Lewthwaite v State of New South Wales (Southern NSW Local Health District)

CERTIFICATE OF DETERMINATION OF MEMBER
CITATION:	Lewthwaite v State of New South Wales (Southern NSW Local Health District) [2025] NSWPIC 398
APPLICANT:	Michelle Lorraine Lewthwaite
RESPONDENT:	State of New South Wales (Southern NSW Local Health District)
MEMBER:	John Turner
DATE OF DECISION:	12 August 2025
CATCHWORDS:	WORKERS COMPENSATION - Workers Compensation Act 1987; claim for medical and treatment expenses; reasonably necessary; injury; consequential condition; sections 4 and 60; Kooragang Cement Pty Ltd v Bates, Briginshaw v Briginshaw, King v Collins, Nominal Defendant v Clancy, Davis v Council of the City of Wagga Wagga, Trustees of the Roman Catholic Church for the Diocese of Parramatta v Brennan, Moon v Conmah Pty Limited, Watson’s Culcairn Hotel Pty Ltd v Dwyer, Diab v NRMA Limited, and Murphy v Allity Management Services Pty Ltd cited and applied; Held – there is an award for the respondent in respect to the alleged injury to the right knee; the applicant sustained a consequential right knee condition due to the accepted left knee injury; the proposed total right knee replacement surgery is reasonably necessary as a result of the injury; the respondent is to pay pursuant to section 60 the costs of and incidental to total right knee replacement surgery.
DETERMINATIONS MADE:	The Commission determines: 1. There is an award for the respondent in respect to the alleged injury to the right knee on 19 April 2012. 2. That the applicant sustained a consequential right knee condition due to the accepted left knee injury. 3. That the proposed total right knee replacement surgery is reasonably necessary as a result of the injury. 4. The respondent is to pay pursuant to s 60 of the Workers Compensation Act 1987 the costs of and incidental to total right knee replacement surgery. A brief statement is attached setting out the Commission’s reasons for the determination.

STATEMENT OF REASONS

BACKGROUND

Michelle Lewthwaite (applicant) has brought proceedings in the Personal Injury Commission (Commission) in which she relevantly alleges that she sustained injury to both her knees on 19 April 2012 when she slipped on a wet ramp whilst in the course of her employment with State of New South Wales (Southern NSW Local Health District) (respondent).
The relief which the applicant seeks is the costs of and ancillary to bilateral total arthroplasty including patella of both knees pursuant to s 60 of the Workers Compensation Act 1987 (1987 Act).
The respondent has accepted liability for the left total knee replacement surgery in respect to which a direction was made on 26 May 2025. The respondent disputes liability in respect to the right knee.

ISSUES FOR DETERMINATION

The following issues remain in dispute:
(a) whether the applicant sustained the alleged injury to her right knee as defined by s 4 of the 1987 Act;
(b) whether the applicant sustained a consequential condition of the left knee, and
(c) whether the proposed treatment is reasonably necessary as a result of injury: s 60 of the 1987 Act.

PROCEDURE BEFORE THE PERSONAL INJURY COMMISSION

The matter was listed for conciliation conference/arbitration hearing before me on
14 April 2025. Ms Nicole Compton, counsel, instructed by Ms Emma Thomson, appeared for the applicant, who was present. Mr Justin Heng, solicitor, appeared for the respondent. The proceedings were conducted via MS Teams. I am satisfied that the parties to the dispute understand the nature of the application and the legal implications of any assertion made in the information supplied. I have used my best endeavours in attempting to bring the parties to the dispute to a settlement acceptable to all of them. I am satisfied that the parties have had sufficient opportunity to explore settlement and that they have been unable to reach an agreed resolution of the dispute.
Following the arbitration hearing a Certificate of Determination with Statement of Reasons was issued dated 24 April 2025 providing a determination in respect to a dispute that had arisen as to the matters in dispute. The parties have subsequently provided written submissions in respect to the substantive matter.

