Thompson and Comcare (Compensation) - [2020] AATA 431

Thompson and Comcare (Compensation) [2020] AATA 431 (10 March 2020)
Division:GENERAL DIVISION
File Number(s): 2018/1706
Re:Douglas Thompson
APPLICANT

AndComcare
RESPONDENT

DECISION
Tribunal:Emeritus Professor P A Fairall, Senior Member
Date:10 March 2020
Place:Sydney

The Tribunal sets aside the reviewable decision and remits the matter to Comcare for reconsideration, on the basis that Comcare has by reason of section 14 an ongoing liability under section 16 for medical expenses and section 19 for incapacity payments in relation to the applicant’s left hip injury.
............................[sgd]............................................
Emeritus Professor P A Fairall, Senior Member
CATCHWORDS
COMPENSATION – workers compensation – osteoarthritis of the left hip – bilateral hip replacements – claim for ‘frank’ injury to right hip rejected – whether original determination of liability in relation to left hip was correct – Telstra Corporation Ltd v Hannaford – whether employment no longer contributed to a significant degree – decision under review set aside and remitted
LEGISLATION
Safety, Rehabilitation and Compensation Act 1988 (Cth) ss 5A, 5B, 14, 16, 19, 62, 68, 69
CASES
Comcare v Nichols [1999] FCA 209
Comcare v Power [2015] FCA 1502
Prain v Comcare [2017] FCAFC 143
Telstra Corporation v Hannaford [2006] 151 FCR 253
Thompson and Comcare (Compensation) [2018] AATA 2707
REASONS FOR DECISION
Emeritus Professor P A Fairall, Senior Member
10 March 2020
OVERVIEW

