1. On 6 December 2024 Mr Alan Dekker (the appellant) lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Dr Yiu-Key Ho, a Medical Assessor, who issued a Medical Assessment Certificate (MAC) on

5 December 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).

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. The appellant did not request that he be re-examined by a Medical Assessor who was also a member of the Appeal Panel.
3. As a result of its preliminary review, the Appeal Panel determined that the worker need not undergo a further medical examination because even though the Appeal Panel found error, there was sufficient material before the Appeal panel to enable a determination to be made.

1. Section 328(3) of the 1998 Act provides that evidence that is fresh evidence or evidence in addition to or in substitution for the evidence received in relation to a medical assessment appealed against may not be given on an appeal by a party unless the evidence was not available to the party before the medical assessment and could not reasonably have been obtained by the party before that medical assessment.
2. The appellant does not seek to admit additional evidence however the respondent has attached various reports including that of Dr Machart, the IME qualified to provide an opinion on behalf of the respondent to its submissions attached to its notice of opposition. The respondent seeks to rely on the following documents attached to the notice of opposition:

(a) bone scan 1 September 2022;

(b) bone scan 3 April 2021;

(c) MRI 15 June 2020, and

(d) reports of Dr Machart dated 8 September 2020 and 26 June 2024.

1. It is noted that the matter was referred to the Medical Assessor by the Commission with only the Application to Resolve a Dispute and attached documents. This is because the respondent did not file a Reply despite having the opportunity to do so.
2. The parties, in an upfront filing system as provided by the Personal Injury Commission's (Commission) rules and practice directions, each had the opportunity to provide expert medical opinions.
3. The respondent did not file a Reply annexing the documents upon which it relied that it sought to be forwarded to the Medical Assessor. The respondent had opportunity to do so but did not avail itself of that opportunity. The dispute was referred to the Medical Assessor. At the appeal stage the respondent seeks to have considered various radiological reports and the IME report of Dr Machart all of which predate the medical assessment. The appellant objects to that evidence being received on appeal at this stage in the proceedings.
4. The reports including those of Dr Machart all predate the medical assessment and as such clearly do not fall into the category that the evidence was not available to the party before the medical assessment and could not reasonably have been obtained by the party before that medical assessment. Accordingly the Appeal Panel declines to admit the additional evidence attached to the submissions of the respondent.

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. They are not repeated in full, but 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.
3. The matter was referred by the Commission to the Medical Assessor as follows:

"The following matters have been referred for assessment (s 319 of the 1998 Act):

• Date of injury: 29 October, 2019 - frank injury
• Body parts/systems referred: Right Lower Extremity, Scarring TEMSKI
• Method of assessment: Whole Person Impairment
• Date of injury (2): 26 March, 2024 - deemed - due to nature and conditions of employment
• Body parts/systems referred: Right Lower Extremity, Scarring - TEMSKI
• Whole Person Impairment"

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 (expressed as a fraction)

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

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

1. The worker appealed.
2. The complaint on appeal does not concern the assessment of the overall level of permanent impairment of the right lower extremity at 20% WPI (based on a fair result for the knee replacement).
3. The complaint on appeal does not concern the assessment for scarring of 2% WPI.
4. The complaint on appeal does not concern itself with the fact that the Medical Assessor found the impairment resulting from the two injuries referred to him to be an indivisible impairment.
5. What the appellant complains about on appeal is the one-tenth deduction made by the Medical Assessor under s 323 in respect of the pre-existing condition, abnormality or injury to the right lower extremity (knee). In so doing the appellant submits that the Medical Assessor made an assessment on the basis of incorrect criteria and/or a demonstrable error.
6. In summary, the appellant submitted on appeal that the Medical Assessor made an assessment on the basis of incorrect criteria and/or made demonstrable error for reasons which included the following:

(a) in finding the impairment between the two dates of injury to be an indivisible impairment, the Medical Assessor has then applied a deduction under one-tenth apparently only applying it to the frank injury;

(b) that the making of a one-tenth deduction was inadequately reasoned, and

(c) that the making of a one-tenth deduction did not take account of the injury by reason of the nature and conditions of employment wherein the appellant had worked in physically heavy employment for the respondent since 1996.

1. In summary, the respondent employer Shellharbour City Council (the respondent) submitted that the Medical Assessor did not make an assessment on the basis of incorrect criteria and did not make demonstrable errors and that the MAC should be confirmed for reasons which included that the reasoning was adequate and the one-tenth deduction was justifiable on the basis of the available evidence and not at odds with the available evidence given the underlying osteoarthritic condition of the knee and that a knee being asymptomatic prior to injury is not determinative.
2. The role of the Medical Assessor is to conduct an independent assessment on the day of examination. The Medical Assessor is required to take a history, conduct a medical examination, make a diagnosis and have due regard to other evidence and other medical opinion that is before the Medical Assessor. The Medical Assessor must bring his clinical expertise to bear and exercise his clinical judgement when making an independent assessment of impairment and must apply the correct criteria for assessment under the Guidelines.
3. The path of reasoning disclosed by the Medical Assessor must be adequate. This is also dependent on the extent of the history taken and a thorough examination of the appellant so with an adequate record of examination findings so that it can readily be understood by the reader that the correct criteria under the Guidelines have been applied. The MAC must be read as a whole.
4. The Medical Assessor recorded the following history:

"Brief history of the incident/onset of symptoms and of subsequent related events, including treatment:

Mr Alan Dekker worked with Shellharbour Council for twenty eight years. From 1996 until 2012 he worked as a concreter and labourer. From 2012 up to now he worked as a Building Coordinator. He had an injury on the 29 October, 2019, five years ago. He went to a site inspection where there was flooding and he slipped and he ended up with hyperextension of the right knee with pain. He could continue to finish the job and then made a claim. He decided to treat it conservatively and observe the progress with a brace and there was more pain after Christmas so he went to see his family doctor

Dr Ooi with MRI done and then he was referred to see Orthopaedic Surgeon Dr Stackpool where the first consultation happened around July, 2020. He was recommended first to consider steroid injection, it did not help, and reviewed in August as the x-ray showing bad medial compartment OA. He was recommended to have knee replacement. Surgery was done on the 12 October, 2020. Unfortunately the progress of the operation was not good. There was constant pain and worst of all he certainly had a lot of instability, the knee was too loose. He even felt the knee being loose walking on level ground, not just on the stairs which should be the usual complaint for this sort of flexion instability. Dr Stackpool certainly did a lot of tests, failed to find any obvious reason as flexion instability was very difficult to diagnose. Alan was advised to see Dr Antony Leong for a second opinion and further investigation in terms of blood investigation, MRI were done around September, 2021, about a year after the operation. He was just advised to have pain management. He went back to see Dr Stackpool and further investigations failed to pick up any abnormalities so a tentative diagnosis of flexion instability was made, a revision surgery was done on the 24 October, 2022, two years after the indexed operation. The liner exchange was done, it was originally 10mm in thickness, and ultimately a 13mm thickness polyethylene was put in. According to the patient the operation was good and it made the knee less unstable and there is less pain although there is still residual problem.

He has constant pain so he needs to take pain killers which include Panadol, Nurofen and Mersyndol all of these every day. He just avoids overuse and has learned to live with the problem.

He still has constant pain, it has improved, right after the surgery the pain was much worse than now after changing the liner to a thicker one, made it more stable but there is still residual pain. He found the revision surgery was good but he also agrees that the knee replacement has helped him in terms of the initial pain after the injury. He cannot walk for too long as his job still involves a lot of walking so on the weekend after work he does not like to walk and there are a lot of physical activities he is not able to do.

• Details of any previous or subsequent accidents, injuries or condition:

He declined any previous or subsequent accidents, injuries or condition.

He claims to be in good health only taking tablet for blood pressure.

• Work history including previous work history if relevant:

He still works with Shellharbour City Council at the moment for twenty eight years. There is no restriction with work.

His knee is painful. He cannot walk as long as he likes. He has to be restricted with physical activities."

1. The Medical Assessor made the following comment in relation to special investigations:

"X-ray 7 August, 2020: Showing medial compartment OA changes nearly bone on bone.

X-ray 8 July, 2022: Post op x-ray showing the alignment of the component is good."

1. The Appeal Panel notes that there is no radiology of the right knee predating the commencement of employment as a concreter and labourer with the respondent in 1996 or indeed proximate to that commencement. The first radiology investigation undertaken post dated the "frank" injury in October 2019 which was the X-ray undertaken some 10 months later in August 2020.
2. The Medical Assessor undertook a physical examination. His examination findings were recorded and are not the subject of complaint on appeal.
3. The Medical Assessor summarised the injury and diagnosis as follows:

Mr Alan Dekker had a hyperextension injury at work on the 29 October, 2019, aggravating the pre-existing degenerative changes of the knee to a stage that he required right knee replacement. The initial operation was improving the symptoms but it was left with reasonable flexion instability. A revision two years later improved the outcome but he is still left with residual problem of pain and synovitis.

I believe the consistency of clinical presentation to the history of injury, physical finding and radiological outcome."

1. The Medical Assessor explained his assessment of permanent impairment of the right knee which equated to 20% WPI based on a fair result for the knee replacement. This is not the subject of complaint on appeal. To which he assessed 2% WPI for scarring leaving an overall impairment of 22% WPI. Again this is not the subject of complaint on appeal.
2. From the WPI of 22%, the Medical Assessor went on to make a one-tenth deduction under s 323 and to explain that he considered the resulting impairment could not be apportioned between the two dates of injury as follows:

"So altogether there is a 22% whole person impairment. I believe there should be a deduction for pre-existing condition. There are pre-existing degenerative changes, even though the patient claimed them to be asymptomatic, I think a 1/10 deduction is appropriate and that will leave behind 20% whole person impairment. For this permanent impairment it is due to both, as in the referral, injury a) 29 October 2019 the frank injury and injury b) 26 March, 2024 deemed to nature and condition of employment. I find it difficult to apportion the permanent impairment into these two different dates of injury."

