DETERMINATION OF REVIEW PANEL	
	
CITATION:	Bridgefoot v Allianz Australia Insurance Limited [2024] NSWPICMP 194	
		
CLAIMANT:	Gelsomina Bridgefoot	
		
INSURER:	Allianz Australia Insurance Limited	
		
REVIEW Panel	 	
		
MEMBER:	Bridie Nolan	
		
MEDICAL ASSESSOR:	Alan Home	
		
MEDICAL ASSESSOR:	Sophia Lahz	
		
DATE OF DECISION:	28 March 2024	
		
CATCHWORDS:	MOTOR ACCIDENTS – Motor Accident Injuries Act 2017; medical dispute; claimant suffered two injuries to knees in school bus accidents on two separate occasions in 2018 and 2019; the 2019 accident aggravated the pre-existing symptomatic injuries from the 2018 injury of to the right knee; ensuing severe right knee pain which did not improve with conservative treatment of further physiotherapy and came to a self-funded right total knee replacement; whether the right knee injuries the subject of the claims in the 2018 accident and the 2019 accident are injuries caused by the motor accident and whether such an injury is a threshold injury; whether total knee replacement an injury caused by a motor vehicle accident; whether total knee replacement a “soft tissue injury”; Held – Medical Assessment Certificate revoked; contusions to right knee in 2019 accident caused the need for a total knee replacement; total knee replacement does not satisfy the definition of “soft tissue injury” in section 1.6, in that it is not harm or disturbance done to the tissue that connects, supports or surrounds other structures or organs of the body, alone; total knee replacement is the total replacement of this soft tissue joint material, namely, cartilage with a prosthesis.

DETERMINATIONS MADE:  	CERTIFICATE OF DETERMINATION
Medical Assessment – Threshold injury
Review Panel Assessment of Threshold Injury
Replacement Certificate issued under s 7.23(1) of the Motor Accident Injuries Act 2017 
The Review Panel revokes the certificate dated 21 February 2024 and certifies that: 
1.	The following injuries were not caused by the motor accident:
(a)	right knee - traumatic meniscal injury and traumatic patellar fracture resulting in total knee replacement.
2.	The following injuries caused by the motor accident:
(a)	lumbar spine;
(b)	cervical spine;
(c)	thoracic spine, and
(d)	left foot,
are THRESHOLD INJURIES for the purposes of the Act. 
3.	The following injury caused by the motor accident:
(a)	right knee – bony oedema resulting the aggravation of pre-existing degenerative arthritic changes to the knee and a total knee replacement;
is not a THRESHOLD INJURY for the purposes of the Act.	

STATEMENT OF REASONS
introduction
1.	The claimant, Gelsomnia Bridgefoot, claims she sustained injuries in two motor vehicle accidents: 30 November 2018 (R-M10564912/23) (the 2018 accident) and 6 December 2019 (R-M10564888/23) (the 2019 accident). On both occasions, the claimant was a passenger on a bus insured by the insurer. The insurer therefore has a liability to pay the claimant any damages and/or statutory compensation entitlements under the Motor Accident Injuries Act 2017 (the Act).
2.	These reasons support the certificates which the Review Panel (Panel) has issued in respect of both the 2018 accident and the 2019 accident. 
THE MEDICAL ASSESSMENT THE SUBJECT OF REVIEW
3.	In relation to the injuries sustained in the accident of 2018 accident, the claimant lodged an application for determination of whether her injuries were minor or non-minor [viz. threshold or non-threshold] as defined in the Act. In that application the claimant alleged, relevantly, she sustained injuries to her:
(a)	head;
(b)	cervical spine;
(c)	sacrum/coccyx;
(d)	lumbar spine;
(e)	ribs;
(f)	right knee - anterior, posterior, and medial crush injury to the right knee; acceleration and deterioration of osteoarthritis; soft tissue injury;
(g)	left and right shoulder;
(h)	thoracic spine, and
(i)	left foot.
[our emphasis added]
4.	In relation to the injuries sustained in the accident of 2019 accident, the claimant lodged an application for determination of whether her injuries were threshold or non-threshold as defined in the Act in relation to the injuries sustained in the accident of 2019 accident. In that application the claimant alleged, relevantly, she sustained injuries to her:
(a)	right knee - traumatic meniscal injury and traumatic patellar fracture resulting in total knee replacement;
(b)	lumbar spine;
(c)	cervical spine;
(d)	thoracic spine, and
(e)	left foot.
      [our emphasis added]
5.	By a certificate dated 21 February 2023, Medical Assessor Ian Cameron assessed the claimant in relation to the above injuries finding that the above injuries were minor [viz. threshold] and determined, relevantly, that the claimant had suffered a soft tissue injury to her right knee in both the 2018 accident and the 2019 accident and as such that injury, and all other injuries were minor injuries.
