1. On 17 December 2024 the appellant, Hendrikus (Henry) Johannus Bielderman 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 18 November 2024.
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 Guidelines) and the American Medical Association Guides to the Evaluation of Permanent Impairment, 5th ed (AMA 5), "WPI" is reference to whole person impairment. "Baseline WPI" is a reference to the total WPI assessed before deduction or modification pursuant to the relevant legislative authority

1. On 2 September 2024, this matter was referred to the Medical Assessor for an assessment of whole person impairment (WPI) caused by injury to the right lower extremity on 16 April 2020. Mr Bielderman was employed as a ground worker and on 16 April 2020 whilst collecting bottles that had fallen off a jammed production line, stepped on one. Although he did not fall, as he stabilised himself on a handrail, he had immediate pain and swelling in his right knee.
2. He was eventually referred to Dr Qurashi, orthopaedic surgeon and came to a knee replacement with him on 24 October 2022.
3. The Medical Assessor found there to be a baseline impairment of 18% but reduced from that one third giving an entitlement of 10% WPI.

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. Mr Bielderman requested to be re-examined by a member of the Appeal Panel but as the issue concerned the application of s 323 of the Workers Compensation Act 1987 (the 1987 Act) the Panel had the relevant evidence before it and a further examination would not have assisted its deliberations.

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. The Medical Assessor took a consistent history and found there to be a baseline WPI of 15%, in common with the other expert opinion contained in the referral.
2. At [6] of the MAC he said in relation to the "special investigations" before him:

"I note in the documents supplied report of an MRI from 12/07/2020 demonstrating a tear of the medial meniscus, grade 3 degenerative changes in the medial compartment and grade 4 changes in the patellofemoral compartment.

X-ray from 21/04/2020 notes an effusion with medial and patellofemoral component osteoarthritis."

1. At [10c] the Medical Assessor noted that Dr Endrey-Walder had made no deduction for the pre-existing degenerative disease, whereas Dr Wallace had made a deduction of 10%.
2. At [11], in explaining his deduction for the proportion of impairment that was due to Mr Bielderman's pre-existing arthritis, the Medical Assessor said:

"The injury sustained was an aggravation of pre-existing degenerative disease. In the absence of the pre-existing condition, it is unlikely any impairment [would] have been assessable subsequent to the injury."

"In the absence of pre-existing degenerative condition, a knee replacement would not have been required. The surgery undertaken was to address a pre-existing constitutional pathology, not a consequence of injury in the knee. [Deduction] of 1/3 is applied."

1. Mr Bielderman submitted that in making a deduction of one third pursuant to s 323 of the 1998 Act the Medical Assessor did not explain how the pre-existing condition had actually contributed to his current degree of impairment.
2. Further Mr Bielderman submitted that no explanation was given as to why the figure of one third had been applied.
3. Mr Bielderman then set out six discrete issues.

The failure to properly refer to and accurately account for the investigations which record the true extent of the underlying osteoarthritis, and the subsequent post-traumatic increase

1. Mr Bielderman submitted that the Medical Assessor did not acknowledge the opinion of Dr Endrey-Walder that the injury had significantly aggravated and exacerbated some mild pre-existing arthritic changes.
2. Mr Bielderman submitted that the imaging confirmed that the osteoarthritic changes were mild and as a matter of common sense they would not have been worthy of investigation but for the injury.
3. The subsequent MRI examination of 11 November 2021 confirmed there had been a significant post-traumatic increase in the degenerative changes in Mr Bielderman's knee. However, the Medical Assessor failed to mention that MRI at all.
4. With regard to the earlier investigations of 21 April 2020 (X-ray) and 12 July 2020 (MRI), Mr Bielderman submitted that the Medical Assessor failed to acknowledge that both reports spoke of "mild osteoarthritic changes".
5. The Medical Assessor acknowledged that the MRI of 12 July 2020 demonstrated a tear in the medial meniscus, but he did not mention that pathology when providing his assessment. He failed to consider whether the tear was pre-existing or caused by the impact of the subject injury, which affected his reasoning regarding the s 323 deduction at [11] of the MAC.
6. The failure by the Medical Assessor to accurately record the pathology revealed in those investigations resulted in an erroneous assessment.

