Body systems/parts: right lower extremity (knee, hip), left lower extremity (hip), and lumbar spine.

1. The documents to be reviewed by the Medical Assessor are:

(a) Application to Resolve a Dispute and attached documents;

(b) Reply and attached documents, and

(c) applicant's Application to Lodge Additional Documents dated 27 May 2025 and attached documents.

1. The matter is to be listed for a further preliminary conference to deal with the applicant's claim for weekly benefits and medical or related expenses if appropriate following the completion of the medical assessment process.

A brief statement is attached setting out the Commission's reasons for the determination.

1. Mr Carter, the applicant, was employed as a full time high cleaner by the respondent at a nursing home for close to five years at the time of his 2017 injury.
2. On 14 February 2017 the applicant turned and twisted his right knee when he collided with a co-worker in his manager's office. He lodged a claim on 15 February 2017 and the claim was disputed on 18 April 2017. The dispute was maintained following internal reviews on

13 September 2017 and 14 July 2021. 3. The applicant claimed lump sum compensation for 33% permanent impairment of his right knee, lumbar spine and consequential injury to both hips on 9 February 2023. This claim was disputed on 22 February 2023. 4. A dispute notice was issued under s 78 of the Workplace Injury Management and Workers Compensation Act 1998 on 28 May 2024 with respect to both knees, the lumbar spine and consequential injury to both hips. 5. On 21 May 2025 the applicant claimed weekly payments and medical expenses as a result of the injury on 14 February 2017. 6. The applicant lodged an Application to Resolve a Dispute (ARD) with the Personal Injury Commission (Commission) on 27 May 2025 claiming weekly benefits, medical or related expenses and lump sum compensation. 7. The dispute was listed for conciliation conference and arbitration hearing on 20 August 2025.

1. The parties agree the following issues remain in dispute:

(a) whether the applicant sustained injuries to his right knee and/or lumbar spine on 14 February 2017 pursuant to ss 4, 9A and/or 4(b) of the Workers Compensation Act 1987 (1987 Act),

(b) whether the applicant sustained consequential bilateral hip and/or lumbar spine injuries as a result of injury on 14 February 2017,

(c) the extent and quantification of any entitlement to weekly benefits in the period

8 February 2019 to date and continuing pursuant to ss 37 and 38 of the 1987 Act, and

(d) whether the applicant is entitled to the payment of reasonably necessary medical or related expenses as a result of injury pursuant to s 60 of the 1987 Act.

1. The parties appeared for conciliation conference and arbitration hearing by audio visual link (MS Teams) on 20 August 2025. Mr Greg Young of counsel appeared for the applicant instructed by Ms Elizabeth Nguyen, legal practitioner. Mr Brendan Jones of counsel appeared for the respondent instructed by Ms Caitlin Malone, legal practitioner.
2. During conciliation the respondent withdrew the dispute with respect to the right knee injury. The parties agreed if the applicant was successful in the determination of whether he also sustained injuries to his lumbar spine and hips, the matter should be remitted to the President for referral to a Medical Assessor to assess permanent impairment. A further preliminary conference is to be held with respect to the applicant's claim for weekly compensation and medical expenses following the medical assessment process if appropriate.
3. I am satisfied 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 the parties have had sufficient opportunity to explore settlement and that they have been unable to reach an agreed resolution of the dispute.

1. The following documents were in evidence before the Commission and considered in making this determination:

(a) ARD and attached documents;

(b) Reply and attached documents, and

(c) applicant's Application to Lodge Additional Documents dated 27 May 2025 and attached documents.

1. No application was made to adduce oral evidence.

1. The applicant's Incident Personal Statement Form of 16 February 2017 describes the incident on 14 February 2017.
2. After filling out a maintenance request the applicant was turning to leave the manager's office when he and a co-worker knocked into each other. He tried to turn away at the last moment. He could not walk or bear weight on his right leg.
3. He had previously fallen on an electric cord in 2016 cutting the flesh down the right knee cap.
4. Ms Roz Sullivan, the applicant's co-worker, describes the incident in an Incident Personal Statement Form of 16 February 2017. She was filling out her time sheet in the office that day and she and the applicant both turned at the same time to move away, bumping each other. The applicant turned the opposite way to move away and his knee did not turn.
5. The applicant signed a statement on 10 August 2022. He continued to work after injuring his right knee in 2016 despite being in pain. On 27 January 2017 he stood on a chair at home, lost his balance and fell. He believes this was due to a reduced strength in his knee from the 2016 incident at work. He returned to work as normal although the pain from the 2016 incident was ongoing.
6. He was still limping in February 2017. He attended his doctor on 14 February 2017 who referred him for a right knee ultrasound and provided a certificate of capacity.
7. On returning to work that day the incident described above took place when he collided with his co-worker. He immediately felt a significant sharp pain in his right knee and some lower back pain. The applicant continued to work in some capacity until he stopped work in June 2018. He was terminated on 3 May 2019.
8. After the 2017 incident the applicant walked with an obvious limp to alleviate his right knee and lower back pain. He favoured his left side to avoid straining his right knee and placed more weight on his left hip and lower back.
9. The applicant provides an update in his further statement of 29 November 2024.
10. The pain in his right knee and back has deteriorated and he developed an abnormal gait. As a result he began to experience increasing pain in both hips. He had a left total hip replacement on 10 August 2020 and a right total hip replacement on 9 January 2023.
11. The 2017 incident aggravated his right knee symptoms. He suffered back pain at the time of the 2017 incident when he felt a twinge in his back. He felt like he jarred it. He required walking sticks to access his car due to pain in both his right knee and lower back.
12. The applicant's view is his hip condition resulted from his knee and back injuries. Both hips began to suffer as he overcompensated for the pain in his right knee and back. His limp resulted in unnatural and abnormal movements where he tended to favour his left side. The pain increased in both hips.
13. He describes his current treatment as including swimming, consulting his general practitioner and medications. He describes the ongoing effects of the injuries.
14. The workers injury claim form dated 15 February 2017 shows the injury as a right knee injury from being knocked by another employee while in the office at work causing twisting of the right knee.