THE REVIEW
6.	The applications for referral of the medical assessments to a review panel were made by the claimant within 28 days after the parties were issued with the original certificate for the medical assessment for which the review is sought.
7.	On 19 April 2023, the President’s delegate referred the medical assessments to the Panel as he was satisfied that there was reasonable cause to suspect that the medical assessment was incorrect in a material respect having regard to the particulars set out in the application.
8.	Clause 14F of Schedule 1 of the Personal Injury Commission Act 2020 (the PIC Act) provides that the new review provisions apply in relation to a decision of a new decision-maker. A "new decision maker" is defined in cl 14A(1) of Schedule 1 of the PIC Act. As the medical assessment, the subject of the review, was made on or after 1 March 2021, the new review provisions apply.
9.	The new review provisions provide that a review panel consists of two Medical Assessors and a member assigned to the Motor Accidents Division of the Personal Injury Commission (Commission).
10.	Section 41(2) of the PIC Act enables the Commission to make rules with respect to the practice and procedure before the Commission including proceedings before a panel reviewing a decision of a Medical Assessor.
11.	Rules 127 to 130 of the Personal Injury Commission Rules 2021 (PIC Rules) are made pursuant to Part 5 of the PIC Act. A review panel determines how it conducts and determines the proceedings and may determine the proceedings solely based on the written application.
12.	Section 7.17 of the Act defines a “medical dispute” to include dispute between the parties about a “medical assessment matter”.
13.	Pursuant to Schedule 2, cl 2 of the Act, various matters are declared to be a medical assessment matter including whether “the injury caused by the motor accident is a threshold injury for the purposes of the Act”. This is the relevant question of which the Panel is presently seized. 
14.	A medical assessment matter is determined in accordance with Division 7.5 of the Act, in this case pursuant to s 7.26 of the Act, on review by a review panel.
15.	The Panel issued a direction dated 14 July 2023 to the parties requesting the provision of respective bundles and submissions on the review with which the parties complied.
16.	In her submissions on the review, the claimant narrowed the ambit of the medical assessment matter to the determination of whether the injury she claims she suffered to her right knee in both the 2018 accident and the 2019 accident was a threshold injury. The insurer has engaged with that contention in its submissions. It is relevantly the only dispute between the parties about the medical assessment matters which arise for determination in respect of both the 2018 accident and the 2019 accident. 
17.	Accordingly, the Panel has confined its determination to the matter stated in Schedule 2, cl 2(e) as to whether the right knee injuries the subject of the claims in the 2018 accident and the 2019 accident are injuries caused by the motor accident and whether such an injury is a threshold injury for the purposes of the Act. 

EVIDENCE BEFORE THE REVIEW PANEL
18.	The following is a summary of the evidence before the Panel on the review relevant to the medical assessment matter regarding the claimed injuries to the right knee. 
19.	The claimant is a primary school teacher with Sydney Catholic school since 1980 and continued in that employment. She was teaching primary school at the time of the accidents.
20.	In 2008, at school squatting down the floor level to talk to a year 1 pupil, the claimant tore the medial meniscus of her right knee. She saw Dr Walker who performed an arthroscopy on 
6 July 2008 incorporating a partial medial and lateral meniscectomy and a chondroplasty to the medial femoral condyle.
21.	In the latter half of 2008 and 2009 she reported continuing knee pain.
22.	On 1 October 2015, the claimant attended her general practitioner (GP) with what was thought to be knee arthritis. It is recorded that when she had the right meniscal surgery.  She was told that she may need a knee replacement in about five years time.
23.	There is an X-ray of both knees dated 1 October 2015. There were small bilateral knee joint effusions. There were no fractures. There were mild/moderate tricompartmental degenerative changes bilaterally but worse on the right.
24.	In 2016, she had a fall at school on to all fours. She reported bilateral knee pain.
25.	On 29 December 2016, the claimant had right knee pain and tendinitis in the left foot. She thought that she may have done too much walking the following week.
26.	On 20 March 2017, her GP recorded that the Department of Endocrinology at Royal North Shore Hospital had diagnosed her with osteoporosis.
27.	On 28 July 2017, she attended her GP with a painful right knee. It was recorded that she had been taking Actonel since November 2016. She was to be referred by 
Dr Walker and to have further scans.
28.	There is an X-ray of the right knee dated 1 August 2017. This showed advanced degenerative disease of the medial compartment, with nearly complete loss of the joint space. A tripartite patella was noted.
29.	In 2018, the claimant was able to do yoga and walk 300km of the Camino del Santiago pilgrimage in 2018 with no reported knee issues.