The failure to have regard to the evidence that the appellant was asymptomatic prior to injury, with a fully functioning right knee

1. Mr Bielderman said that he commenced employment in 1985. He was required to bend, squat and crouch and he submitted that there was no evidence of any complaints in relation to his right knee before the subject injury, nor of any difficulty in the performance of his duties as a result of right knee weakness [see Dr Wallace]
2. It was submitted that the Medical Assessor failed to address the work related cause of the material change in Mr Bielderman's condition, where he had gone from having a fully functional and pain free knee to finally needing an arthropathy as a result of his increasing symptoms since the injury date.

The failure to appreciate that the need for the right total knee replacement on 25 October 2022 was directly attributable to the workplace injury on 16 April 2020, and that the evidence does not indicate that the appellant would have undergone such surgery had he not suffered the subject injury.

1. Mr Bielderman submitted that there was no dispute about the effect of the subject injury on the subsequent development of his previously asymptomatic condition.
2. It was not disputed that Mr Bielderman had injured his right knee on 16 April 2020 and the respondent paid for successive forms of treatment, ultimately meeting the costs of and associated with his right total knee replacement.
3. The Medical Assessor did not give any reasons for his conclusion that Mr Bielderman would have undergone the total knee replacement in any event and there was no basis for that conclusion contained within the evidence.
4. The dispute proceeded on the basis that the right knee replacement was attributable to the subject injury and the assessment needed to be conducted on the basis that the impairment assessed subsequent to the arthroplasty had been caused by the subject injury.
5. Mr Bielderman noted that both Dr Endrey-Walder and Dr Wallace assessed 15% level of impairment as a result of a good outcome from the right total knee replacement. Their difference was whether a deduction should be made under s 323.
6. The Medical Assessor made the same baseline assessment, notwithstanding that he had found the injury was not work related.
7. Mr Bielderman made further submissions as to the failure by the Medical Assessor to assess the s 323 contribution in accordance with the evidence, which he discussed under the following headings. We have not reproduced them in full, as they are to a large extent incorporated in our determination:
   • "The misdirection in speculating that the appellant would not have had any post-injury impairment, and would not have required a knee replacement if he did not have pre-existing constitutional pathology
   • The assumption that the surgery was 'to address a pre-existing constitutional pathology not a consequence of injury'.
   • The failure to consider and address the tear of the medial meniscus as evidence of injury and work-related pathology warranting knee.
   • The error relating to the proportion of impairment assessed as being due to a pre-existing condition or abnormality."
8. Mr Bielderman referred to the well-known authorities regarding the application of s 232 which will be considered in the statement of reasons, below.

1. Mr Bielderman noted that Dr Endrey-Walder assessed 1% WPI as a result of his surgical scar. That, when added to Dr Endrey-Walder's impairment assessment of 15% of the right knee, gave an aggregate of 16%, Mr Bielderman said.
2. The referral did not include scarring, and that omission needed to be corrected.