Dr Alan Hopcroft, independent general surgeon (orthopaedics)

1. Dr Hopcroft reports on 7 March 2019 that on the applicant's return to work on light duties following the incident in February 2017 he found with the ongoing limp that he had he developed quite marked pain in his lumbosacral spine with radiation of pain into his right leg. Dr Hopcroft sets out the treatment the applicant has received for his lumbar spine pain.
2. Dr Hopcroft's opinion is that the applicant wrenched his lower back at the time on the collision with a fellow employee in February 2017. There is a direct relationship between the applicant's ongoing right knee symptoms where he has incurred a right medial meniscus tear and has significantly aggravated pre-existent lumbar spondylitic problems, incurring for the first time a sciatic syndrome. Employment has been the main contributing factor.
3. On 15 April 2019 Dr Hopcroft assesses 7% whole person impairment of the lumbar spine, and 2% whole person impairment of the applicant's right knee, totalling 9%.
4. On 15 January 2020 Dr Hopcroft reports the applicant continues to have problems with his right knee and he has significant and advancing ongoing problems of low back pain and left sided sciatica while also developing a significant problem of pain and restriction in movement of his left hip and pain along the medial joint of the left knee.
5. An adequate summation of the applicant's ongoing problems requires X-rays and MRIs of the lumbar spine and left hip.
6. On 4 March 2020 Dr Hopcroft reports on investigations that confirm significant degenerative changes and avascular necrosis in the left hip and changes in the left knee. He believes these investigations confirm significant post-traumatic pathology since the work related injuries in February 2016 and February 2017. He was yet to receive the MRI scan of the lumbar spine.
7. On 8 February 2021 Dr Hopcroft reports on the applicant's bone scan of 18 July 2019 and comments that the radiologically proven changes in the left hip and lumbar spine are significantly the result of the injury of February 2017. He confirms his opinion that the applicant should proceed to left hip replacement as a result of his injury. He should continue with conservative treatment for his lumbar spine.
8. On 10 October 2023 Dr Hopcroft re-examines the applicant. Dr Hopcroft diagnoses right knee medial meniscal tear from the February 2017 injury with a significant weight bearing rotational strain to both his lumbar spine and right knee, aggravating his right knee symptoms, and he developed back pain and sciatic symptoms from changes to his lumbar spine. The applicant continued to limp severely and he had left total hip joint replacement surgery from which he obtained an excellent result. Limping over several years and deterioration in his right hip joint led to a right total hip joint replacement surgery in January 2023.
9. Dr Hopcroft's opinion is there is a direct relationship between the 2016 and 2017 work-related injuries and his current significant pathology affecting his lumbar spine and causing sciatic symptoms and the deterioration in hip joint function with avascular necrosis developing on the left necessitating total joint replacement surgery. The surgery may have been avoided to his hip joints for many years. The applicant suffered from degenerative changes in both hips and his lumbosacral spine which Dr Hopcroft believes have been significantly progressed by the nature and conditions of his work with the respondent.
10. Dr Hopcroft comments that he does not agree with Dr Harrington's summation in his reports of 30 November 2022 and 30 January 2023 for the reasons in this report.
11. The assessment of whole person impairment totals 33%, a combination of 15% for each hip, 5% for the lumbosacral spine and 2% for the right knee.

1. Radiology reports include the bone scan of left hip and lumbar spine of 18 July 2019 which concludes there is moderately active arthritis in the left hip joint and at right L3/4 and L4/5 facet joints.
2. The X-ray pelvis/both hips and right knee of 14 September 2020 that includes severe degenerative changes of the right hip articulation, notes degenerative changes of the lumbar spine, and the impression of mild to moderate right knee osteoarthritis.
3. Radiology reports regarding the right knee date from 16 February 2017 to 12 September 2023.
4. The X-ray lumbosacral spine of 12 September 2013 found degenerative changes, osteophyte formation, moderate narrowing of the L2/3 and L3/4 spaces, moderate narrowing of the L4/5 and marked narrowing of the L5/S1 disc spaces.
5. The MRI lumbar spine of 1 June 2017 concludes there is multilevel pathology including right L3 nerve root compression and disc herniation in the upper lumbar spine. On 5 February 2018 the MRI lumbar spine concludes there are discovertebral changes with mild canal stenosis, potentially lateral recess L5 compression bilaterally, with the changes relatively stable compared to the June 2017 study.
6. The CT lumbar spine on 29 September 2018 report notes a small protrusion at L5-S1 and L4-5, a left protrusion at L1-2, facet joint arthropathy, and slight canal narrowing at L2-3 and moderate canal narrowing at L3-4 and L4-5.
7. On 6 June 2019 the MRI lumbar spine report concludes there are discovertebral changes throughout the lumbar spine, a right L4/5 focal disc protrusion with right L5 root impingement.
8. Records of injections into the right knee in March 2023 and the lumbar spine in July 2017, February 2018 and June 2018 are with the ARD.
9. The X-ray of the applicant's hips and pelvis on 28 September 2011 shows no abnormality identified in either hip joint.
10. The MRI left hip report of 17 January 2020 includes the impression of severe degenerative changes in the left hip joint.
11. The X-ray pelvis and left hip report dated 20 January 2020 concludes there is significant degenerative changes and avascular necrosis in the left hip. The report of 27 June 2020 evaluates the total left hip replacement.
12. The X-ray pelvis and left hip radiograph report of 1 March 2021 also notes degenerative changes of the lumbosacral spine. The X-ray pelvis and right hip of 8 June 2022 found severe degenerative arthropathy of the hip.

1. Mr Gavin Jackson, physiotherapist, reports on his treatment of the applicant's right knee

27 February 2017 and refers to his antalgic gait. 2. Dr Johan C le Roux, orthopaedic surgeon, reports on the applicant's right knee on

27 April 2017, on 22 May 2017 he requests an MRI of the applicant's back, on 7 July 2017 he notes the MRI shows L3 nerve root compression, on 31 January 2018 he reports relentless lower back pain and that the applicant needs to see a spinal surgeon and a pain specialist with a repeat MRI. On 1 February 2018 he refers the applicant to Dr Michel at the Mayo Specialist Centre and Dr Simon Abson, spinal surgeon, with respect to his back. 3. On 8 February 2018 Dr Abson arranges an L4/5 interlaminar injection, he reports on

1 March 2018 on a good result from the injection, on 31 May 2018 he arranges another injection as the applicant has had an exacerbation and is in severe distress, and on

28 June 2018 after his third injection he remains on a waiting list for surgery. The applicant was removed from the waiting list at his request on 22 August 2019. 4. Dr Abson provides a file review and report on 10 October 2018. The applicant thought he has had radicular pain for approximately two years following an injury at work when he also had a knee injury. There is some impingement of the L5 nerve root at the L4/5 traversing point which explains his symptoms clinically, and which the injections confirmed. The time frame and course of his problems indicate this was most likely caused at the time of his twisting injury. 5. Dr John Christie, neurosurgeon, reports on 4 June 2019 the applicant was certainly favouring his left leg when walking, he has generalised degenerative change in the lumbar spine and an up-to-date MRI was organised. Dr Christie reports on 3 July 2019 the applicant was hobbling quite noticeably on his left leg and his left hip was painful on rotation, however he could not make a definite diagnosis. On 2 July 2019 Dr Christie reports the applicant's bone scan suggest some arthritis in the left hip. 6. Dr Rishi Narasimhan, orthopaedic surgeon, reports on 15 April 2020 regarding the applicant's left hip which requires a left hip replacement. This was carried out on

10 August 2020. On 25 September 2020 Dr Narasimhan reports the applicant is walking unaided and he can commence driving. The applicant consults him for his right hip pain on 30 April 2021 seeking a surgical solution. On 1 August 2023 Dr Narasimhan reports the applicant is doing well following surgery, appears to have a normal gait although he is having right knee pain and struggles walking long distances. 7. Mr Daniel Luther, physiotherapist at the John Hunter Hospital Neurosurgery Unit, reports on 25 August 2019 the applicant has had back pain since the 2017 injury. The clinical picture did not appear to match the MRI findings and the applicant would benefit from an orthopaedic consult for his left hip. No neurological intervention was required at that time. 8. Dr Lawrence Nguyen, general practitioner, reports on 22 February 2018 the applicant fell on his knee and now has lower back pain, a cortisone injection helped and he is fit for all duties and normal hours. 9. The Manning Base Hospital Discharge Referral dated 18 January 2018 reports the applicant attended with ongoing lower back pain radiating down the right leg, with the primary diagnosis acute exacerbation of back pain.