30.	On 30 November 2018, the claimant says she was seated in a terraced old-style bus with steps at the front of the bus beside the driver at the front. The bus was not fitted with seat belts.  The bus pulled out from the kerb at high-speed, mounted a gutter and struck a brick wall. It then reversed, also at high-speed, and hit the side of the road, jamming the front door.  The claimant was thrown forward by the impact and hit both knees and her left foot on a low horizontal bar on the seat in front of her. She was thrown into the centre aisle of the bus, landing heavily on her back, with her right shoulder partially trapped under the seat across the aisle from where she had been sitting. Her lower back landed against the step, which led up to the second row of seats on the bus, while both feet were on the lower level at the front of the bus. She injured her knees and left foot, and she sustained an injury to her neck and lower back.
31.	The claimant was taken by ambulance to Royal North Shore Hospital. The ambulance notes refer to the claimant being thrown forward in the air and landing on her back and side, denying a loss of consciousness, some central cervical and low back coccyx pain, some right shoulder pain, and a mild trauma to the head with minor swelling and no bleeding.
32.	The hospital notes referred to neck, back and right shoulder being the main symptomatic areas at the time. An X-ray of the lumbar spine was suspicious for a fracture of the sacrum (S3), however, the CT scan of the lumbosacral spine showed no acute fracture. The claimant was given opioid tablets (6) and discharged home late at night. She was told to see the GP on the following Monday. She had to be cleared by the physiotherapist, who made sure that she was able to walk independently, before she was discharged from hospital.
33.	In undated, handwritten notes from her physiotherapist. The claimant was reported to have a painful knee upon walking. She also had painful left foot. She had X-ray of her feet, and the GP told her that it was arthritis.
34.	She had physiotherapy from February 2019, when the swelling and bruising had settled enough for her to be able to tolerate physical therapy, which continued through until November 2019. She had stopped physiotherapy prior to the second accident on 
6 December 2019. She had physiotherapy to the neck and back and quad strengthening exercises for her knee.
35.	The claimant was seen by Dr McGee-Collett on 29 August 2019, who noted neck pain with headaches, upper and lower back pain to the right, right buttock, right knee pain and left mid – foot pain. He diagnosed facet joint degeneration in the neck and back and advised a bone scan and possibly facet joint blocks. He also diagnosed right knee and left mid – foot arthropathy.  He opined there was no indication for neurosurgery. 
36.	The claimant did not undergo any investigations for the right knee.
37.	At the time of the second accident on 6 December 2019, the claimant was taking Panadol and Mobic and over the counter Voltaren, as required.
38.	X-rays of both knees dated 12 July 2019 (before the 2019 accident) were reported as showing moderate to severe medial compartment, osteoarthritis of the right knee. It recorded there was a bipartite patella. It also recorded that there were signs of osteoarthritis in the left knee.
39.	On 6 December 2019, the claimant was travelling again in a school bus with school students in a chatter bus, when the bus made a steep turn to the left and went over a speed bump. The seat that the claimant was sitting on, which was not bolted in properly, lifted and moved forward causing her to hit both knees on the metal part of the seat in front. She twisted to her left and dropped into the void where the seat pan had been located and felt instantaneous pain in her right knee and low back.
40.	An X-ray of the right knee dated 9 December 2019 showed right knee narrowing of medial compartment.
41.	A report of an MRI of the right knee 24 February 2020 noted a meniscal tear and degenerative changes.
42.	The accident aggravated the pre-existing symptomatic injuries from the earlier injury of 
30 November 2018 to the right knee and low back. After this subsequent accident, she continued to have severe right knee pain, which did not improve with conservative treatment of further physiotherapy and came to a self-funded right total knee replacement on 
1 June 2020 at the hands of Dr Broe.
43.	Dr Broe noted that the claimant had had a good recovery from the 2008 surgery. He said there was advanced severe osteoarthritis predominantly of the medial compartment of the right knee. He said that the previous bipartite patella however appears to have loosened and fractured following her recent anterior direct collision. He said there was significant disability, which was the basis upon which he recommended knee replacement surgery.
SUBMISSIONS
Claimant’s submissions
44.	The claimant submits that there is sufficient radiological evidence to show that after the first accident and before the second the claimant suffered a bipartite patella fracture. Dr Broe as referred to a “previous bipartite patella however appears to have loosened and fractured following a recent anterior direct collision”. The claimant submits she eventually came to a total knee replacement and that the injury sustained on 30 November 2018 increased the symptoms and led to the need for knee surgery.
45.	The claimant submits that this is sufficient evidence to support that the injury to the right knee was caused either after the first accident and/or aggravated by the second accident. She submits that a bipartite patella fracture is not a threshold injury.
46.	The claimant relies on the decision of Venizelou v AAI Ltd [2021] NSWPCMP 215 where the Panel held that the motor accident aggravated and accelerated degenerative changes and caused further tearing of a degenerate lateral meniscus: this was held to be a non-threshold injury as defined in s 1.6 of the Act. The review panel there noted that the motor accident need only be a material contribution to the need for treatment, or as the claimant submits in the present case, the motor accident need only be a material contribution to the injury.