The applicant was employed as an aviation firefighter by a Commonwealth agency, Airservices Australia, for more than thirty years. Over the course of his working life he developed osteoarthritis in both hips, a degenerative disease.
In 2013 his left hip became symptomatic, and he applied for compensation. Comcare determined that his employment had contributed in a significant way to the condition of his left hip. The determination was made under section 14 of the Safety, Rehabilitation and Compensation Act 1988 (Cth) (‘the SRC Act’), a necessary step for recovery of medical expenses and compensation.
By 2016, the applicant had end stage hip disease (‘ESHD’) and had bilateral hip replacements. The left hip was replaced in March, and the right was replaced five months later in August.
Comcare paid for the new left hip but refused to accept liability for the right hip, and the applicant paid for the replacement himself. Comcare’s refusal was upheld by the Administrative Appeals Tribunal (‘the Tribunal’) in August 2018,[1] whereupon he made a fresh claim, on the basis that he had suffered a ‘frank’ injury to his right hip in December 2015 whilst on duty. Comcare rejected the new claim.
[1] Thompson and Comcare (Compensation) [2018] AATA 2707.
By a separate process, on 28 March 2018 Comcare determined that the applicant was no longer experiencing the effects of his employment and therefore had no present entitlement to compensation for his left hip condition (‘the reviewable decision’).
The matter came before the Tribunal on review of both determinations, but on the first day the applicant withdrew the ‘frank injury’ claim for his right hip.
In light of all the evidence now available, I find that the correct or preferable decision is to set aside the reviewable decision and remit the matter to Comcare for further consideration.
REASONS FOR DECISION
In 2013 the applicant suffered a workplace injury to his left hip. As a Commonwealth employee, he is entitled to access a compensation scheme provided for under the SRC Act.
The present proceedings involved two applications by the applicant:
(a)for his left hip – seeking review of a ‘no present entitlements’ determination (2018/1706); and
(b)for his right hip – seeking review of a ‘no liability’ determination (2018/7730).
Both matters were listed for hearing before the Tribunal and were heard simultaneously on 4 – 5 February 2020. Both parties were legally represented.
On the afternoon of the first day the applicant withdrew the second application relating to his right hip, and later formalised the withdrawal in writing. No reasons were provided, as none were required. Neither counsel sought to withdraw any of the materials admitted into evidence before the Tribunal, some of which related to the earlier proceeding before the Tribunal relating to the right hip, including the complete transcript of those proceedings.[2]
[2] Thompson and Comcare (Compensation) [2018] AATA 2707 (2016/3772), per Deputy President Rayment QC: T82, 237; Transcript, 27 September 2017, ST49/390; 28 September 2017, ST49/462; and 6 April 2018, ST49/491.
The witnesses before the Tribunal were as follows:
(a)For the applicant:
(i)The applicant; and
(ii)Dr Roger Pillemer, Orthopaedic Surgeon.
(b)For the respondent:
(i)Professor Peter Youssef, Consultant Rheumatologist, Clinical Professor at the University of Sydney.
The following materials were before the Tribunal:
·2018/1706 section 37 documents;
·2018/1706 supplementary section 37 documents;
·2018/7730 section 37 documents;
·Exhibit A1 Douglas Thompson 05/02/2020 - Letter to Comcare dated, 15 August 2013;
·Exhibit A2 Douglas Thompson 05/02/2020 - Report of Dr Roger Pillemer, dated 1 May 2019;
·Exhibit A3 Douglas Thompson 05/02/2020 - Report of Dr Roger Pillemer, dated 2 May 2019;
·Exhibit R1 Comcare 05/02/2020 - Report of Professor Peter Youssef, dated 9 July 2019;
·List of Academic papers before the Tribunal:
oGanz et al, “Femoroacetabular impingement: a cause for osteoarthritis of the hip”, Clinical Orthopaedics and Related Research (2003) No 417, 112-120.
oReichenbach at al, “Association between Cam-Type Deformities and Magnetic Resonance Imaging-Detected Structural Hip Damage”, Arthritis and Rheumatism (2011) No 63, 4023-4030.
oDoherty et al, “Nonspherical Femoral Head Shape (Pistol Grip Deformity), Neck Shaft Angle, and Risk of Hip Osteoarthritis”, Arthritis and Rheumatism (2008) No 58, 3172 – 3182.
oNicholls et al, “The Association between Hip Morphology Parameters and Nineteen-Year Risk of end-Stage Osteoarthritis of the Hip”, Arthritis and Rheumatism (2011) No 63, 3392-3400.
oAgricola et al, “Cam impingement causes osteoarthritis of the hip: a nationwide prospective cohort study (Check) (sic)” Ann Rheum Dis 2013: 72: 918-923; and
oCroft at al, “Osteoarthritis of the hip and occupational activity”, Scandinavian Journal of Work and Environmental Health (1992), 59-63.
Some key medical concepts and acronyms are outlined below:
·Acetabulum - the concave surface of the pelvis, within which the femoral head is located so as to form the hip joint.
·Cam lesion (CL) - an indentation caused by cam type deformities on the femoral head.
·End stage hip disease (ESHD) - marks the end point of osteoarthritis associated with acute pain requiring a hip replacement.
·Femoral head - the ball of the upper thighbone.
·Femoroacetabular impingement (FAI) - a condition of abnormal contact between the femoral head-neck junction and the acetabulum, due to a bone shape abnormality on either the femoral or acetabular side.[3]
·Hip dysplasia - refers to a condition where the hip socket does not fully cover the femoral head.
·Orthopaedic surgeon (OS) - a surgeon who specialises in the treatment of bone disease.
·Osteoarthritis (OA) - is a chronic joint disease.
·Rheumatologist - a medical specialist in the treatment of muscle and bone disease.
·Total Hip Arthroplasty (THA) - total hip replacement.
[3] Agricola et al, “Cam impingement causes osteoarthritis of the hip: a nationwide prospective cohort study (Check) (sic)” Ann Rheum Dis (2013) No 72: 918.
THE COMMONWEALTH COMPENSATION SCHEME
Section 68 of the SRC Act establishes a body called Comcare and section 69 outlines its statutory functions including the making of determinations in relation to claims made to Comcare under the Act.
Section 62 provides for reconsideration of determinations at the instigation of the applicant or the determining authority, and reconsideration under section 62 is essential to found jurisdiction for an appeal to the Administrative Appeals Tribunal (‘the Tribunal’).[4]
[4] See Sutherland and Ballard, Annotated Safety Rehabilitation and Compensation Act 1988, 11^th ed, 496.
Section 14 provides that Comcare is liable to pay compensation in accordance with the SRC Act in respect of an injury suffered by an employee if the injury results in death, incapacity for work, or impairment.
Section 16 provides that where an employee suffers an injury, Comcare is liable to pay, in respect of the cost of medical treatment obtained in relation to the injury (being treatment that it was reasonable for the employee to obtain in the circumstances), compensation of such amount as Comcare determines is appropriate for that medical treatment.
Section 19 applies to an employee who is incapacitated for work as a result of an injury and provides compensation according to a formula based on pre-injury earnings less any earnings potentially available or actually received by the injured employee from suitable employment. These are called incapacity payments.
Section 5A contains an extended definition of ‘injury’ and section 5B contains the definition of ‘disease’:
5A Definition of injury
(1) In this Act:
injury means:
(a) a disease suffered by an employee; or
(b) an injury (other than a disease) suffered by an employee, that is a physical or mental injury arising out of, or in the course of, the employee’s employment; or
(c) an aggravation of a physical or mental injury (other than a disease) suffered by an employee (whether or not that injury arose out of, or in the course of, the employee’s employment), that is an aggravation that arose out of, or in the course of, that employment;
but does not include a disease, injury or aggravation suffered as a result of reasonable administrative action taken in a reasonable manner in respect of the employee’s employment.
(2) [omitted]
5B Definition of disease
(1) In this Act:
disease means:
(a) an ailment suffered by an employee; or
(b) an aggravation of such an ailment;
that was contributed to, to a significant degree, by the employee’s employment by the Commonwealth or a licensee.
(2) In determining whether an ailment or aggravation was contributed to, to a significant degree, by an employee’s employment by the Commonwealth or a licensee, the following matters may be taken into account:
(a) the duration of the employment;
(b) the nature of, and particular tasks involved in, the employment;
(c) any predisposition of the employee to the ailment or aggravation;
(d) any activities of the employee not related to the employment;