1. Extracts of clinical records from Medisense Health Care, Main Surgery, Taree Medical Centre and Mayo Healthcare Centre are with the ARD.
2. The applicant's additional documents include a summary of certificates of capacity and medical certificates as at 20 May 2020 with the certificates, and schedules of earnings and medical expenses with supporting documents. There is a Medical Assessment Certificate of Dr Murray Hyde Page dated 2 June 2015 for 2% whole person impairment of bilateral upper extremity, not the subject of these proceedings.

1. The initial notification of the injury dated 14 February 2017 is with the Reply. The various dispute notices between 18 April 2017 and 28 May 2024 are relied on by the respondent.
2. The respondent also relies on the reports of Dr le Roux dated 27 April 2017 and

22 May 2017, the clinical records of Taree Medical Centre, X-ray reports dated

28 September 2011, 12 September 2013 and 20 January 2020, and the bone scan dated

Dr Chris Harrington, independent orthopaedic surgeon

1. Dr Harrington provides a report to the respondent on 30 November 2022. His diagnosis and opinion is that the applicant aggravated his right knee at work in February 2017 for which his employment was the main contributing factor, and he strained his lumbar spine at that time. The applicant subsequently developed problems with his left hip, and he has also noticed trouble with his contralateral left knee with degenerative changes on that side.
2. In Dr Harrington's opinion the bilateral hip arthritis is constitutional. The lower back strain in February 2017 would be consistent with a minor strain and an aggravation of pre-existing changes in the lower lumbar levels. Any work-related aggravation has ceased.
3. On 30 January 2023 Dr Harrington provides a supplementary report. The February 2017 incident is more likely to be responsible for the applicant's meniscal pathology than the direct blow in 2016. The hip arthritis and avascular necrosis is constitutional and not related to his right knee pathology (or altered gait). The normal timeframe for an aggravation of the lumbar spine from the 2017 incident to resolve would be three months. Dr Harrington does not believe there is sufficient evidence to suggest the applicant's back pain is a result of an altered gait.
4. On 3 April 2024 Dr Harrington reports following his re-examination of the applicant. His back is now his main complaint and interferes more with his activities than his right knee.

Dr Harrington's opinion is the direct blow in February 2016 would be in keeping with an aggravation of underlying arthritis. The twisting injury in February 2017 could have caused the torn meniscus. These injuries would be work related. 5. The applicant had a soft tissue injury to his lumbar spine when he pivoted on his right leg and twisted his knee at work in 2017. This was an aggravation to pre-existing asymptomatic changes in his lower lumbar levels and Dr Harrington maintains his previous opinion that any work-related aggravation has ceased. The bilateral hip replacements for avascular necrosis would not be work-related. 6. Dr Harrington assesses 7% whole person impairment of the right knee, 5% whole person impairment of the lumbar spine however this is not work-related, and assesses no work-related impairment for either hip.

1. The applicant made oral submissions which have been recorded and form part of the Commission's record. These are set out below.
2. The applicant's submission is in addition to the undisputed right knee injury he sustained a frank injury to his lumbar spine in 2017 and consequential injuries to his hips.
3. The applicant's statement evidence is he immediately felt significant sharp pain in his right knee and some lower back pain when he twisted his right knee on 14 February 2017.
4. The applicant describes going up stairs required twisting, leaning and leveraging on his left side which caused pain in his left hip. There is a change in biomechanics with an overcompensation and greater stress and strain put on the contralateral side, the left being the previously uninjured side. Even doing things at home puts the greatest strain on the left side and strain on his left hip.
5. Dr le Roux treats the back and certainly the right knee. Although nothing specific is mentioned in his treating notes about the hip there is pain in around that region.
6. Consistent with a direct injury to the lumbar spine the applicant submits is the complaints and specialist treatment for that specific body part. Even Dr Harrington accepts the lumbar spine was directly injured. Certainly when it comes to investigations and treatment it happens a relatively short time after the injury and there is not great trouble accepting the lumbar spine injury in the applicant's submission.
7. Dr Christie starts treating the applicant in about 2019 and it is pretty clear at this stage the applicant's gait is antalgic, he is definitely putting a greater strain on his left side, and then explicit left hip complaints are noted certainly by Dr Christie. It is no surprise that Dr Christie, a neurosurgeon, later refers the applicant to the hip surgeon Dr Narasimhan. There are scans early in the piece that that look at the left hip.
8. The applicant's submission is that the right knee injury that is now conceded puts in train a change in biomechanics for the applicant leading to the limp which features early on, within weeks of the injury. Once is it accepted there is a limp caused by the right knee injury, the applicant has had great difficulty mobilising and he had to adjust his gait thereby putting greater strain on the left side.
9. In his supplementary statement the applicant says his right knee and lower back have deteriorated by 2024 and he has an abnormal gait. As a result he experienced pain in both hips. A total left hip replacement was performed in 2020 and later a right total hip replacement by Dr Narasimhan through the public system.
10. As the hips are consequential conditions there are no contemporaneous complaints. It is easier to accept the left hip the applicant submits because there is Dr Abson and Dr Christie clearly noticing the development of an antalgic gait and the development of pain in the left leg and then the left hip. This treatment is within three years of the date of the accident.

Because of the change in gait the applicant says there is now the left hip condition.

Dr Harrington with respect does not in the applicant's submission consider the correct test for consequential conditions. Dr Harrington says there is avascular necrosis in the hips which he says is not work-related, therefore the hips cannot be compensable.

The error in this analysis the applicant says is that there is a left hip aggravation that results from altered gait, and there is no argument that avascular necrosis is not work-related. The avascular necrosis, a constitutional pre-existing condition, has been aggravated by the altered gait on the basis of the test on Kooragang v Bates.[1] The aggravation of the left hip results from the altered gait.

The applicant accepts the left hip injury is stronger for him than the right hip for two reasons; when there is altered gait naturally enough as a matter of common sense you put greatest strain on the other side being the left hip, and the left hip has been aggravated to the point of needing a total hip replacement by August 2020, being roughly three years, and the right hip is not operated on until January 2023, six years after the accident.

If you accept the left hip results from the original work injury and the left hip has required a total hip replacement, then in recovering from that hip replacement it would necessarily require rehab, movement and then a shift in the other direction to mobilise, and the applicant submits that is what has happened. It is no wonder the underlying avascular necrosis has been aggravated on the right side, albeit three years after the left hip replacement, which is consistent with there being another change in biomechanics.

