1. Causation of injury is addressed from cl 1.5 of the Guidelines. Clauses 1.6 and 1.7 provide:

"1.6 Causation is defined in the Glossary at page 316 of the AMA4 Guides as follows:

Causation means that a physical, chemical or biologic factor contributed to the occurrence of a medical condition. To decide that a factor alleged to have caused or contributed to the occurrence or worsening of a medical condition has, in fact, done so, it is necessary to verify both of the following:

1. The alleged factor could have caused or contributed to worsening of the impairment, which is a medical determination.
2. The alleged factor did cause or contribute to worsening of the impairment, which is a non-medical determination.'

This, therefore, involves a medical decision and a non-medical informed judgement.

1.7 There is no simple common test of causation that is applicable to all cases, but the accepted approach involves determining whether the injury (and the associated impairment) was caused or materially contributed to by the motor accident. The motor accident does not have to be a sole cause as long as it is a contributing cause, which is more than negligible. Considering the question 'Would this injury (or impairment) have occurred if not for the accident?' may be useful in some cases, although this is not a definitive test and may be inapplicable in circumstances where there are multiple contributing causes."

1. In determining the issue of causation, the Panel is to also have regard to s 5D of the Civil Liability Act 2002 (CL Act):[7]

(1) A determination that negligence caused particular harm comprises the following elements -

(a) that the negligence was a necessary condition of the occurrence of the harm (factual causation), and

(b) that it is appropriate for the scope of the negligent person's liability to extend to the harm so caused (scope of liability).

(2) In determining in an exceptional case, in accordance with established principles, whether negligence that cannot be established as a necessary condition of the occurrence of harm should be accepted as establishing factual causation, the court is to consider (amongst other relevant things) whether or not and why responsibility for the harm should be imposed on the negligent party.

(3) If it is relevant to the determination of factual causation to determine what the person who suffered harm would have done if the negligent person had not been negligent -

(a) the matter is to be determined subjectively in the light of all relevant circumstances, subject to paragraph (b), and

(b) any statement made by the person after suffering the harm about what he or she would have done is inadmissible except to the extent (if any) that the statement is against his or her interest.

(4) For the purpose of determining the scope of liability, the court is to consider (amongst other relevant things) whether or not and why responsibility for the harm should be imposed on the negligent party."

1. Pursuant to Part 3 of the MAI Act the insurer is liable for the payment of statutory benefits, including treatment and care benefits as set out under Division 3.4.
2. Section 3.24(2) of the MAI Act provides that:

"No statutory benefits are payable for the cost of treatment and care to the extent that the treatment and care concerned was not reasonable and necessary in the circumstances or did not relate to the injury resulting from the motor accident concerned."

1. The test of whether the subject treatment and care is reasonable and necessary is generally considered a stricter test than the corresponding test in the New South Wales workers compensation benefits scheme that requires a worker to establish that the treatment is "reasonably necessary".[8]
2. The cases relating to the workers compensation scheme, whilst not binding, provide some guidance. In Diab v NRMA Ltd 2014 NSWWCCPD 72 (Diab) at [88] the following factors were found to be relevant to, but not determinative of the criteria of reasonableness in the workers compensation scheme:

(a) the appropriateness of the treatment in dispute;

(b) the availability of alternative treatment;

(c) the cost effectiveness of the treatment;

(d) the actual or potential effectiveness of the treatment, and

(e) the acceptance by medical experts of the appropriateness of the treatment.

1. The words "did not relate to the injury resulting from the motor accident" contained in s 7.26 of the MAI Act require the Panel to determine the issue of causation of the subject injury before determining whether the treatment relates to that injury.
2. The Panel has considered the case of AAI Limited t/as AAMI v Phillips [2018] NSWSC 1710 (Phillips), when determining the issue of whether the treatment is related to the injury caused by the motor accident. The case of Phillips involved a claimant involved in three separate motor accidents and the Court, dealing with the issue of causation for surgical treatment found at [28] and [29]:

"The requirements in s 58(1)(b) is to determine whether the treatment relates to the injury caused by the accident. If the injury that existed at the time of the Panel's assessment was not the injury caused by the accident (the mild soft tissue injuries superimposed on the chronic degenerative changes) but, rather, simply the continuation of those pre-existing degenerative changes, then the treatment cannot relate to 'the injury caused by the motor accident'.

