Glen Innes Severn Council v Faint

DETERMINATION OF APPEAL PANEL
CITATION:	Glen Innes Severn Council v Faint [2024] NSWPICMP 702
APPELLANT:	Glen Innes Severn Council
RESPONDENT:	Diana Faint
APPEAL PANEL
MEMBER:	Catherine McDonald
MEDICAL ASSESSOR:	Christopher Oates
MEDICAL ASSESSOR:	Doron Sher
DATE OF DECISION:	9 October 2024
CATCHWORDS:	WORKERS COMPENSATION - Workplace Injury Management and Workers Compensation Act 1998; assessment of whole person impairment after bilateral knee replacements; Medical Assessor made section 323 deduction of 1/10^th; analysis of contemporaneous evidence as to arthritis; Cole v Wenaline Pty Ltd, Secretary, Department of Communities and Justice v Lewandowski; Southwell v Qantas Airways Limited; Medical Assessment Certificate revoked.

BACKGROUND TO THE APPLICATION TO APPEAL

On 16 July 2024 Glen Innes Severn Council (the Council) lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Medical Assessor Peter Honeyman, who issued a Medical Assessment Certificate (MAC) on 19 June 2024.
The Council relies on the grounds of appeal under s 327(3)(c) and (d) 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.
The President’s delegate was satisfied that, on the face of the application, at least one ground of appeal was made out, being that the assessment was made on the basis of incorrect criteria with respect to a deduction under s 323 of the 1998 Act. We conducted a review of the original medical assessment, limited to the grounds of appeal on which the appeal is made.
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.
The assessment of permanent impairment is conducted in accordance with the SIRA NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4^th ed 1 March 2021 (the Guidelines) and the American Medical Association Guides to the Evaluation of Permanent Impairment, 5^th ed (AMA 5).

RELEVANT FACTUAL BACKGROUND

Ms Faint suffered an injury on 16 November 2012 when she tripped while walking up a ramp. Though the main treatment immediately following the injury was for her left knee, it is agreed between Ms Faint and the Council that she suffered injury to both knees. She underwent a right total knee replacement in 2019 and a left total knee replacement in 2020. Ms Faint had undergone previous surgery to her left knee in 1998 and 2000.
The matter was listed before the Personal Injury Commission (Commission) on 5 March 2024 and the disputes between the parties were resolved with the exception of the extent of the permanent impairment suffered by Ms Faint, including any deduction under s 323 of the 1998 Act. By the orders made, Ms Faint accepted that the injury was not caused by the nature and conditions of her employment. The parties agreed that the Medical Assessor should assess the impairment arising from an injury on 16 November 2012 to both of Ms Faint’s knees.
The Medical Assessor assessed 30% WPI in respect of each of Ms Faint’s knees and applied a one-tenth deduction under s 323, resulting in 27% WPI for each. He added 1% for scarring under the Table for the Evaluation of Minor Skin Impairments. The total WPI was 48%.

PRELIMINARY REVIEW

We conducted a preliminary review of the original medical assessment in the absence of the parties and in accordance with the Procedural Direction PIC7.
As a result of that preliminary review, we determined that it was not necessary for Ms Faint to undergo a further medical examination because there is sufficient information in the file to determine the appeal.

EVIDENCE

We have all the documents that were sent to the Medical Assessor for the original medical assessment and have taken them into account in making this determination.
The parts of the MAC that are relevant to the appeal are set out below.

SUBMISSIONS

Both parties made written submissions. They are not repeated in full, but we have considered them.
In summary, the Council submitted that the Medical Assessor did not make an appropriate deduction under s 323 of the 1998 Act where medical evidence showed that Ms Faint had undergone left knee surgery in 1998 and scans taken at the time of the injury showed pre-existing osteoarthritis. The Council said that the Medical Assessor had not provided reasoning to explain why it would be too difficult or costly to determine the extent of the deduction when there was considerable medical information in the file. The Council did not make any submission as to the appropriate deduction. It did not take issue with the primary assessments that the Medical Assessor made.
In reply, Ms Faint submitted that a s 323 deduction was not applied merely because she may have had “issues” with the same body part before the injury. Referring to Cole v Wenaline Pty Ltd[1] (Cole), she submitted that the assessment must have regard to the actual consequences of the earlier injury. Ms Faint said that when the MAC as a whole was considered, it was clear that the Medical Assessor had regard to her underlying issues. She noted that the Medical Assessor was not bound by the opinions of other doctors.
[1] [2010] NSWSC 78.