Insurer’s submissions
47.	The insurer submits that this matter is complex matter because the claimant has been involved in numerous other incidents of injuries both prior and subsequent to the subject motor accidents. It submits that the effects of those incidents of injury need to be considered. The insurer submits that when the medical records though are read as a whole that the determination of whether injuries were threshold injuries is reasonably straight forward:  the need for right knee surgery arose out of pre-existing issues and would have occurred even if this accident did not.  To support this submission the insurer, relies on the following medical evidence:
(a)	the first consultation in relation to the claimant's knee was 12 October 2006. Major complaints though started on 6 February 2008, following an incident when the claimant was kneeling at school. Complaints continued thereafter leading up to the arthroscopy at the hands of Dr Peter Walker on 6 July 2008;
(b)	on 25 November 2008, the claimant injured her right knee injury injured on playground duty;
(c)	on or about 12 May 2009, the claimant’s knee pain was exacerbated after she fell in a hole;
(d)	on 20 September 2016, the claimant slipped in teacher’s bathroom, landing on all fours, hurting her knees and wrists as well as her left thumb;
(e)	on 29 December 2016, the claimant complained to her GP of right knee pain and tendonitis in the left foot, and
(f)	on 1 October 2015, the claimant attended her GP with what was thought to be knee arthritis. It is recorded that when she had the 2008 right meniscal surgery she was told that she may need a knee replacement in about 5 years time.
48.	The insurer relies on this latter entry to submit that the knee replacement, which the claimant had in 2020 was a result of these pre-existing problems. It relies on the report of Dr Wallace, who expressed the opinion that the claimant would have proceeded to have the total knee replacement even if the accident had not occurred.
MEDICAL EXAMINATION
49.	Ms Bridgefoot attended the rooms of Panel member, Medical Assessor Alan Home on 
25 September 2023.  She was unaccompanied.   A history was obtained directly from 
Ms Bridgefoot as follows.
Medical history
50.	The claimant reported a history of right knee pain following a workplace accident in February 2008 whilst crouching in a classroom.  She experienced subsequent medial knee pain.
51.	She came under the care of Dr Walker, orthopaedic surgeon, who conducted a partial medial meniscectomy of her right knee.  She required a subsequent period of hydrotherapy and exercise physiotherapy.
52.	She confirms that knee pain continued over the next one to two years, during which time she received treatment with analgesia.
53.	She recalls that she did experience recurrent right knee pain leading to further medical presentations in 2012, 2015 and 2016.
54.	She further attended her doctors in July 2017, at which time X-ray and MRI scans of the right knee were performed.
55.	She states that in the period leading up to the subject accident, she continued to experience intermittent right knee pain.  She was, however, able to walk comfortably over long distances on the flat.
56.	She would experience right knee pain with vertical climbing, kneeling, and crouching.  She recalls that the pain was periodic rather than constant.
Details of first subject accident
57.	The claimant reported that in the 2018 accident, she was sitting in the aisle seat on the left side of the bus facing the driver.  The driver took off from a stationary position rapidly before striking a wall.  She recalls that she was thrown forward in her seat, hitting the seat.  The driver then reversed before striking a stop sign with the passenger’s side of the bus.  She recalls that she was thrown into the aisle.
58.	She recalls that she struck her lower back and upper back against the upper level of a split-level floor with her legs falling into the bottom level.
59.	She does recall neck and back pain and pain about the right buttock.  She was dazed but did not lose consciousness.  She was trapped on the bus for two hours before the front door could be cut open.
60.	She recalls that she was then taken by ambulance to the Royal North Shore Hospital where she underwent an X-ray and CT scan imaging of the lumbar spine.  She was subsequently seen by her general practitioner the following week with suspected right-sided rib fracture that was not, however, confirmed on X-ray.
61.	She received treatment with strong analgesia to manage her back pain including Endone, Targin and Panadol Osteo.
62.	She was referred for physical therapy which continued from January 2019 until the date of the subsequent accident.
63.	In relation to the right knee condition, she recalls persisting intermittent pain.  She was, however, able to weight bear following the 2018 accident.  She recalls that she may have received physical therapy directed toward her knee complaint.
64.	She confirms that she attended Dr McGee-Collett, spinal surgeon, who recommended conservative management of her spinal condition, and particularly a referral for active exercise.
Details of second subject accident
65.	On 6 December 2019, the claimant was involved in a second accident, travelling on a bus toward the same Ryde Aquatic Centre.  She reported that the bus driver turned left from Victoria Road into a street and then into the carpark.  As the bus turned into the carpark, the seat on which she was sitting came loose from its mooring collapsing downwards.
66.	She says that she struck her right knee on a horizontal bar in front.  She also experienced exacerbation of her previous symptoms of lower back pain.  She recalls that she managed to assist the students from the bus.