(e) any other matters affecting the employee’s health.
This subsection does not limit the matters that may be taken into account.
(3) In this Act:
significant degree means a degree that is substantially more than material.
In considering whether a person is entitled to compensation by reason of Commonwealth employment the factors referred to in section 5B(2) must be considered.
BACKGROUND
The applicant was employed as an aviation firefighter by Airservices Australia for 32 years, retiring from service on 1 July 2017.
The lot of an aviation firefighter is not for the feint-hearted. It is arduous work, requiring both mental and physical strength and fitness. They are required to develop and maintain high levels of fitness and strength, sufficient to handle heavy water hoses and waterlogged dummies, in a state of constant preparation for a serious event. High fitness levels are expected of firefighters as part of the job.
Gym facilities are provided at airport fire stations, and like all firefighters, the applicant was required to engage in vigorous weight building exercises in order to achieve and maintain the required levels of strength and fitness. The actual tasks he performed as part of his daily duties included activities such as crawling and weight training that imposed heavy loads on his hips.
This was apparently no hardship for the applicant, who from a young age enjoyed robust physical exercise, playing rugby league until 27 and later, squash at competitive levels. Although his employer did not mandate participation in such sports, the applicant believed that they were aware of his participation and were happy about it.[5]
[5] Transcript, 2018/1706, 5 February 2020, 119, [40].
On or about 27 July 2013 the applicant injured himself while exercising in the work gym. He saw his physician, Dr Owen Brookes, who referred him for an ultrasound which was carried out by the Southern Radiology Group on 1 August 2013.[6] The Report states:
[6] T6/22.
The hip joint is normally aligned. There is reduction in the anterior femoral head/neck offset resulting from a broad based femoral head/neck “bump” associated with elevation of the alpha angle (65 degrees). Occasional small subcortical cysts associated with patchy marrow oedema at the anterior femoral head/neck junction suggest impingement lesions. The acetabulum defines normally.
A focal segment of irregular under surface erosion of the anterosuperior labrum measuring at least 0.3cm adjacent to the chondrolabral junction at the 2 o’clock position is evident. Subtle degenerative fraying of the anterosuperior labrum at the 1 o’clock position is evident. There is subtle myxoid degeneration within the lateral labrum anteriorly at the 12.30 position. Intact anterior and posterior labra, fovea capitis and pulvinar. There is myxoid degeneration within the foeval insertional fibres of the ligamentum teres.
There is hip joint osteoarthritis characterised by small irregular marginal femoral head and irregular sclerotic superolateral acetabular osteophytes associated with denudation of most of the weight bearing superolateral acetabular and femoral head articular cartilage associated with subchondral cysts and patchy subchondral bone marrow oedema within the axial femoral head and a little patchy subchondral bone marrow oedema within the superolateral acetabulum along the lateral joint line. At least one 0.6 geode is evident within the midline anterosuperior acetabulum.
…
Comment
1.Moderately advanced hip osteoarthritis, notable for grade IV involvement
2.Predisposing factors for CAM type FAI with impingement lesions providing a degree of evidence of active impingement
3.Subtle under surface erosion of the anterosuperior labrum, also supportive for cam type FAI
4.Myxoid degeneration within the lateral labrum
5.Myxoid degeneration of the foveal insertional fibres of the ligamentum teres
6.Mild psoas tendonosis.
On 29 July 2013 the applicant applied for workers compensation for ‘persistent hip pain/sprain’ and ‘bilateral direct inguinal hernia’ to the ‘left hip area’ caused by exercising in the gym in the Ayers Rock Airport Fire station on 27 July 2013.[7]
[7] ST3/275.
On 15 August 2013, Comcare asked Dr Brookes for a report.[8] On 28 August 2013, Dr Brookes, having reviewed a radiology report, responded along the following lines:
As you are aware, [the applicant] works for the aviation fire brigade and has done so for many years. This certainly will put a significant amount of pressure on his body throughout his day to day activities. That is why his employer provides gym facilities at his place of work to help maintain the level of fitness required for his work…
I believe that [the applicant] is suffering from early moderate arthritis of the left hip. I believe this has been significantly caused by his long term employment as a firefighter and the demands this places on his body. While it is partially age and genetically implicated I think his work is definitely a significant contributor to his condition. (At least 70%) He may also have a soft tissue anterior hip sprain caused by the immediate incident of walking on the treadmill. I also believe he has bilateral direct inguinal hernias that have also been caused by his work activity.
My current recommendation is that he undergo physiotherapy for his hip and hope that in the short term it settles (6-8 weeks). If this fails I would suggest CT guided cortisone injection to the hip and referral to an orthopaedic surgeon to assess the extent of his hip arthritis and whether he will require surgery. I also recommend he has the US [ultrasound] of both inguinal regions to confirm my clinical diagnosis of hernia. If hernias are confirmed I would recommend laproscopic hernia repair.
His symptoms currently are not severe and he remain (sic) fit for his current duties pending further treatment and investigation.[9]
[8] T7.1/28, 31.
[9] T7/24.
On 10 September 2013 a further ultrasound scan confirmed the existence of indirect inguinal hernia.[10] On 12 September 2013 Dr Brookes advised Comcare of the ultrasound results, stating:
[The applicant’s] US has confirmed the presence of LEFT INDIRECT INGUINAL HERNIA. I believe that it is a result of straining lifting and otherwise exercising in the course of his long term employment. He needs to have surgery to repair this defect…[11]
[10] T10/37.
[11] T11/38.
On 16 September 2013, Comcare accepted liability under section 14 of the SRC Act for ‘sprain of other specified sites of hip and thigh (left groin)’ and ‘aggravation of osteoarthritis – localised – pelvis and thigh (left hip)’.[12] The delegate advised the applicant as follows:
…I am satisfied you suffer from an “ailment” as defined in the SRC Act, namely, a left groin sprain and an aggravation to your pre-existing degeneration to the hip...
I have considered the evidence before me and I am satisfied that your condition was contributed to, to a significant degree, by your employment.
[12] T13/40.
On 23 September 2013 Comcare extended cover to include ‘left inguinal hernia’.[13] On 3 October 2013 Comcare accepted liability for the applicant to undergo ‘laproscopic surgical repair of left inguinal hernia’,[14] which was duly carried out on 9 October 2013 by Dr Ken Loi.[15]
[13] T14/48.
[14] T19/55.
[15] T20/57.
In March 2015 Dr Brookes referred the applicant to an orthopaedic surgeon, Dr Darren Chen. Dr Chen had seen the applicant in October 2014 in relation to advanced arthritis of the left knee following work-related duties. On 9 April 2015 Comcare wrote to the applicant and accepted liability for the costs of referral to Dr Chen.[16] On 9 April 2015, Dr Chen reported that the applicant’s left knee had ‘settled down’ and that ‘no further intervention is required for it at this stage’.[17]
[16] T26/70.
[17] T25/69.
Dr Chen further noted that an MRI scan confirmed advanced degenerative changes to the left hip joint with impingement type lesions on the femoral head. He told the applicant that his symptoms ‘will progress over time’ but that he was a good candidate for hip replacement surgery in the future. On 3 July 2015 Comcare wrote to the applicant accepting liability for the costs of X Ray and Ultrasound relating to Dr Chen’s report,[18] and on 18 August 2015 Comcare wrote to the applicant accepting liability for the consultation with Dr Chen.[19]
[18] T28/73.
[19] T29/75.
On 27 August 2015 Dr Chen wrote to Dr Brookes stating that the applicant had returned for a review of the left hip and that he was in constant pain and not far off requiring a left hip replacement.[20] On 4 February 2016 Sydney Knee Specialists sought approval from Comcare for a left hip replacement.[21]
[20] T30/76.
[21] T38/93.
On 18 February 2016 Comcare determined under section 16 of the SRC Act that compensation was payable for the applicant’s left hip replacement to take place on 2 March 2016.[22] Comcare agreed to cover the reasonable medical expenses for the left hip replacement, and the operation was carried out on 2 March 2016.[23]
[22] T41/99.
[23] T42/101.