FINDINGS AND REASONS

The procedures on appeal are contained in s 328 of the 1998 Act. The appeal is 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.
In Campbelltown City Council v Vegan[2] the Court of Appeal held that an 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.
[2] [2006] NSWCA 284.
In Queanbeyan Racing Club Ltd v Burton[3] the Court of Appeal held that an Appeal Panel is not limited to the ground held to have been made out by the delegate but may consider all grounds of appeal raised in the application. However, the panel is not permitted to look for errors which are not part of the grounds of appeal on which the appeal is made. We have only considered those grounds specifically raised by the appeal.
[3] [2021] NSWCA 304 at [26].

The MAC

The Medical Assessor set out a history of the injury:
“On the date of injury, she tripped while walking up a ramp. She fell onto both knees. She had excessive bruising with the left more affected than the right. She continued at work, going through investigations and various treatments until eventually the right knee was replaced in 2019 and the left in 2020.
She remained at work until 2016, when the Council did a reorganisation and made her redundant. She has not worked since, except for some voluntary work.”
The Medical Assessor described Ms Faint’s current symptoms and her previous condition, saying:
“She says that she had her right patella rearranged in 1999. She had a fall, which fractured her right ankle and had a pin in 2006. Prior to the accident, there was a work fitness program that had her going to the gym and she felt that she was active and well up until 2012.”
The Medical Assessor described his findings on examination. With respect to the radiology, he observed:
“Much of the material for review tracks the progress of injuries. It confirms that there was existing osteoarthritis close to time of injury.”
The Medical Assessor’s diagnosis was “bilateral osteoarthritic knees replaced by total knee replacements”. He said:
“There was a fall 1999 that resulted in left patella re alignment surgery. There was a fracture of the left ankle. There was long standing osteoarthritis present at the time of fall in 2012. This was asymptomatic, but the natural history for osteoarthritis is to be progressive.”
The Medical Assessor assessed 30% WPI in respect of each of Ms Faint’s knees and 2% for scarring. He explained his calculations:
“The knees are rated using ORE estimates as set out 17-33, p 546-547. AMA 5.
This requires an assessment of function as set out p21, T17-35 NSW guides.
For the right knee, moderate pain is reported, (20) range of motion full (14), stability is full (5 and 10) with deductions 5. A score of 44 is a poor result. This suggests a right knee 75% LEI.
For the left knee, severe pain is reported, (0) reduced range of motion (22), stability is full (10 and 5) with deductions of 10. A score of 29 is a poor result. This suggests a left knee 75% LEI.
The scaring is most noticeable. She is conscious of the scars and hides them. Scarring remains sensitive. This is rated with reference to T14.1 p 74 NSW Guides at 1%WPI.”
With respect to s 323, the Medical Assessor said that Ms Faint had the relevant pre-existing condition of “Osteoarthritis both knees. Asymptomatic”. He said:
“I have taken into account that the injury in 2012 has accelerated the osteoarthritis by disturbances of gait and reduced activity resulting in major weight gain,”
And:
“The proportion is difficult to assess so 1/10 should be deducted.”

