1. On 6 August 2025 the appellant, Mitchell Burns lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Dr Phillip Truscott, a Medical Assessor, who issued a Medical Assessment Certificate (MAC) on 9 July 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 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 16 April 2025 this matter was referred for a WPI assessment caused by injury to the "Lumbar spine, right lower extremity (hip), scarring (TEMSKI), digestive system (upper gastrointestinal tract)" which occurred on 12 July 2012.
2. Mr Burns was employed at the Sydney University Veterinary School as a labourer/kennel hand. He suffers from dyspraxia, an intellectual disability that prevents him from learning to read or write.[1]
3. On 12 July 2012 Mr Burns had to lift a Dalmatian dog weighing about 25 kg. He had to lift the animal as a single lift and carry it upstairs for emergency treatment. He felt a sudden onset of severe back pain as he did so.
4. He was taken to Royal Prince Alfred Hospital where it was noted he had right-sided lower back pain and a fixed flexion of his right hip from previous surgery.
5. That surgery occurred in 1995, when Mr Burns was 13 years old. He had dislocated his right hip and came to surgery in the form of a right hip fusion, secondary to vascular necrosis, from a slipped epiphysis. This resulted in an altered gait pattern as a result of his fixed flexion in the hip.
6. On 12 July 2012 Mr Burns was discharged from the Emergency Department after about five hours and consulted his general practitioner (GP). He was then referred to Dr Davor Saravanja, spinal surgeon.
7. When seen by Dr Saravanja on 7 November 2012, it was noted that Mr Burns' right leg was shorter by approximately one inch and he walked with a stiff hip gait with excessive lumbar lordosis associated with his hip fusion. He had a flexed pelvic to lumbar spine posture.[2]
8. A CT scan identified a L4/L5 disc eccentric to the right and paracentral and associated early degenerative changes in the facet joints of L4/L5 and L5/S1.
9. Dr Saravanja diagnosed an aggravation by the work injury of pre-existing lower back degenerative change.
10. The Medical Assessor cited Dr Saravanja's opinion:

"...The fused right hip was causing an increase in the likelihood of the degenerative change in the lumbar spine due to his altered gait pattern. Consideration in my opinion needs to be given to a review by a hip surgeon with regards to a take-down of his fusion and a total hip replacement."

1. Mr Burns was referred to Dr Michael Solomon, hip and knee surgeon at Prince of Wales Hospital. He saw Dr Solomon on 5 March 2013, who noted that the right leg was 2cm shorter than the left and that although the hip did not hurt because of the fusion, it was clearly putting pressure on his lumbar spine.
2. Dr Solomon noticed some tearing of the gluteal medius and minimus muscles on the right and after a conference with the orthopaedic department at Prince of Wales Hospital, it was decided that the fusion should be taken down and a right hip replacement was performed.
3. This occurred on 1 October 2013 and the Medical Assessor said:

"My comment: This procedure was clearly performed to improve Mr Burn's back pain."

1. When reviewed on 24 July 2014 by Dr Saravanja, Mr Burns' hip replacement was regarded as a success. He still had some ongoing lower back pain radiating to the right buttock but he had no neurological signs.
2. On 19 August 2014 Dr Saravanja indicated that the back pain had gradually improved.
3. About five years later, on 9 January 2019 because of right hip pain Mr Burns returned to

Dr Solomon. Investigations showed that there had been a stress fracture around the prosthesis, which was improved by using a walking stick. 4. On 18 February 2020 Mr Burn's underwent a further revision and the femoral component was replaced and an osteotomy was performed. 5. A prophylactic cable was placed distal to the ETO. 6. In August 2020 further revision plating was required which included removal of wires. Further hardware was removed by Dr Solomon in March 2024. 7. Mr Burns return to light duties in August 2014 where he had to take multiple episodes of intermittent time off work because of his back pain. 8. The pain became worse towards the end of 2018 requiring multiple admissions to hospital such as at Northern Beaches Hospital on 17 December 2018, 30 December 2018 and

2 May 2019. 9. The Medical Assessor made the following assessments: * lumbar spine 7%; * right hip 0%; * upper digestive tract 0%, and * scarring 2% less one half equals 1%,

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 one was not sought by

Mr Burns, the issue being concerned with the application of s 323 of the 1998 Act and the evidence before the Medical Assessor. A further examination of Mr Burns would not have assisted the Panel.