67.	She applied ice to her lower back.
68.	She recalls that following that bus accident, she experienced increased pain at the anterior and medial aspects of her right knee.  She attended upon Dr Dorrigan.
69.	She was referred to a Feldenkrais therapist for management of her back complaint.  She was subsequently referred for imaging of her right knee including X-ray and MRI scans performed on 24 February 2020.  The Panel has carefully reviewed the X-ray and MRI scan imaging (see below).
70.	The claimant was seen by Dr Broe, orthopaedic surgeon, in March 2020.  He recommended knee replacement surgery, which was scheduled at Prince of Wales Hospital on 
1 June 2020.  The workers compensation insurer later repaid her for the treatment.  She did not return to work as a teacher after the total knee replacement.
71.	She has since received a period of rehabilitation at Wolper Rehabilitation Hospital where she remained for two weeks before attending further physiotherapy at the outpatient clinic at Hunters Hill.  She recalls ongoing use of strong analgesia.  She continued hydrotherapy exercise.  She attended group exercise sessions at Lilyfield.  She recalls that exercise was periodically interrupted periodically by COVID-19 restrictions.
72.	She currently takes Voltaren and/or Mobic three to four days per week and Paracetamol daily.
Current symptoms
73.	She describes constant pain in the lower back, average intensity 5-6/10 increasing to 8/10 on a bad day.  The pain is usually right-sided.  There is frequent radiation of pain to the back of the right thigh and occasionally into the calf.  There are no complaints of lower limb paraesthesia or numbness.  She describes some mild bladder dysfunction.
74.	She reports constant moderate right knee pain associated with intermittent swelling.  The pain is felt primarily at the medial and posterior aspects of the knee.  She feels the knee is somewhat loose and prone to episodes of instability. She does not fall but she sometimes reaches for an adjacent wall or furniture.  There is intermittent stiffness.
Functional capacity and reported tolerances
75.	The claimant is right hand dominant.
76.	She describes a sitting tolerance of 30 to 45 minutes and a similar tolerance for driving.  She reports a walking tolerance for up to an hour.  She can crouch and kneel.  Stair-climbing is difficult.
77.	She is independent for activities of self-care.  She limits lifting to 6kg.
Social history
78.	The claimant is divorced. Her children are aged 30, 33 and 35.  She is a non-smoker.
79.	She does perform cooking, dishwashing, bench height cleaning and places clothes in the washing machine.
80.	Prior to the accidents, she enjoyed regular yoga, walking and swimming.
Physical examination
81.	On examination, Ms Bridgefoot is a 64-year-old woman standing at 160cm and weighing 59kg.
Right knee
82.	At the right knee, there has been a total knee replacement.  There is a healed anterior surgical scar without adverse features.  There is a mild knee joint effusion.  There is an extension lag of 15° at the right knee.  Active flexion is performed to 110°.  There is grade 2 anteroposterior laxity and grade 1 mediolateral laxity at the knee.
REVIEW OF IMAGING
83.	Pre-accident X-ray imaging of July 2017 demonstrates an underlying tripartite patella.  Advanced degenerative change in all three knee joint compartments is apparent.  The appearance of the tripartite right patella is seen in the images below:
[IMAGE UNABLE TO RENDER]
Post-accident X-Ray of the right knee performed 24 February 2020
84.	There is visible in this imaging (again), an underlying tripartite patella.  Advanced degenerative change in all three knee joint compartments is apparent.  The appearance of the tripartite right patella is seen in the image below:
[IMAGE UNABLE TO RENDER]
85.	There is no evident change in the appearances of the patella when comparing the pre and post-accident imaging (2017 and 2020).
86.	An MRI scan of the right knee was performed 24 February 2020.  Apparent in this imaging is an oblique longitudinal tear through the posterior horn of the lateral meniscus extending to the inferior articular surface.  No displaced lateral meniscus fragment is identified.  There is an apical radial tear through the mid body segment.  There is an extensive complex tear of the medial meniscus with quite marked truncation of the posterior horn and body segments with the body segment markedly extruded into the medial gutter.  The crucial ligaments are intact.  There is mild signal hyperintensity of the anterior cruciate ligament consistent with the development of an intra ligamentous ganglion.  The posterior cruciate ligament is intact.  The extensor tendons are intact.  The patella is bipartite and there is quite extensive oedema at the margins of the synchondrosis.  There is full thickness chondral loss of the apex of the patella with abut and osteophyte in situ and there is chondral flap extending into the apex into the medial patella facet.  There is corresponding extensive full thickness chondral loss involving the trochlear floor.   In the medial compartment, there is full thickness chondral loss involving the condyle and plateau with associated subchondral bony marrow oedema.  Within the lateral compartment, there is full thickness chondral loss involving the central aspect at the plateau posteriorly with associated moderate depth loss of the condyle.  There is a small effusion with reactive synovitis within the suprapatellar recess.