Assessment after total knee replacement

Total knee replacement is generally undertaken as treatment for arthritis. The Guidelines point out in paragraph 3.19 that impairment due to arthritis following a work-related injury is uncommon and that the presence of arthritis may indicate a pre-existing condition. The aggravation of the pre-existing condition of arthritis in Ms Faint’s knees by the injury led to the need for total knee replacement.
Section 323 requires that there “be a deduction for any proportion of the impairment that is due to a previous injury”. Section 323(2) only permits a deduction of one-tenth of the impairment assessed if the extent of the deduction would be difficult or costly to determine and provides an example of circumstances in which that may be the case – “the absence of medical evidence”.
As Wilson J said in Mercy Centre Lavington Ltd v Kiely & Ors:[4]
“Even were s 323(2) available to assess an appropriate deduction, the provision is not open-ended. It permits a ten per cent deduction to be made in circumstances where it would be “difficult or costly” to make a more specific assessment, the example given in the provision being because of a lack of medical evidence. Here, there was a great deal of evidence to which the MAP could have had regard, and no evidentiary basis upon which to conclude that it would be too difficult or costly for it to do so.”
[4] [2017] NSWSC 1234 at [62].
In this case there are some medical reports which predate the injury and considerable contemporaneous radiological evidence. The clinical observations of those who examined Ms Faint are relevant so that it was therefore necessary to consider the contemporaneous medical evidence in detail before determining the s 323 deduction. The Medical Assessor did not do that and he was in error in failing to do so, particularly when he had observed that there was longstanding arthritis present at the time of the fall and that the natural history for arthritis is to be progressive.