The other flaw the applicant submits in Dr Harrington's analysis is that if the applicant has avascular necrosis in his hips that was always something that was going to happen and has nothing to do with the work injury, even on a consequential level, then the question is why is it that the left hip is so symptomatic that it requires a replacement in August 2020 and yet the right hip has surgery performed in January 2023.

It makes sense as the applicant says he has had to put a greater strain on his left hand side to cope with his bad right knee, hence the troubles in his left hip, and it is the left hip exclusively for a number of years up to and including the August 2020 total hip replacement.

Once that is established and accepted then it is unfortunate but unsurprising that there is no break in the chain of causation resulting from the original injury.

On 3 April 2024 Dr Harrington says the applicant developed problems with his left hip which was later diagnosed as avascular necrosis and required total hip replacement and he then developed pain in his right hip.

Dr Harrington concludes the applicant had a soft tissue injury to his lumbar spine when he pivoted on his right leg and twisted his knee at work in 2017, and there has been an aggravation to pre-existing changes in his lower lumbar levels. Dr Harrington concedes direct injury to the lumbar spine.

There is no explanation behind Dr Harrington's opinion that the bilateral hip replacements for avascular necrosis, the left in 2020 and the right in 2023, would not be work-related.

Dr Harrington does not consider the possibility of a consequential condition or whether altered biomechanics have aggravated the avascular necrosis or not. The doctor has not considered why the left hip required surgery in 2020 and the right hip needed surgery in 2023 if not as a result of the altered biomechanics, and why are they not symptomatic at the same time, or very close in time?

Dr Harrington refers to the direct blow to the applicant's right knee in 2016 which has probably aggravated some underlying patellofemoral arthritis, and then in February 2017 he twisted his right knee which could have caused a torn meniscus. No wonder the applicant has been limping.

Dr Harrington then says the applicant strained his lumbar spine in February 2017 which has aggravated underlying changes in the lower lumbar levels, however given the timeframe and nature of his injury the work-related aggravation has ceased.

Dr Harrington says he does not believe the lumbar spine condition has resulted from the right knee injury in the sense of any secondary problem such as altered gait. He says the hip problems were caused by avascular necrosis which is not related to the injury to the right knee, but he does not consider altered gait.

On 7 March 2019 Dr Hopcroft takes a history of the right knee being injured and the applicant continued to work albeit with a limp. The knee is then getting worse and not better and there is a limp. There is swelling around the knee.

Dr le Roux arranged the MRI of the lumbar spine on 1 June 2017, four months after the accident, then a CT guided foraminal injection of L4/5 and a repeat MRI on 5 February 2018.

Dr Hopcroft diagnoses a medial meniscus tear of the right knee and that the applicant wrenched his low back at the same time. There is now bilateral radiculopathy. Not only does that confirm the injury to the lumbar spine but by April 2019 there is pain radiating from the back into the legs, and in the applicant's submission this is consistent with pain in the hip regions.

By January 2020 Dr Hopcroft records the applicant's symptoms are deteriorating and

Dr Christie is treating the applicant. There is significant low back pain radiating into the left leg down to his knee. The applicant also has significant ongoing pain in his left groin, increasing since the February 2017 injury. He also has restriction in movement of the left hip joint suggestive of an advancing arthritis problem.

Dr Hopcroft also says on examination the applicant walks with a marked left sided limp, so it is not only common sense or the applicant who says this but also a clinician observing this contemporaneously in the lead up to this surgery.

Dr Harrington would have you believe the avascular necrosis in the left hip is unrelated and totally unconstitutional and if that is so why is the applicant putting extra strain on that side and limping more that warrants surgery in 2020? Dr Harrington examines the left hip, finds marked restriction. It is clearly symptomatic in the context of an antalgic gait and marked left sided limp.

1. Dr Hopcroft under the heading diagnosis, opinion and prognosis talks about the right knee and says significant and advancing ongoing problems of low back pain and left sided sciatica while also developing a significant problem of pain and restriction in movement of the left hip with pain along the medial joint line of the left knee.
2. On 4 March 2020 Dr Hopcroft notes the MRI scan of the lumbar spine and significant degenerative changes and avascular necrosis within the left hip. Dr Hopcroft believes these investigations confirm the significant post-traumatic pathology since his work injuries in 2016 and 2017. With his left hip function deteriorating rapidly he is a candidate for surgery.
3. In his next report Dr Hopcroft has seen the bone scan and he believes the radiologically proven changes are significantly the result of the 2017 injury. He confirms his opinion the surgery is warranted.
4. On 10 October 2023 Dr Hopcroft refers to the abnormal forces and the significantly abnormal gait from the two injuries which brought around the symptoms which developed in the applicant's right hip joint, and without such protracted limping it is far more likely than not the left hip joint symptoms would not have developed for many years. Dr Hopcroft squarely attributes the development of the left hip symptoms to altered gait.
5. The low grade ongoing pain in his right hip joint progressed to his grossly abnormal gait and he had the right total hip replacement procedure on 9 January 2023.
6. Dr Hopcroft sees a quite definitive link between the two work-related injuries, the applicant's grossly abnormal gait, his deteriorating back with radiculopathy and the development thereafter of avascular necrosis in the left hip joint.
7. His diagnosis and opinion are that the applicant continued to limp severely, X-ray changes showed avascular necrosis developing in his left head of femur which led to the decision being undertaken for him to progress to left total hip joint replacement surgery from which he obtained an excellent result.
8. If the finding is made that the left hip condition results from the altered gait the Commission would be satisfied also that the left hip replacement was reasonably necessary especially as there has been an excellent result.
9. Dr Hopcroft then shifts his attention to the right hip and says limping over several years and the deterioration in his right hip joint led to his undergoing right total hip joint replacement surgery on 9 January 2023 with a slightly lesser result than he achieved with the left procedure. His opinion is that there is a direct relationship between the applicant's two work-related injuries and his current significant pathology affecting his lumbar spine and causing sciatic symptoms and deterioration in his hip joint function with avascular necrosis developing in his left hip joint function necessitating total hip replacement surgery.
10. The chain of causation has not been broken, leading to the left hip replacement. Dr Hopcroft also says the left total hip replacement was reasonably necessary as a result of the injury.
11. The applicant concedes that the complaints of left hip feature but there do not appear to be right hip complaints until after close to the time that the left hip is operated on. Dr Hopcroft however provides his opinion regarding both hips and assesses both hips.
12. The applicant made submissions about the radiology reports including the bone scan that shows severe pain in the left hip and back symptoms. There are severe degenerative changes in the right hip and the lumbar spine on X-ray in 2020, and the MRI of the lumbar spine in 2017 that shows significant symptoms including multilevel pathology including nerve root compression. The symptoms progress over time.
13. The physiotherapist Gavin Jackson within weeks of the accident notes the right knee caused him to limp, so almost from the start. Dr le Roux focuses on the right knee but within months he turns his attention to the back and this becomes a focus with the MRI from this point on.
14. Dr Abson focuses on the back and suggests a range of treatment options. Dr Abson reviews the applicant after an injection to the back and while there is good relief for right leg symptoms his left side is still an issue. Thus is the first sign where clinically it is becoming clear that something is going on in the left hip because the focus from the spine now moves to the hip.
15. Dr Christie takes a history that the applicant developed some back pain and he offered the option of a decompression. Dr Christie says in the last few months the applicant has actually developed quite severe pain involving the left leg. The pain seems to radiate around the left hip down the left leg to the knee and calf and can go to the ankle. On examination he was certainly favouring his left leg when he was walking.
16. Dr Christie on 3 July 2019 says the applicant was hobbling quite noticeably on his left leg. Overall he cannot make a definitive diagnosis but Dr Christie is looking at the back and orders investigations. The bone scan suggests some arthritis in the left hip.
17. There is a report from the Neurosurgery Unit at the John Hunter Hospital where the applicant was treated through the public system.
18. Dr Narasimhan who then treats the applicant does not know about Dr Abson or Dr Christie's involvement and how the development of the treatment has finally uncovered and detected what is going on in the left hip and left leg. He sees the X-rays and the MRI that reveal advanced avascular necrosis collapse of the left femoral head and the applicant needs a hip replacement. There is an operation report on 10 August 2020.
19. In April 2021 Dr Narasimhan sees the applicant about his right hip as he has been having pain in his groin on the right side for some time now, he is unable to sleep at night and his mobility has significantly decreased and he came in walking with a stick for his right hip.
20. The applicant has an antalgic gait and seeks a surgical solution. After the right total hip replacement in August 2023 he appears to have a normal gait, so it is finally normal.
21. The Commission would be satisfied there was a direct injury to the lumbar spine, that an antalgic gait that developed within weeks of the undisputed right knee injury caused a worsening of the lumbar spine and it caused a biomechanical change leading to symptoms in and around the left hip that could not be treated properly and in a timely manner because of the denial of the claim. The applicant saw Dr Abson and Dr Christie, Dr Hansen in the Neurosurgical Unit, and finally Dr Narasimhan, a hip surgeon, who found he needed a hip replacement.
22. The applicant submits the Commission would also be satisfied on a Kooragang basis that the left hip condition results from the original work injury and the development within three years and the need for surgery to the right hip results from the left hip surgery which results from the right knee surgery.

