, as he had made a one half deduction in respect of each knee.
2. Mr Byrne referred to the evidence before the Medical Assessor regarding an arthroscopy to his knee in 1990, prior to his employment with the respondent in 1998. However, Mr Byrne said, the prior surgery had only been to the right knee (although erroneously referred to by Dr Sorrenti at one point as the "left" knee). There had been no treatment prior to

Mr Byrne's employment to his left knee. 3. Mr Byrne said that there had been no further issue with his right knee until 5 September 2008, some 18 years later. At that time he had been a stevedore for 10 years. A perusal of the records showed that there had been nine references to work related injuries to the right knee prior to the injury on 30 June 2008. 4. Mr Byrne observed that his expert Dr Dixon had found that Mr Byrne suffered a frank injury on 30 June 2008, and that his right knee had been "only mildly uncomfortable prior to this". Since that time he had suffered significant pain, Dr Dixon had said. Dr Dixon's summary of the investigations at that time found Grade III condyle damage on the medial femoral condyle, and other pathology. 5. Mr Byrne submitted that the twisting injury of 30 June 2008 changed the status of his right knee from being "mildly uncomfortable" to causing him significant pain which led to the surgery in September 2008. 6. In 2008, Mr Byrne submitted that the Medical Assessor, whilst noting the arthroscopy in 2008, failed to note the succession of work-related right knee injuries prior to the frank injury. Whereas the Medical Assessor referred to significant degenerative disease, he failed to consider whether the degeneration had been caused by strain to his knees when working as a stevedore since 1998. 7. Mr Byrne referred to the "multitude" of right knee injuries recorded in the First Aid Employee Record and in his chronology in that regard. 8. Mr Byrne noted that the first complaint regarding his left knee was on 21 June 2010 and reference was again made to Mr Byrne's chronology of knee injuries in 2009 and 2010 (this is at CC70 in his statement at [19]). 9. Mr Byrne submitted that the Medical Assessor had not acknowledged that his left knee arthroscopy had been performed following work related injuries to his left knee. He said, "The reader would not, on reviewing the limited history provided by the Medical Assessor, appreciate the causal significance of repeated work-related trauma to the left knee". 10. After referring to the 2010 arthroscopy, Mr Byrne said, the Medical Assessor failed to acknowledge that over the next 12 years there were a multitude of injuries to both knees in the course of his duties as a stevedore for the staff. 11. The history taken that "over the years his pain deteriorated and he progressively was limping" was said to be "astonishingly limited". 12. Mr Byrne again referred to many of the work-related injuries and aggravations as were set out in his chronology. 13. Mr Byrne submitted that the Medical Assessor had failed to discharge his statutory responsibility by ignoring that evidence. He had proceeded therefore on the basis of an assumption that there was significant pre-existing arthritis affecting both knees, and he did so without reviewing the evidence of the condition of Mr Byrne's knees prior to the commencement of his employment. 14. He submitted that there was an obvious difference between the history of the right knee, which had been the subject of surgery prior to commencement of his employment, and the left knee which had no such treatment. 15. Mr Byrne submitted that the MAC conveyed an impression that the surgery was merely to address degeneration and was unrelated to Mr Byrne's duties. That impression, he said, was misconceived and at odds with the unchallenged evidence of a multitude of work- related stressors. 16. Mr Byrne referred to the report of Dr Millons, who noted Mr Byrne's chronology and recorded that there were about 30 reports of injuries to the right knee and 40 reports of injuries to the left knee from 2000 through to 2022. 17. Mr Byrne submitted that the Medical Assessor did not acknowledge any injury to either of the knees on any of the dates recorded in the chronology and in the First Aid Employee Record. 18. Thus the history on which the Medical Assessor based his assessment was "demonstrably deficient and unreliable".