1. The respondent noted the diagnosis made by the Medical Assessor of the aggravation of pre-existing arthritis.
2. The respondent referred to the X-ray of 21 April 2020 and following MRI scan of 12 July 2020 and the pathology therein disclosed.
3. The further MRI scan of 11 November 2021 also showed the degenerative changes, but that the pathology had accelerated.
4. The respondent submitted that on 12 August 2020, the treating orthopaedic surgeon Dr Qurashi conceded that there was arthritis in the right knee which predated the subject injury. The respondent noted Dr Qurashi's opinion that apart from the injury the arthritis might not have worsened for a long period of time.
5. It was submitted that an inference was therefore available that the arthritis would have been present regardless of whether there was an injury or not.
6. We were referred to the opinion of Dr Wallace, who noted the MRI investigation of 12 July 2020 and said that there might have been a work-related aggravation but that a degree of the current impairment was due to the pre-existing degenerative changes. Accordingly, it was submitted, a deduction was warranted.
7. We referred to Cole v Wenaline Pty Ltd [2010] NSWSC 78 at [16], Vitaz v Westform (NSW) Pty Ltd [2011] NSWCA 254 at [42]- [43] and Marks v Secretary, Department of Communities and Justice [2021] NSWSC 306 and [2021] NSWSC 616. The result of those cases, it was argued, was that even if the previous injury were asymptomatic, a Medical Assessor had to identify whether it had impacted the relevant body part and that a vulnerability arising out of a pre-existing dormant condition could be found to contribute.
8. We were referred to an authority usually cited in cases involving psychological injury, Glenn William Parker v Select Civil Pty Limited [2018] NSWSC 140. A clinician's observations were not to be underrated, the respondent submitted,
9. Further, it was submitted that a Medical Assessor was not obliged "to list every single document included in the referral to justify [his] reasoning."
10. Alternatively, it was submitted that a one tenth deduction should be made.
11. With regard to the claim for scarring, the respondent repeated the terms of the referral, and submitted that, on the authority of Skates v Hills Industries Ltd, that the Medical Assessor was bound by a referral's terms. As an alternative, it was submitted that no impairment should be found, in terms of the relevant Guides.

(a) means personal injury arising out of or in the course of employment,

(i) a disease that is contracted by a worker in the course of employment but only if the employment was the main contributing factor to contracting the disease, and

(ii) the aggravation, acceleration, exacerbation or deterioration in the course of employment of any disease, but only if the employment was the main contributing factor to the aggravation, acceleration, exacerbation or deterioration of the disease, ..."

1. Section 323 of the 1998 Act provides relevantly:

323 Deduction for previous injury or pre-existing condition or abnormality

(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 is well accepted that there are three steps to be considered in the application of this section. In Cole v Wenaline Pty Ltd[1] Schmidt J held that firstly the level of impairment caused by the subject injury should be assessed. In the present case it was 26% for the lumbar spine, and that assessment has not been challenged. Her Honour said:

"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. The first step, the baseline WPI assessment for Mr Bielderman's injury, was not challenged, and the parties agreed that it was 15% WPI. The second step however, the assessment of whether a proportion should be deducted or not, it is more problematic. It is necessary that this question be considered in the light of the actual evidence before a Medical Assessor, and not be based on speculation, hypothesis or assumption.
2. The Medical Assessor appeared to apply a different test to this process. He stated at [11] of his MAC:

"The injury sustained was an aggravation of pre-existing degenerative disease. In the absence of the pre-existing condition, it is unlikely any impairment [would] have been assessable subsequent to the injury."

1. His opinion therefore was that Mr Bielderman probably had no assessable baseline impairment, as the injury had been caused by the aggravation of Mr Bielderman's pre-existing degenerative disease. In view of the terms of the referral, which required the Medical Assessor to accept that Mr Bielderman's injury had occurred on16 April 2020, that opinion was erroneous. It accordingly affected both the first and second steps. Nonetheless, he certified a 15% WPI.
2. The Medical Assessor also said:

"In the absence of pre-existing degenerative condition, a knee replacement would not have been required. The surgery undertaken was to address a pre-existing constitutional pathology, not a consequence of injury in the knee. [Deduction] of 1/3 is applied."

1. Thus, the Medical Assessor confirmed his opinion that the knee replacement had been caused because of the pre-existing degenerative pathology.
2. The Medical Assessor did not explain the basis of this hypothesis. He had noted the results of the investigations, which beside showing degenerative changes in the medial and patellofemoral compartments, also demonstrated a tear of the medial meniscus. However, he failed to relate those results to his hypothesis, or to give any further explanation.
3. In the light of the reasoning of the Medical Assessor, it was also difficult to comprehend why he had chosen a deduction of one third. If his hypothesis were correct, it would logically follow that there should have been a deduction of 100%.
4. Accordingly, the MAC must be revoked. In order to reassess the deduction it is necessary to consider the evidence. Mr Bielderman was born in 1963 and had been employed with the respondent since 1985.
5. In Craigie v Faircloth & Reynolds Pty Ltd[2] Johnson J reviewed consent orders that had been filed setting aside an Appeal Panel's determination. In confirming the orders, his Honour referred to counsel's submission at [33]:

"Mr Hickey, counsel for the Plaintiff, submitted that the Medical Appeal Panel had missed a critical aspect of the Plaintiff's argument, namely that, as Cullen requires, before the Approved Medical Specialist could proceed to assess the extent of any deduction for a pre-existing condition, it was necessary to determine that such condition relevantly pre-existed at the commencement of the Plaintiff's employment in 2007. It was submitted that neither the Approved Medical Specialist nor the Medical Appeal Panel made any such critical finding and thus had committed the same type of error as found in Cullen[3]."