1. The respondent made oral submissions which have been recorded and form part of the Commission's record. These are set out below.
2. The respondent relies on the opinion of Dr Harrington with respect to the lumbar spine and that there would be prima facie evidence of a primary injury. That is contingent upon one very critical fact and that is the immediate presence of symptoms in the lumbar spine which the respondent submits does not accord with the reality in this case in respect to the hips.
3. The only expert to draw a definitive causal link between the altered gait and the hip problems in explicit terms is Dr Hopcroft and there are problems with that opinion.
4. The respondent's submission is that it is far more complicated than looking at the pathology and what the treating specialists say and accepting the commonsense approach finding there is an injury, there is limping and then there are hip problems. It is far more complicated than that because we know there is avascular necrosis which the applicant accepts is not a condition caused by his employment. Dr Harrington deals with this properly and says the condition is constitutional and will always lead to this result.
5. The respondent accepts the applicant's statement that he immediately felt significant sharp pain in his right knee and some lower back pain, although by this stage there is disputation and that history does not accord with anything contemporaneous to the incident, such as the applicant's Incident Personal Statement Form of 16 February 2017 which only seems to be in respect to the right knee. The lower back was not included in answer to a direct question about bodily injury from the incident and it ought to have been included. The respondent acknowledges it might be said the focus was on the right knee but the lower back would have featured if it was so problematic.
6. The respondent does not rely on the applicant's testimony alone in that regard as there are other incident reports or statements from witnesses who were there at the time that refer only to the right knee.
7. This correlates with the notes of the Taree Medical Centre on 14 February 2017 where there is a reference to the right knee pain that started after stepping on something and came back with rehab and the rehab lady suggested suitable duties. The applicant then goes to work and on 20 February 2017 there is a record of the right knee not red and swelling. On

1 March 2017 there is an examination of the right knee which is not red, it is swollen and medially tender with restricted range of motion. This is more than a mere cursory discussion. If there was a problem with the lumbar spine one would infer that would have been the subject of a complaint and made its way into the consultation note. 8. The respondent is cognisant of Mason v Demasi[2] and the reliance that can be placed on clinical notes, but this is of a different character as there is an absence of complaints over consecutive consultations. 9. The applicant urges upon the Commission many features of the physiotherapy report of

Mr Jackson in terms of altered gait, but absent is a recording of any lumbar problems in that first consultation or the next consultation, in circumstances where treatment is being rendered for this workplace injury. 10. The applicant sees Dr le Roux regarding the right knee and it is not until July 2017 that there is any reference in his reports to the lumbar spine following an MRI. It says nothing about the causative element that we know is an aggravation of degenerative changes. 11. If you find there is no contemporaneous complaint or symptoms that would tell against the history Dr Harrington proceeds on, you would not accept there is an injury. 12. Dr Hopcroft himself does not really understand what is going on in the lumbar spine as in his initial reports it is treated as a frank injury however he resiles from that opinion. By the time of his latest report on 10 October 2023 why he resiles is completely unknown and there is no explanation for the backtrack. Dr Hopcroft says that following his second knee injury in 2017 with a significant weight bearing rotational strain to both his lumbar spine and right knee aggravating right knee symptoms he developed back pain and sciatic symptoms from the changes to his lumbar spine. That is a consequential injury or condition rather than a frank injury, the hypothesis in his first report.

Dr Hopcroft says on 7 March 2019 the applicant collided with a fellow employee and wrenched his low back at the same time, that is the immediate onset of lower back pain.

Dr Harrington has taken the not unreasonable approach of accepting at face value that reporting. That much is evident when one looks at his first report on 30 November 2022 when he discusses the original incident as occurring when the applicant was rushing out of an office when a colleague startled him and he twisted his right knee and he remembers also straining his back at the same time. Accepting that as a matter of fact the doctor proceeds on that false assumption. Dr Harrington says that again in this report, that the applicant also strained his lumbar spine which was treated conservatively, mainly hydrotherapy and exercise.

There is no error in Dr Harrington's approach other than to accept at face value that history. That does not undermine his overall opinion and it is open to accept some aspects of his report and not others. That is not an uncontroversial proposition.

The situation in respect of the hips is far more complicated.

To an extent Dr Harrington's opinion is that everything that results is due to the avascular necrosis and the degeneration and that is itself a condition removed from the effects of any altered gait. It is because of the avascular necrosis that the surgery ultimately proceeds, with the consequential effect on the right. This is a simple path of reasoning but when properly understood a little more needs to be said.

It is not caused by work, it is a condition that is always going to get worse and it is therefore not work-related.