87.	Although the Panel note that the knee is described in several reports as a bipartite patella, this is a tripartite patella as seen on plain X-ray imaging both before and after the accident.  This is a developmental/ congenital condition and is not caused by trauma.
88.	Comparing the pre- and post-accident imaging of the knee, there is no evidence of loosening of disruption of the previous tripartite patella.
89.	The Panel notes the MRI findings of bone marrow oedema (bone bruise) at the margins of the synchondrosis.  This does not amount to a fracture of the patella. 
90.	The Panel notes the findings of an oblique longitudinal tear through the posterior horn of the lateral meniscus extending to the inferior articular surface, without a displaced lateral meniscus fragment and an apical radial tear through the mid body segment.  
91.	The Panel further notes an extensive complex tear of the medial meniscus with quite marked truncation of the posterior horn and body segments with the body segment markedly extruded into the medial gutter. 
92.	The Panel finds that these meniscus tears are pre-existing tears and post-surgical changes, noting that there had been previous medial and lateral meniscectomy surgery in the right knee in 2008.
93.	In the Panel’s opinion a direct impact to the front of the knee would not cause a further meniscal injury – meniscal tears occur with weight bearing twisting injuries. A blow to the front of the knee, as occurred in the 2019 accident, would aggravate/induce patellofemoral joint symptoms but would not cause a meniscal injury.
DIAGNOSIS AND CAUSATION
94.	The Panel notes the history of knee pain. 
95.	The Panel notes that there is evidence of significant pre-existing degenerative changes seen on X-ray and MRI scan imaging of the right knee performed in August 2017, which has been reviewed.
96.	Imaging was performed in 2017, before the 2018 accident, which showed advanced degenerative disease of the medial compartment nearly complete loss of the joint space. The tripartite patella was noted.
97.	Whilst the claimant recalls that she may have suffered right knee pain after the 2018 accident, for which she underwent physiotherapy for strengthening the joint, there is no history of acute trauma to the knee reported in her medical notes.  Likewise, there is no history or record of any pain or swelling at the knee.  There is no record of right knee pain in the hospital reports or indeed in her general practitioner’s reports. There was no imaging of the right knee following the first subject accident. There is no documentation of right knee pain in the subsequent medical records. 
98.	The Panel is not satisfied therefore that the claimant suffered a distinct injury to the right knee in the 2018 accident, which constituted any contributory factor to her ongoing knee condition.
99.	In the 2019 accident, the claimant suffered a contusion of the right knee with post-accident imaging demonstrating bony oedema in the region of the underlying tripartite patella.  For the reasons set out at [90] – [94] above, the Panel finds that the mechanism of accident, a blow to the front of the knee, would not result in a meniscal tear.   In the context of prior meniscus surgery in 2008, the appearances in the MRI scans of February 2020 reflect longstanding meniscal degeneration. 
100.	The Panel has considered whether the 2019 accident has occasioned the requirement for the total knee joint replacement surgery.
101.	The Panel notes early documentation of aggravation of right knee pain in the medical records arising out of the 2019 accident.  There was a subsequent requirement for stronger analgesia, which continued thereafter.
102.	The Panel is satisfied that the bony contusion or bone bruise of the patella following the 2019 accident constituted an aggravation of underlying degenerative change in the claimant’s patellofemoral joint causing an aggravation and accelerated progression of symptoms from the underlying pathology resulting in the total knee replacement. 
103.	The Panel has considered that in October 2015, the claimant attended her GP with what was thought to be knee arthritis, at which time the GP recorded that when she had the right meniscal surgery (2008) and that she was told that she may need a knee replacement in about 5 years time, that is, in approximately 2020. It also notes the opinion of Dr Wallace, who opined that the accident did not bring forward the requirement for total knee replacement at an earlier stage than would have occurred in the absence of the 2019 accident. 
104.	However, the Panel is of the opinion that the indication for a total knee replacement is most commonly incapacitating pain and/or loss of function/mobility. The presence of severe arthritis on an X-ray is an insufficient basis to recommend a knee replacement.  Indeed, severe X-ray changes may be asymptomatic or minimally symptomatic. 
105.	By reason of the fact that the claimant suffered a bony contusion to the knee, the claimant suffered significantly greater level of symptoms in her right knee than were present prior to the 2019 accident, compelling the claimant to proceed to total knee replacement sooner than would have been the case but for the 2019 accident. That is, the total knee replacement surgery was occasioned by an accelerated progression of symptoms from the underlying pathology that was aggravated by the 2019 accident.
106.	Thus, the Panel finds that the 2019 accident was a necessary condition of the right total knee replacement in this case.