1. Mr Byrne made a number of further submissions related to alleged errors made by the Medical Assessor. It is convenient to refer to the headings under which these submissions were made as there is no utility in repeating them in detail in view of our determination below. Mr Byrne submitted that the Medical Assessor made further errors under the following headings:

Ground 3: Failing to acknowledge and address the opinion of the appellant's treating surgeon Dr Solomon, dated 19 December 2022

1. Mr Byrne referred to authority regarding the obligation by a decision-maker to consider all the evidence.[1]

Ground 4: Misdirecting himself by asserting that the knee replacements were required to treat a constitutional condition rather than a work-related injury

1. Mr Byrne addressed further on the facts, arguing that the Medical Assessor fell into error in this regard.

Ground 5: Misdirecting himself by asserting that "[i]n the absence of the constitutional injury", i.e. the pre-existing condition, the appellant would not have required surgery, and would not have had any work-related impairment

1. Similarly, Mr Byrne argued that this conclusion was at odds with the evidence before the Medical Assessor.

Ground 6: Making an arbitrary deduction of 50% pursuant to section 323 of the 1998 Act, without establishing any objective basis for that proportion

1. Again, Mr Byrne argued that this assessment of the s 323 contribution was erroneous and based on assumption rather than the evidence before him. Mr Byrne referred to authority regarding the application of s 323.[2]
2. Mr Byrne concluded with an appeal that a correct assessment be made by the Panel as to whether a s 323 deduction should be made, and if so, the basis and extent thereof.

1. The response by the employer was that the Medical Assessor was not required to outline an extensive summary of the history on the evidence before him. There were approximately 200 pages of material and it would not have been reasonable to expect him to demonstrate his engagement with each and every piece of evidence. It could be assumed, the respondent said, that the Medical Assessor had reviewed and considered all the evidence before him. Thus his failure to outline an extensive history of the work-related injury did not amount to a demonstrable error, it was argued.
2. We were referred to authority that a pre-existing asymptomatic condition could be the subject of a deduction pursuant to s 323, as we understood the submission.[3] The respondent also relied on Vegan to found a submission that a Medical Assessor's obligation to give reasons was limited in that they did not need to be extensive or detailed.
3. The Medical Assessor was required to use his clinical expertise and experience, referring we assume to Chapter 1.6b of the Guides, and it was argued that because the Medical Assessor was an orthopaedic surgeon, he had the requisite amount of expertise regarding "issues of osteoarthritis of the knees and knee replacements." The question determined by the Medical Assessor it was argued was a "medical question" and within his clinical judgement.
4. The respondent submitted that the 50% deduction was consistent with the deduction assessed by Dr Miniter and that, although the Medical Assessor was not bound by the opinions of others, his assessment "should be more persuasive, given it is consistent with previous medical opinions."
5. Further, the respondent submitted, there was no dispute that there was a pre-existing condition because the basis of the applicant's claim was that he had aggravated such a condition.
6. Moreover, there was evidence upon which the Medical Assessor could base such a deduction, in the form of "previous medical reports" which confirms that "surgeries" had been undertaken prior to the commencement of the applicant's employment. Dr Miniter's opinion also established that Mr Byrne's pre-existing conditions had contributed to the impairment.
7. The Medical Assessor had the benefit of "all of the relevant medical evidence available to him" and in making his 50% deduction said that the amount of the deduction was large on the available evidence and that a deduction of 1/10 would be at odds with that evidence.
8. As to the Medical Assessor's finding that Mr Byrne would have come to a total knee replacement in any event, such a finding was within the clinical skill and expertise exercised by the Medical Assessor, the respondent argued. We were referred to a 2019 Medical Panel decision[4] in support of a submission that the Medical Assessor had undertaken an evaluation of the medical evidence before him, the history provided by Mr Byrne, and the clinical examination to form his conclusion to reach his conclusion.
9. The respondent then sought to raise an issue regarding the date of injury following a recent Court of Appeal decision[5] the purpose of which was unclear. If it was intended that the employer objected to any part of the MAC, then its remedy was to lodge an appeal.

1. Section 323 of the 1998 Act provides relevantly:

"(1) In assessing the degree of permanent impairment resulting from an injury, there is to be a deduction for any proportion of the impairment that is due to any previous injury (whether or not it is an injury for which compensation has been paid or is payable under Division 4 of Part 3 of the 1987 Act) or that is due to any pre-existing condition or abnormality.