Dr Harrington when asked about consequential injuries says the right knee injury was not the main or substantial contributing factor. Whilst the timing of his hip arthritis seems consequential to his right knee and lumbar spine he would say the pathology and complaints are constitutional in the sense that due to the avascular necrosis he had a successful left total hip replacement and is now struggling more with his right hip and right knee, even though he has had problems with his right knee since 2016. The aggravation to the back would have resolved.

In his report of 30 January 2023 Dr Harrington deals with the hips and notes the applicant reports he was hobbling for about 18 months due to right knee pain, subsequently experiencing back pain. The applicant alleged he also strained his lower back at the same time as his twisting injury in 2017, which suggests two separate and distinct episodes of lumbar problems, a history also embraced by the treating doctors.

Dr Harringtons does not believe there is a work-related aggravation or consequential condition involving the left knee or left hip with his arthritis and avascular necrosis not related to the right knee or altered gait. His opinion on 3 April 2024 is critically that the hip problems were caused by avascular necrosis which is not work-related and there is no commonsense causal chain from the right knee injury.

The clinical notes of Dr Echano on 26 September 2011 include right hip pain, and on

27 September 2011 right hip pain, "dull made worse by wrong movement".[3] On examination there was limited range of motion and diagnostic imaging is requested for both the right and left hips. There is recurrence of that in October 2011 and it is still present in June 2012 where right hip pain, foot pain, and recurrent limping a bit is recorded. These are records before the injury on 14 February 2017.

There is a not insignificant history of hip issues. There is a medical certificate of Dr Echano on 1 February 2012 for shoulder pain and recurrent right elbow pain and right hip pain on

2 September 2011 and a follow up consultation on 4 October 2011 for right hip pain.

Dr Hopcroft does not grapple with this history and he sees subsequent scans and jumps to the conclusion that because of the altered gait it has been caused or aggravated by work.

Dr Narasimhan grapples with the hip issue. In his report of 1 August 2020 he describes severe end stage arthritis with collapse of the femoral head, suggesting progression of the condition has simply continued to the inevitable point. There is a notation of how the applicant is going and then on 30 April 2021 it is right hip and groin pain on the right side for some time now, and he came in walking with a stick for his right hip. On 1 August 2023 only minor osteoarthritis is shown on X-ray in the medial compartment. It is not language that seems to link it back to any work injury.

Given the previous history and the complexity it does not lend itself to the commonsense test of causation. That is why Dr Hopcroft's opinion is critical in the applicant's case.

Dr Hopcroft in his first report focuses on the knee and lumbar spine and is not concerned with the hip. In his next report Dr Hopcroft assesses whole person impairment and again the hip is absent. On 15 January 2020 Dr Hopcroft perhaps makes a gratuitous comment about the insurer, suggesting something of an advocate's approach. He discusses the ongoing symptoms including pain in the left groin and increasing problems since the second injury.

There is a curious use of language in the sense that there is significant ongoing pain increasing since that date but that is contingent upon the history. In circumstances where we know the avascular necrosis end stage osteoarthritis, it is equally probable it is just the natural decline of the condition. It is not suggested it is new or there for the first time.

The pathology discussed by the applicant is equally explainable with reference to the degenerative nature of the condition getting worse.

Dr Hopcroft expresses his opinion that the applicant has ongoing problems in the lower back, left sided sciatica developing a significant problem of pain and restriction in movement of the left hip and knee, but he requests further imaging, an unconventional approach from a medico legal expert removed from the treatment of the applicant.

In his supplementary report of 4 March 2020 Dr Hopcroft refers to the results of the pelvis, left knee and left hip X-ray where there is a notation of severe degenerative change.

Dr Hopcroft's interpretation is of significant post-traumatic pathology from his work injuries of 2016 and 2017. This does not sit well with the degenerative change or his earlier hypothesis about previous symptoms getting worse, suggesting it is not post-traumatic.

On 8 February 2021 Dr Hopcroft has a scan of the lumbar spine and says it proves it is the significant result of the workplace injury, and he confirms his early opinion about the need to progress to a left total hip replacement.

The final report of 10 October 2023 in respect of the hips notes continuing problems of limp through his right leg and increasing back pain, the applicant developed quite marked pain in both hip joints with radiological studies including the left hip MRI describing severe degenerative change.

It is not quite right to say it had developed in that context given the history he had received but nor is it correct to say both sides became symptomatic at the same time as it appears there is some sort of delay, suggesting the hip problems are removed. He then had the X-ray indicating avascular necrosis within the left hip but Dr Hopcroft then says without saying why that it is due to the altered gait and the abnormal forces.

This dated from the two injuries that brought the symptoms which developed in the right hip. Without protracted limping it is far more likely than not that symptoms of the left hip will not have developed for many years, but again why has it been brought forward?

In terms of diagnosis and opinion Dr Hopcroft deals with the applicant continuing to limp and X-ray changes that show avascular necrosis developing in the left head of the femur, which lead to the decision being undertaken by him to progress the left hip joint replacement surgery from which he obtained an excellent result. There is no doubt the avascular necrosis necessitated the surgery. The question is how was that aggravated by work through the limping as opposed to natural progression.

The respondent's submission is that you would not feel actual persuasion that despite the history of limping which cannot be disputed on the records, there is a sufficient explanation that the avascular necrosis brought it forward. Dr Harrington tells you the avascular necrosis is what caused it.

Did the applicant sustain a lumbar spine injury on 14 February 2017 and/or a consequential lumbar spine injury as a result of the accepted right knee injury

1. Section 4 of the 1987 Act includes that an 'injury';

"(a) means personal injury arising out of or in the course of employment,

(i) a disease that is contracted by a worker in the course of employment but only if the employment was the main contributing factor to contracting the disease, and

(ii) the aggravation, acceleration, exacerbation or deterioration in the course of employment of any disease, but only if the employment was the main contributing factor to the aggravation, acceleration, exacerbation or deterioration of the disease, and..."

1. What is required to constitute 'injury' is a sudden or identifiable pathological change.[4] The applicant's statement evidence, Dr Hopcroft and Dr Harrington each refer to immediate low back pain on 14 February 2017, described variously as a twinge, jarring, wrench, or strain.
2. By May 2017 Dr le Roux is investigating the applicant's lower back pain and arranges an MRI. Dr Abson's opinion is the timeframe and course of the applicant's problems indicate his lumbar spine condition was most likely caused at the time of the twisting injury in 2017.
3. I accept the applicant's evidence that he had immediate lumbar spine symptoms on