On 24 May 2016 Comcare wrote to the applicant accepting liability for general practitioner consultations and related pharmaceuticals relating to the original 2013 claim.[24] On 22 June 2016 Comcare approved compensation for time off work in respect of the original claim.[25] On 8 November 2016 Dr Brookes provided a medical certificate certifying that the applicant was unfit for work as a consequence of his total hip replacement.[26]
[24] T58/133.
[25] ST31/329.
[26] T66/155.
The left hip review
In December 2017,[27] Comcare informed the applicant that his entitlement to ongoing compensation for his left hip condition was being reviewed. The applicant responded through his law firm, which communicated with Comcare.[28]
[27] T79/227. On 13 December 2017 Comcare wrote to the applicant concerning his left hip condition: T79, 227. The letter is referred to but not contained in the materials.
[28] Letters dated 11 and 30 January 2018 from Slater and Gordon to Comcare referred to but not included in the T-documents.
On 13 February 2018 Comcare wrote to the applicant indicating that the file review into his ‘left hip condition’ had been completed, and a determination had been made that he was no longer entitled to compensation or to claim medical expenses for his left hip condition.[29] The delegate referred to various medical reports.[30] In light of those reports the delegate concluded that it is ‘reasonable to conclude that [the applicant] does not presently suffer from a left hip condition as a result of his employment with Airservices Australia. This determination will be effective from 14 February 2018…’. The letter stated:
I have determined that Comcare has no present liability for the following in regards to:
·medical expenses under section 16 of the [SRC Act]
·incapacity payments under Section 19 of the [SRC Act].
[29] T79/227.
[30] Reports prepared by Dr Bodel and Professor Youssef for the purpose of proceedings before the Tribunal in relation to the applicant’s right hip condition: 2018/7730, see below paras [52] & [53].
On 28 March 2018 the review officer upheld the determination made on 13 February 2018, noting:
The issue to be decided in this reconsideration is whether you are entitled to compensation for medical expenses and incapacity payments in respect of sprain of other specified sites of hip and thigh (left groin) and aggravation of osteoarthritis – localised –pelvis and thigh (left hip).
To be entitled to compensation, the evidence must satisfy on the balance of probabilities, that you continue to experience the effects of your compensable conditions, and they continue to be significantly contributed to by your Commonwealth employment. [31]
[31] T81/231 at 232.
The delegate also observed that the applicant no long experienced the effects of ‘aggravation of osteoarthritis – localised – pelvis and thigh (left hip)’ because the arthritic areas of the hip had been removed when the original hip joint was replaced by a prosthetic.
The first right hip claim: 2016/3772
There is no doubt that the applicant’s challenge to the refusal to compensate him for his right hip condition provided material that was available to Comcare to be used, quite properly, to review his entitlements to compensation in relation to his left hip condition. That challenge arose under the following circumstances.
In late December 2015, the applicant claimed to have had an incident involving the right hip while on work location in the Northern Territory. He consulted his general practitioner Dr Brookes on 7 January 2016.[32] Dr Brookes referred him to the orthopaedic surgeon Dr Darren Chen.
[32] T37/89.
He also contacted Comcare on the same day. Comcare wrote back immediately outlining what he needed to do to make a claim of compensation for the right hip.[33]
[33] T31/77.
On 14 January 2016 the applicant applied for a medical certificate for Workers’ Compensation for his right hip, described as ‘Increased R hip pain due to work caused arthritis and extra pressure from left hip disease’. On 20 January 2016 Comcare accepted liability for general practitioner consultations and specialist consultations to enable consideration of surgical intervention.[34]
[34] T34/84.
On 28 January 2016 Dr Chen responded to the referral from Dr Brookes.[35] He noted that the patient had advanced bilateral hip arthritis and that the left hip was at the point now where he could no longer manage. Dr Chen noted that the left hip was ‘under compensation’ and the right hip had followed the same path [of progressive deterioration] and ‘it is reasonable to expect that this has occurred as a result of his occupation as a firefighter’.
[35] T35/86.
On 2 February 2016 Comcare wrote to the applicant to inform him that approval had been given to pay for a further three sessions of physiotherapy, making a total of eight sessions.[36]
[36] T36/87.
On 2 May 2016 Comcare wrote to the applicant disallowing his claim for the secondary condition of ‘increased right hip pain due to work caused arthritis’. The delegate was satisfied that the applicant had suffered an injury but was not satisfied on the balance of probabilities that there was a causal link to his employment.[37] Specifically, Comcare referred to Dr Chen’s letter dated 28 January 2016 and noted:
In his report dated 28 January 2016, Dr Chen discusses the reasonability of your condition arising from your occupation as a fire fighter, further accounting that the right hip should be given consideration based on the “left hip has been approved for hip arthritis”. However, Dr Chen did not consider that the left hip condition has been approved by Comcare as an aggravation of a pre-existing arthritis following an identifiable event. He also did not provide any substantial medical evidence which would link your right hip condition to your compensable condition.[38]
[37] T51/118, 118-119.
[38] T51/121.
On 5 May 2016 Dr Chen wrote to Dr Brookes about the applicant’s condition. He noted that Comcare had refused a work related claim in respect of the right hip. Dr Chen described this decision as defying logic, given that both hips had been subjected to the same stressors throughout his work history as a firefighter.[39]
[39] T52/122.
On 10 May 2016 Dr Brookes wrote to Comcare asking it to reconsider the decision not to allow compensation in respect of the right hip.[40] It is worth setting out the letter in full:
I am writing in behalf of [the applicant] in regard to his claim for his right hip. As you are aware [the applicant] works for the Fire Brigade and has done so for many years. This is a very active job that requires a high level of fitness that needs to be maintained by regular exercise. Indeed, he is required to work out in the gym facilities on a daily basis at his work, including running, jogging and walking for 30 to 60 minutes per day. In addition to formal exercise, his work includes regular drills carrying heavy firefighting equipment, including hoses and other ancillary equipment. There are also regular duties for maintenance of all equipment including the firetruck. These activities again involve the lifting and carrying of heavy equipment. [The applicant] works 10 hour shift and he estimates that only 30 minutes on average would be spent sedentary.
[The applicant] has been diagnosed with bilateral hip arthritis. This condition is caused by wear and tear on the hips through exercise, running and lifting, all activities required in his workplace. It is certainly my belief that this arthritis is largely caused by his activity in his workplace, this is not the natural consequences of ageing, [the applicant] has premature hip arthritis due to the demands of his work place. He is not overweight and has no other predisposition to hip arthritis.
COMCARE has quite rightly accepted that work related wear and tear has caused the degeneration of his left hip and quite rightly paid for total hip replacement on that side. It makes no logical sense that if the left hip arthritis was caused by his work, that the right hip degeneration was not. There is no history of injury to either hip.
In summary, it is my belief that [the applicant] has premature osteoarthritis of both hips caused by his work as a fireman. His orthopaedic surgeon, Dr Darren Chen agrees with my findings. I respectfully request COMCARE to reconsider its decision about compensatable injury to the right hip.(emphasis added)
[40] T54/127.
On 12 May 2016 the applicant wrote to Comcare about the decision to decline compensation for his right hip,[41] and lodged a reconsideration request.[42]
[41] T55/128.
[42] T56/130.
On 8 June 2016 Comcare affirmed the determination.[43]
[43] T63/143.
On 19 August 2016 the applicant underwent a total replacement of the right hip, which he paid for himself,[44] and less than a year later, on 1 July 2017 he ceased work at Airservices Australia.
[44] ST33/333.
The applicant applied to the Tribunal to review the refusal by Comcare to grant the claim for compensation for the right hip.[45] On 11 November 2016 Comcare requested Professor Youssef, a consultant rheumatologist, to provide an expert opinion with respect to the applicant’s right hip condition.[46] His report is dated 15 November 2016.[47] Reports were also obtained by Dr James Bodel. His primary report is dated 7 March 2017,[48] with supplementary reports dated 1 June 2017[49] and 22 August 2017.[50]
[45] The Tribunal file is 2016/3772.
[46] T68.1/176.
[47] T68/158.
[48] T69/181.
[49] T73/212.
[50] T74/217.
The matter was heard by the Tribunal (Deputy President Rayment QC presiding) in September 2017 and April 2018. Each of the parties relied on expert witnesses. The applicant relied on the evidence of three physicians: Dr Brookes, his general practitioner; Dr Chen, the orthopaedic surgeon who operated on his left hip; and Dr James Bodel, an orthopaedic surgeon called as an expert witness. Each expressed the view that his employment by Airservices Australia over more than three decades was a factor that contributed in a material way to the aggravation of his osteoarthritis. Dr Bodel expressed the opinion that the progression of the disease to end stage hip disease could have been as much as three to five years. Comcare called Professor Youssef, who expressed a contrary view. Dr Bodel and Professor Youssef gave concurrent evidence, and Deputy President Rayment QC had the benefit of their exchange and was able to ask them questions together.
The parties both invited me to review the evidence presented at this earlier hearing.
Evidence of Professor Peter Youssef – Report dated 15 November 2016
Professor Youssef interviewed and examined the applicant on 15 November 2016,[51] which is also the date of his report. He was provided with background medical reports from Doctors Brookes, Chen and Loi, as well as various Tribunal documents. He was not provided MRI or ultrasound reports pertaining to the right hip. It appears that none existed. He also carried out a physical examination and commented upon various aspects of the applicant’s physical functioning, including his lower limbs, upper limbs, and spine. He described the applicant’s temperament as pleasant and cooperative.[52] His assessment is as follows:
[The applicant] has degenerative disease of both hips. This has been predisposed to by the fact that he has femoroacetabular impingement. The Cam lesions were seen on the MRI of the left hip dated 1 August 2013. This is based on the presence of Cam lesions, which are bumps on the edge of the femoral head, results in grinding of the cartilage inside the acetabulum. A non-spherical femoral head could result in damage to the acetabular labrum by either pressing against the labrum or by a pincer type effect with the femoral neck abutting against the labrum. This may result in repetitive mechanical impingement. These lesions predispose the development of osteoarthritis.
I have not seen a report of an MRI of the right hip or x-rays of the right hip. These are also likely to show similar lesions as the condition is almost always bilateral.[53]
[51] T68/158.
[52] T68/162.
[53] T68/169.
He relied on academic papers to support his conclusion that:
Therefore, it is my opinion that the major factor in the development of his osteoarthritis was the underlying femoroacetabular impingement. The other major factor is age as osteoarthritis is increased in older patients. His employment is at most a minor factor in the development of this condition and he would have developed this condition independent of his employment. In fact, he was likely to have been symptomatic from degenerative disease of the left hip in his late 40s while he was playing squash. This is almost certainly the cause of him needing to take time off from the game from groin pain. The reason why he developed left groin pain earlier than right groin pain is because the left hip disease was worse than the right hip disease at that time. He would have become symptomatic from hip osteoarthritis independent of his work.[54]
[54] T68/169.
Although Professor Youssef did not see any Magnetic Resonance Imaging (MRI) or x-rays of the right hip, he reiterated at hearing that ‘these are also likely to show similar lesions as the condition is almost always bilateral’.[55]
[55] Transcript, 6 April 2018, ST49/502 [30], 503 [5].
In response to specific questions, Professor Youssef stated:
I do not consider that his work was a significant contributor to his condition. If there was any contribution, it was small. The movements that result in impingement are mainly those of abduction of the hip. The drills that he performed required some hip abduction such as when crawling in small spaces. In fact, playing squash for many years was likely to be a greater contributor to the progression of his condition than his work.
…
I do not consider that his current condition was contributed to in any significant way by his employment. If there was a contribution, it was small and may have been related to some of the drills he was performing such as twisting and crawling in small spaces. Even these drills may not have required a significant amount of hip abduction.
…
I do not consider that he suffers from a condition significantly contributed to by his employment.[56]
[56] T68/173 to 174.
Question 5 refers to aggravation but does so in a confusing and elliptical manner. The question asked was:
If you do not consider that the effects of any employment related condition or employment contribution to the aggravation of another condition continue, please provide your opinion as to when those effects ceased. [57]
[57] T68/174.
His answer was as follows:
He reports developing symptoms of his hip pain during his employment. This is not surprising in view of the significant degenerative disease of the hip. This does not mean that his employment was the cause of the problem but that activities during employment caused him to experience symptoms related to the hip. In fact, it is very likely that he first experienced symptoms of degenerative disease of the hip while playing squash because of the high impact of this activity and because this activity requires hip abduction when stretching for a ball.(emphasis added)
In response to a question whether ‘the left hip’ replacement surgery related to a work-caused condition, he stated that:
No, the left hip replacement surgery was for degenerative disease of the left hip which is not a work caused condition for the reasons that I have already explained.[58]
[58] T68/174.
Professor Youssef maintained this position in oral testimony during the hearing. He relied heavily on epidemiological studies about the association of osteoarthritis and FAI. The papers were included in the material before the Tribunal.
Evidence of Dr James Bodel
Dr Bodel interviewed the applicant on 3 March 2017 and finalised his primary report on 7 March 2017.[59] In his primary report Dr Bodel outlined the strenuous nature of the activities undertaken by firefighters. Under the heading Causation, Dr Bodel stated:
…[the applicant] has a pathological process known as osteoarthritis involving the hip joints. The nature and conditions of his work, which is quite physical work and he has been doing that since the early 1980s, has caused significant aggravation to that underlying disease process by way of aggravation, to a significant degree, caused by work in general.[60]
[59] T69/181.
[60] T69/186.
Dr Bodel provided commentary in terms of the degree of whole person impairment, which he described as follows:
Clearly this gentleman does have a pre-existing degenerative condition. The nature and conditions of work has caused permanent aggravation, by a significant degree, and has brought forward the timing of the inevitable total hip replacements by a number of years.[61]
Based on the medical evidence available, I would indicate that about one-third of the total 15% Whole Person Impairment for either lower extremity is due to pre-existing pathology and the remaining two thirds due to the aggravation by significant degree that has occurred as a consequence of work over all those years at the workplace (31 years).[62]
[61] T69/188.
[62] Ibid.
In his first supplementary report[63] dated 1 June 2017 he was invited to comment on the Report prepared by Professor Youssef dated 15 November 2016.[64] He noted:
I do confirm that I agree with Professor Youssef that primarily the osteoarthritic change is a constitutional matter genetically based aggravated by a number of factors including age, obesity and the like although this gentleman has never been overweight and then the factors associated with his work.
Once the osteoarthritis is established, the nature and condition of his work becomes a more important factor. The joint is then abnormal and is more easily materially aggravated by the nature of the work that he had been doing.
…The arthritis was not caused by his work but I am still satisfied that the nature of his work particularly towards the latter part of his career has caused a material aggravation of the underlying constitutional arthritic process.(emphasis added)
[63] T73/212.
[64] T68/158.
In his second supplementary report[65] Dr Bodel addressed the issue of sport, as well as the academic foundation for the views expressed by Professor Youssef. His conclusion was:
This gentleman’s history is quite clear. He has had a very physical, energetic lifestyle since about the age of 8. He did suffer a knee injury playing football in his late teens or early 20s for which he had had two arthroscopies but he has had no specific accident or injury involving either hip. He did stop squash in about the year 2006 primarily because he was no longer competitive because of his age and he did not specifically stop squash because of the hip pain although it was apparently present.
He does give a history of having had “abductor strains in both hips but principally the left hip throughout his squash career and he modified his squash activities and these would settle”. He had no x-rays or other tests at that time to indicate whether there was any arthritic change in the hip joints. He ceased playing squash about seven years prior to the onset of significant symptoms in the left groin which led to the hernia repair and then the hip replacement.
On balance therefore I have reviewed all of this material. I note the causal link that Professor Youssef draws between the existence of a CAM lesion and the increased risk of osteoarthritic change in the hip joints and I acknowledge that that is correct.
There is however no definite causal link between his playing squash and the development of this condition as he was playing squash and a number of sporting activities as well has having a very physical work environment throughout he period of his employment with Airservices Australia and that work began in September 1984. He was doing this very physical work therefore for a total of more than 30 years before he developed the hip pain which led to the diagnosis of the arthritic change. (emphasis added)
[65] T74/220.