EVIDENCE

Documentary evidence

The following documents were in evidence before the Commission and considered in making this determination:
(a)    Application to Resolve a Dispute and attached documents;
(b)    Reply and attached documents;
(c)    documents attached to an Application to Lodge Additional Documents (ALAD) lodged on behalf of the respondent dated 8 April 2025;
(d)    documents attached to an ALAD lodged on behalf of the applicant dated
9 April 2025 with the exception of pages 13 to 19 and 21 to 28, and
(e)    documents attached to an ALAD lodged on behalf of the applicant dated
15 May 2025.

Oral evidence

No oral evidence was adduced.

FINDINGS AND REASONS

Injury

The applicant alleges that she sustained injury to both her knees in the fall at work on
19 April 2012.
Issues of causation must be determined on the facts in each case through a commonsense evaluation of the causal chain.[1] The applicant bears the onus of establishing injury on the balance of probabilities. For a tribunal of fact to be satisfied on the balance of probabilities of the existence of a fact, it must feel an actual persuasion of the existence of that fact.[2]
[1] Kooragang Cement Pty Ltd v Bates (1994) 35 NSWLR 452; (1994) 10 NSWCCR 796 (Kooragang).
[2] Briginshaw v Briginshaw [1938] HCA 34; 91938) 60 CLR 336 (Briginshaw).
It is the applicant's evidence that she slipped whilst walking down a ramp when her feet slipped from underneath her and she landed directly onto both her knees experiencing instant pain in both knees.[3]
[3] ARD p. 5.
The applicant did not report an injury to the right knee to the respondent directly following the fall. An AIMS Incident Detail form[4] in which the injury description appears to have been completed by the applicant as it is recorded in the first person, and which appears to have been completed on 20 April 2012 or at the latest on 23 April 2012 records that the applicant fell onto her left with injury being sustained to the lower back and left knee. It contains no mention of the right knee or of any injury being sustained to the right knee.
[4] Reply pp. 1-3.
The applicant also did not report an injury to her right knee to her general practitioner (GP) or her other health care providers or complain of right knee symptoms.
On 20 April 2012 the applicant attended on Dr Shireen Macabulos. The clinical record of the consultation records the history that the doctor took from the applicant of the applicant slipping and falling at work on to her left knee the previous day. The doctor undertook an examination of the applicant with extensive notes of the examination being recorded. The clinical record contains no mention of the applicant having sustained an injury to her right knee or of any right knee complaints.
Prior to the applicant attending on Dr Macabulos an X-ray had been performed of the applicant’s left knee at Bega District Hospital. No X-ray appears to have been performed of the right knee.[5]
[5] ARD pp. 290-291.
On 20 April 2012 Dr Macabulos referred the applicant to Matthew Lehoczky for physiotherapy. The referral records that the applicant had sustained a left knee injury with no mention of the right knee.[6] Also on 20 April 2012 an MRI was performed of the left knee. No scan was performed of the right knee.
[6] ARD pp. 401-402.
On 23 April 2012 the applicant consulted Dr Ben Harkness, GP, who recorded left knee pain as one of the reasons for the visit and on examination observed a “slightly” antalgic gait. The clinical record contains no mention of the right knee.[7]
[7] ARD p. 291.
On 2 May 2012 the applicant consulted Dr Jacqueline Lam, GP, who noted that the left knee was improving “but still painful.” The clinical record of the consultation again contains no mention of the right knee.[8]
[8] ARD p. 292.
On 3 May 2012 Dr Macabulos responded to a questionnaire from the workers compensation insurer in which the doctor recorded that the applicant had suffered injury to her left knee with no mention of any injury to the right knee.[9]
[9] ARD pp. 394-396.
On 8 May 2012 Matthew Lehoczky, physiotherapist, reported to Dr Sam Tormey in respect to injury to the left knee.[10]
[10] ARD p. 397.
On 9 May 2012 the applicant again consulted Dr Lam in respect to her left knee. The clinical record of the attendance once again records no mention of the right knee.[11]
[11] ARD p. 292.
On 17 May 2012 the applicant attended on Dr Macabulos in respect to her left knee. Again, the clinical record of the attendance records no mention of the right knee.[12]
[12] ARD p. 293
On 31 May 2012 Dr Macabulos referred the applicant to Dr Mervyn Cross. The referral records that the applicant had sustained injury to her left knee with no mention of the right knee.[13]
[13] ARD pp. 403-404.
On 13 June 2012 Dr Mervyn Cross, orthopaedic surgeon reported to Dr Macabulos in respect to the applicant’s left knee[14] and on 17 August 2012 Dr Cross performed a left knee arthroscopic partial medial meniscectomy.[15]
[14] ARD p. 398.
[15] ARD pp. 27-28.
On 22 August 2012 the applicant attended on Dr Giles Ellingworth, GP, in respect to her left knee. The clinical record of the consultation records that the applicant was walking with a limp but again contains no mention of the right knee.[16]
[16] ARD p. 295.
On 3 September 2012 the applicant again attended on Dr Harkness in respect to the left knee with the clinical record of the attendance again recording no mention of the right knee.[17]
[17] ARD p. 296.
On 17 September 2012 the applicant attended on Dr Erika Jaensch, GP. The clinical record of the attendance records that the left knee was very painful but again contains no reference to the right knee.[18]
[18] ARD p. 296.
On 2 October 2012 Dr Harkness noted that the knee was much improved with swelling and pain settling post arthroscopy. Again, there is no mention of the right knee in the clinical record of the attendance.[19]
[19] ARD p. 297.
On 16 November 2012 the applicant attended on Dr Harkness for finalisation of her knee medical certificate. The clinical record of the attendance records that the knee was much improved however there was some ongoing discomfort.[20] Again there is no mention of the right knee.