14 February 2017. On the basis of the applicant's statement and medical evidence I do not agree with the respondent's submission that Dr Harrington's opinion is then based on a false assumption in this regard. 4. Dr Hopcroft describes a direct relationship between the right knee symptoms which have significantly aggravated the applicant's pre-existing spondylitic problems, incurring sciatic syndrome for the first time. The radiology confirms degenerative changes in the applicant's lumbar spine, which Dr Hopcroft notes are demonstrated from 2013.[5] The applicant is able to rely on a frank injury despite the existence of a disease.[6] 5. I do not accept Dr Harrington's opinion that an aggravation of the applicant's pre-existing asymptomatic lower back condition in 2017 would have ceased. 6. The medical evidence shows the applicant's lower back pain worsened after the 2017 injury. In January 2018 as an example the applicant attends the Manning Base Hospital with acute exacerbation of back pain. 7. The applicant submits his lumbar spine condition worsened as the result of his altered gait from the accepted right knee injury. The undisputed evidence of altered gait is in the applicant's statement evidence and is observed by Mr Jackson in February 2017, and by

Dr Hopcroft and Dr Christie from 2019. 8. While Dr Harrington does not believe there is sufficient evidence to suggest the applicant's back pain is a result of altered gait, a commonsense evaluation of the causal chain on the basis of the evidence in accordance with Kooragang establishes the applicant's back pain results from the incident in February 2017 and from his altered gait following that incident. 9. There is no reference to the applicant's back pain in the incident report of 14 February 2017, the claim form of 15 February 2017, the two Incident Personal Statement Forms of

16 February 2017, the clinical records of Dr Echano which refer only to the right knee until the L3 nerve block in July 2017, or in Mr Jackson's 2017 report, as the respondent submits. 10. The focus of his treating practitioners at the time is on the applicant's more significant right knee injury, which also appears to be the focus of the applicant's concerns following the 2016 injury, and the impact of the second injury on his capacity for work. The lower back appears less significant, described as "some lower back pain" by the applicant in his first statement. 11. This provides an explanation for the absence of complaints or treatment of the lumbar spine until the applicant consults Dr le Roux in April 2017, which as the applicant submits is within a relatively short time. 12. Dr Hopcroft's opinion on 7 March 2019 is that the applicant sustained an injury to his lower back on 14 February 2017 and he had an ongoing limp. On 10 October 2023 Dr Hopcroft refers to a significant weight bearing rotational strain to the lumbar spine in the 2017 incident, and that the applicant developed back pain and sciatic symptoms from the changes to his lumbar spine. 13. I do not agree with the submission that Dr Hopcroft has resiled or backtracked from his opinion that the applicant sustained a frank injury in 2017. 14. As the applicant sustained a lumbar spine injury on 14 February 2017, it is not controversial that his employment with the respondent was a substantial contributing factor to that injury in accordance with s 9A of the 1987 Act. 15. I am persuaded on the basis of the evidence[7] that the applicant sustained a lumbar spine injury on 14 February 2017 and his condition worsened as a result of his altered gait arising from the accepted right knee injury.

Did the applicant sustain consequential bilateral hip injuries

1. There is a clear distinction between a finding of 'injury' pursuant to s 4 of the 1987 Act and a finding that a consequential condition results from an 'injury'. The finding of a consequential condition does not necessarily involve the identification of pathology; the existence of symptoms may be sufficient.[8]
2. In Kumar [9] Roche DP confirmed Kooragang is the test to determine whether a consequential condition arises from an injury. The question of causation is determined on the facts of each case and requires a "commonsense evaluation of the causal chain" based on the evidence, including expert opinions where applicable.[10] There must be actual persuasion of the occurrence or existence of a fact before it can be found.[11]
3. The respondent accepts the applicant injured his right knee and I have found he also injured his lumbar spine on 14 February 2017. Whether he also sustained consequential injury to both hips as a result of the 2017 injury is disputed.
4. The applicant must establish the accepted right knee injury and lumbar spine injury have materially contributed to his bilateral hip condition even where there may be other causes.[12]
5. The applicant's submission is that from the right knee injury there is a change in biomechanics leading to a limp, with increased overcompensation and greater stress and strain put on the contralateral side, the left side, causing the left hip condition. The limp was observed by practitioners, and as the respondent submits cannot be disputed on the records.
6. The applicant's statement evidence is that he walked with an obvious limp favouring his left side to alleviate his right knee and lower back pain. This placed more weight on his left hip and lower back. As the pain in his right knee and lower back deteriorated and he developed an abnormal gait, the applicant began to experience increasing pain in both hips.
7. Dr Hopcroft's reports set out his opinion with respect to the applicant's hips as follows;

(a) the applicant has a significant and advancing ongoing problem of pain and restriction in his left hip in January 2020;

(b) there is significant degenerative changes and avascular necrosis within the left hip confirmed by MRI scan on 17 January 2020, with left hip function deteriorating rapidly;

(c) on review of the bone scan of 18 July 2019 which suggested moderately active arthritis, Dr Hopcroft believes the radiologically proven changes are significantly the result of the 2017 injury. The applicant needs to proceed to left total hip replacement surgery if he is to see any improvement in the pain and limp from the post-traumatic changes at that joint;

(d) the ongoing significant problems of right-sided limp and increasing back pain resulted in the development of quite marked pain in both hip joints. It was the abnormal forces and the significantly abnormal gait dating from the 2016 and 2017 injuries which brought around the right hip symptoms, and it is far more likely than not that the left hip symptoms would not have developed for many years;

(e) the low grade ongoing pain in his right hip joint from the two injuries progressed due to the applicant's grossly abnormal gait, and he proceeded to right total hip replacement surgery on 9 January 2023;

(f) there is a quite definitive link between the two work-related injuries, the applicant's grossly abnormal gait, his deteriorating back function with radiculopathy and the development thereafter of avascular necrosis in the left hip joint;

(g) the need for the left hip surgery is attributed to the applicant continuing to limp severely, and X-ray changes showing avascular necrosis developing in the left head of femur;

(h) the limping over several years and the deterioration in the right hip joint led to the right total hip replacement surgery in January 2023;

(i) there is a direct relationship between the two work injuries, his current significant hip significant pathology affecting his lumbar spine causing sciatic symptoms, and the deterioration of hip joint function with avascular necrosis developing in the left hip necessitating surgery. The applicant may otherwise have been able to avoid hip surgery for many years. The degenerative changes in both hips have been significantly progressed by the nature of his work for the respondent, and

(j) Dr Hopcroft concludes the aggravating injury to the applicant's right knee in 2017 along with the back symptoms caused gross disturbance of gait that led to the rapid deterioration of hip joint functionality bilaterally.