(2) If the extent of a deduction under this section (or a part of it) will be difficult or costly to determine (because, for example, of the absence of medical evidence), it is to be assumed (for the purpose of avoiding disputation) that the deduction (or the relevant part of it) is 10% of the impairment, unless this assumption is at odds with the available evidence."

1. It can be seen that the Medical Assessor used some of the language in s 323(2) to justify his assessment of the contribution that the pre-existing condition to the baseline assessment. He stated that the extent of the deduction was difficult or costly to determine but found nonetheless that the "available evidence" demonstrated that the "deductible proportion" was large so that a 1/10th assessment was at odds with that evidence.
2. Mr Byrne submitted at some length that the Medical Assessor made no mention of the "available evidence". The Medical Assessor referred only to what Mr Byrne had apparently told him during the consultation at [4] of the MAC. The history commenced with the phrase "Mr Byrne attributed problems in his knees to the nature and conditions of his employment as a Stevedore." The Medical Assessor had before him unchallenged medical evidence and contemporaneous records, considered below, that demonstrated the accuracy of

Mr Byrne's attribution. 3. Moreover, the Medical Assessor recorded that "[o]ver the years, pain deteriorated and he progressively was limping," without any explanation as to whether he accepted that history, and if he did, without giving any reasons as to why he found the fact of the progressive deterioration to be irrelevant. 4. Further, the Medical Assessor found it necessary at [7] to repeat that Mr Byrne "attributes the arthritis in his knees to the nature and conditions of his employment," without further comment. 5. It might be concluded that the Medical Assessor accepted that there was some basis for accepting that the nature and conditions of Mr Byrne's employment had caused the injury as he only deducted one half of the baseline impairment pursuant to s 323. However, he did not explain why that was so. 6. Beyond the attribution above referred to, the Medical Assessor's summary at [7] simply recorded that Mr Byrne "developed osteoarthritis in both of his knees" and had a "good" result from the subsequent knee replacements. No assistance either was to be gained from his comments at [10c] regarding the opinions of Dr David Millons, orthopaedic surgeon, in his report of 7 May 2024 and Associate Professor Paul Miniter, orthopaedic surgeon of

31 July 2024, as the Medical Assessor simply recorded his agreement with the baseline assessments and noted the difference between the s 323 deductions. 7. Since the High Court decision of Wingfoot[6] it has been accepted that a Medical Assessor is obliged to give reasons. In El Masri v Woolworths Ltd[7] Campbell J stated at [50]:

".....Basically, the statement of reasons must explain that actual path of reasoning in sufficient detail to enable a court to see whether the opinion does or does not involve any error of law...."

1. The reasons given by the Medical Assessor, with respect, failed that test.
2. In his statement dated 1 December 2022[8] Mr Byrne compiled a chronology of the complaints made by him regarding his knees from entries in the accident record. He has not been challenged and we accepted it as being accurate:

Hit by falling lashing bar- soreness to left knee and forearm

Struck right knee on ladder while descending straddle causing redness & swelling

Whilst ascending straddle ladder hit knee on ladder

Sore left knee from old injury 07/07/2005. Unable to complete shift. Left knee too sore for straddle driving

Left knee giving pain from old injury pressing on straddle brakes during the course of reoccurrence

Stiffness to left knee due to continual straddle driving

Sharp pain to left knee and ankle when foot slipped off ladder

Pain to right knee. Tripped on steel plate incident at 19:45 hours

Whilst taking top dogs out of shipping container twist left knee

Slipped on lashing bar on ship. Swelling and pain to the left knee

Both knees giving pain after continual straddle driving

Bumped left knee on straddle ladderway causing slight swelling and bruising

Bruising swelling and pain to left knee as descending heavy forklift

Recurrence of pain to left knee. Hit plate on wharf

! Whilst climbing down straddle ladder pain in right hamstring and knee

Pain in right hamstring down to knee. Recurring injury

Climbing up straddle ladder. Felt pain to left knee. Knee swelling badly

Slipped on deck of ship causing wound to left lower leg and pain to right knee

Pain to back of right leg hamstring. Tripped and fell whilst carrying lashing bar

Lashing climbing across lid. Pain down right side of leg from hamstring to right ankle

Getting out of car at work heard cracking noise in right knee (outside)

Rope handrail gave way causing fall ... knee still sore

Both knees and both hamstrings sore from walking at truck grids

Getting off forklift heard crack in right knee. Immediate pain.