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 below 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 extensive history which we have referred to above established that the Medical Assessor took a history of a sudden onset of lower back pain when Mr Burns was lifting the dog.
2. When discussing Mr Burns' previous condition the Medical Assessor noted that Mr Burns did have "episodic minor back injuries whilst working as an animal attendant." He noted that there were several episodes of back pain in October 2008.[3]
3. On physical examination the Medical Assessor noted that Mr Burns "Walked with a limp involving his right leg with a slow and somewhat wide-based gait."
4. The Medical Assessor had available a comprehensive set of investigations.
5. In his summary at [7] of the MAC, He stated the following: [4]

• Summary of injuries and diagnoses:
  • Aggravation of pre-existing degenerative lumbosacral disease
  • Right hip revision to aggravation of degenerative disease of lumbar spine due to previous hip fusion
  • Gastroesophageal reflux
  • Irritable bowel syndrome"

1. From [8e] the following appears:[5]

"e. Is any proportion of loss of efficient use or impairment or whole person impairment, due to a previous injury, pre-existing condition or abnormality?

1. If so, please indicate which body part/system is affected by the previous injury, preexisting condition or abnormality.

Mr Burns suffers from right femoral head necrosis which required subsequent right hip fusion which led to degenerative disease of the back."

1. The Medical Assessor explained his assessment at [10b] of the MAC. He found that

Mr Burns was suffering a 7% WPI in relation to his lumbar spine. 2. With regard to the right hip the Medical Assessor in accurately applying the relevant guidelines assessed the results of the hip replacement as achieving a fair result which carried with it a 20% WPI. 3. The Medical Assessor then said:

"Mr Burns' hip replacement was due to this previous hip fusion and it was the opinion that his back pain was being aggravated by the fusion. This was secondary to femoral hip necrosis which was constitutional.

From Dr Solomon's assessment dated 5 March 2013, he described the hip as being fused in 20° flexion. He also had gluteal muscle damage.

This fusion was clearly pre-existing and unrelated to his back injury and according to the WorkCover Guides, it should be deducted. The fusion was considered a major aggrevating [sic] factor in his back pain."

"Reference is then made to Table 17-9 in relation to the hip and join which is fused. This would indicate that Mr Burns' flexion would have been less than 50°, extension would have been less than 30°, there would be no internal or external rotation. Adduction would have been less than 5°. Each of these provides a 8% whole person impairment.

If just four planes of movement are taken, 8+ 8 + 8 + 8 - 32% whole person impairment. This then would be deducted from 20% whole person impairment, which in practical terms equals 0%.

A 0% whole person impairment would therefore be assigned."

1. The Medical Assessor considered the opinions of the experts from the opposing parties at [10c].
2. With regard to the report by Dr Endrey-Walder of 8 June 2021 the Medical Assessor considered that the right thigh wasting recorded by Dr Endrey-Walder "To be due to his previous hip fusion and not to the back injury. ...".
3. With regard to Dr Endrey-Walder's assessment of the hip surgery, the Medical Assessor said :

"...He then, however, assessed Mr Burns as having a 20% whole person impairment in relation to his hip surgery. He should have made a deduction as his hip surgery was due to his previous femoral head necrosis. It was thought that this abnormal gait aggravated his back pain. Had it not been for his right hip fusion, a hip replacement would not have been necessary. This should be fully deducted."