[20] ARD p. 300.
The applicant attended on Dr Harkness on 8 February 2013 who recorded that the knee was good.[21] On 10 February 2014 Dr Sam Tormey recorded that the knee was better than usual.
[21] ARD p. 302.
The first record of any right knee symptoms is not until 5 July 2017 when Dr Konrad Reardon, GP, recorded in respect to knee pain that the left side was “worse”. I accept the respondent’s submission that that this implies that there was also right sided knee pain.
The next complaint in the clinical records in respect to the applicant’s knees and the first direct reference to right knee symptoms is recorded by Dr Reardon on 8 April 2021. The clinical record of the attendance records that the applicant was suffering from severe right knee pain. No history is recorded at that time of the applicant having injured the right knee in the work incident on 19 April 2012.
The consultation on 8 April 2021 occurred after the applicant slipped on her right knee in March 2021 on her driveway at home.
Dr Anthony Cadden in his report of 29 November 2023 took a history that following the slip on the right knee in March 2021 there was swelling of both knees, that the applicant required a week off work, attend physiotherapy and tried a TENS machine without benefit. That she experienced limitation with walking and gradually had improvement in the pain after December 2021, but she was not able to return to her previous level of activity. She found that the pain persisted in both knees which limited her ability to walk.
Having changed GP practices the applicant attended on Dr Prem Mathiazhagan on
[22] ARD pp. 49-50.
4 February 2023 with bilateral knee osteoarthritis. Significantly Dr Mathiazhagan took a history of the applicant sustaining injury to her left knee on 19 April 2012.[22]
The applicant then completed a recurrence report of injury on 6 February 2023[23] in which she records that the right knee complaints were “due to compensating for past 10 years.” The applicant also records that she had not been pain free since 2012 and that she had walked with a limp since the injury in 2012.
[23] Reply p. 4.
The first recorded history of the applicant sustaining injury to her right knee in the slip and fall on 19 April 2012 is recorded by Dr Alice Chang, orthopaedic surgeon, who examined the applicant at the request of the respondent on 24 March 2023 and provided a forensic report to the respondent dated 27 March 2023.[24] Dr Chang took a history that the applicant fell onto both knees on 12 April 2012 and that following the fall the required crutches to walk due to worsening bilateral knee pain.
[24] Reply pp. 19-27.
In the respondent’s submission the contemporaneous clinical records as well as the report of the injury to the respondent does not support that the applicant sustained injury to the right knee on 19 April 2012 as alleged. I accept the respondent’s submission.
Whilst care must be taken in attributing to much weight to clinical notes[25] and care needs to be taken in relying upon them,[26] in the current matter the applicant was seen by
[25] King v Collins [2007] NSWCA 122 (King).
[26] Nominal Defendant v Clancy [2007] NSWCA 349 (Clancy); Davis v Council of the City of Wagga Wagga [2004] NSWCA 34 (Davis).
Dr Macabulos the day after the slip and fall at work. The doctor undertook an extensive examination of the applicant and recorded extensive notes as well as referring the applicant to a physiotherapist for treatment without any history of injury to the right knee being recorded. Prior to attending on Dr Macabulos, the applicant had an X-ray performed at the Bega District Hospital at which time only the left knee appears to have been scanned and again only the left knee was the subject of an MRI scan on 20 April 2012.
The applicant is then seen not by one GP but rather by multiple GP’s none of whom take a history of the applicant having sustained a right knee injury on 19 April 2012 or even of any right knee complaints. It is not until July 2017 some five years later that there is any reference in the clinical records to right knee symptoms. The physiotherapist, Mr Lehoczky, and the treating orthopaedic surgeon Dr Cross also record no mention of a right knee injury however this may be accounted for by the applicant only being referred in respect to the left knee.
Having changed GP practices the applicant attended on Dr Mathiazhagan on
4 February 2023 with bilateral knee osteoarthritis. Significantly whilst the applicant attended on Dr Mathiazhagan with bilateral knee osteoarthritis the doctor only took a history of the applicant sustaining injury to her left knee on 19 April 2012. Shortly following the attendance on Dr Mathiazhagan, the applicant completes a recurrence claim form which attributes her right knee symptoms to limping not to having sustained a right knee injury on 19 April 2012.
It is not until over a decade after the subject incident that the applicant reports to Dr Chang that she had sustained injury to her right knee in the slip and fall on 19 April 2012.
In my view it is highly improbable that the applicant would not have reported any injury to her right knee to her treating doctors and it been recorded in circumstances where she has consulted multiple doctors over a duration of years especially given the applicant’s evidence that the right knee became increasingly more painful overtime. This is then combined with the applicant’s failure to report any right knee injury to the respondent in the AIMS Incident Detail form which was completed within days of the event on 19 April 2012.
Applying a commonsense evaluation of the causal chain I am not satisfied on the balance of probabilities that the applicant sustained an injury to her right knee in the slip and fall at work on 19 April 2012. I feel no sense of persuasion. For the above reasons the applicant has not discharged her onus and find that the applicant did not sustain injury to her right knee on
19 April 2012 as alleged.