I accept the plaintiff's submission that for any of the three motor accidents to have been causative of the need for the suggested surgery, the accident would have to have made at least a material contribution to the need for surgery. Further, the Panel should have considered whether the proposed surgery would not have arisen but for the occurrence of one or more of the accidents being considered."

1. Medical Assessor Kenna noted that the claimant attended an examination on 6 August 2024 and appeared to have no limp upon entering the examination room, which was in contrast to the documentary medical evidence. The claimant advised that she had undergone recent left hip surgery by Dr Dewar, orthopaedic surgeon on 16 July 2024. The claimant was noted to be no longer on medication.
2. The left hip was not examined, on account of the surgery taking place only three weeks prior. Medical Assessor Kenna, however, observed the claimant to have no obvious limp and was smiling, with the claimant providing a history that she can walk up to 500+ metres. The claimant told the Medical Assessor that she was extremely pleased with the result and the pain levels had been such that she self-funded the operation.
3. The Medical Assessor summarised the medical and other documentary evidence and concluded that there was no clear evidence that the left hip was in anyway injured in the motor accident or the events as they unfolded. He also noted that there were pre-existing conditions and factors with conflicting diagnosis as to the cause. He therefore concluded that the total left hip replacement was not related to the injuries caused by the motor accident and is not reasonable and necessary in the circumstances.

Claimant's review submissions dated 24 September 2024

1. It is submitted that the Medical Assessor did not have any or any adequate regard to the treating medical history, and gave a much greater emphasis to the insurer's submissions.
2. It is further submitted that the Medical Assessor applied the incorrect test of causation.
3. The submissions refer to treating evidence that are said to corroborate left hip injuries. This includes radiology reports, and records of Mitchell Integrated Therapy. Also referred to is a report of Associate Professor David Dewar who reported to Detective Senior Constable Jeff Castle who stated the claimants' hips were injured as a result of the accident and she will need a hip replacement.
4. The claimant also submits that the Medical Assessor failed to refer to the provided police photographs that revealed "the extensive bruising that she suffered following the subject accident".
5. In respect of causation, the claimant submits:

"Against the evidence of no previous complaints of left hip symptoms, Assessor Kenna failed to consider that the subject accident was a contributing cause which was more than negligible to the development of symptoms and to the need of a left hip replacement procedure. There was clearly a sufficient basis for a finding that the trauma of the subject accident was a cause, which was more than negligible, of the development of left hip symptoms and for the need for the left hip replacement surgery."

Insurer's original submissions dated 13 June 2024

1. The insurer refers to the documentary evidence and submits there is no contemporaneous evidence to indicate that the claimant sustained any injury to the left hip from the accident that would give rise to the condition.
2. The insurer submits that the medical evidence demonstrates that any development of avascular necrosis of the left hip relates to pre-accident comorbidities and is not casually related to the accident.

Insurer's review submissions dated 14 October 2024

1. The insurer submits that the Medical Assessor was not required to expressly refer to evidentiary material or accept competing opinion over another (Golijan v Motor Accident Authority of NSW [2012] NSWSC 1106).
2. It is submitted that the Medical Assessor placed clear emphasis on a number of issues that suggest that the left hip injury was not caused by the accident, and was "...clearly persuaded that the presence of avascular necrosis was the result of something other than an injury caused by the subject accident because of its presence on the right side."

1. The Panel has considered all documents provided by the parties in compliance with Panel directions.

Application for personal injury benefits dated 10 October 2020

1. The claimant describes the circumstances of the accident as follows:

"Mr X was leaving in his vehicle but had been drinking all afternoon, I tried to stop him from leaving. I put my hand through car door which was open attempted to get keys. He drove forward, I slipped he ran over my left arm, he then stopped reversed up his car and ran over me again running over my leg, back and head on left."

1. The claimant's description of injuries is as follows: "soft tissue damage to left ankle still cannot flex or extend/soft tissue damage hematoma to left arm and wrist - loss of strength in hand cartilage in ribs, ongoing pain, disc herniation caused by impact of car on back now nerve damage."

1. The police report notes the incident being reported on 5 September 2020. The report includes the following crash summary details:

"About 10pm on Friday the 4th of September 2020 a male driving a white Toyota utility has come to collide with a female pedestrian causing her to fall under the wheels of the vehicle. The female sustained chest and shoulder injuries."