1. The Medical Assessor noted a later report from Dr Endrey-Walder dated 8 June 2012 in which he reported that Dr Endrey-Walder had deducted one half for the right hip and one tenth for the lumbar spine. "These deductions are not explained."
2. At [11], the following appeared:

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

1. In his general observations Mr Burns submitted that the Medical Assessor had erred in his assessment of the right hip.
2. At the time of his injury Mr Burns already had a fused right hip, but he submitted that following the back injury his continued altered gait pattern from his fusion was putting pressure on his lower back and thus aggravated his back pain.
3. Mr Burns said that he underwent the total hip replacement on 1 October 2013 to treat his back injury as it included the removal of the fusion which was responsible for his altered gait pattern.
4. Mr Burns noted that the Medical Assessor had accepted that the procedure "was clearly performed to improve Mr Burns' back pain" and that "the fusion was considered a major aggravating factor in his back pain".
5. Mr Burns referred to a consent Certificate of Determination of 9 November 2021, the second paragraph of which read:[6]

"The matter is remitted for referral to a Medical Assessor (MA) for assessment of a degree of permanent impairment, if any, as a result of injury to the lumbar spine on 12 July 2012, and consequential condition in the right hip and scarring with a date of injury of 12 July 2012."

1. Mr Burns submitted there was a subsequent admission or confirmation of that consent order and we were referred to a s 78 notice dated 18 June 2024, which stated that the physical injury to Mr Burns' lumbar spine, right hip and scarring had been accepted.[7]
2. Mr Burns submitted that the hip replacement had resulted in impairment which the Medical Assessor assessed as a fair result, with an entitlement to 20% WPI.
3. Mr Burns then turned to eight specific grounds.

1. Mr Burns submitted that the Medical Assessor had fallen into error by finding that the back injury was "due to a previous hip fusion".

1. This finding was also inconsistent with the Medical Assessor's assessment for the lumbar spine of 7% without deduction.

1. Notwithstanding the above finding, Mr Burns said, the Medical Assessor was further inconsistent in that he said the impairment resulting from the fusion "should be deducted", but later said at [11] that there was "no deductible proportion."

1. Mr Burns referred to a case of some vintage, Wikaira v Registrar of the Workers' Compensation Commission in NSW & Anor[8] in submitting that the Medical Assessor fell into error because he failed to "follow the President's referral."
2. Mr Burns stated that the right hip was agreed to be a consequential condition, and therefore the finding by the Medical Assessor that the right hip replacement did not result from the agreed and accepted back injury was erroneous.

1. Mr Burns submitted that the Medical Assessor failed to properly apply the provisions of s 323.
2. We were referred to the methodology set out in Southwell v Qantas Airways Limited.[9] Because the Medical Assessor did not follow those steps he had fallen into error, it was submitted.

1. The Medical Assessor was required by the terms of the referral to accept that the right hip condition resulted from the injury to the back, Mr Burns contended. He referred to Ryder v Sundance Bakehouse[10] in arguing that the Medical Assessor had erred in the manner he calculated the deduction. He had failed to consider whether the impairment caused by the right hip replacement had been contributed to by the earlier right hip fusion, but rather simply evaluated the level of impairment caused by the fusion. He had found that the hip replacement resulted in 20% WPI but failed to apply the correct test in considering whether the fusion contributed to that impairment, and if so what proportion that contribution was.

1. As a further alternative Mr Burns submitted that the Medical Assessor had erred as he based his assessment of pre-existing impairment on an assumption as to what the restrictions would have been, thus offending the principle in Cole v Wenaline Pty Ltd.[11]

1. Mr Burns submitted that in any event the Medical Assessor had misapplied the combined values chart in aggregating the ranges of motion he assumed would have been found as a result of his fusion.

1. The referral required the Medical Assessor to assess permanent impairment sustained as a result of an injury to Mr Burns' back on 12 July 2012. This, the respondent said, is what the Medical Assessor had done.

The Medical Assessor took an accurate history of the subject injury and noted that there was a background of minor episodes of back pain prior to the subject injury and that investigations showed in 2012 the L4/L5 disc eccentric to the right and the paracentral and associated early degenerative changes in the facet joints of L4/5 and L5/S1.

1. The respondent submitted that the Medical Assessor did not find that the back injury was due to the previous hip fusion but rather that the injury to the lumbar spine was caused by the aggravation of a pre-existing degenerative condition pursuant to s 4(b) of the 1987 Act.