Consequential condition

The applicant also alleges that she sustained a consequential right knee condition due to the accepted left knee injury. In the applicant’s submission she developed a consequential right knee condition as a result of biomechanical overload and altered gait mechanics. The respondent disputes the alleged consequential condition.
To establish a consequential condition of the right knee the applicant is not required to prove an injury within the meaning of s 4 of the 1987 Act.[27] All that is required is that the condition has resulted from the accepted s 4 injury.[28]
[27] Trustees of the Roman Catholic Church for the Diocese of Parramatta v Brennan [2016] NSWWCCPD 23 at [100] (Brennan); Moon v Conmah Pty Limited [2009] NSWWCCPD 134 (Moon).
[28] Watson’s Culcairn Hotel Pty Ltd v Dwyer [2016] NSWWCCPD 5 (Dwyer).
The applicant bears the onus of establishing on the balance of probabilities that she has developed a consequential right knee condition as a result of the accepted left knee injury.
It is the applicant’s evidence that following the injury on 19 April 2012 she always parked as close as possible to the office to minimise the walking distance due to her knee pain and that if her knees were particularly bad she would use the ramp rather than the stairs.[29] That once she moved to “SERH Hospital” she felt increased pain when walking to the office and people would ask her if she was “ok” due to her noticeable limp.[30] That her right knee pain increased over time and became worse than the left knee injury.[31]
[29] ARD p. 6.
[30] ARD p. 6.
[31] ARD p. 6.
It is the applicant’s evidence that when she got her final Certificate of Capacity for her left knee, she was still in discomfort but realised it was never going to be like it was. It is the applicant’s evidence that neither of her knees were the same following the fall and that over time they have gotten worse.
The applicant completed a recurrence report of injury on 6 February 2023[32] in which she records that the right “due to compensating for past 10 years.” The applicant also records that she had not been pain free since 2012 and that she had walked with a limp since the injury in 2012.
[32] Reply p. 4.
The evidence supports that the applicant did have a limp directly following sustaining injury to her left knee on 19 April 2012.
Dr Macabulos observed on 20 April 2012 that the applicant had an antalgic gait[33] and on
[33] ARD pp. 290-291.
[34] ARD p. 291.
[35] ARD p. 292.
[36] ARD p. 293
23 April 2012 Dr Harkness observed a “slightly” antalgic gait.[34] On 2 May 2012 Dr Lam noted that the left knee was improving “but still painful” but did not record any observations as to the applicant’s gait.[35] However, on 17 May 2012 Dr Macabulos noted that the applicant was walking better which would indicate that the applicant had been limping.[36]
On 17 August 2012 Dr Mervyn Cross, orthopaedic surgeon, performed a left knee arthroscopic partial medial meniscectomy.[37] Following the arthroscopy Dr Ellington noted on 22 August 2012 that the applicant was walking with a limp.[38]
[37] ARD pp. 27-28.
[38] ARD p. 295.
On 17 September 2012 the applicant attended on Dr Jaensch who recorded that the applicant’s left knee was very painful but does not record whether she was limping.[39] On
[39] ARD p. 296.
[40] ARD p. 297.
27 September 2013 the applicant’s treating orthopaedic surgeon, Dr Cross, noted that the applicant’s left knee had “recovered extremely well” and on 2 October 2012 Dr Harkness noted that the knee was much improved with swelling and pain settling post arthroscopy.[40]