Previous medical evidence

Ms Faint’s statement dated 30 October 2017 does not commence with the injury but with treatment in 2016 when Dr McKenzie declined to operate on her left knee due to complex regional pain syndrome. She denied that she had an underlying condition and said that the condition in her left knee was entirely the result of the injury. She did not recall her right knee being a problem before the left knee injury.
Ms Faint described the injury in her statement dated 2 July 2018. In her statement dated 25 July 2023 she said that Dr Pearce undertook a right knee replacement on 12 March 2018 and a left knee replacement on 8 April 2019. She said the outcome from the right knee was reasonably good but the left knee was poor.
There is some confusion in the file as to the extent of previous surgery on Ms Faint’s left knee. The file contains reports concerning surgery on Ms Faint’s left knee (under her previous surname) by Dr Wallace on 18 March 1998, being a “patellofemoral realignment with advancement of the medial vastus, medial retinaculum over the anterior aspect of the patella and associated lateral release”. His handwritten operation report appears to show grade III changes on the posterior aspect of the patella.
Dr Diebold said that he undertook surgery in 2000. When Ms Faint saw A/Prof Fearnside at the request of her solicitor in 2016, she said that she had suffered an injury to her left knee on 31 December 1999 when she had fallen on a boat and she had seen Dr Diebold and undergone a patellar realignment with a good result. Dr Shatwell, who saw Ms Faint in 2015 at the request of the Council, obtained a similar history.
Dr Harrison, who saw Ms Faint at the request of her solicitors attempted to grapple with the issue in his report dated 1 September 2016. He came to the view that there was one operation. He observed both a 22cm scar and arthroscopy portals.
A medical history form completed for Dr MacKenzie on 3 October 2015 refers to a patellar realignment and two arthroscopies of the left knee.
We consider that the appropriate conclusion is that there had been two previous operations – one in 1998 and one in 2000 after an injury at the end of 1999.
Ms Faint suffered an injury to her left ankle in mid 2003 and was referred to Dr Diebold who undertook a lateral ligament repair of her left ankle in October 2003. In a report dated 23 February 2004, Dr Diebold said:
“She now has some right knee soreness which clinically is patellofemoral in origin. This is undoubtedly secondary to the limp and favouring of her left leg increasing the work load on the right knee.”
Ms Faint underwent an X-ray of her left knee on 19 November 2012, three days after the injury. The report shows that the purpose of the X-ray was to exclude a fractured patella and the reference to previous left patellar realignment was noted in the history. The findings were:
“Moderate osteoarthritis affects medial femorotibial compartment, which is mildly narrowed with patient standing, with mild margin irregularity. Lateral femorotibial compartment appears well preserved. Small locus of ossification is present in the infra patella fat pad – this is extra synovial.
Moderate to severe osteoarthritis affects the lateral patellofemoral compartment, with variable joint space narrowing and development of prominent lateral margin osteophytes and bony irregularity. The patella is intact – no sign of fracturing.
No joint effusion. Mild pre-patella soft tissue density suggests bruising.”
A bone scan undertaken on 19 December 2012 showed increased vascularity in both knees, joints, mild on the right and moderate on the left. There was increased uptake in both knees, consistent with degenerative arthropathy, with more focal uptake on the right medial compartment, left medial compartment, and lateral edge of the left patella.
An MRI scan of the left knee reported on 24 January 2013 showed:
“patellofemoral joint OAA, and evidence of tibiofemoral joint OAA, which is a little more marked medially, where there is complete loss of articular cartilage over the dependent portion of the medial femoral condyle.”
The scan also showed a meniscal tear, a large amount of fluid and a Baker’s cyst which showed no sign of having ruptured.
Those scans, taken within two months of the injury, confirm that Ms Faint had significant arthritis in both knees. The extent of the arthritis indicates that it predated the injury in 2012.
Dr Diebold, orthopaedic surgeon, wrote to Ms Faint’s general practitioner on 8 February 2013. He diagnosed a flare up of patellofemoral osteoarthritis of her left knee. He said:
“On 16 November 2012 she fell onto the front of both knees when she slipped on some non-slip strips at work. She developed increased pain, swelling and bruising to both knees over some hours, more so the left than the right. She has had persisting pain that is particularly bad with stairs and limits her walking to about 20 minutes at present. She is slowly improving. She had a history of a patellofemoral realignment by me in 2000, which was a tibial tubercle transfer.”
Though he had a history of a fall onto both knees, Dr Diebold only described ongoing symptoms in Ms Faint’s left knee. He expected the flare up to take time to settle. On 2 May 2013 Dr Diebold recommended an arthroscopy to treat an active meniscal tear and an accompanying tibial tubercule transfer. He considered that the treatment step after that would be a total knee replacement.
Dr Rimmington reported to the Council’s insurer on 29 June 2013. He set out his examination findings and considered that the fall had stirred up arthritis and that the prognosis was poor. He said that the next step was an arthroscopy but that may make the situation worse. He considered that knee replacement would be required but recommended putting it off as long as possible. He said that the need for arthroscopy was a result of the aggravation but knee replacement would be more directed to the pre-existing condition.
On 13 August 2013 Dr Rimmington performed an arthroscopic debridement and partial meniscectomy on Ms Faint’s left knee. His operative findings were:
“Medial compartment, osteoarthritis, grade four changes medial edge, medial compartment, osteophytes throughout. ACL, PCL intact. Grade three changes both sides of the patellofemoral joint. Lateral compartment reasonably pristine. There looked to be a new tear of the posterior horn of the medial meniscus, and it was trimmed. There was a horizontal stitch to it and the inferior leaf was removed.”
In a report to the Council’s insurer dated 12 November 2013 Dr Rimmington expressed the opinion that the injury was the aggravation of a pre-existing condition. At that early stage, Dr Rimmington recommended that Ms Faint see a chronic pain specialist and he had concerns that a knee replacement would not be successful.
Dr Ray, pain management specialist, saw Ms Faint on 7 May 2014. He recorded that Ms Faint had an injury to her left knee in 2000 which was fixed by a patella realignment operation. After that surgery, she recovered well and was back at the gym twice a week. He set out his examination findings, some of which were suggestive of chronic regional pain disorder, though he did not make that diagnosis. He diagnosed mixed mechanical and neuropathic pain and recommended multidisciplinary pain management.
X-rays undertaken on 21 May 2015 (commented on by Dr Shatwell in his report dated 2016) showed severe medial compartment of both knee joints with varus deformity. Dr Shatwell said that there was no joint space in the medial compartment of either knee. Lateral views showed significant patellofemoral joint arthritis. The reference to a lack of joint space indicates that the arthritis Dr Shatwell observed was significant.
Dr Diebold saw Ms Faint again and reported on 31 August 2015. He told Ms Faint’s general practitioner that the left knee replacement should not be “accepted as a Work Cover claim” because she has marked arthritis in her knee before the injury and any contribution from her work related injury is “well and truly gone by now”. He said that if her arthritis justified a knee replacement, it would have happened without the fall. Dr Diebold estimated a 50% chance if there not being a good result and referred Ms Faint to Dr MacKenzie.