1. The respondent submitted that it agreed with the proposition that there should have been a deduction from the assessment regarding the lumbar spine, if that was what Mr Burns was suggesting.
2. The respondent referred to evidence in support of its submission, but as it made no appeal to that effect, this submission may be put to one side.

1. The respondent conceded that the findings ought to have been more clearly outlined by the Medical Assessor regarding both the lumbar spine and the right hip. However, it submitted that the Medical Assessor's comments that the right hip replacement would not have been necessary but for the right hip fusion, was sufficient to be described as adequate reasoning.

1. The Medical Assessor appreciated that the referral to him included the assessment of a consequential injury to the right hip, it was submitted. The Medical Assessor had noted that the right hip replacement procedure in 2013 was performed to improve Mr Burns' back pain.
2. However, it argued that the question of whether any impairment had been sustained to the right hip as a result of the subject back injury, and whether any deduction should be made therefrom if there were, in view of the significant pre-existing condition in the right hip, was a separate issue.

1. As these grounds were concerned with the application of s 323, the respondent dealt with them together.
2. It agreed that the Medical Assessor had been unclear with regard to the deductible portion in his consideration of the claims for both the lumbar spine and the right hip. However, it argued that an application of the three-step process outlined in Southwell to the established facts would have resulted in the same, or even a more conservative assessment as those which the Medical Assessor had found.
3. The baseline impairment was said to be 7% WPI for the lumbar spine and 20% WPI for the right hip. Pre-existing conditions to both areas contributed to the impairment, the respondent submitted, as that was conceded by Dr Endrey-Walder and the respondent's expert

Dr Bentivoglio. 4. As to the third step, the quantum percentage to be deducted, the respondent conceded that the Medical Assessor had fallen into error in failing to make a deduction with regard to the lumbar spine. It submitted that at the least a deduction of 10% ought to have been made. However, as earlier noted, the respondent did not appeal this point, and this submission is accordingly rejected. 5. With regard to the contribution to the baseline impairment caused by the condition of the right hip, the respondent submitted that the Medical Assessor appeared to have taken the same approach as Dr Bentivoglio in his report of 15 July 2021. Dr Bentivoglio had found that the impairment rating for the hip replacement was exactly the same as the rating for the preceding hip fusion. 6. The respondent concluded by conceding that the Medical Assessor had not clearly applied the three-step process required regarding the application of s 323 but submitted that for the reasons it advanced, the deduction of 0% was correct and ought not to be disturbed. It conceded in doing so that the right hip condition was a consequential condition.

1. As noted, the referral sought a WPI assessment for injury to:
   • the lumbar spine;
   • the right lower extremity (hip), (hereinafter described as "the right hip");
   • scarring (TEMSKi), and
   • the digestive system (upper gastrointestinal tract).
2. As noted in the definition paragraph above it is convenient to refer to the total impairment assessed for the subject injury prior to any deduction or modification as the "baseline WPI."
3. Despite it being the subject of some conjecture from the respondent, the assessment of the lumbar spine has not been challenged. The baseline WPI for injury to the lumbar spine was assessed at 7%.
4. The baseline WPI for the scarring (TEMSKI) injury was assessed at 2%, from which the Medical Assessor deducted 50% pursuant to s 323 of the 1998 Act, leaving a subtotal of 1%. There has been no appeal against this rating.
5. The baseline WPI for injury to the digestive system as referred was assessed at 0%, from which there has again been no appeal.
6. The baseline WPI for the right hip was not assessed as 0%, as appeared by error in the Table 2 certificate[12], but as 20%, being a "fair" result for Mr Burns' right hip replacement pursuant to Table 17-33 of AMA5. There has been no appeal against that 20% rating.