On 16 November 2012 the applicant attended on Dr Harkness for finalisation of her knee medical certificate. Consistent with the applicant’s evidence the clinical record of the attendance records that the knee was much improved however there was some ongoing discomfort.[41] Thus whilst Dr Cross had observed on 2 October 2012 that the left knee had “recovered extremely well” the clinical records support that the applicant did have ongoing symptoms.
[41] ARD p. 300.
The clinical records support that the applicant continued to have ongoing left knee symptoms that appear to have fluctuated.
The applicant attended on Dr Harkness on 8 February 2013 who recorded that the knee was “good”.[42] On 10 February 2014 Dr Sam Tormey recorded that the knee was better than usual which again indicates that the left knee continued to be symptomatic.
[42] ARD p. 302.
On 5 July 2017 Dr Reardon recorded in respect to knee pain that the left side was “worse”. I accept the respondent’s submission that this implies that there was also right sided knee pain. The applicant’s right knee had therefore become symptomatic by July 2017.
On 9 August 2019 Dr Duncan Mackinnon, GP, noted that the applicant had a normal gait when the applicant attended in respect to lower back pain.[43]
[43] ARD p. 353.
The next mention of the applicant’s knees in the clinical records following July 2017 is on
[44] Ard p. 366.
8 April 2021 when the applicant complained to Dr Reardon of severe right knee pain.[44] Whilst the clinical record of the consultation records no mention of the left knee as previously discussed this consultation occurred after a slip on the right knee in March 2021 which occurred on the applicant’s driveway at home.
On 10 May 2021 Dr Warwick Lee reported on an X-ray of the right knee to Dr Reardon observing moderate osteoarthritis.[45]
[45] ARD p. 29.
The next recorded entry in the clinical notes is on 20 October 2022 after the applicant had changed GP’s. On 20 October 2022 the applicant attended on, Dr Mathiazhagan. The clinical record of the consultation records that the applicant was complaining of left knee pain.[46]
[46] ARD p. 52.
I note that it is the applicant’s evidence that prior to this attendance she had experienced pain and swelling in both knees in September 2022 when repeatedly walking up and down a steep driveway and that she subsequently attended on her GP after she realised that the exacerbation in both knees was not subsiding.[47]
[47] ARD p. 8.
On 4 February 2023 the applicant attended on Dr Mathiazhagan with bilateral osteoarthritis of the knees. The doctor at that time recorded that the applicant was struggling to walk and noted an antalgic gait.[48] The clinical notes reveal that from this point onwards the applicant has had ongoing problems with both knees which has affected her gait.
[48] ARD pp. 49-50.