In his letter to Dr MacKenzie dated 2 September 2015, Dr Diebold noted that Ms Faint’s condition “may be complicated somewhat by non-organic factors” that she walked with a “rather bizarre gait with two sticks”.
Dr MacKenzie saw Ms Faint on the referral of Dr Diebold and reports on 21 January 2016. He noted that she had severe bilateral osteoarthritis and commented that:
“She does have severe bilateral osteoarthritis, interesting the x-ray appearance is worse on the right than the left. She has some symptoms on the right but not really that severe. Her issues date back to a fall in November 2012, when she landed on her knee and started getting pain. Someone up in Brisbane decided to do a knee arthroscopy for her despite the direct blow the nature of her injury and her bone on bone medial compartment osteoarthritis. Following this arthroscopy, she developed chronic regional pain syndrome.”
Dr MacKenzie considered that there was a risk that total knee replacement would make Ms Faint’s knee worse, and he considered that pain management treatment was required before considering that. He referred her to Dr Russo and in his referral letter dated
21 January 2016 said that her pain was disproportionate to her arthritis, even though he described the arthritis as very severe. He said Ms Faint’s right knee was “just as bad radiologically”.
In February 2016 Ms Faint’s general practitioner, Dr Hebblewhite, referred her for consideration of bariatric surgery.
Dr Diebold saw Ms Faint again and reported on 23 November 2016. He noted that the pain management treatment had not been undertaken and that recent X-rays showed severe medial arthritis in both knees. He said that Ms Faint needed knee replacements but expected a “stormy course” in respect of pain control and rehabilitation. He did not consider that she should have the surgery in Armidale and referred her to Dr Kinny in Lismore.
On 17 January 2017 Ms Faint saw Dr Kinny “complaining of significant right knee osteoarthritis, which is severe enough to justify knee replacement”. Dr Kinny was unable to perform the operation in the absence of an accepted injury or private health insurance.
Ms Faint was then referred to Dr Pearce in 2017 in respect of her right knee. He declined to provide any medicolegal reports or comments in respect of her left knee. He said that her right knee had become a problem three to four years before. He recommended a right total knee replacement which he undertook on 12 March 2018. In May 2018 Dr Pearce recommended that Ms Faint join the public hospital waiting list for a left total knee replacement. The left knee surgery was undertaken on 8 April 2019. At operation he observed “old surgery scarring”.

Medico-legal reports

The Medical Assessor’s comments on the reports of Drs Bodel and Powell were very brief and he did not consider the way they dealt with s 323, to the extent that they did.
Dr Bodel assessed Ms Faint in June 2020 and obtained a history that she fell on both knees but mostly the left. He obtained a history of a previous injury in 1998 and that her knee functioned normally thereafter. He said that Ms Faint had a reasonable outcome from her right knee replacement but was left with pain, swelling, increased heat and stiffness on the left. He diagnosed an aggravation of a previously asymptomatic disease process. Dr Bodel considered that the level of symptoms of which Ms Faint complained was an unacceptable outcome which required further investigation. He assessed a good outcome for the right knee, resulting in 15% WPI and anticipated further improvement in respect of the left knee.
Dr Bodel saw Ms Faint again and reported on 21 June 2021. He considered that she had a good result in respect of her right knee (15% WPI) and a fair result in respect of her left knee (20% WPI). He declined to make a deduction under s 323 because Ms Faint was asymptomatic before the injury.
Dr R Powell provided an assessment of permanent impairment dated 27 June 2023. Ms Faint had previously been seen by Dr J Powell at the request of the Council in 2013. Dr R Powell did not believe that the knee replacement surgery was required as a result of injury and did not assess permanent impairment.