Getting off?. Slipped off last step. Twisted left knee

Unlocking ? over height. Jumped down from?. Injured left leg.

Sore left knee and left quad working under hook. Overuse

Walking and left leg went into pothole - left knee jarred

1. This evidence, and the accident reports upon which it was based, raises a very real doubt as to whether respondent's submission that the Medical Assessor had considered and reviewed all the evidence before him may be accepted. There is a presumption of regularity that applies to the actions of administrative decision makers, of which a Medical Assessor is one[9] but this evidence is of such relevance to his task that his failure to consider it amounts to a rebuttal of any presumption that he had reviewed it at all.
2. The task of a Medical Assessor when applying the provisions of s 323 has been considered in many authorities, most if not all adopting what fell from Schmidt J in Cole at [38]:

"38 What s 323 required, however, was that the evidence be considered, so that it could be determined, firstly, what the level of impairment after the second injury was. Secondly, whether a proportion of that impairment was due to the first injury. Thirdly, what that proportion was. Undoubtedly in undertaking this exercise, the medical members of an Appeal Panel must utilise their medical judgement, knowledge and experience. Nevertheless, all stages of the statutory exercise must be undertaken in the light of the evidence and without the making of assumptions not provided for by the section."

1. With regard to her Honour's latter point, she had said earlier at [30]:

"30 Section 323 does not permit that assessment to be made on the basis of an assumption or hypothesis, that once a particular injury has occurred, it will always, 'irrespective of outcome', contribute to the impairment flowing from any subsequent injury. The assessment must have regard to the evidence as to the actual consequences of the earlier injury, pre-existing condition or abnormality...."

1. In the absence of any acknowledgement of the above evidence, we are reluctantly drawn to the conclusion that indeed the Medical Assessor has acted on assumption and hypothesis. The respondent's submission that a Medical Assessor was indeed able to make a deduction in the presence of an asymptomatic pre-existing condition can be accepted, but not in the circumstances of the present case. The respondent relied on well-known dicta in Vitaz, where Basten JA, McColl JA and Handley AJA agreeing, said at [43]:

"...In the absence of any medical evidence establishing a contest as to whether the pre-existing condition did contribute to the level of impairment, the complaint about a failure to give reasons must fail. An approved medical specialist is entitled to reach conclusions, no doubt partly on an intuitive basis, and no reasons are required in circumstances where the alternative conclusion is not presented by the evidence and is not shown to be necessarily available."

1. The above chronology, and the evidence upon which it was based, established an obvious contest where the alternative conclusion advanced by Mr Byrne was clearly presented. The respondent submitted variously that there were "previous medical reports" and that the Medical Assessor had available to him "all of the relevant medical evidence" without referring us to any report that had not considered the contemporaneous evidence set out in Mr Byrne's chronology, above.
2. The respondent's reliance on the 2019 Medical Appeal Panel decision of Prakash is of no assistance, as Member Perrignon, on behalf of the Medical Appeal Panel, stated quite accurately that a Medical Assessor has to assess the extent of the deduction pursuant to s 323 as an evaluative exercise "having regard to the history and medical evidence before him, and to the results of his own clinical examination".
3. The history taken by the Medical Assessor was deficient as the manner in which he recorded Mr Byrne's assertion that the "nature and conditions" of employment were causative, and his failure to thereafter consider the relevant evidence regarding Mr Byrne's duties as a stevedore indicated that indeed he had not taken a proper history, and was dismissive of Mr Byrne's assertion. The history taken by the Medical Assessor was not reflective of the relevant history which he was required to take into account.
4. As we have noted already, the Medical Assessor did not have regard to the medical evidence before him, but simply noted that the experts agreed that the outcome of the bilateral arthropathies had been "good" and therefore entitled Mr Byrne according to the Guides to 15% WPI as a baseline assessment for each knee. The failure to either take a proper history or have regard to the relevant medical evidence rendered the clinical examination by the Medical Assessor to be of little probative use.
5. Having regard to these deficiencies, the opinion given by the Medical Assessor that