1. The report notes that the crew arrived at the home post the claimant being run over by a car. The claimant as rolling around on bed and appeared in distress. She initially refused to tell police or paramedics information as to what had happened. The claimant is recorded as complaining of pain in chest, wrist and arm with abrasions to same. The claimant agreed to walk to the ambulance and did not appear to be in pain when ambulating. She eventually advised the officers that she had been hit by a ute at 5-10kmph and had been run over twice by the tyre of the car. The claimant is noted to complain of "severe pain to left side of chest/flank/shoulder/shoulder tip/ear/epigastric and left abdo/left wrist/left foot..." Tenderness to the cervical spine was noted but the claimant refused a collar. It is further noted that "...T-pod placed on pt pt refused pain to pelvis or femurs..." The report notes that it was very difficult to gain IV access.

1. The file provided includes record of the claimant presenting in January 2020 with complaints of progressive headache and vertigo and right sided weakness. It was noted the claimant was a regular amphetamine user.
2. A discharge referral relevant to the subject accident dated 5 September 2020 records the claimant being knocked to the ground by a car and the car then running over her head and chest and then reversed and ran over her again "over the same area". Noted to be distressed with left sided chest pain, left flank pain, and left shoulder pain.
3. Tyre marks on her head, left chest and left arm were noted on presentation. Paraesthessia and reduced sensation over L5 distribution and normal motor function is noted.
4. Investigations were carried out including a CT Pan Scan, that noted no fracture in the cervical, thoracic and lumbosacral spine and no acute injury in the chest, abdomen and pelvis. A plain X-ray of the left shoulder/wrist/ankle demonstrated no bony injury. An MRI of the lumbosacral spine was also undertaken.

General practitioner file - Greta Medical Centre

1. The clinical records commence in May 2018. The first recorded consultation notes the claimant to smoke 30 cigarettes daily. The reason for contact is noted as pelvic inflammatory disease.
2. Leading up to the accident the claimant attends on the practice with various unrelated complaints including vertigo and an elbow injury. On 6 July 2020 the claimant noted the claimant having a swollen left ankle after being run over by a motorcycle on the weekend. On 27 August 2020 the claimant was noted to have been apparently diagnosed with posttraumatic stress disorder and was seeing a psychiatrist.
3. A note of 10 September 2020 documents a telephone consult with the claimant having been admitted to the John Hunter Hospital after being struck and ran over by a motor vehicle. The claimant attended the practice on 17 September 2020 and apparently would not disclose the details of the events leading to the hospitalisation and she walked out from the consultation.
4. The claimant attended again on 12 October 2020 with a note that she presented for "CTP: and back/ankle/wrist pain. The claimant is noted to be "still sore" at the left wrist, left ankle, left foot, and back." The claimant said she was managing okay but had restricted hours at work due to pain. Her back was causing intermittent tingling and numbness. On examination diffuse tenderness was noted at the left wrist and left ankle. Her gait was reported as normal.
5. The claimant was referred to Dr Salaria on 23 October 2020. On 3 November 2020 the claimant stated she was upset after the consultation with Dr Salaria and felt nothing about her hand or foot was addressed properly. She was noted to be quite sore in most places in her body. The claimant was provided with referrals to Dr McLelland and Dr O'Sullivan.
6. The claimant attended again on 25 November 2020 and was noted to have seen a foot surgeon and was still in pain in respect of the left wrist, left foot, lower back and she complained of numbness in the left leg. MRI scan referrals were provided for the lumbar spine and left hip. She was noted to have constant pain in the lumbar spine with tenderness at L3/L5 with left L5 facet joint tenderness with left sciatica.
7. On 18 December 2020 the claimant is noted to have seen a hand surgeon. He hand was better but still complained of worse pain in the back with right hip and right upper thing symptoms.
8. By 23 July 2021 the claimant was noted to have hip and leg intermittent pain. On 7 September 2021 her hip pain was noted as much better following injection.
9. Blood results were discussed on 21 September 2021 that apparently revealed raised white blood cell count and raised mean corpuscular volume. The claimant stated she had a bone marrow biopsy in New Zealand 20 years prior due to an apparently elevated hemolysis in gel (HIG) test.
10. The claimant is recorded on 17 May 2022 as having felt a snap in her right groin the week prior when walking on uneven ground. On 2 August 2022 the claimant complained that her hip pain was getting worse and found walking difficult.

