1. On 19 March 2025 the appellant employer, Cerebral Palsy Alliance, lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Dr David Crocker, a Medical Assessor, who issued a Medical Assessment Certificate (MAC) on 18 March 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 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. "Baseline WPI" is a reference to the total WPI assessed before deduction or modification pursuant to the relevant legislative authority

1. On 14 January 2025 this matter was referred to the Medical Assessor for an assessment of WPI caused by injury to the right upper extremity and scarring (TEMSKI) which occurred on 16 August 2020.
2. Ms Thorburn (the respondent) had been employed as a carer with Cerebral Palsy Alliance for a period of just under 30 years, being medically retired in 2022.
3. On 16 August 2020, whilst trying to use a hoist to transfer a disabled obese client in residential care from a chair to a bed, she injured her right shoulder when the hoist moved unexpectedly.
4. On 8 December 2020 Ms Thorburn underwent arthroscopic surgery of the right shoulder but went on to develop adhesive capsulitis.
5. She came to further surgery on 12 October 2021 in the form of an open capsulotomy and bursectomy.
6. The Medical Assessor certified a combined table value of 11% WPI. He found 10% in relation to the injury to the right upper extremity and 1% for the scarring.

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 no error was established by the appellant employer.

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.
3. The appellant employer relied on one issue relating to the relevance of the measurements regarding the contralateral shoulder.

1. The Medical Assessor took the above history regarding the factual background of the injury. He considered details of any previous or subsequent accidents in answer to a templated question.[1]
2. The Medical Assessor noted that Ms Thorburn had suffered multiple injuries in a motorbike accident in 1984 which involved injuries to her right ankle and foot.
3. He also noted the following:

"Ms Thorburn stated that in the 1990s she had endeavoured to reposition a client in bed in the course of her usual work duties. This resulted in pain to the region of the left shoulder girdle. She required multiple medical reviews with a general practitioner and orthopaedic surgeon. Investigation included MR arthrography. Arthroscopic surgery followed."

1. On physical examination the Medical Assessor took the following range of motion of both shoulder girdles:[2].

1. The Medical Assessor commented as to his examination findings:[3]

"Pain and mechanical factors appeared to negatively impact upon the above findings.

Poorly localised tenderness was reported to be present with palpation overlying both shoulder girdles, more so anteriorly to the right side."

1. In his summary the Medical Assessor noted that Ms Thorburn presented with a cooperative and undemonstrative manner. He said:

"...There were nil overt features of embellishment upon the history or augmentation on the physical examination. As such, I consider that consistency was apparent."

1. In giving his explanation for his calculations[4] the Medical Assessor said:[5]

"With respect to the region of the right upper extremity and taking into account limitation with active range of motion at the shoulder girdle, a 17% upper extremity impairment has been determined which converts to a 10% whole person impairment.

Nil deduction is appropriate taking into account the findings of the contralateral side given the previous history of injury, surgery and longstanding ongoing complaints referable to the shoulder girdle."

1. At [10c] the Medical Assessor considered the opinions of the opposing medical experts. He noted the reported of Professor Youssef Ghabrial consultant orthopaedic surgeon of 7 February 2024. He said:[6]

"...Respectfully, the report was noted to be relatively brief. ..."

1. With regard to the report prepared for the appellant employer by Associate Professor Leon Kleinman, consultant orthopaedic surgeon the Medical Assessor said:[7]

"Professor Kleinman had deduced a similar finding pertaining to the right shoulder girdle based upon limitation with active range of motion, ie 11% whole person impairment. The doctor, however, had deducted 5% taking into account the finding pertaining to the contralateral side.

Respectfully, Professor Kleinman had not appeared to elicit a history pertaining to an injury affecting the left shoulder and requirement for surgical treatment. Ms Thorburn also describes ongoing clinical features pertaining to this region. As such, it is my opinion that a deduction of this type is inappropriate."

1. The appellant employer did not challenge the baseline assessment of 11% found by the Medical Assessor.
2. The respondent submitted that the Medical Assessor had made a demonstrable error on the basis that there was no evidence in the material before the Medical Assessor that corroborated the history he took, namely that Ms Thorburn had suffered a left shoulder injury in the 1990s. Reference was made to Skates v Hills Industries Limited[8] in submitting that the medical dispute the subject of the referral will have been identified in correspondence and existed because the parties had made different claims about the degree of WPI suffered by the worker as a result of the injury.
3. The appellant employer referred to the competing opinions of the parties' medical experts.
4. The appellant employer noted that Dr Ghabrial assessed the right shoulder range of motion without referring to Ms Thorburn's left shoulder when determining impairment.
5. Dr Kleinman on the other hand had done so, and the appellant employer noted that he had accordingly deducted 5% WPI because of the limitation of the range of motion that was found in the contralateral left shoulder.
6. The appellant employer noted that there was no evidence before the Medical Assessor that related to a left shoulder injury by Ms Thorburn. She had not mentioned it in her statement nor was it part of the histories taken by either medical expert.
7. The Medical Assessor did not apply the relevant guideline on the assumption the left shoulder had indeed been previously injured, the appellant employer said. The appellant employer submitted that the Medical Assessor's finding was "solely based on the Respondent's newly provided history of a work- related left shoulder injury from the 1990s, in which [the Medical Assessor] found it inappropriate (to now use) the left shoulder ROM as a baseline in his assessment."
8. The appellant employer submitted that there was no medical evidence to support the worker's "newly provided history" regarding the left shoulder injury, and neither was there any factual evidence which would support that history.
9. It was submitted that the claim for impairment was based on a report which lacked adequate evidence to support the rejection of Dr Kleinman's opinion as being "inappropriate".
10. The left shoulder history, the appellant employer submitted, was not a matter which could form part of the medical dispute as Ms Thorburn had introduced this history as part of the medical dispute "after the parameters of the dispute were confined by the assessments of Dr Kleinman and Dr Ghabrial."
11. Accordingly the appellant employer contended that the Medical Assessor was required to have incorporated reference to the contralateral left shoulder range of motion and should have subtracted from the range of motion he found for the right shoulder the limited range of motion that existed in the left shoulder.
12. The appellant employer concluded by submitting that the "Medical Assessor went beyond the terms of the referral when assessing the right shoulder and did not appropriately rely on the medical evidence on which the claim defined the medical dispute between the parties."