The Tribunal also received a report from Dr Brookes.[66]
[66] T7/24.
A decision in favour of Comcare affirming the determination was delivered by Deputy President Brian Rayment QC on 9 August 2018. On the evidence presented, and especially the evidence of Professor Youssef, the Tribunal was unable to be satisfied that any acceleration of the applicant’s symptoms was caused by his employment to a degree which was significant in the required sense. Therefore, the determination refusing liability for the right hip condition was affirmed.[67]
[67] Thompson and Comcare (Compensation) [2018] AATA 2707: T82, 243; Transcript, 27 September 2017, ST49/390; 28 September 2017, ST49/462; and 6 April 2018, ST49/491 (2016/3772).
The second right hip claim: 2018/7730
On 10 August 2018 the applicant made a fresh application based on a ‘frank injury’ to the right hip whilst on duty.[68] On 5 October 2018, Comcare declined to accept liability under section 14 of the SRC Act,[69] and on 16 November 2018 Comcare affirmed its decision.[70] Comcare found that the right hip condition had been addressed under the previous 2013 claim 79932/12, and there was no evidence to support the claim as a new condition. And if it were, the notice requirements under section 53 had not been complied with. The claim was refused.
[68] T83/258.
[69] T84/263.
[70] T86/266.
This matter and the left hip condition were both listed for hearing before the Tribunal and were heard simultaneously before me on 4 – 5 February 2020. However, as previously noted, the applicant withdrew the right hip application on the first day of hearing. Therefore, the only reviewable decision before me is the decision made on 28 March 2018 relating to the left hip.[71]
[71] T81/231.
THE PRESENT HEARING
The hearing was conducted over two days. The applicant gave evidence in person and both his statement and his evidence at the previous hearing was admitted into evidence. The parties invited me to refer to the transcript and evidence tendered in the earlier Tribunal proceedings, as well as updated reports from Professor Youssef, and a new report from Dr Roger Pillemer, a consultant Orthopaedic Surgeon, who was to be called by the applicant. The parties each proposed to call an expert witness. The parties indicated at the outset that they wished the expert witnesses to give concurrent evidence, and after some discussion as to how that would work, I agreed to the arrangement.
At the commencement of the hearing the respondent argued that the reviewable decision dated 28 March 2018 (that the applicant had no entitlement to compensation as of 13 February 2018) should be affirmed on either of two grounds:
(a)the original determination of liability made by Comcare on 16 September 2013 was incorrect and therefore at no point was he entitled to compensation under the Act;
(b)as of 13 February 2018 his employment by the Commonwealth no longer contributed in a relevantly significant way to his left hip condition.
He called these the primary and secondary arguments.
The primary argument involves a challenge to the original determination of liability made by Comcare in September 2013. The respondent noted that liability was originally accepted by Comcare under section 14 as a workplace aggravation of a pre-existing ailment. He invited the Tribunal to reconsider that determination in light of current medical evidence which, he said, showed that the applicant’s employment by the Commonwealth did not contribute to the requisite degree to the aggravation of the applicant’s pre-existing ailment. In essence, he argued that the original 2013 determination was in error. He said that in some cases, and he suggested that this was one of them, it was permissible to consider the original determination in a present entitlement case. Whether that would lead to recovery of any monies paid to the applicant was not a matter for the Tribunal to consider in deciding this matter.
His second argument was to the effect that even if the original determination was soundly made in September 2013, by 13 February 2018 the applicant’s employment by the Commonwealth no longer contributed in a material way to his left hip condition, and therefore he was not entitled to compensation in respect of that condition.
The experts commenced their joint session by clearly identifying points of agreement. They agreed that the applicant had osteoarthritis of the left hip. They agreed that this was a constitutional condition for him, and importantly, that it was not caused by his work, and that he would have needed a total hip replacement at some stage, irrespective of the nature and condition of his employment.
The point of difference they said related to issues around aggravation and acceleration, that is, how much the nature and conditions of work might have contributed to an aggravation or acceleration of his condition or made the need for a hip replacement come on earlier than might otherwise have been the case.[72]
[72] Transcript, 5 February 2020, 65-66; 99-100.
Their respective reports were before the Tribunal. Dr Pillemer reported as follows:
[The applicant] suffers from constitutional/idiopathic osteoarthritis of both hips. That is, the nature and conditions of his work was not the cause of the development of the osteoarthritis in both hips. However, once osteoarthritis develops, excessive stress to the hips can certainly hasten the progression of the osteoarthritic change.
[The applicant] in my opinion has a constitutional condition as noted, but I would certainly accept that the nature and conditions of his work as described and commented above, could certainly have been an aggravation of his underlying condition and in my opinion it is certainly possible that the nature and conditions of his work might well have made the need for total hip replacements being required earlier than might otherwise have been the case. I do not feel I could be more specific than this.
…
It is difficult to be certain of the significance of the CAM lesions prior to his total hip replacement. The jury is still out on this, although the majority opinion at this stage is that CAM lesions can certainly precipitate early osteoarthritic change of hip joints.
In my opinion the nature and conditions of his employment as a firefighter over 30 years can be regarded as an aggravation of his underlying constitutional bilateral hip osteoarthritis. As noted in my opinion, it is more likely than not that the nature and conditions of his work meant that his total hip replacements were carried out earlier than might otherwise have been the case.[73] (emphasis added)
[73] Report of Dr Pillemer, 1 May 2019, pp 3-4 (Ex A2).
In his report of 2 May 2019 Dr Pillemer examined x-rays of the left hip taken in 2015 and confirmed his previous opinion.[74]
[74] Report of Dr Pillemer, 2 May 2019 (Ex A3).
In Professor Youssef’s report of 9 July 2019, he reiterated the opinion expressed in his 2016 report:
I do not consider that his work with Airservices Australia has significantly contributed to the development of the hip degenerative disease. At the time he made his initial WorkCover claim in 2013, there were already significant degenerative changes in the left hip on x-ray.
…
It is my opinion that his employment never significantly contributed to the degenerative disease of the left hip.[75]
[75] Report of Professor Youssef, 9 July 2019, 11 (Ex R1).
Comcare relies heavily on the evidence of Professor Youssef. Studies showed an association between cam lesions and osteoarthritic degenerative disease by a process of femoroacetabular impingement, leading to end stage hip disease. The rate of degeneration could be very rapid.[76] One study showed that the mean age for hip replacement therapy was about 57, close to the applicant’s age at the time of surgery.[77] Professor Youssef thought that regardless of other factors the applicant would probably have reached end stage hip disease at around the time or even sooner than he did:
There’s no indication when I compare [the applicant] to the studies that he reached any point earlier than would be expected, such as the need for a hip replacement, and in fact he seems to have developed symptoms to the right hip maybe perhaps a little later than might be expected. I may have expected him to develop symptoms in his 40s in the right hip but he didn’t. Again, to me indicating that perhaps work and squash were not major factors in the development of symptoms.[78]
[76] See Transcript, 5 February 2020, 85.
[77] Agricola et al, “Cam impingement causes osteoarthritis of the hip: a nationwide prospective cohort study (Check) (sic)” Ann Rheum Dis (2013) No 72: 918, at 921.
[78] See Transcript, 5 February 2020, 83-84.
It was for this reason that he discounted workplace factors as significant.
With regard to points of difference with Dr Pillemer, Professor Youssef commented as follows:
I agree with Dr Pillemer that [the applicant] has the constitutional disorder of degenerative disease.
I disagree with Dr Pillemer that it is difficult to be certain of the significance of the cam lesions prior to the total hip replacement. I disagree with him that the jury is still out on whether cam lesions predispose to the development of premature degenerative disease. I have provided significant literature documenting that there is a relationship between cam lesions and osteoarthritis of the hips. What the jury is still out on is whether early interventions such as surgical intervention prevents the development of osteoarthritic change in the hip joints.[79]
[79] Report of Professor Youssef, 9 July 2019, 12 (Ex R1).
Professor Youssef remained opposed to the suggestion that workplace factors contributed in other than a small way to the aggravation of the underlying osteoarthritis. He said simply, that in the absence of studies:
We don’t know whether putting some strain on an abnormal hip joint may necessarily lead to a great and rapid reduction in hip degenerative disease…[80]
[80] Transcript, 5 February 2020, 87 [10].