On 17 August 2023 Dr Anthony Leong, treating orthopaedic surgeon, reported to
[49] ARD pp. 30-31.
Dr Mathiazhagan recording a history of both knees sustaining injury in 2012 with ongoing limping pain and limping which has gradually worsened. In the opinion of Dr Leong extra load had been placed through on the right knee due to the injury to the left knee.[49]
Dr Cadden, orthopaedic surgeon, provided a report to the applicant dated
[50] ARD pp. 14-23.
29 November 2023.[50] Dr Cadden, like Dr Leong, records a history of both knees being injured in the fall at work on 12 April 2012 and that since the fall she had experienced bilateral knee pain. That her left knee was the predominant area of pain for the first five to six years causing her to “often” limp on the left placing more stress through her right leg and that over the past four years the right knee symptoms had become progressively worse.
Dr Cadden diagnosed progressive degenerative changes to both knees because of the work-related injury. The doctor in coming to his opinion relied on a history of the applicant always having right knee pain since the injury on 12 April 2012 and that she had always limped following the injury due to the left knee symptoms.
Dr Cadden recorded that the applicant reported falling heavily directly onto the anterior aspects of both knees which the doctor observed can cause injury to the patellofemoral joint and be responsible for progressive development of degenerative changes.
Dr Cadden also observed that the applicant described a left knee limp which had persisted following the injury and subsequent surgery which would have caused compensatory increased overload of the work-related injury to the right knee and accelerated any degenerative changes that had developed over time as a result of the fall onto both knees.
Dr Cadden provided a supplementary report to the applicant dated 8 September 2024[51] in which the doctor expressed the opinion that the subsequent incidents such as the slip on the driveway at home in March 2021 highlighted the advanced changes that have occurred to both knees, where she had progressive symptoms since the time of the original injury in April 2012.
[51] ARD pp. 24-25.
In the opinion of Dr Cadden, on the balance of probabilities, the fall at work onto both knees has led to a cascade of changes occurring to the knees as indicated by the ongoing symptoms that had been present, on the history taken by the doctor, since the time of the original fall. In Dr Cadden’s opinion the subsequent injuries that she has suffered would have caused further acceleration of the degenerative changes that had been occurring up until that time and leading to the need for the bilateral total knee replacement to be undertaken.
Dr Chang provided a report to the respondent dated 27 March 2023.[52] Dr Chang, like
Dr Leong and Dr Cadden, records a history of the applicant falling onto both knees on
[52] Reply pp. 19-27.
12 April 2012 and that following the fall the applicant had suffered from worsening right knee pain.
In the opinion of Dr Chang, the right knee pain is secondary to a combination of osteoarthritis which would likely have happened anyway at a later stage of life but which had happened early due to the increased reliance on her right leg as a result of her left knee injury.
In the opinion of Dr Chang, the alleged work incident likely precipitated and accelerated the bilateral knee osteoarthritis. In the opinion of Dr Chang, the applicant’s knees had deteriorated much more than she would normally expect within the next 10 years since the scans performed on the left knee following the slip and fall at work.
Dr Chang provided a supplementary report to the respondent dated 19 July 2023.[53] In the doctor’s opinion the knee arthritis is long standing and not due to the falls in 2021.
[53] Reply pp. 28-29.
Dr Chang provided a further report to the respondent dated 20 January 2025 following a file review.[54] The doctor maintained her opinion.
[54] Reply pp. 30-33.
Whilst I do not accept that the applicant sustained injury to her right knee in the slip and fall at work on 19 April 2012, I am of the view that the evidence does support that the applicant had ongoing left knee symptoms thereafter. I accept the applicant’s evidence that she had accepted that her left knee was not going to return to its pre-injury condition.
The applicant appears to have largely just put up with the ongoing left knee symptoms with few complaints being recorded in the clinical records. However, the clinical record of
Dr Tormey of 10 February 2014, almost two years after the work injury was sustained, in particular highlights the ongoing nature of the left knee symptoms when the doctor records that the knee was better than usual which to my mind indicates that the left knee symptoms at that point were not insignificant.
There is little mention of the applicant limping in the clinical records after 2012 until 2023 however the applicant seems to have simply put up with her left knee symptoms as a fact of life and not consulted her doctors in respect to her left knee symptoms. It also seems likely that the doctors did not always record that the applicant was limping when she would have been. For example, on 8 April 2021 the applicant complained of severe right knee pain to
Dr Reardon however the clinical record of the consultation contains no mention of a limp even though a trial of a knee brace was recommended.
On 9 August 2019 Dr Mackinnon did note that the applicant had a normal gait when the applicant attended in respect to lower back pain. However, the applicant’s knee symptoms do appear to have fluctuated from time to time I don’t believe that any inference can be drawn from this single clinical entry given the background of ongoing left knee symptoms.
As previously noted, the applicant’s right knee was symptomatic by July 2017, and whilst the applicant did suffer a slip in March 2021 on her driveway at home on 10 May 2021
[55] ARD p. 29.
Dr Warwick Lee reporting on an X-ray of the right knee observed moderate osteoarthritis.[55] The degenerative changes were therefore already present prior to the subsequent incidents at home.
Whilst I do not accept the histories taken by Dr Leong, Dr Cadden and Dr Chang of the applicant sustaining a direct injury to the right knee on 19 April 2012 I do accept their opinions that the applicant’s limping due to the left knee injury would have placed additional stress and load on the right knee which would have contributed to the degeneration of the right knee.
I do not accept the respondent’s submission that the opinions of the doctors are wholly unreliable due to the histories relied upon by the doctors as the doctors provide to mechanisms of injury one being a direct blow to the right knee on 19 April 2012 and the second being due to the overloading of the right leg due to the left knee injury. I accept the second of the mechanisms whilst rejecting the first.
I also do not accept the respondent’s submission at [40] of their initial submissions that
Dr Chang considered that the applicant would be in a similar condition regardless of whether she sustained the fall in 2012. Dr Chang in her supplementary report of 19 July 2023 was not referring to the fall on 19 April 2012 but rather to the subsequent no work related falls in 2021.
For the above reasons I find that the applicant sustained a consequential right knee condition due to the accepted left knee injury.