Mr Byrne would not have required knee replacement surgery had it not been for the pre-existing constitutional condition is speculative in any event and lacks any adequate explanation of the facts and circumstances on which it was based. 6. There remains one further matter relating to the terms of the referral. 7. Mr Byrne's claim as pleaded in the ARD as being the "aggravation, acceleration or exacerbation or deterioration of disease as a result of the nature and conditions of the applicant's employment more fully described in his statements".[10] 8. The Medical Assessor was accordingly required to consider whether Mr Byrne's duties as a stevedore had caused the aggravation, acceleration or exacerbation or deterioration of his underlying bilateral knee osteoarthritis. He had then to identify the "relevant date" of the onset of the pre-existing condition. In Craigie v Faircloth & Reynolds Pty Ltd[11] Johnson J stated from [36]:

"36 In Cullen, Beech-Jones J (as his Honour then was) said (at [46]) that to establish a pre-existing condition for the purpose of s.323(1) WIM Act, there must, at a 'relevant date', be an actual condition, although it may be asymptomatic. His Honour observed in Cullen (at [56]) that the Medical Appeal Panel had not identified "any point in time much less prior to his employment commencing when Mr Cullen may have first developed osteoarthritis albeit asymptomatic.

37 Beech-Jones J identified the error in Cullen at [57]:

... the MAP concluded that once it was established that Mr Cullen had osteoarthritis that had a 'constitutional pathology' then it automatically followed that it was a pre-existing condition. In this case that approach was erroneous in law and constitutes an error of law on the face of the record (and that is the case irrespective of whether the condition had to pre-date the commencement of his employment or some later time)."

1. However, in order to have an injury assessed as a disease injury pursuant to s 4(b) of the 1987 Act, the terms of the referral require the date of injury to be noted as a "deemed" injury. This was not done in the present case - an omission that in other circumstances may have been significant. However, the point was not raised before us, and we note the parties have approached this matter on the assumption that it was a case that involved the aggravation, exacerbation, acceleration or deterioration of a pre-existing disease condition. We note that the Medical Assessor did not address this aspect of the dispute, but his MAC was otherwise so deficient, with respect, that nothing turns on this point.
2. It is necessary to consider all the evidence when assessing the contribution made by the pre-existing condition to the impairment caused by the subject injury.[12] Mr Byrne commenced work as a stevedore in 1998, when he was about 33 years old. He had undergone a prior arthroscopy to his knee on 10 October 1990 following an injury sustained whilst playing rugby league. His evidence was that he made a full recovery from the surgical repair of a chondral flap tear to the right knee, which Dr Sorrenti reported on

25 October 1990 had "settled down very very well",[13] and certified Mr Byrne fit to resume all normal activities. There was no evidence of any left knee problem, although some confusion was caused by Dr Sorrenti initially identifying the left knee as that which was injured in 1990.[14] 3. In his statement of 1 December 2022 Mr Byrne described his duties as a stevedore when he became employed by the respondent in 1998, and reported that his knees had been strained in the various jobs he was required to do. His work included being frequently in cramped and confined spaces and scaling the many sets of vertical ladders to various deck levels. His employment also involved walking considerable distances of up to 12,000 steps per shift. 4. We have reproduced Mr Byrne's chronology above, and it can be seen that his first report of injury to his knee was not until 23 November 2000 after which time there were regular entries related to knee injuries - predominantly the right knee, in respect of which he came to surgery on 5 September 2008. Thereafter the chronology listed injuries from various mishaps to both knees. 5. This history was taken by Dr Byrne's expert, Dr Millons, who said in his report of

"There have been many reports of episodes of left and right knee pain over the years which merely serve to indicate that his problem can be considered to be a disease of gradual onset, perhaps not occasioned by his work but certainly aggravated by the nature and conditions of his work on the waterfront since 1998."