1. It is axiomatic that a Medical Assessor is bound by the terms of the referral. That is the document that informs the parameters of his inquiry.[13] The full referral to the Medical Assessor read:

1. MEDICAL DISPUTE REFERRED FOR ASSESSMENT (s319 WIM Act)

• □ the degree of permanent impairment of the worker as a result of an injury (s319(c))
• □ whether any proportion of permanent impairment is due this to any previous injury or pre- existing condition or abnormality, and the extent of that proportion (s319(d))
• □ whether impairment is permanent (s319(f))
• □ whether the degree of permanent impairment of the injured worker is fully ascertainable (s319(g))

Body part/s referred: lumbar spine, right lower extremity (hip), scarring

(TEMSKI), digestive system (upper gastrointestinal tract)

1. The Medical Assessor took an accurate history that Mr Burns had injured his back whilst lifting a Dalmatian dog, then diagnosed that Mr Burns had suffered:

"Aggravation of pre-existing degenerative lumbosacral disease."

1. Secondly, the summary of injuries at [7] of the MAC noted:

"Right hip revision due to aggravation of degenerative disease of lumbar spine due to previous hip fusion."

1. Thirdly, the Medical Assessor then found at [8f] and [8g] that:

"Mr Burns suffered from right femoral head necrosis which required subsequent right hip fusion which led to degenerative disease of the back.... Mr Burns' hip replacement was due to this previous hip fusion and it was the opinion that his back pain was being aggravated by the fusion. This was secondary to femoral hip necrosis which was constitutional.

From Dr Solomon's assessment dated 5 March 2013, he described the hip as being fused in 20° flexion. He also had gluteal muscle damage.

This fusion was clearly pre-existing and unrelated to his back injury and according to the WorkCover Guides, it should be deducted. The fusion was considered a major aggrevating [sic] factor in his back pain.

There has been no subsequent injury, other than aggravation of Mr Burns pre-existing degenerative disease of his back."

1. It is unremarkable that a frank injury can have as its cause, the aggravation of a pre-existing disease.[14] In Bindah v Carter Holt Harvey Woodproducts Australia Pty Ltd[15] Meagher JA (Ward and Emmett JJA agreeing) said at [24]:

"In their exchanges the parties did not treat the injury as consisting only in the acceleration of a disease within s 4(b)(ii) and s 16 of the 1987 Act. There was good reason for that. In Rail Services Australia v Dimovski this Court (Handley JA, Hodgson JA and Young CJ in Eq) held .... that s 16 applies if the relevant injury only "consists in" the acceleration or exacerbation of a disease. Where, as in the present case, there is an event causing injury within s 4(a), the circumstance that the injurious event and injury included the aggravation of an existing disease does not mean that the injury, or some part of it, is an injury within s 16: Dimovski at [29] (Handley JA) and [68] (Hodgson JA). Rather the exacerbation or aggravation of the existing disease is part of the pathology of the injury within s 4(a)."

1. However, the Medical Assessor has made an error of fact when ascribing the cause of the aggravation to the pre-existing condition of Mr Burns' right hip. The evidence, as set out in our summary of the relevant factual background, shows that Mr Burns was referred by his spinal surgeon Dr Saravanja to a hip and knee surgeon, Dr Solomon.
2. In his report of 7 November 2012, Dr Saravanja took a history that:[16]

"...Mitchell [Mr Burns] is a fit and large gentleman who is about six foot four and normally has no difficulty with heavy weights.

(Dr Sarvanja then set out the history of the injury).

Mitchell has had no major back problems prior to this injury"

1. Dr Sarvanja noted that Mr Burns had returned to work on light duties, but that his back pain had increased in the previous 10 days or so. Dr Sarvanja said:

"....[H]is walking is variable so that when he is in severe pain, his walking is limited. When he is not in severe pain he can walk without significant limitation."