1. The Medical Assessor explained where his opinion differed from other medical opinion as follows:

"My assessment more or less concurs with Dr Brett Courtenay with both assessed him to be 22% with 20% whole person impairment with fair result of total knee replacement and 2% for scar. The only difference is I take away 1/10 for contribution of pre-existing condition while Dr Courtenay had no deduction. I am not aware of any other permanent impairment assessment. I think the main problem in this case is the poorly execution of the initial knee replacement. The liner had to be changed to 3mm thicker to make the knee stable enough to function so the initial problem of flexion instability is quite obvious and due to two years of living with the problem of flexion instability, even with a successful revision, we are not going to give a good result compared to a case when initially it was done properly without instability."

1. In respect of the deduction, the Medical Assessor restated his opinion that a deduction was required as there were pre-existing degenerative changes as follows:

"DEDUCTION (IF ANY) FOR THE PROPORTION OF THE IMPAIRMENT THAT IS DUE TO PREVIOUS INJURY OR PRE-EXISTING CONDITION OR ABNORMALITY

In my opinion the deductible proportion is 1/10 for the following reasons:

(i) There was pre-existing degenerative changes."

1. In respect of the s 323 deduction, the appellant complains on appeal that the Medical Assessor made a deduction for the pre-existing condition or abnormality of the worker's right knee and this was reasoned inadequately and at odds with his consideration that the impairment indivisibly resulted from both the "frank" injury and the "disease" injury.
2. The respondent submitted that the deduction was available on the evidence of the underlying osteoarthritic condition and was adequately reasoned.
3. A deduction can only be made under s 323 if the pre-existing condition, abnormality or injury has contributed to the level of permanent impairment assessed. If the extent of the deduction would be too difficult or costly to assess, a one-tenth deduction applies if not at odds with the available evidence.
4. The fact that a condition may be asymptomatic is to be taken into account but is not determinative.
5. Whilst the MAC must be read as a whole, there is no other reasoning to be found in the MAC which suggests that the Medical Assessor had any regard to the lack of any radiology prior to or proximate to the commencement of employment with the respondent in 1996 (working from 1996 to 2012 in employment as a concreter and labourer which was heavy and repetitive and then from 2012 as a building coordinator about which he gives evidence of the physical demands of the job impacting his knee). There is no radiological investigation in evidence until the X-ray dated August 2020 (some 10 months after the October 2019 injury). That is, there is no radiological investigation to show the condition of the right knee prior to commencing employment in 1996. There are no clinical records in evidence recording complaints about the knee until after the "frank" injury in October 2019.
6. The Medical Assessor in his clinical assessment found the impairment to result from both the frank injury and the disease injury and to be indivisible between them but when he came to issue the final certificate he just referred to the frank injury date.
7. He found that there were pre-existing degenerative changes in the right knee which has formed the basis of the one-tenth deduction but there is no available evidence that predates a 23-year period of employment (initially from 1996 to 2012 as a concreter and labourer and then as a building coordinator) that supports that the degenerative changes pre-existed the commencement of employment.
8. The presence of degenerative changes on imaging of the knee do not, per se, correlate with any degree of loss of function with respect to ADL's, as demonstrated by the appellant's ability to continue physically arduous work for many years without documented evidence of any problems, and therefore they do not make any contribution to the assessed permanent impairment, which is a requirement for making a s 323 deduction.
9. He says the appellant claimed to be asymptomatic. The fact that a pre-existing condition is asymptomatic is relevant but not determinative.
10. Relevantly there are no clinical records in evidence which support any complaint about the right knee prior to the injury in 2019 and certainly none that support any problems with the right knee prior to the commencement of employment in 1996.
11. Having found the overall impairment of 22% WPI to indivisibly result from both the frank injury and the disease injury the Appeal Panel considers that there was no basis on the available evidence to make any deduction under s 323 and the Medical Assessor was in error in making a deduction.
12. This means the MAC will be revoked and a new MAC issued as set out below. As the Medical Assessor clearly found in his MAC that the impairment resulted from both the frank injury on 29 October 2019 and the injury deemed to have occurred on 26 March 2024 and was indivisible between the days of injury, the Table should reflect that as well as the removal of the deduction under s 323 as follows:

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 (expressed as a fraction)

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

29/10/2019 - frank injury and 26 March 2024 (deemed)

29/10/2019 - frank injury and 26 March 2024 (deemed)

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

1. For these reasons, the Appeal Panel has determined that the MAC issued on

5 December 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 Yiu-Key Ho 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 (expressed as a fraction)

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

29/10/2019 - frank injury and 26 March 2024 (deemed)

29/10/2019 - frank injury and 26 March 2024 (deemed)

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

The above assessment is made in accordance with the SIRA NSW Guidelines for the Evaluation of Permanent Impairment for injuries received after 1 January 2002.