1. Associate Professor Miniter also accepted that Mr Byrne's employment was contributory to his condition. In his report of 2 May 2023 Dr Miniter said:[16]

"[Mr Byrne's] occupation has been reasonably heavy, and it would be reasonable to assume that a portion of this matter is related to the workplace. I also note that under WorkCover, he has undergone arthroscopic surgical procedures at both knees, which could possibly have accelerated the development of the osteoarthritic change.

It is therefore impossible to completely discount the association between Mr Byrne's current presentation and his employment, even though I feel this is dominantly, a constitutional problem."

1. Mr Byrne was asymptomatic when he commenced work with the respondent, and it was not until he had been working there for 10 years that he first came to surgery on his right knee in 2008. His further surgery to his left knee occurred in 2010. His work was arduous, and the chronology evidences constant reports for his knee complaints. We accordingly find that Mr Byrne's pre-existing condition had a negligible role to play in contributing to the baseline assessment. The relevant date to establish the onset of the pre-existing condition is difficult to determine. There is no evidence that Mr Byrne was suffering from osteoarthritis in the left knee when he commenced employment with the respondent, and accordingly we cannot find that the condition of the left knee was "pre-existing". It is common, however for an early onset of osteoarthritis in a knee that has been subject to surgery, and it may be that the 1990 procedure contributed to an earlier onset of osteoarthritis in that knee. However, it is difficult to determine to what extent it existed when Mr Byrne commenced employment, if at all.
2. Accordingly, the MAC will be revoked and we find that there should be no deduction with regard to the left knee, and that a 10% deduction as provided by s 323(2) should be applied for the injury to the right knee.
3. For these reasons, the Appeal Panel has determined that the MAC issued on

7 January 2025 should be revoked, and a new MAC should be issued. The new certificate is attached to this statement of reasons.

This Certificate is issued pursuant to s 328(5) of the Workplace Injury Management and Workers Compensation Act 1998.

The Appeal Panel revokes the Medical Assessment Certificate of Medical Assessor Rob Kuru and issues this new Medical Assessment Certificate as to the matters set out in the Table below:

Chapter, page and paragraph number in NSW workers compensation guidelines

Chapter, page, paragraph, figure and table numbers in AMA 5 Guides

Proportion of permanent impairment due to pre-existing injury, abnormality or condition

Sub-total/s % WPI (after any deductions in column 6)

Total % WPI (the Combined Table values of all sub-totals)

[1] Beale v GIO (NSW) (1997) 48 NSWLR 430 at 442-444), Whitely Muir & Zwanenberg Ltd v Kerr (1966) 39 ALJR 505 (at 506), Craig v The State of South Australia [1995] HCA 58, Minister for Immigration and

Multicultural Affairs v Yusuf [2001] HCA 30.

[2] Cole v Wenaline Pty Ltd [2010] NSWSC78 ("Cole"), Ryder v Sundance Bakehouse [2015] NSWSC526 (Ryder), Fardell v Clinton Industries Pty Ltd [2022] NSWSC 111.

[3] Vitaz v Westform (NSW) Pty Limited [2011] NSWCA25.

[4] Prakash v Novartis Australia [2019] NSWWCCMA 69.

[5] Haddad v The GEO Group Australia Pty Ltd [2024] NSWCA.

[6] Wingfoot Australia Partners Pty Ltd v Kocak [2013] HCA 43; 88 ALJR 52.

[7] [2014] NSWSC 1344.

[9] See e.g. Jones v The Registrar WCC [2010] NSWSC 481.

[11] [2021] NSWSC 1211.

[12] Elcheikh v Diamond Formwork (NSW) Pty Ltd [2013] NSWSC 365 per Schmidt J at [91] and [124].