Consideration

Our review of the evidence – and in particular the contemporaneous radiology - shows that Ms Faint had severe osteoarthritis at the time of the injury in 2012. The opinions of Ms Faint’s treating doctors from the early stages of her post-injury treatment were that she would require total knee replacements, though they had doubts as to whether they would be successful. The finding from the arthroscopy in 2013 were that the left knee arthritis was severe.
Ms Faint said that she recovered from the effects of the previous injury and surgery. She may not have had symptoms but the scans taken after the injury show severe arthritic change which would have existed for a long time and which would have been progressive. Ms Faint’s significant weight contributed. It was the presence of severe arthritis which led to the need for total knee replacements.
The fact that Ms Faint said she was asymptomatic before the injury is not relevant to the s 323 deduction. Basten JA said in Vitaz v Westform (New South Wales) Pty Limited[5] that “if a pre-existing condition is a contributing factor causing permanent impairment, a deduction is required even though the pre-existing condition had been asymptomatic prior to the injury.”
[5] [2011] NSWCA 254 at [43].
Once knee replacement is undertaken, the result is assessed under Table 17-35 of AMA 5 as amended by paragraph 3.30 of the Guidelines. The assessment is made on the basis of six criteria to which points are ascribed. Under Table 17-33 of AMA 5, a score of 85 to 100 points is a good result, resulting in 37% lower extremity impairment (LEI) or 15% WPI, 50 to 84 points is a fair result (50%LEI or 20% WPI) and less than 50 points is a poor result (75% LEI or 30% WPI). The Medical Assessor assessed both of Ms Faint’s knee replacements as poor results.
After joint replacement surgery, it is no longer possible to identify the proportion of the impairment due to the pre-existing condition because there is a new, resurfaced joint. The outcome of the surgery may vary from person to person and the extent of pre-existing osteoarthritis does not necessarily determine the outcome of the surgery. However, it is the pre-existing arthritis, aggravated by the injury that led to the need for joint replacement surgery.
Ms Faint’s submission that the Medical Assessor engaged with s 323 as set out in Cole cannot be accepted. As we said above, there is ample medical evidence as to the condition of Ms Faint’s knees at the time of the injury. It cannot be said that the deduction is difficult or costly to determine.
Griffiths AJ summarised the effect of Cole in Secretary, Department of Communities and Justice v Lewandowski,[6] referring also to Schmidt J’s decision in Elcheikh v Diamond Formwork (NSW) Pty Ltd (in liq):[7]
[6] [2023] NSWSC 334.
[7] [2013] NSWSC 365.
“… it is well-settled that s 323 of the 1998 Act requires a medical assessor or a Panel hearing an appeal to reach a conclusion as to whether or not any proportion of permanent impairment assessed has resulted from an earlier injury, pre-existing condition or abnormality. Moreover, that conclusion must generally be reached on the evidence adduced concerning the actual consequences of the earlier and later injury (unless the assumption provided for in s 323(2) applies). It is well to set out the following relevant paragraphs from Cole v Wenaline Pty Ltd [2010] NSWSC 78 at [29]–[31] per Schmidt J (emphasis added):
[29] As the plaintiff argued, to so approach the exercise required to be undertaken by s 323, was to fall into an error of law. The section is directed to a situation where there is a pre-existing injury, pre-existing condition or abnormality. For a deduction to be made from what has been assessed to have been the level of impairment which resulted from the later injury in question, a conclusion is required, on the evidence, that the pre-existing injury, pre-existing condition or abnormality caused or contributed to that impairment.
[30] Section 323 does not permit that assessment to be made on the basis of an assumption or hypothesis, that once a particular injury has occurred, it will always, ‘irrespective of outcome’, contribute to the impairment flowing from any subsequent injury. The assessment must have regard to the evidence as to the actual consequences of the earlier injury, pre-existing condition or abnormality. The extent that the later impairment was due to the earlier injury, pre-existing condition or abnormality must be determined. The only exception is that provided for in s 323(2), where the required deduction ‘will be difficult or costly to determine (because, for example, of the absence of medical evidence)’. In that case, an assumption is provided for, namely that the deduction ‘is 10% of the impairment'. Even then, that assumption is displaced, if it is at odds with the available evidence.