1. Dr Sarvanja diagnosed an aggravation of pre-existing lower back degenerative change. He noted that Mr Burns' back function had "been significantly debilitated by this injury."
2. As treatment for this injury, Dr Sarvanja recommended a cortisone injection but also advised that the fused right hip was causing a likely increase in degenerative change on account of the altered gait pattern.
3. As a form of treatment therefore Dr Saravanja recommended that the question of a take down of Mr Burns' fusion and a total hip replacement be investigated, and Mr Burns was consequently referred to Dr Solomon.
4. In a subsequent report of 20 December 2012, Dr Saravanja suggested that "the solution for [Mr Burns'] lumbosacral problems would be a lumbosacral fusion....after hip replacement..."[17]
5. Dr Solomon wrote on 5 March 2013:[18]

"I had a long discussion with Mitchell with respect to his hip and back. Whilst the hip does not hurt in view of the fusion, clearly his weight [145kg] and build is putting a lot of stress on his lumbar spine causing discomfort. It is possible to take down the fusion but at best he will gain about 50% of the movement that he has on the opposite side. It should relieve a lot of his lumbar spine pressure..."

1. The subsequent history, as we related, was that Mr Burns came to a hip replacement on

1 October 2013, with positive results. On 19 August 2014 Dr Saravanja noted:[19]

"...[Mitchell] has gradually improved after this last exacerbation of his L4/5 spinal problem which dates back to his work injury. Mitchell is not in need of any acute intervention on my part."

1. It can thus be seen that the hip replacement (and the subsequent revisions in 2020 and 2024) had as its purpose the treatment of the lumbar spinal injury of 12 July 2012.
2. As we noted, the Medical Assessor acknowledged this in relating Mr Burns' history, as he said of the hip replacement procedure:[20]

"My comment: This procedure was clearly performed to improve Mr Burn's back pain."

1. This acknowledgment demonstrates the central premise of Mr Burn's submissions; that the referral for the assessment of the right hip was on the basis that it was a consequential condition, and not an injury per se.
2. We are satisfied that the condition of the fused right hip did not become a significant issue until after 12 July 2012. Mr Burns did not have any major back problems until that date, and certainly none that impaired him from doing his job as a labourer/kennel hand with the respondent for any significant period of time. The aggravation made his degenerative condition symptomatic to the extent that he needed hospital treatment immediately following the lifting incident, when he was unable to sit or stand. Mr Burns in his statement of

4 August 2021 set out his prior problems with his back.[21] He listed back claims on: * 6 December 2006; * 7 January 2007 (there appears to be a typographical error in the date '2006'); * 28 February 2007; * 14 February 2008, and * 9 October 2008. 3. These were, however, self-limiting. Mr Burns had worked with the respondent from around 2000 doing work which he described at [12] of his statement:

"12. The nature and conditions of my employment were very arduous. It included handling large loads of laundry, repetitive lifting of animals including live and dead animals and reaching down into low and awkward kennels and cleaning them. It was physically demanding and repetitive work..."

"(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. The parties have both referred to Southwell, in which Wright J considered the authorities that govern the application of s 323. He considered the section and stated at [50]:

"Thus, it has been held, in cases such as Elcheikh v Diamond Formwork (NSW) Pty Ltd (in liq) [2013] NSWSC 365 at [126] (Schmidt J) and Secretary, Department of Communities and Justice v Lewandowski [2023] NSWSC 334 at [52] (Griffith AJ), that what must be determined under s 323 involves, at least, three enquiries:

• Firstly, what the extent of the resulting impairment is

• Secondly, whether the pre-existing condition contributed to the impairment

• Thirdly, if it did, what proportion of the impairment was due to the pre-existing condition."

"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 proposition advanced by Mr Burns appeared to be that the impairment level after the "second injury" referred to by her Honour was the baseline WPI assessed for the lumbar spine of 7%. The "first injury"[22] was the pre-existing right hip condition, but limited to an assessment of the right hip replacement that had been a consequence of the lumbar spine injury.
2. The submissions were however framed in the context of the deduction made for the right hip. The premise of this submission seems to be that the subsequent surgery on the right hip had resulted from the lumbar spine injury, and was therefore assessable.
3. This submission however has a problem. A perusal of the terms of the above referral shows that there is no reference to the right lower extremity (hip) as being consequential. The Medical Assessor was simply asked to assess the right hip as if it too had been injured on