1. This orthopaedic specialist reported to Dr Deep, general practitioner, on 27 October 2020. The doctor records a history of the claimant being ran over her left arm, body and leg. The doctor records swelling in the left hand, and MRI of the left ankle showing incomplete ankle ligament injuries corresponding with a Grade II ankle sprain. The claimant also complained of sharp pain in the left groin and lower back but was mobilising well and the spine had a good range of movement. The doctor opined that the claimant likely had a sprain type injury but would review in six weeks with an MRI of the lumbar spine and hip if she had not improved significantly.
2. A "back pain questionnaire" filled out by the claimant is included in the file but is undated. On a body graphic the claimant indicates symptoms at her cervical spine and top of back and down her right arm. In addition to lower back, left buttock and pins and needles down the left leg. She provides a description of the injury as: "someone ran over my arm as I had tried to stop them from driving - they had pushed me I feel [sic] to ground, they ran over arm, stopped then reversed up and ran over my leg - back and head." The claimant denied previous back pain.
3. The claimant's general practitioner referred the claimant back to Dr Salaria on 1 December 2020, asking for an extremely urgent appointment noting the MRI demonstrated a L4/5 disc protrusion with compression of the L5 nerve root and left hip MRI revealed a femoral head subchondral fracture and early osteonecrosis.
4. Upon review, the doctor recommended a L4/5 microdiscectomy and noted that the hip was better since the last review, and that he would continue to observe the hip.
5. In a report dated 6 April 2021, Dr Salaria noted the claimant was still having sharp pains in both groins and the left hip joint had been clicking and giving way. He stated that this would correspond with the left hip findings of a small chondral lesion correlating with avascular necrosis type of pathology. He organised repeat MRI scans and standing X-rays of both hips. On 14 April 2021 the doctor reported that the scans showed stable osteonecrosis of the left femoral head and no loose fragment progression of the osteonecrosis in both the hips.
6. By 3 August 2021 the doctor noted the left hip and groin pain was affecting the claimant's walking with a limp and sometimes the hip giving way. He stated that the symptoms corresponded with the MRI scan findings of avascular necrosis type of lesion to the femoral head.
7. On 2 November 2021 the doctor reported to the claimant's general practitioner that the left groin and buttock pai was getting worse and affecting all aspects of her life. He stated: "this groin pain corresponds with the avascular necrosis left femoral head since her accident. She also has the L4/5 disc herniation but that pain has improved thus we had deferred the spine surgery." Due to the symptoms in the hip not improving he discussed option of a femoral head core decompression surgery, but the claimant would at some stage require a total hip replacement.

Dr O'Sullivan - Newcastle Orthopaedic Foot & Ankle Clinic

1. The doctor reports to the claimant's general practitioner on 23 November 2020, with a history of the claimant presenting with pain and swelling over the lateral aspect of the left ankle and leg having been run over. He states the claimant was run over her left side including left ankle, left upper limb and even neck and head. The claimant apparently showed a photo of her left ankle taken at the time of the injury which suggests she had an almost degloving injury.

1. The claimant was referred to Dr Dewar in respect of her hip issues. In a report to Detective Senior Constable, Jeff Castle dated 15 February 2022, the doctor noted he had seen the claimant the year prior for bilateral femoral avascular necrosis with a history that the hips had no pain prior to the accident. He states: "most likely the AVN was caused by the accident and I suspect that in the long term she will need hip replacement."
2. In an initial report to the claimant's general practitioner, Dr Jyoti, dated 14 December 2021, the doctor noted that updated X-rays show development of early osteoarthritis and the MRIs demonstrating mild avascular necrosis. He states that the right side is of more concern due to a small step in the articular surface. Hip replacement was described as required, with a delay as long as possible.
3. On 1 September 2023 the doctor states in a report that the claimant attended on 21 August 2023 and felt ready to proceed to a left hip replacement. The claimant described daily pain with the left leg giving way.
4. The file of the doctor includes an MRI report of both hips dated 8 April 2021. The report concludes as follows:

"Essentially stable osteonecrosis left femoral head with no loose fragment or crescent sign. Less marked similar position changes in the right femoral head. Mild arthropathy more severe on the right. Labral mucoid cystic degeneration bilaterally more severe on the right. Labral mucoid cystic degeneration bilaterally more severe on the right. Gluteus medius tendinopathy and trochanteric bursitis bilaterally."