Dr Pillemer argued that the applicant’s service as a firefighter was a potent contributing factor. He said:
[A]s an orthopaedic surgeon say you have a person in his fifties who’s got arthritis in the hip and who needs a hip replacement we would say to that person leave it as long as possible because we know that hips don’t last forever. And we would say – give instruction to avoid excessive stress to the hip, don’t run, don’t jog, don’t jump, keep walking because you’ve got to keep mobile but avoid any excessive stress to the hip because we sort of feel that that might well hasten the need for a hip replacement. So once you’ve got a damaged joint excessive stress to that joint will hasten the need for a hip replacement. That’s not the case in a normal hip. In a normal hip stress is actually good for the joint, that’s the way the cartilage gets its nutrition. But once you’ve got some damage to the joint excessive stress impact loading can in my opinion aggravate that and hasten the development of the condition.[81]
…
[I]f he would have been doing the work as a fireman for two months, I would say negligible, six months, slightly. Two years, three years, the longer you do it for the more effect it would have. I don’t think anybody can say for certain how much earlier it would have occurred but it seems to me I would say the word obvious and common sense that if you are putting that sort of stress on a damaged hip over a long period of time, the chances are that you will need a hip replacement earlier than would otherwise have been the case. Can I say how much earlier? Can’t say.[82]
[81] Transcript, 5 February 2020, 66, [25].
[82] Transcript, 5 February 2020, 67, [10] - [15].
As to the average age argument, Dr Pillemer was dismissive:
Q: It’s the case, isn’t it, that the average age for a person with femoroacetabular impingement, such as [the applicant] has, the average age for that person to reach end stage osteoarthritis is somewhere in their late 50’s?
Dr Pillemar: Average age, absolutely, I’ll accept that. Significance, in my opinion, not significant. It could’ve been 47, 57, 67.[83]
[83] Transcript, 5 February 2020, 97 [25].
The academic studies
As noted above, Professor Youssef referred to various academic studies that had informed his expert opinion. The papers highlight that the underlying causes of osteoarthritis are not well understood, although a genetic connection is accepted. Some of the studies are concerned to validate detection methods.[84] If the disease is predictable on the basis of bone morphology then some economic screening methods may be available for early detection. For example, the 2003 paper by Ganz et al has this purpose:
A multitude of factors including biochemical, genetic, and acquired abnormalities may contribute to osteoarthritis of the hip…we propose femoroacetabular impingement as a mechanism for the development of early osteoarthritis for most nondysplastic hips. The concept focuses more on motion than on axial loading of the hip...
Osteoarthritis is a disorder of diverse etiologies, which commonly can affect the hip…Based on our clinical experience spanning more than a decade, we have evidence that in many case of idiopathic arthritis, predisposing factors, in the form of femoroacetabulaur impingement, are present that are not appreciated readily using the traditional diagnostic modalities.[85]
[84] Reichenbach at al, “Association between Cam-type Deformities and Magnetic Resonance Imaging-Detected Structural Hip Damage”, Arthritis and Rheumatism (2011) No 63, 4023-4030; Doherty et al, “Nonspherical Femoral Head Shape (Pistol Grip Deformity), Neck Shaft Angle, and Risk of Hip Osteoarthritis”, Arthritis and Rheumatism (2008) No 58, 3172 - 3182; Nicholls et al, “The Association between Hip Morphology Parameters and Nineteen-Year Risk of end-Stage Osteoarthritis of the Hip”, Arthritis and Rheumatism (2011) No 63, 3392-3400.
[85] Ganz et al, ‘Femoroacetabular impingement, a cause for osteoarthritis of the hip’, Clinical Orthopaedics and Related Research (2003) No 417, 112-120, at 111.
Importantly for present purposes, the 2003 Ganz paper proposed femoroacetabular impingement (FAI) as a mechanism for the development of early osteoarthritis for most nondysplastic hips.[86]
[86] Ganz et al, ‘Femoroacetabular impingement, a cause for osteoarthritis of the hip’, Clinical Orthopaedics and Related Research (2003) No 417, 112-120, at 111.
The paper written ten years later by Agricola et al credits Ganz et al with introducing the concept of FAI, defined as a ‘condition of abnormal contact between the femoral head-neck junction and the acetabulum, due to a bone shape abnormality on either the femoral or acetabular side’.[87] The Agricola paper states cautiously that ‘no causal relationship between cam impingement and the development of osteoarthritis has been established’ and concludes merely that cam impingement ‘is strongly related to the development of hip osteoarthritis’.[88]
[87] Agricola et al, “Cam impingement causes osteoarthritis of the hip: a nationwide prospective cohort study (Check) (sic)” Ann Rheum Dis (2013) No 72: 918-923, at 918.
[88] Agricola et al, “Cam impingement causes osteoarthritis of the hip: a nationwide prospective cohort study (Check) (sic)” Ann Rheum Dis (2013) No 72: 918-923, at 922.
Professor Youssef relied heavily on the Agricola study for his opinion that cam lesions could accelerate the progress of osteoarthritis.[89] But the Agricola study does not show a causal relationship, merely an association.[90] An association is undoubtedly important because it demonstrates a level of interconnectedness, but given the newness of this research field, as acknowledged by the Agricola team, it is hard to assess the latency of this mechanism in a particular case. This is the basis of the critique by Dr Pillemer, who agreed with Professor Youssef that there was an association, but was more conservative in applying conclusions about that association in a particular case. He observed:
There’s no doubt they’ve found with follow ups that people who have cam lesions will get osteoarthritis more frequently than people who don’t have them…that’s a constitutional condition and it causes arthritis. No problem with that, I accept that, but that’s simply another cause of arthritis. So, [the applicant] had cam lesions, he developed arthritis. The issue that’s in dispute…is whether the nature and duties of his work would have aggravated the arthritis that developed as a result of constitutional cam lesions…[91]
[89] Transcript, 5 February 2020, 85, [20]; 93 [35].
[90] Agricola et al, “Cam impingement causes osteoarthritis of the hip: a nationwide prospective cohort study (Check) (sic)” Ann Rheum Dis (2013) No 72: 918-923, at 922.
[91] Transcript, 5 February 2020, 94 [10].
The studies provide little guidance as to whether or how the specific workplace factors involved in this case may have tended to abbreviate or extend the period to end stage hip disease. It is not clear from any of the studies whether the disease can be slowed down, for example, by therapeutic treatments, or accelerated by excessive stress. It is not clear whether end stage hip disease is the inevitable outcome for those with cam lesions. The studies say little about the rate of change or the pace of the disease. There were no studies dealing with the therapeutic value of particular activities for those with arthritic joints, although such studies undoubtedly exist. There is no study before me dealing specifically with long serving firefighters with arthritic joints. Or for that matter persons engaged in other heavy industries - other than farming.
Only one study in the group addresses workplace acceleration, the 1992 study of agricultural workers in England by Croft et al,[92] and it suggested that at least in the case of famers in England the workplace was mildly implicated, for in some cases there was an elevated risk of osteoarthritis of the hip. One hypothesis is the stress on hip joints caused by heavy lifting and walking over rough ground and standing for long periods of time. The study suggests that the data accords with the hypothesis that:
…severe disease was associated with standing, walking, and lifting at work, and these associations could not be explained by a confounding effect of obesity or sporting activity…
Most studies of top athletes and sportsmen have found no increase in the occurrence of osteoarthritis of the hip.
These findings agree with our own findings that suggest that sport is unlikely to contribute greatly to the burden of disease in the general population.
[92] Croft at al, ‘Osteoarthrosis of the hip and occupational activity’, Scandinavian Journal of Work and Environmental Health Vol 18 (1992), 59-63.
Professor Youssef was critical of this study and suggested that the data did not support the conclusion. Had the paper been submitted to the journal of which he was subeditor, he would not have published it without more substantiation.[93] At the earlier Tribunal hearing he was also very critical of this study.
[93] Transcript, 5 February 2020, 78 [15].
My assessment is that these particular academic studies cast little light on the specific issue raised before the Tribunal in this case. They add little to understanding the impact of the hip abnormality on the journey from the early onset of osteoarthritis to end stage hip disease, apart from providing a mean time for the journey, and they provide an unsafe foundation for drawing inferences about acceleration and aggravation in this particular case. They do not assist much in understanding the impact of the workplace.
CONSIDERATION
As noted previously, the respondent invited the Tribunal to affirm the reviewable decision on two distinct but interrelated grounds, and I will deal with each in turn.
In relation to both grounds, the respondent accepted what he called the ‘practical onus’ of showing that the applicant’s prior employment by the Commonwealth no longer contributed, to the required degree, to the left hip condition.[94]
[94] Transcript, 4 February 2020, 12 [20].