[31] The reason for this statutory approach can readily be seen. It is entirely possible that a person could suffer such a catastrophic injury, that the presence or absence of any previous injury, pre-existing condition or abnormality, would make no difference at all to the impairment which resulted from the later injury. An injury which results in death, is an obvious example, albeit not one which would arise for consideration under this section. A more relevant example, in this case, is a second injury which severed the spine. Or, as was discussed in the authorities, an earlier injury which was asymptomatic, may or may not contribute to the impairment which results from a second injury. That is a matter of fact to be assessed on the evidence led in each case. An assumption of the kind here made, namely that surgery to the lumber spine, irrespective of outcome, must always result in a level of residual impairment which contributes to the level of impairment which follows a later injury, has no role to play in that assessment. What must be determined on the evidence is whether any proportion of the permanent impairment present after the second injury was due to the earlier injury.
Her Honour affirmed those principles in Elcheikh and summarised the relevant steps to be taken under s 323 at [126]:
As discussed in Cole v Wenaline Pty Limited at [30], in the case of a workplace injury caused by an exacerbation or acceleration of a pre-existing condition, what must be determined by a medical specialist under s 323 is:
•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.” (emphasis in original).
The Medical Assessor assessed the extent of impairment on the basis of poor knee replacement results in both knees and there is no appeal with respect to his primary figures. The Medical Assessor said that the pre-existing condition contributed to the impairment.
With respect to the third aspect of his task, the Medical Assessor noted that there was existing osteoarthritis in Ms Faint’s knees close to the time of the injury but failed to engage with the findings on the scans or to note the examination finding of treating doctors, who considered early in Ms Faint’s treatment that knee replacements were likely. Those practitioners also considered that the surgery was problematic because of Ms Faint’s weight, medication intake and response to the injury. The Medical Assessor’s comment that the injury accelerated the osteoarthritis by disturbance of gait and major weight gain places the wrong emphasis on the history. Those factors are relevant, but the primary cause of the surgery was the underlying arthritis.
In the case of joint replacement, it is not possible to identify a component of the condition which relates to the pre-existing condition in the manner discussed in Qantas Airways Limited v Southwell.[8] Section 323 must be addressed by considering the role that the underlying condition played in the need for joint replacement surgery.
[8] [2024] NSWSC 497.
Reassessment is appropriate. We consider there is ample material in the file to reassess the deduction.
With respect to Ms Faint’s left knee, we consider that the appropriate deduction is one third. While it is accepted that Ms Faint injured both knees, the primary impact of the injury was to her left knee so that the injury played a greater part in the acceleration of the underlying condition. The arthritis in her left knee was severe at the time of the injury, as observed on the scans and on arthroscopy in 2013. The total knee replacement surgery was accelerated by the injury but was anticipated, and even warranted, at that time. It was not undertaken until 2018 because Ms Faint’s treating doctors were concerned by the development of chronic regional pain syndrome following the arthroscopy, by her intake of narcotic analgesia and by her weight. We consider that the appropriate deduction was one third. This results in an assessment of 20% WPI for Ms Faint’s left lower extremity.
A larger deduction of one half is appropriate in respect of Ms Faint’s right knee in which she had not had previous surgery or complaints, apart from the right knee aggravation in 2004 (when Ms Faint was limping after ankle surgery). While that was temporary, it confirms the impact of additional loading on an arthritic knee. There was minimal complaint and limited treatment to her right knee immediately after the injury in 2012. Many of Ms Faint’s treating doctors noted that her right knee was in fact worse than the left before knee replacement surgery and surgery to her right knee was undertaken first. Those factors indicate that the underlying condition contributed more to the need for surgery.
For these reasons, we have determined that the MAC issued on 19 June 2024 should be revoked, and a new MAC should be issued. The new certificate is attached to this statement of reasons.

WORKERS COMPENSATION DIVISION

APPEAL PANEL

MEDICAL ASSESSMENT CERTIFICATE

Injuries received after 1 January 2002

Matter number:	W53/24
Applicant:	Diana Faint
Respondent:	Glen Innes Severn Council

This Certificate is issued pursuant to s 328(5) of the Workplace Injury Management and Workers Compensation Act1998.

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

Table - whole person impairment (WPI)

Body Part or system	Date of Injury	Chapter, page and paragraph number in NSW workers compensation guidelines	Chapter, page, paragraph, figure and table numbers in AMA 5 Guides	% WPI	Proportion of permanent impairment due to pre-existing injury, abnormality or condition	Sub-total/s % WPI (after any deductions in column 6)
Right lower extremity (knee)	16/11/2012	Chapter 3, paragraph 3.30, Table 17-35 as amended	Table 17-33, p 547	30%	½	15%
Left lower extremity (knee)	16/11/2012	Chapter 3, paragraph 3.30, Table 17-35 as amended	Table 17-33, p 547	30%	1/3^rd	20%
Scarring TEMSKI	16/11/2012	Chapter 14	1%	1%
Total % WPI (the Combined Table values of all sub-totals)					33%

[2024] NSWPICMP 702

9 October 2024