1. It is not likely that Mr Bielderman had acquired any degenerative disease when he started work with the respondent when he was 22 years old. Whilst his condition may or may not have been present at the time of the injury on 16 April 2020, it would not have been present at the commencement of his employment, some 35 years before. The claim by the Medical Assessor was that Mr Bielderman's pre-existing condition was the cause of the injury. However, whilst Mr Bielderman's degenerative disease, if any, might have been asymptomatic prior to 16 April 2020, it could not also have been called "pre-existing," had the injury been pleaded as a deemed injury.
2. A further difficulty with the Medical Assessor's reasoning was that he did not discuss the injurious event on 16 April 2020, nor explain why it was irrelevant to his findings.
3. As noted above, the date of injury in the referral was given as " 16 April 2020 ." Accordingly, whilst Mr Bielderman's degenerative disease may have developed as a disease of gradual onset, in considering the application of s 323, the status of the injury was required to be considered as a "frank" injury pursuant to s 4(a) of the 1987 Act. In such circumstances it is moot whether the protection to a long-term worker such as Mr Bielderman by the rule in Craigie would be available. It is arguable that the term "pre-existing condition" in s 323 would indeed include a degenerative disease in those circumstances, and the relevant date for considering whether a re-existing injury existed, would be the date of injury.
4. This is the approach necessitated in this matter, notwithstanding that it has been accepted by the parties that the injury includes the degeneration of Mr Bielderman's condition. Dr Wallace's diagnosis included "aggravation of pre-existing degenerative osteoarthritis"[4] as did that of Dr Endery-Walder.[5] The matter was, however, referred and pleaded as a personal injury.
5. In all the circumstances, Mr Bielderman had been involved in the work of a ground worker, which we accept entailed bending, squatting and crouching to check equipment, for 35 years.[6] He worked without any symptoms in his right knee until he stepped on a fallen bottle on 16 April 2020, twisting his knee in the process.
6. This evidence must be balanced with the medical evidence as to the pre-existing condition of his knee on 16 April 2020, which is the 'relevant date' for assessment of a personal injury. The investigations demonstrated grade 3 degenerative changes in the medial compartment, and grade 4 changes in the patellofemoral compartment. These grades are based on the extent of the damage and range from 0 (normal) to 4 (the most severe). It can be seen that the results of the MRI scan taken on 12 July 2020 showed significant pathology some three months following the injury. The scan also demonstrated a medial meniscus tear. It is likely that the meniscal tear was caused by the circumstances of the injury, but it is unclear as to what degree of degeneration, if any, had occurred once Mr Bielderman's right knee became symptomatic, or indeed whether the degenerative changes had been post-traumatic.
7. In all the circumstances the extent of the deduction is difficult to determine. Mr Bielderman's condition being asymptomatic, there is no medical evidence to establish the degree of degenerative change prior to the injury and accordingly the statutory deduction of 10% is applicable pursuant to s 323(2).
8. The other issue that Mr Bielderman raised was that his scarring as a result of the knee replacement had not been assessed. This was hardly surprising, as it had not been made part of the referral. We accordingly made the following call on 28 April 2025:

1. We note that Mr Bielderman claimed in his submissions that the Notice of Claim included an assessment of 1% for scarring as it was assessed by Dr Endrey-Walder.
2. We further note the respondent's Reply that relied on the decision of Skates v Hills Industries Ltd [2021] NSWCA 142 which it said was authority for the proposition that a Medical Assessor is bound by the terms of referral
3. We agree with that summation as far as it goes, but a reading of the decision demonstrates quite plainly that a Medical Assessor is not so bound if through inadvertence a body part that was agreed to be assessed between the parties had not been referred. It is nothing to the point therefore to submit, as the respondent has, that because the referral was available to the parties well in advance of the assessment, the failure by the appellant to amend the referral meant that it could not now claim the assessment.
4. Rather, the relevant point is as to whether the parties agreed that such an assessment was to take place. In that regard we note that Dr Wallace gave an assessment for the scar on 12 February 2024, albeit that he found that there was a 0% WPI assessable.
5. We would accordingly be grateful if the parties would advise by 5 May 2025 whether there was such an agreement. If it is suggested that such an agreement did not exist, evidence should be filed in that regard."
6. Mr Bielderman responded with further submissions on 5 May 2025, presumably after the respondent wrote to him, indicating that it would not object to an amendment to the ARD to include scarring, notwithstanding that it had not originally been claimed in the ARD of

9 August 2024. 7. Mr Bielderman then addressed the evidence, which demonstrated that the experts from each party had assessed the scarring. Mr Bielderman suggested that the Commission amend the referral, which had occurred through "administrative inadvertence" to include the scarring. He referred to ss 42 and 43 of the Personal Injury Commission Act 2020, and he attached an amended ARD, following the indication from the respondent that it would not oppose such an amendment. 8. In view of the response of the respondent, which we acknowledge as a responsible and thoughtful solution, we amend the referral nunc pro tunc to include "scarring/TEMSKI" as a matter for assessment. There being no consensus between Dr Endrey-Walder and Dr Wallace as to whether any WPI should be assessed in respect of the scarring, a re-examination thus became warranted. 9. Accordingly, Mr Biederman was re-examined on 25 June 2025 by Dr Tommasino of the Panel. His report follows:

1. The workers medical history, where it differs from previous records

The history as recorded in the MAC by Dr Kuru was confirmed by the claimant.

1. Additional history since the original Medical Assessment Certificate was performed

There has been no further treatment and no further injuries since the original Medical Assessment Certificate was performed.

I am a member of the Medical Panel that decided that a re-examination was necessary to assess the scar.

I asked the claimant about the scar and he said that the scar was expected after the surgery and not an issue as far as he is concerned. I specifically asked whether he is conscious of the scar and he replied that it does not bother him at all.

Examination of the scar reveals a 17cm surgical scar at the front of the knee consistent with surgery for a total knee replacement. The scar is not pigmented and there is a good colour match with the surrounding skin. The scar is not obvious. The claimant can locate the scar easily. There were no trophic changes and suture marks are barely visible. The anatomic location of the scar is not clearly visible when wearing shorts which he was wearing today. There is no contour defect, no effect on ADLs, no treatment is required, and there is no adherence.

Under the best fit principle of the TEMSKI classification the scar best fits the descriptors for 0% WPI.

I note the report of Dr P Endrey-Walder dated 13 July 2022 and 12 October 2023. He wrote 'prominent surgical scar right knee with 1% WPI'. Under "Examination" there is no description of the scar.

I note the report of Dr Raymond Wallace dated 12 February 2024. Under "Examination" he described the scar as healed to a fine red line and is minimally visible and assessed 0% WPI.

There was no red line on today's examination as the scar has matured since February 2024.

1. The Panel adopts the report of Dr Mastroianni. It is clear that the scar now attracts no WPI.
2. For these reasons, the Appeal Panel has determined that the MAC issued on 18 November 2024 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 Dr Rob Kuru and issues this new Medical Assessment Certificate as to the matters set out in the Table below:

page and paragraph number in NSW workers compensation guidelines

Chapter, page, paragraph, figure and table numbers in AMA5 Guides

% WPI deductions pursuant to S323 for pre-existing injury, condition or abnormality

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

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

[1] [2010] NSWSC 78 at [38]

[2] [2021] NSWSC 1121.

[3] Cullen v Woodbrae Holdings Holdings Pty Ltd [2015] NSWSC 1415.

[6] See Mr Bielderman's statement of 8 August 2024, appeal papers page 54.