12 July 2012. Thus, whilst he commented that the hip replacement was clearly performed to improve Mr Burn's back pain, he was under no obligation to consider the implications of that finding. His function was to assess the right hip on the basis that it had been injured as if it had been injured on the date of injury. 4. Mr Burns alleged that the Medical Assessor was obliged to treat the claim regarding the right hip as if it were consequential to the injury to the lumbar spine. This, it was argued, was because on 9 November 2021 an order was made by Member Jane Peacock to that effect. This submission was, with respect, misconceived. The submission that the COD dated

9 November 2021 somehow bound the Medical Assessor, overlooked both the terms of the Member Whiffen's subsequent COD dated 16 April 2025 and the terms of the referral itself. It was nothing to the point that in 2021 a different order was made. There is no evidence that Member Peacock's order was ever the subject of a referral, indeed there is no evidence as to what became of that matter, which we assume was not proceeded with, bearing in mind the limits imposed by s 66 (1A) of the 1987 Act. 5. There was no identification within the referral to the fact that the Medical Assessor was to approach the assessment of the right hip on the basis that it had been caused as a consequence of the injury to the lumbar spine. Had there been one, then the Medical Assessor may well have re-assessed his opinion. Thus Mr Burns could not claim that the Medical Assessor had erred in this respect, as he simply complied with the terms of the referral. 6. The Medical Assessor then considered that baseline WPI of 20% in the light of the history of the right hip fusion when Mr Burns was 13 years old, some 27 years earlier, as a result of a constitutional femoral necrosis. 7. The Medical Assessor made assumptions as to the probable contribution of that fused hip condition to the baseline impairment, and explained his conclusion by reference to the appropriate guideline, Table 19-9 of AMA5. The appellant criticised this assessment because it was hypothetical, but as the Medical Assessor had not examined Mr Burns until after the right hip replacement, he could only use his experience and expertise to inform his assumption regarding the effects of the fusion.[23] A Medical Assessor is at liberty to make findings of fact in exercising his function[24] and we are satisfied that his assumptions using Table 17-9 of AMA5 were open to him. 8. Accordingly, although the Medical Assessor has erred in his assumption that the lumbar spine injury had been due to Mr Burns' right hip condition, that error has not resulted in any outcome in Mr Burns' favour, as the Medical Assessor made no deduction to the baseline WPI of 7%. We note the respondent's concession that the Medical Assessor's reasons were not clearly outlined. 9. The final result might have been therefore that the MAC would be confirmed. However, we note the respondent's submission at [14] of its submissions:[25]

"In the respondent's submission, the MA understood and appreciated that it had been accepted that the worker sustained a consequential injury to his right hip as a result of the injury on 12 July 2012...."

1. As indicated, we are satisfied to the contrary that the Medical Assessor was not aware that he was required to either understand or appreciate that the assessment of the right hip was supposed to have been referred as a consequential condition. Nonetheless, the respondent did not cavil with the appellant's submission that "the right hip was a consequential condition" and made no demur to such a suggestion.
2. As indicated above, Skates is authority for the proposition that the referral informs the parameters of the inquiry, and a Medical Assessor is bound by its terms. There is, however, one exception, and that is that if a term of the referral does not reflect the parties' agreement as to the dispute they wish to be assessed, that agreement takes precedent. Accordingly, we may correct the error that has been made in the referral, noting that it is inexplicable, to use the description used by Basten JA in Skates, as to how the parties ever agreed to both the consent order before Member Whiffen, or to the referral being issued as it was.
3. In order to reassess the right hip on the basis that it was the parties' intention that it be assessed as a consequential condition resulting from the lumbar spine injury, it is necessary to consider the whole of the evidence. It is the right hip replacement that has resulted in an entitlement to 20% WPI by the application of Table 17-33 of AMA5, which provides an arbitrary impairment quotient:

Whole Person (Lower Extremity) [Foot] Impairment (%)

1. In Elcheikh[26] a similar situation pertained. The claimant had in fact been asymptomatic with a condition of Scheuermann's disease which he aggravated at work. He became entitled to an arbitrary entitlement by virtue of the surgery that was consequentially performed to treat the condition. Schmidt J said at [104]:

"The Appeal Panel approached what it had to determine by adopting what the medical specialist had asked himself as to whether the underlying condition was a necessary factor in the decision to carry out the surgery undertaken in 2010. He concluded that it was, observing that 'if not for the underlying Scheuermann's disease, there is no way that surgery would have even been considered'. If this was a relevant consideration in the factual circumstances, what clearly also required consideration, given that the condition had been asymptomatic, was whether, without the impact of his heavy work the pre-existing condition would have required such surgery."