I note in passing that the reference to a practical onus has been the subject of comment, not entirely favourable, by the Federal Court in Comcare v Power [2015] FCA 1502, at [57] where it was described as an ‘enigmatic’ expression, the court emphasising that to speak of a party having any onus of proof (whether legal or evidential) in proceedings before the Tribunal is apt to mislead.[95] There is no evidential onus of proof in proceedings under the SRC Act.[96]
[95] Comcare v Power [2015] FCA 1502, at [57].
[96] See Comcare v Power [2015] FCA 1502, [61].
The respondent’s primary argument
The respondent’s primary argument invited the Tribunal to affirm the reviewable decision on the basis that the determination made on 16 September 2013 by Comcare was incorrect, with the consequence that there was not, and never had been, any entitlement in the applicant to compensation in accordance with the SRC Act.[97] His secondary argument proceeded on the basis that the left hip condition was, on 13 February 2018, no longer a disease for the purposes of the SRC Act, in that the applicant’s employment by the Commonwealth could not be said to have contributed to the post-operative left hip condition.
[97] In the first right hip case counsel for Comcare argued that the delegate misconceived the medical evidence and that Comcare should never have paid for the left hip: ST49, 395-396.
In relation to the primary argument, the respondent argued on the basis of Telstra Corporation Ltd v Hannaford that a determination of liability under section 14 is not immune from reconsideration in a ‘present entitlements’ case if the evidence clearly shows that a material fact upon which it was based never existed.[98]
[98] See Telstra Corporation v Hannaford [2006] 151 FCR 253 at 273.
He argued that in circumstances where some new evidence had come to light, which cast past events in a different way or a different light, or undercuts the correctness of the primary decision-maker to accept liability for the aggravation of the ailment in the first place, then it is not only appropriate for the Tribunal to take that new evidence into account, but also, incumbent to do so to avoid entitlements being paid that are contrary to the Act.[99]
[99] Transcript, 5 February 2020, 110 [30].
This case is distinguishable from Hannaford at least to the extent that the question whether the applicant in that case did or did not suffer from Ross River fever at the time of the claim was the subject of a clinical test, which raised doubt as to whether he had ever suffered from the condition. The clinical tests made at the time of the claim cast doubt on the existence of a material fact upon which the original determination was made.[100]
[100] Telstra Corporation v Hannaford [2006] 151 FCR 253, at 261.
The essence of the case before me is a dispute between the medical experts as to the medical significance of agreed facts and the validity of a particular form of reasoning used by Professor Youssef. It is his theory that is put forward as the new evidence that effectively undercuts the original determination. Given the controversies that exist in medical science and the propensity for eminent experts to disagree on basic matters of causation it would be unsettling were determinations under the Act to be affected by the passing parade of medical opinion. The present case is distinguishable from Hannaford, where the presence of a disease was detectable by a clinical test widely accepted as accurate and reliable. This is a case which turns on a relatively new scientific ‘discovery’ regarding the relevance of cam lesions and the process of femoroacetabular impingement. While all the experts supported this theory as a possible cause of aggravation of osteoarthritis, they were not unanimous in its application to this case. Of course there may come a point where a new theory is ‘settled’ and agreed upon by the medical profession as a whole. But that is not this case.
In light of all of the medical evidence, my conclusion on the primary argument is that I am unable to be satisfied on the evidence before me that workplace factors did not contribute to the requisite degree to an aggravation or acceleration of the left hip condition. In light of the state of the medical evidence overall, a finding that the applicant’s employment by the Commonwealth over 32 years contributed, in a material way, to the aggravation of the osteoarthritis of his left hip, resulting in the need for an artificial hip, would be open. However, for present purposes it is sufficient to state my conclusion in a negative way, namely, that I am unpersuaded that his employment did not contribute in the requisite way to his left hip condition. On the basis of that conclusion there is no rational basis for making any positive finding that undercuts, diminishes or detracts from the original 2013 determination. I have come to this specific conclusion for the following reasons.
The weight of medical opinion presented to the Tribunal favours the hypothesis that the applicant’s employment aggravated his underlying osteoarthritis. This was the considered opinion of three experienced orthopaedic surgeons, Drs Chen, Bodel and Pillemer, together with the applicant’s general practitioner Dr Brookes. They speak with the authority of more than a century and a half of clinical practice, and have done thousands of hip replacements. They relied heavily on their clinical experience. This body of opinion supports the original 2013 determination and I am not persuaded that it was incorrect.
The dissenting voice belongs to Professor Youssef. His opinion is primarily based on epidemiological studies. His evidence supports an association between FAI and the progress of the disease, but provides no basis for assessing the impact of the applicant’s specific workplace conditions. It may well be that FAI will lead to end stage hip disease over a finite timeframe, but that says very little about the rate of progress or the impact of other factors such as robust training exercises, and long periods of standing and exertion.
Professor Youssef agreed that workplace factors, when considered with other matters such as playing squash, could provide a ‘small’ (as opposed to a ‘very small’) contribution towards end stage hip disease.[101] The proverb about the camel whose back was broken by a flea suggests that in particular circumstances, even a small contribution may be ‘substantially more than material’.
[101] Thompson and Comcare (Compensation) [2018] AATA 2707; Transcript, 6 April 2018; ST49/524 [40] (2016/3772).
I hope I do no injustice to Professor Youssef in saying that his argument appears to be that the workplace contribution was too insignificant to influence the outcome of the disease, simply because the applicant also suffered from FAI which would in the fullness of time (but relentlessly) take him to the point of needing new hips.
Professor Youssef’s reasoning seems to proceed on the footing that if A causes B, then the significance of other potential causes of B can be ignored. The definition of ‘disease’ in section 5B(1)(b) does not require that the workplace is the sole or exclusive aggravating factor of an ailment. It is illogical to exclude workplace factors simply because, on average, a patient with FAI would need a hip replacement at and about the age of the applicant at the time of his hip operations. That form of reasoning does not address, let alone exclude, the possibility that workplace factors may have accelerated the rate of degeneration, and the extent of that acceleration. On the basis of Professor Youssef’s reasoning, workplace contribution might be ruled out for anyone with hip morphology similar to that of the applicant, provided they had reached the mean date for carrying out end stage hip surgery.
The likelihood of an event happening within a particular timeframe is a subject of statistical science; generalising from the outcome of many instances to the likelihood of a single instance. In the world of actual events, the dice often falls against the odds. It is commonplace that expected occurrences may be upset by particular circumstances. And small changes can be amplified to great effect, changing the expected result. I note that Dr Pillemer was disdainful of the statistical reasoning – ‘Statistics, I think you can make them say and do what you want them to do’ he said.[102]
[102] Transcript, 5 February 2020, 87 [35].
Quite apart from this, there is no evidence of a standard rate at which an arthritic hip associated with cam lesions will degrade to the point of needing an artificial hip. The process is not linear or constant, and there is expert evidence before me that the rate of deterioration is affected by stress factors that might aggravate the underlying condition.[103] Clearly the progress of a disease is unlike the firing of a cannonball, the trajectory of which can be predicted by reference to Newtonian physics.
[103] Transcript, 5 February 2020, 69 [20].
As to the degree to which squash was implicated, the medical experts were not in agreement. Professor Youssef did not think that squash was a significant aggravator of the underlying osteoarthritis. He would not have counselled the applicant against playing squash. Dr Pillemer was of the view that once a joint became diseased by osteoarthritis, squash was capable of aggravating the condition and should be discouraged. Dr Bodel stated in his Second Supplementary Report that there was no definite causal link between squash and the development of his condition.[104] The Review Officer dismissed Dr Bodel’s opinion as ‘not persuasive’.
[104] See para [67] above.
There is insufficient evidence before the Tribunal to draw any reliable inference as to the implications for the applicant’s left hip condition based on his history of playing squash. It may well have been a contributing factor, but it is not possible to determine precisely what if any impact it had given his employment as a very fit firefighter.
In summary, Dr Brookes, and the two orthopaedic surgeons, Dr Chen and Dr Bodel, expressed the opinion that the strenuous nature of the applicant’s work as a fireman was a potential aggravator of the underlying osteoarthritis. Dr Bodel suggested that the nature of his employment may have brought forward the need for surgery by as much as three to five years. There is now a further medical opinion from a very experienced orthopaedic surgeon, Dr Pillemer, which supports this thesis. Only Professor Youssef stands against this weight of opinion, and despite his learning and status in the profession, and with the greatest of respect, I did not find his statistical form of reasoning persuasive. The argument that end stage hip disease was inevitable and would happen around the time it did, based on statistical averages, and without taking into account significant external factors, is not to my mind compelling.
Inconsistency and issue estoppel
My conclusion on the respondent’s primary argument leaves the original 2013 left hip determination unaffected by any finding in this case. Does this create a formal contradiction with the finding of the Tribunal in the right hip case? Do the hip claims stand or fall together? At one point the applicant’s counsel thought so, saying: ‘it’s really got to be both hips or no hips’.[105] This is after all a tale of two hips belonging to the same person and exposed to the same stress factors at work. Is it the case that the rejection of the respondent’s primary argument will result in inconsistent or divergent decisions of the Tribunal on the same or similar evidence?
[105] Thompson and Comcare (Compensation) [2018] AATA 2707 (2016/3772); Transcript, 27 September 2017; ST49/396 [5].
In short, the answer is no. In the right hip case the Tribunal was not persuaded on the balance of probabilities that certain conditions existed which supported a determination of liability under section 14 of the SRC Act. The medical evidence did not persuade the Tribunal of the liability requirements.[106] Deputy President Rayment QC said:
I did not take Professor Youssef expressly to agree that the mechanism by which femoroacetabular impingement causes osteoarthritis may be accelerated by arduous employment. I did not take him to dispute it categorically, and indeed I took him to assert that it likely made a small difference. Dr Bodel’s assertion that it may have accelerated the onset of symptoms such that it requires surgery by three or up to five years seems, with respect, to require more reliable evidence that is available to me in this matter, and I am unable to be satisfied that any acceleration of the onset of [the applicant’s] symptoms were caused by his employment to a degree which was significant in the sense mentioned in s 5B of the Act.
[106] There is a different question whether under the particular circumstances the second right hip case based on a ‘frank injury’ that was before me was affected by any factual findings made by the Tribunal in the first right hip case. The discontinuance of the second right hip case makes it unnecessary to explore this issue.
The medical evidence presented before me was more extensive than that available in the previous case, and I had the benefit of Dr Pillemer’s opinion. The evidential material was not the same in each case. The right hip decision by Deputy President Rayment QC does not determine the case I have to decide.
There is a deeper point. In every case it is incumbent on the decision-maker to identify the decision under review.[107] In the first Thompson case the relevant decision was the refusal of Comcare to make a determination of liability under section 14 in relation to the right hip. In this case, the question under review is the refusal of Comcare to give effect to a previous determination of liability under section 14 on the basis that its effect was spent. In either case the question to be decided is to be resolved in a positive way on the balance of probabilities. In short, in the previous case, the Tribunal was not satisfied on the balance of probabilities that the workplace had contributed in a material way to the aggravation of his right hip condition; whereas in this case, I am not persuaded on the balance of probabilities that it did not contribute in a material way to the aggravation of the left hip condition.
[107] See Comcare v Nichols [1999] FCA 209.
No present entitlement - the secondary argument
I turn to consider the respondent’s second argument in support of affirming the reviewable decision. The secondary argument invited the Tribunal to affirm the reviewable decision on the basis that the left hip condition was, on 13 February 2018, no longer a disease for the purposes of the SRC Act, in that the applicant’s employment by the Commonwealth could not be said to have contributed to the post-operative left hip condition. The section 14 determination was made in respect of the aggravation of an underlying osteoarthritis, a condition which came to an end when the diseased hip was replaced with a prosthetic hip joint.[108] He argued that any further medical treatment sought for the left hip would be in respect of the underlying osteoarthritis rather than for the aggravation of that condition, and therefore was not recoverable under the SRC Act.[109]
[108] Transcript, 4 February 2020, 9 [15].
[109] Transcript, 4 February 2020, 10 [33].
The definition of ‘disease’ in section 5B of the Act includes the aggravation of an ailment ‘that was contributed to, to a significant degree, by the employee’s employment by the Commonwealth’. The respondent referred to Prain v Comcare [2017] FCAFC 143, for the proposition that in a present entitlements case it is permissible to approach the matter through the lens of section 5B of the SRC Act, thus elevating the issue of workplace contribution to a position of primacy. Whilst this decision must be accepted, the argument that this definitional element requires an ongoing material employment contribution to the aggravation of the underlying osteoarthritis is less obvious.
The reviewable decision proceeds on the assumption that the medical condition in respect of which the test of present entitlement should be applied is the original condition identified by the section 16 determination. Comcare noted that the left hip was pain free following the operation with unrestricted activities, a normal gait pattern and full pain free movement. For these reasons the delegate wondered what the impairment to the left hip was, considering the total replacement of the left hip. The inevitable conclusion followed, namely, that the applicant ‘no longer experiences the effect of aggravation of osteoarthritis – localised – pelvis and thigh (left hip)’.[110]
[110] T81/234.
Counsel for the applicant reminded the Tribunal on several occasions that the applicant did not any longer suffer from osteoarthritis of the left hip. No doubt he had in mind the argument made by Comcare, that because the arthritic left hip has been replaced by an artificial one, he no longer suffered from the injury in respect of which the original determination was made.
I have reviewed the medical evidence in this case in considerable detail, including the evidence presented at the previous Tribunal hearing, and for the reasons previously stated, I am unable to be satisfied on the balance of probabilities that his employment by the Commonwealth no longer contributes, to a significant degree, to the applicant’s ongoing incapacitation as a result of his workplace injury. For the avoidance of doubt, I reach this conclusion whether the relevant injury is regarded as the pre or post-operative condition of the left hip. The underlying osteoarthritis is the ailment ‘in relation to’ which compensation is claimed. It was the disease which led to the need for artificial hips. Aggravation of the ailment is not of itself a constitutional condition but a process pertaining to an ailment. In this context, to draw a distinction between the underlying osteoarthritis and the aggravation of the underlying osteoarthritis is, with respect, to mix categories. Were it necessary to do so, I would find that the relevant injury suffered by the applicant is, for the purposes of sections 16 and 19, the post-operative condition of the left hip, which may require medical treatment from time to time, as post-operative hips sometimes do.
Payments made under sections 16 and 19 are conditional upon a determination under section 14. Section 14 provides that Comcare is liable to pay compensation in accordance with the Act ‘in respect of’ an injury suffered by an employee if the injury results in death, incapacity or impairment. It is a matter for Comcare to determine whether the applicant is incapacitated ‘as a result of’ an injury in respect of which a determination under section 14 exists.
The question whether Comcare is liable to pay for any claim from time to time depends upon an application of the relevant provisions of the SRC Act. For example, section 16 provides that where an employee suffers an injury, Comcare is liable to pay, in respect of the cost of medical treatment obtained ‘in relation to’ the injury (being treatment that it was reasonable for the employee to obtain in the circumstances).
It is a matter for Comcare to determine whether such claims as they arise are reasonable and whether they arise ‘in relation to’ the injury. The fact that a diseased limb has been replaced by a prosthetic joint does not insulate Comcare from any further claim for medical expenses ‘in relation to’ the original injury. The fact that the disease may have triggered some other condition in respect of which a claim for medical expenses is made does not dispose of that question. For example, a claim for medical expenses relating to the control of secondary infections arising from a hip replacement would arguably arise ‘in relation to’ the original injury. I expect that a second hip operation consequent on the failure of the first operation would also arise ‘in relation to’ the original injury.