1. Regarding the left hip, Dr Abson in June 2018 comments on good relief in the applicant's right leg symptoms from an intralaminar injection but the applicant's left side is still an issue. The applicant submits this shows it is becoming clear clinically that there is a left hip issue at this time.
2. Dr Christie in June 2019 reports the applicant's pain seems to radiate from around the left hip, down the left leg to the knee and calf. A recent left hip X-ray was thought to be normal. Dr Christie notes hip movements seemed to be reasonable although a little restricted. In July 2019 the applicant was getting quite a bit of pain around the hip, and when Dr Christie rotated his left hip it was quite painful. The bone scan suggests some arthritis in the left hip.
3. Mr Luther, physiotherapist at the John Hunter Hospital, records in August 2019 the applicant recently experienced left thigh and groin pain. He had a reduced range of motion in the left hip quadrant with left groin and thigh pain on adduction and abduction.
4. The respondent's submission is that it is far more complicated than finding limping caused hip problems as there is avascular necrosis, a constitutional condition not caused by the employment. There is no commonsense causal chain from the right knee injury. Dr Hopcroft is the only expert to draw a definitive causal link in explicit terms between altered gait and the hip problems and there are problems with his opinion.
5. There is a history of right hip pain from 2011 that the respondent submits Dr Hopcroft does not grapple with, jumping to the conclusion the altered gait causes the hip problems.
6. Dr Hopcroft does not refer to the history of right hip pain in 2011 and 2012 in Dr Echano's clinical records as the respondent submits, however the X-ray of both hips and pelvis

Dr Echano's requests in September 2011 identifies no abnormality in either hip joint. A consideration of right hip pain in the clinical records in 2011 and 2012 may not have altered Dr Hopcroft's conclusion. 7. There are clear changes in the applicant's left hip by 2019. Dr Hopcroft considers the MRI left hip of 17 January 2020 that refers to severe degenerative changes in the left hip joint, the bone scan on 18 July 2019 that concludes there is moderately active arthritis in the left hip joint, and the left hip X-ray of 20 January 2020 that finds significant degenerative changes and avascular necrosis. 8. I accept the respondent's submission that the pathology may be equally explainable with reference to the degenerative condition getting worse, however I do not accept that is the explanation in this case based on the weight of expert evidence. 9. While in Dr Harrington's opinion the deterioration in the applicant's hip is a natural progression of his condition, he provides no explanation as to why the limp would not have increased pressure on the left hip and aggravated the condition, or on an expected rate of natural progression given the left hip function was rapidly deteriorating by 2020. 10. That the applicant had severe degenerative changes in the left hip joint and avascular necrosis was considered by Dr Hopcroft who then concludes it is far more likely than not the left hip symptoms would not have developed for many years without such protracted limping. 11. Dr Harrington's view is that the timing is coincidental with the applicant's work-related injury however I am persuaded by Dr Hopcroft's opinion that the 2017 injury resulted in a significant limp which added stress to the left hip aggravating his pre-existing condition. 12. As a treating orthopaedic surgeon Dr Narasimhan does not provide an opinion on causation. I do not agree with the respondent's submission that Dr Narasimhan's treatment suggests the progression of avascular necrosis simply continued to the inevitable point. The doctor does not address causation in his reports and there is no other evidence regarding the natural progression of this condition. 13. I prefer Dr Hopcroft's opinion that the applicant's limp and back symptoms resulted in an aggravation of his left hip condition leading to the surgery in August 2020. 14. With respect to the right hip, the applicant's statement evidence is that he began to experience increasing pain in both hips due to his abnormal gait. 15. Dr Hopcroft's opinion is the gross disturbance of gait from the 2017 right knee injury along with the back symptoms led to the rapid deterioration of hip joint functionality bilaterally. The abnormal forces and the significantly abnormal gait from the 2016 and 2017 injuries brought around the right hip symptoms which progressed to the right total hip replacement surgery. In his opinion limping over several years and deterioration in the right hip joint led to the surgery. 16. The applicant's submission is his right hip condition deteriorated to the point total hip replacement surgery was carried out in January 2023 as recovering from the left total hip replacement surgery in August 2020 would necessarily require rehabilitation and a shift in the other direction to mobilise, aggravating the underlying condition. 17. There is evidence the applicant had a degenerative right hip condition by January 2020 which deteriorated; the 2011 X-ray shows no right hip abnormality, the January 2020 X-ray finds some minimal degenerative spurring within the right hip laterally, the September 2020 X-ray shows severe degenerative changes, the March 2021 X-ray finds moderate to severe degenerative change of right hip joint, and the 2022 X-ray finds severe degenerative arthropathy of the right hip with no avascular necrosis. 18. Dr Narasimhan notes in June 2020 while treating the applicant's left hip that the right hip is ok. In April 2021 he notes the applicant has been having right sided groin pain for some time and he has decreased mobility, walks with a stick for his right hip and has an antalgic gait. He has groin pain on rotation and severe end stage arthritis on X-ray. 19. In November 2022 Dr Harrington notes the applicant has developed problems with his right hip which are not as bad as his left, and he is scheduled to have a right total hip replacement. His right hip pain is in his groin radiating to his knee which is typical of hip arthritis. On examination his right hip is very stiff, having lost at least half the normal range of movement. 20. In Dr Harrington's opinion the deterioration in the applicant's hip is a natural progression of his constitutional condition, however he provides no explanation as to why the antalgic gait following the left total hip replacement would not have increased pressure on the right hip and aggravated the underlying degenerative condition. 21. Dr Hopcroft sets out the reasoning behind his conclusion; the applicant's right hip joint pain progressed due to the applicant's significantly abnormal gait over several years.

Dr Harrington does not directly respond to this opinion referring only to the natural progression of the condition. 22. There is no other evidence available that the deterioration of the applicant's right hip condition was the result of natural progression. 23. The evidence supports the submission that the applicant had a limp following the left total hip replacement surgery in August 2020, his right hip condition would necessarily have been aggravated as a result, and after nearly two and a half years the right total hip replacement surgery was required in January 2023. 24. On consideration of the expert evidence and a commonsense evaluation of the causal chain, I am persuaded the applicant sustained consequential bilateral hip injuries as the result of the injury on 14 February 2017.

1. The applicant sustained a lumbar spine injury in addition to the accepted right knee injury on 14 February 2017 pursuant to ss 4 and 9A of the 1987 Act.
2. The applicant sustained consequential bilateral hip injuries as a result of the right knee and lumbar spine injury on 14 February 2017.
3. The claim for lump sum compensation is to be remitted to the President for referral to a Medical Assessor.
4. The matter is to be listed for a further preliminary conference to deal with the applicant's claim for weekly benefits and medical or related expenses if appropriate following the completion of the medical assessment process.

[1] Kooragang Cement Ltd v Bates (1994) 35 NSWLR 452; (1994) 10 NSWCCR 796 (Kooragang).

[2] [2009] NSWCA 227.

[4] Castro v State Transit Authority (NSW) [2000] NSWCC 12; (2000) 19 NSWCCR 496.

[6] Zickar v MGH Plastic Industries Pty Ltd [1996] HCA 31; 187 CLR 310.

[7] Nguyen v Cosmopolitan Homes [2008] NSWCA 246.

[8] Trustees of the Roman Catholic Church for the Diocese of Parramatta v Brennan [2016] NSWWCCPD 23 at [164] and [169].

[9] Kumar v Royal Comfort Bedding [2012] NSWWCCPD 8.

[10] Kooragang Cement Pty Ltd v Bates (1994) 35 NSWLR 452 at [464]; 10 NSWCCR 796.

[11] Nguyen v Cosmopolitan Homes [2008] NSWCA 246.

[12] Murphy v Allity Management Services Pty Ltd [2015] NSWWCCPD 49.