THRESHOLD INJURY
107.	The claimant relies upon the decision a differently constituted review Panel in Venizelou v AAI Ltd [2021] NSWPICMP 215 (at [104] – [105]) to submit that the knee replacement surgery is a non-threshold injury. In our view the decision in Venizelou is not dispositive of that question.   There the review panel opined that because the total knee replacement involves replacing the articular surfaces of the knee joint with artificial materials, the surgery itself will involve excising parts of ligaments to insert the artificial materials. Accordingly, the surgery will involve a complete or partial rupture of tendons, ligaments menisci or cartilage within the meaning of s 1.6 of the Act. In that case, however the review panel opined that it did not need to determine whether surgery resulting from injury constituted the injury for the purposes of s 1.6 of the Act. Given its finding that the tear of the lateral meniscus constituted a non-minor injury [viz. non-threshold injury], and, in the absence of submissions from the insurer, it refrained from determining the question.
108.	The relevant question raised by the medical assessment matter before the Panel is whether the injury to the right knee caused by the 2019 accident is a threshold injury for the purposes of the Act. 
109.	This medical assessment matter cannot be divorced from its context: it arises in the context of s 3.11 of the Act which disentitles a claimant to ongoing statutory benefits if the injuries resulting from the accident are threshold injuries. Likewise, the same language is echoed in 
s 4.4 of the Act, which provides that no damages may be awarded to an injured person if the persons only injuries resulting from the motor accident were threshold injuries. 
110.	In Mandoukos v Allianz Australia Insurance Limited [2023] NSWSC 1023; 105 MVR 225 (Mandoukos), a question arose on an application for judicial review of a decision of medical assessor as to whether by failing to consider if a so-called “consequential injury” – being a foraminotomy – was “minor” or not, the Medical Assessor constructively failed to exercise jurisdiction. 
111.	It was accepted in that case that the foraminotomy was occasioned by the presence of radicular symptoms (not radiculopathy) emanating from the C5/6 nerve root which was injured in the motor accident. The Medical Assessor in that case found that the foraminotomy was caused by the accident but he did not assess whether the foraminotomy was a threshold injury. The ground of review was said to require consideration as to whether the foraminotomy was a “consequential injury” and whether the medical assessor was required to consider that injury but failed to do so: at [80]. 
112.	The analysis of these questions proceeded on the proposition that the surgery was a separate injury, or a so-called “consequential” injury, which required analysis as to whether it satisfied the definition of soft tissue injury in s 1.6 of the Act. 
113.	Chen J reasoned that (at [93]):
“Generally speaking, when a surgical procedure is performed to treat an injury sustained in an accident, the total condition resulting from the injury and the surgery is to be attributed to the original injury, subject to the operation being reasonably undertaken by the injured person: Lindeman Ltd v Colvin (1946) 74 CLR 313, 321; [1946] HCA 35; Migge v Wormald Bros Industries Ltd [1972] 2 NSWLR 29, 44-46. The decision in Mahony v J Kruschich (Demolitions) Pty Ltd (1985) 156 CLR 522, 529; [1985] HCA 37 – relied upon by the plaintiff – is to the same effect. However, these authorities do not support the proposition that surgery following an injury is, in and of itself, a separate injury nor a consequential one, and the plaintiff did not develop how or why that result followed here.”
114.	His Honour ultimately reframed the “consequential injury” argument, which he considered vague and distracted attention from the central question of whether the plaintiff’s cervical spine or neck injury was a minor injury or not, having regard to s 1.6 of the Act: at [100]. 
115.	In this case, the injury claimed (in the 2019 accident), is “right knee - traumatic meniscal injury and traumatic patellar fracture resulting in total knee replacement”. The total knee replacement is not framed a separate injury (or consequential injury) but a particular of the right knee injury resulting from the 2019 accident. 
116.	“Injury” is defined in circular terms in s 1.4 of the Act as:
“injury means personal or bodily injury and includes—
(a)  pre-natal injury, and
(b)  psychological or psychiatric injury, and
(c)  damage to artificial members, eyes or teeth, crutches or other aids or spectacle glasses.”
117.	When a word in a statute is defined in terms of itself, then, subject to the context, the Act uses the word as appearing in the definition in its natural and ordinary meaning. In our opinion, the natural and ordinary meaning of the word “injury” construed in its context in 
ss 3.11 and 4.1 of the Act, is the harm, damage or disturbance to a person’s physiology that is done to a person or sustained by a person resulting from a motor accident.  It is thereby necessarily broader than the acute or frank injury sustained in the mechanism of the accident itself. 
118.	The expression’s textual co-location with “resulting from” in ss 3.11 and 4.1 of the Act inform the expression “caused” as it appears in in Schedule 2, cl 2(e) of the Act work to introduce analysis of common sense causal connexion between the mechanism of injury and the harm or disturbance to the person’s physiology (and indeed, psychology) resulting from the accident. Thus “injury” is established if it appears that the motor accident is a necessary condition of the continuum of harm or disturbance suffered. 
119.	 The decisions to which Chen J referred in Mandoukas (at [93]), referred to above, although they refer to in different statutory contexts, nevertheless stand for the application of this well-established common sense evaluation of the continuum of injury. 