Section 19 applies to an employee who is incapacitated for work ‘as a result of an injury’. The calculation of compensation flowing from incapacitation ‘as a result of an injury’ is also a matter for Comcare to decide in light of evidence presented by the applicant as to his present and previous income.
CONCLUSION
In conclusion, the evidence before me shows that the applicant suffered from osteoarthritis of the left hip. He developed this condition whilst working for 32 years as a firefighter employed by the Commonwealth. He had certain constitutional characteristics that predisposed him to developing osteoarthritis. Although there is no evidence that his employment caused the disease, Comcare determined under section 14 of the SRC Act that the arduous circumstances of his work aggravated the disease to a significant degree, that is, a degree that was substantially more than material. I have found insufficient evidence before me to contradict that finding. With respect, I have found Professor Youssef’s statistical averaging theory unpersuasive. I prefer the medical opinions expressed by Dr Bodel, Dr Chen, and Dr Pillemer over those of Professor Youssef.
In the specific circumstances of this case (given that the section 14 determination remains in place) it is not open to Comcare to simply refuse to consider any particular claim arising in accordance with the SRC Act, although it is perfectly proper to consider whether any particular claim arises ‘in respect of an injury’, by which I understand, the injury in respect of which a determination of liability has been made under section 14.
The Tribunal therefore sets aside the reviewable decision and remits the matter to Comcare for reconsideration, on the basis that Comcare has by reason of section 14 an ongoing liability under section 16 for medical expenses and section 19 for incapacity payments in relation to the applicant’s left hip injury.

I certify that the preceding 130 (one hundred and thirty) paragraphs are a true copy of the reasons for the decision herein of Emeritus Professor P A Fairall, Senior Member

............................[sgd].........................................
Associate
Dated: 10 March 2020

Date(s) of hearing: 4 - 5 February 2020

Counsel for the Applicant: Mr J Mrsic

Solicitors for the Applicant: Slater & Gordon Lawyers

Counsel for the Respondent: Mr B Dean

Solicitors for the Respondent: Lehmann Snell Lawyers

Date(s) of hearing:	4 - 5 February 2020
Counsel for the Applicant:	Mr J Mrsic
Solicitors for the Applicant:	Slater & Gordon Lawyers
Counsel for the Respondent:	Mr B Dean
Solicitors for the Respondent:	Lehmann Snell Lawyers