Proposed total right knee replacement surgery

Section 60 of the 1987 Act provides for the payment of “reasonably necessary” medical and treatment expenses that are required as a “result of an injury”.
In the opinion of Dr Leong, the applicant is symptomatically and radiologically ready for bilateral knee replacements. In the doctor’s opinion this is in part secondary to her work-related injury with a meniscal tear and subsequent surgery and extra load placed on the right knee.[56]
[56] ARD pp. 30-31.
In the opinion of Dr Cadden bilateral total knee replacement surgery is reasonably necessary as a result of the workplace injury to both knees. In the doctor’s opinion the left knee limp would have caused compensatory increased overload of the work-related injury to the right knee and accelerated any degenerative changes that have developed over time as a result of the fall onto both knees.
Dr Chang is also of the opinion that the knee replacement is reasonably necessary.
Whilst Dr Leong, Dr Cadden and Dr Chang in formulating their opinions as to the right knee replacement surgery being reasonably necessary as a result of the injury also relied on a history of the applicant sustaining a direct blow to the right knee on 19 April 2012 they are also of the opinion, which I accept, that the applicant has suffered a consequential condition of the right knee due to the additional forces and stress placed on the right leg as a result of the left knee injury. Whilst I accept that there have been other aggravating incidents such as the slip on the driveway as well as a possible contribution from an underlying non work-related arthritic condition the applicant only has to establish that the injury materially contributed to the need for the surgery.[57]
[57] Murphy v Allity Management Services Pty Ltd [2015] NSWWCCPD 49 (Murphy).
In Diab v NRMA Limited [2014] NSWWCCPD 72 (Diab) Roche DP set out the matters to be considered in respect to the reasonableness of the proposed treatment. Considering those matters there is no dispute on the medical evidence that the treatment is appropriate nor is there any dispute as to its effectiveness. The treatment is an accepted treatment the costs of which is often accepted and paid for at workers compensation.
I accept the opinions of Dr Leong, Dr Cadden and Dr Chang and find that the proposed surgery is reasonably necessary as a result of an injury.

[2025] NSWPIC 398

12 August 2025