1. An X-ray report of the pelvis and left hip states the AVN identified in both femoral heads on the MRI is not clearly visualised on the left hip X-ray. Some changes consistent with mild arthropathy bilaterally is noted and some SI joint arthropathy. It is also reported that there is no significant subchondral lucency or cortical break demonstrated on the plain X-ray.

1. Initial consultation notes of 14 December 2020 take a history of the motor accident with an MRI showing disc bulge at L4/5 and a left hip small subchondral fracture with osteonecrosis likely.
2. The MRI of the left hip dated 26 November 2020 demonstrated the following:

"...focal marrow edema/high signal with mild subchondral sclerosis and minimal subchondral depression involving the inner anterosuperior aspect of the femoral head with overlying chondral thinning, probably reflective of small subchondral fracture and early osteonecrosis..."

1. The claimant relies upon the opinion of Dr Bodel. In a report dated 29 September 2021 the doctor noted that due to the Covid-19 pandemic the assessment was conducted via videolink.
2. Dr Bodel took the following history of the accident: "Initially she had her car keys in her hand and the assailant tried to pull them out of her hand. She was subsequently run over, injuring the left hand and the neck and shoulder and back adduction the left hip and the leg."
3. Dr Bodel noted the MRI of the left hip of 26 November 2020 and states that it indicates that there is evidence of significant change in the head of the femur. He concluded that the claimant has early signs of avascular necrosis.
4. In a further report dated 5 February 2024, Dr Bodel noted the ongoing complaints, including the left hip and noted that the claimant had seen Dr Dewar because of apparent avascular necrosis in both heads of the femur. Bilateral total hip replacements were recommended. The doctor noted a history that the claimant states that the car did run over her pelvis.
5. He states:

"Her main area of concern at the moment is the rapidly deteriorating function in the hips and she is booked to have a total hip replacement on the left hand side in April of 2024, and then about three to six months later, she used to have the right side done as well [sic]. This is the management of the post traumatic osteoarthritis and avascular necrosis which appears to have occurred as a consequent of the accident."

1. The claimant also relies upon a report of Dr Porteous dated 18 August 2022. The doctor took a history of the claimant being ran over at the left hand and wrist and then the car reversing and running over the left side of her body.
2. Dr Porteous noted the claimant subsequently developing bilateral avascular necrosis which he stated can occur after trauma.

1. The Panel has carefully considered all material provided. There is no contemporaneous evidence of a direct injury to the left hip caused by the motor accident. The ambulance and hospital records make no mention of hip issues. The ambulance notes state officers observed bruising to left arm, wrist and left side of back. Hips were not mentioned.
2. The photographs provided are noted. There is no photographic evidence of any injury to the left hip area. Whilst the photos do not include that area at all, nonetheless they provide no objective evidence of a hip injury.
3. In the medical expert opinion of the Medical Assessors, avascular necrosis, whilst possible to arise from trauma, would require a direct contact with the hip for such situation to eventuate. Moreover, the avascular necrosis is clearly a bilateral condition of the hips in the claimant's case. Indeed, the medical evidence suggests that the right side was possibly worse than the subject left side.
4. Avascular necrosis of the femoral heads is in most cases asymptomatic in its early stages. The majority of cases are due to an interruption of the blood supply to the femoral heads such as a fracture, dislocation or infection of the hip. The condition is rarely due to Caisson (seen in deep sea divers) or sickley cell disease and can also be seen in persons on long term steroids or cytotoxic drugs. The medical evidence does not establish, on the balance of probabilities, a direct traumatic injury to the hip caused by the motor accident.
5. Whilst complaints of hip pain are evident in the material in the weeks after the motor accident, the Panel considers it more likely that such complaints are coincidental to the motor accident, rather than causative.
6. Accordingly, the Panel has found that on the balance of probabilities, the avascular necrosis of the left hip leading to a total hip replacement, was not caused by the motor accident.
7. The medical certificate of Medical Assessor Kenna is therefore confirmed.

[1] See Division 7.5 and Schedule 2, cl 2 of the MAI Act.

[8] Section 60 of the Workers Compensation Act 1987.