1. It is necessary to consider all the evidence when assessing the third stage of the three-step procedure, the quantum of the contribution. Mr Burns' case is unusual, in that he had suffered the right hip fusion surgery when a boy of 13. The effect of this hip fusion was described in the evidence. We can assume that the hip was fused in a functional position, noting the 20 (degrees) of flexion and very slight external rotation. Mr Burns also had 2cm of shortening of his right leg, so the extent of his fusion would have been about 32%, using Table 17-9 of AMA5. Thus prior to his back injury, Mr Burns' hip condition would have been assessed at 32% WPI.
2. However, that condition was nonetheless essentially asymptomatic. In his statement,

"9. Between 1994 and 2013, I did have some aches and pains, however, I did not have any significant issues with my hip and I do not recall being off school or when the time came, work, for any prolonged period.

10. I was otherwise fit and well when I commenced employment at Sydney University. This was my first job after finishing school."

1. As has been seen, the right hip replacement procedure was carried out to take the stress off Mr Burns' lumbar spine. Dr Solomon described it above:

"It is possible to take down the fusion but at best he will gain about 50% of the movement that he has on the opposite side. It should relieve a lot of his lumbar spine pressure..."

1. Thus the right hip treatment for the lumbar spine has indeed improved Mr Burns' condition - to the extent that Dr Saravanja did not perform the lumbosacral fusion he was contemplating prior to the hip replacement on 1 October 2013. It has, however caused the right hip to become symptomatic, as the history demonstrates.
2. It is significant that during the 12 years or so that Mr Burns was performing the arduous duties he described, his hip was not the subject of any complaint. It was only when it was the subject of the hip replacement that it became symptomatic, so that the incident of picking up the dog has been a significant causal factor. To rephrase the question of Schmidt J in Elcheikh, would the hip replacement surgery have been required but for the heavy work

Mr Burns had been doing? 3. Balancing these considerations, the fact of the hip fusion, albeit when Mr Burns was a teenager, would have left him with an impairment of 32% WPI, due to the restrictions in his motion, as the effect of a fusion is that for every forward step and backward step, the whole pelvis moves with the femur, thus causing stress on the lumbar spine, which has to go from lordosis to kyphosis with every gait step. We are constrained to evaluate that prior condition in the light of the fact that the surgery that ensued has created a further 20% WPI, assessed as an arbitrary number by virtue of the guideline. A deduction is warranted, but it needs to reflect the facts of the case, which include the significance of the frank injury to the lumbar spine, and the fact that Mr Burns' right hip was essentially asymptomatic until that injury on 12 July 2012. 4. We therefore find that the appropriate deduction of the right hip baseline WPI to be one half. 5. For these reasons, the Appeal Panel has determined that the MAC issued on 9 July 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 Phillip Truscott 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] [2005] NSWSC 954.

[9] [2024] NSWSC 497.

[10] [2015] NSWSC 526.

[11] [2010] NSWSC 78.

[13] Skates v Hills Industries Ltd [2021] NSWCA 142.

[14] Rail Services Australia v Dimovski [2004] NSWCA 267.

[15] [2014] NSWCA 264.

[22] The facts of Cole were concerned with a previous injury, rather than a pre-existing condition.

[23] See Wingfoot Australia Partners Pty Ltd v Kocak [2013] HCA 43 at [47].

[24] See generally Bindah v Carter Holt Harvey Woodproducts Australia Pty Ltd [2014] NSWCA 264.

[26] Elcheikh v Diamond Formwork (NSW) Pty Ltd (in liq) [2013] NSWSC 365.