120.	In Lindeman Ltd v Colvin (1946) 74 CLR 313, for example, Latham CJ, said at 317, 318:
“Where a second injury follows upon an original injury it may be causally connected with the original injury, as in cases of injury directly due to medical treatment of the injury. But not everything that happens during a period when a man is undergoing medical treatment can be regarded as part of the medical treatment so as to be causally connected with the injury for which he is being treated. A man undergoing medical treatment must have meals, and in one sense the eating of food may be described as an integral part of his medical treatment. But if these meals consist of normal food and he happens to choke himself and die, and the choking had nothing to do with his original injury, there would be no evidence to justify a finding that the death resulted from the original injury and so arose out of his employment. In this case the cause of the fracture was quite independent of the original injury. The bone condition of the respondent was not due to or aggravated by or otherwise affected by the original injury (cf. Day v Standard Waygood Ltd (3)). The act of walking was not necessitated by the head injury. Walking is a normal activity of ordinary life, and when the respondent was walking in the hospital grounds he was only resuming his normal life. There was no causal connection between the fracture and the original injury, and accordingly, in my opinion, the Commission did err in law in the decisions which it reached, and the questions in the case should be answered in the affirmative."
121.	At 320, Dixon J said:
“The substance of the Commission's finding is that the total incapacity from the broken leg resulted from the head injury. Such a proposition can only be made out by tracing the existence of some of the conditions which were the immediate occasion of the leg breaking back to the influence that the head injury had upon the succession of events, and by treating the connection of each step with that which preceded it and that which followed it as sufficiently establishing that the last event resulted from the first.”
122.	In the dissentient reasons in Migge v Wormald Bros Industries Ltd [1972] 2 NSWLR 29, which were approved by the High Court in Migge v Wormald Bros Industries Ltd (1973) 47 ALJR 236, Mason JA said at 43 - 44:
“Whether incapacity for work 'results from' an employment injury is a question of fact to be determined by the Workers’ Compensation Commission … The approach to be taken to that question, an approach which was endorsed by the House of Lords in Hogan’s case [Hogan v Bentinck West Hartley Collieries Owners Ltd [1949] 1 All ER 588], was expressed by du Parcq L.J. in Rothwell v Caverswall Stone Co. Ltd. [[1944] 2 All ER 350, at p 365]:
'In my opinion, the following propositions may be formulated upon the authorities as they stand: first, an existing incapacity “results from” the original injury if it follows, and is caused by, that injury, and may properly be held so to result even if some supervening cause has aggravated the effects of the original injury and prolonged the period of incapacity. If, however, the existing incapacity ought fairly to be attributed to a new cause which has intervened and ought no longer to be attributed to the original injury, it may properly be held to result from the new cause and not from the original injury, even though, but for the original injury, there would have been no incapacity'.”
123.	His Honour proceeded to give the example of negligent or inefficient treatment by a doctor that may amount to a new cause justifying a finding that the existing incapacity results from the new cause and does not result from the original injury. While relevant, to an assessment of causation, they are not apposite to engage with the statutory question that arises in this case.
124.	In the instant case, the Panel has found that the right knee replacement surgery was necessary condition of the harm suffered in the 2019 accident by reason it being co-extensive of the aggravation to the underlying pre-existing arthritic condition occasioned by the bony oedema and an increase in the level of pain arising from the degenerate knee. 
125.	The knee replacement surgery, therefore, is a component of the continuum of “injury” or harm or disturbance to the right knee resulting from the 2019 accident. It is not a standalone treatment for the harm or disturbance caused, but a natural corollary or incident of the harm and disturbance caused, and thereby an indivisible constituent of the harm and disturbance viz. the injury, resulting from the 2019 accident.  
126.	A total knee replacement self-evidently does not satisfy the definition of “soft tissue injury” in s 1.6 of the Act, in that it is not harm or disturbance done to the tissue that connects, supports or surrounds other structures or organs of the body, alone.  It is the total replacement of this soft tissue joint material viz. cartilage, with a prosthesis. It, thereby, comfortably fall without the statutory exclusion, and accordingly, is a non-threshold injury.  
CONCLUSION
127.	Accordingly, the Panel is satisfied that:
(a)	In respect of the 2018 accident, the right knee - anterior, posterior, and medial crush injury to the right knee; acceleration and deterioration of osteoarthritis; soft tissue injury is not caused by the accident and is thereby not amenable to assessment under s 1.6 of the Act. 
(b)	In respect of the 2019 accident:
(i)	the right knee - traumatic meniscal injury and traumatic patellar fracture resulting in total knee replacement was not caused by the motor accident, and
(ii) 	the right knee – bony oedema resulting the aggravation of pre-existing degenerative arthritic changes to the knee and a total knee replacement was caused by the accident and is a non-threshold injury.