1. Ms Thorburn reproduced Chapter 2.20 of the Guides, which relates to the involvement of contralateral joints. She referred to the inclusion in the guideline of a reference to AMA 5 which (as has been noted in other appeals), contains a misprint as to the page on which Section 16.4C appears. It is not page 543 but page 453.
2. We have noted Ms Thorburn's submissions, which were concerned with whether the range of motion in the left shoulder had been found by the Medical Assessor to have less than average mobility.
3. In making the above submissions It appears that Ms Thorburn did not appreciate that there was indeed a history of injury and surgery to the left shoulder taken by the Medical Assessor.

"When calculating impairment for loss of range of movement, it is most important to always compare measurements of the relevant joint(s) in both extremities. If a contralateral 'normal/uninjured' joint has less than average mobility, the impairment value(s) corresponding to the uninvolved joint serves as a baseline and is subtracted from the calculated impairment for the involved joint. The rationale for this decision should be explained in the assessor's report (see AMA5 Section 16.4c, p 543)."

1. As we have noted above the page number given as quote "543" is incorrect and the actual page number is "453". The relevant portion of Chapter 16.4c of AMA 5 is as follows:

"The measurements reported in the impairment tables and pie charts reflect the accepted average active range(s) of motion for each joint. However, certain people can have either lesser or greater joint flexibility than average. it is therefore most important to always compare measurements of the relevant joint(s) in both extremities.

If a contralateral 'normal' joint has a less than average mobility the impairment value(s corresponding to the uninvolved joint can serve as a baseline and are subtracted from the calculated impairment for the involved joint. The rationale for this decision should be explained in the report."

1. The appellant employer's submission that the Medical Assessor went beyond the terms of the referral by relying on a history he took during the face-to-face consultation which had not hitherto been reflected in the material referred to him, must be rejected.
2. They overlook the often cited dicta of the plurality French CJ Crennan, Bell, Gageler and Keane JJ in Wingfoot Australia Partners Pty Ltd v Kocak.[9] At [47] the Court said:

"The function of a Medical Panel is neither arbitral nor adjudicative: it is neither to choose between competing arguments, nor to opine on the correctness of other opinions on that medical question. The function is in every case to form and to give its own opinion on the medical question referred to it by applying its own medical experience and its own medical expertise."[10]

1. The medical dispute in the present case was defined by the terms of the referral which we have noted above, namely that the dispute involved an argument between the parties about the WPI that had been caused by the injury to the right upper extremity and scarring (TEMSKI) caused by injury on 16 August 2020.
2. The complaint made by the appellant employer was essentially that because the Medical Assessor took a history of a prior left shoulder injury that had not previously been the subject of any evidence, he was thereby prevented from relying on it. That submission is undone by the terms of the High Court dicta in _Wingfoo_t which we have cited.
3. It is not for a Medical Assessor to choose between competing arguments nor to opine on the correctness of other opinions on the medical question that is the subject of the dispute. A Medical Assessor is entitled and indeed required to apply his own medical experience and own medical expertise. It was a matter for the Medical Assessor's judgment as to whether he would accept the history given by Ms Thorburn that she had indeed suffered an injury in the 1990s to her left shoulder which did incorporate surgical treatment.
4. We note that Ms Thorburn's submissions were unfortunately misconceived as they were predicated on the basis that the Medical Assessor had not taken any such history.
5. It can be seen that the contralateral left shoulder could not be described as "normal/uninjured" in view of the history given during the assessment of the prior left shoulder injury. In Ferguson v State of New South Wales[11] Campbell J referred to dicta in an earlier medical appeal panel case. He said from [23]:

"By reference to NSW Police Force v Daniel Wark [2012] NSWWCCMA 36, the Appeal Panel directed itself that in questions of classification under the PIRS:

'... the pre-eminence of the clinical observations cannot be underrated. The judgment as to the significance or otherwise of the matters raised in the consultation is very much a matter for assessment by the clinician with the responsibility of conducting his/her enquiries with the applicant face to face'."

1. We find no error in the Medical Assessor's judgement that he could rely on this history. The appellant employer has not put evidence before us that casts any doubt on Ms Thorburn's history, as it was entitled to do pursuant to s 327(3)(b) and s 328(3) of the 1998 Act. Moreover the Medical Assessor found that Ms Thorburn presented with a cooperative and undemonstrative manner, with no overt features of embellishment and that "consistency was apparent."
2. For these reasons, the Appeal Panel has determined that the MAC issued on 18 March 2025 should be confirmed, although we re-issue the certificate as it contained a typographic error, awarding Ms Thorburn "11%" WPI for the scarring claim when it should have said "1%".

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 David Crocker 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)

[8] [2021] NSWCA 142.

[9] [2013] HCA 43 from [47]. (_Wingfoo_t)

[10] A Medical Assessor has the same functions as a Medical Panel: Western Sydney Local Health District v Chan [2015] NSWSC 1968 at [13].