Smith v Comcare

The AAT's findings 5 The error of law made by the AAT was that it stated conclusions, unnecessarily and ultimately contrary to its own findings on liability, about the issue of when a "disease" within the meaning of s 4 of the Safety Rehabilitation and Compensation Act 1988 (Cth) (as it stood at the time relevant to this litigation: see Safety, Rehabilitation and Compensation and Other Legislation Amendment Act 2007 (Cth), sch 1, s 5) ("SRC Act") should be taken to have been sustained within the meaning of s 7(4) of the SRC Act, for the purpose of the present case. 6 Under s 14 of the SRC Act, Comcare may be liable to pay compensation to a Commonwealth employee who suffers a work related injury. For this purpose, "injury" includes a "disease" and "disease" includes an "ailment" or the "aggravation" of an ailment. 7 In the present case, the appellant suffered from osteoarthritis. That condition was an ailment within the meaning of s 4 of the SRC Act, which provides: "ailment" means any physical or mental ailment, disorder, defect or morbid condition (whether of sudden onset or gradual development). 8 Section 4 of the SRC Act also provided: "disease" means: (a) any ailment suffered by an employee; or (b) the aggravation of any such ailment; being an ailment or an aggravation that was contributed to in a material degree by the employee's employment by the Commonwealth or a licensed corporation. 9 The AAT accepted that the appellant had suffered an aggravation of his ailment. The aggravation of the appellant's osteoarthritis led to the necessity for a hip replacement in 2008. However, it should be noted that, for the purpose of the definition of "disease", an ailment or aggravation of an ailment is only a disease if it was "contributed to in a material degree by the employee's employment by the Commonwealth". It is only in that circumstance that the disease will be an injury compensable under s 14 of the SRC Act. 10 Section 7(4) of the SRC Act provides: 7(4) For the purposes of this Act, an employee shall be taken to have sustained an injury, being a disease, or an aggravation of a disease on the day when: (a) the employee first sought medical treatment for the disease, or aggravation; or (b) the disease or aggravation resulted in the death of the employee or first resulted in the incapacity for work, or impairment of the employee; whichever happens first. (Emphasis added) 11 The enquiry directed by this section concerns the date from which compensation might be payable to an employee who suffers an injury which is (relevantly here) a "disease" within the meaning of s 14 of the SRC Act. One circumstance in which such an enquiry, and a decision about it, becomes relevant is stated by s 16(1) of the SRC Act in the following terms: 16(1) 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 to that medical treatment. 12 In the present case, a claim was advanced by the appellant to the effect that his underlying or constitutional condition of osteoarthritis had been aggravated by his working conditions as a Commonwealth meat inspector which required him at various abattoirs over a long period of time (about 30 years) to involve himself in repetitive heavy lifting, twisting and turning and other movements which contributed to a material extent to the aggravation of his underlying condition. 13 The appellant's case also suggested that, for the purpose of s 7(4), the date of onset of the aggravation (to which a material contribution had been made by a long period of employment) would be either 1990 or 1997 when, on each occasion, the applicant had sought medical treatment. On the appellant's case, an answer to this question was ultimately necessary in order to establish the date from which the applicant's medical expenses would be met by way of compensation (see s 16 of the SRC Act referred to earlier) because he had not been incapacitated from working before either of those dates. However, necessarily, resolution of this question assumed, in the applicant's favour, a finding of liability under s 14 based on satisfaction of all the requirements necessary to show that the appellant suffered from a disease in the defined sense. That included the necessity to show that the appellant's work made a material contribution to the aggravation of his ailment. As the appellant's case was that the relevant material contribution was to be found in working conditions going back as far as 1983 (when he became employed by the Commonwealth as a meat inspector), it was clear that 1990 and 1997 were not advanced as anything other than dates on which medical treatment was first sought for a condition having its genesis commencing years before. 14 Before dealing with the question of whether the appellant's work had made a material contribution to the aggravation of his osteoarthritis, the AAT first identified the date of "onset" of the appellant's symptoms of the aggravation of his osteoarthritis. The AAT did so, in part at least, to address the issue which had arisen about the potential application of s 7(4) of the Act, which it referred to (at [5]) as follows: 5. For the purposes of that provision [s 7(4)] Mr Mrsic submitted that the aggravation of the hip osteoarthritis should be taken to have been sustained in 1990 or, alternatively, in 1997. Mr Richards submitted that the evidence pointed to an onset in 1997. 15 When it came to state its conclusions (having set out the evidence presented to it), that was the first issue with which the AAT dealt. The AAT said (at [63]): 63 Dr McGill described Mr Smith's hip condition as a constitutional and degenerative condition. Mr Smith was treated for a hip problem in 1970 but this settled in a few days. He received an injection in 1997 but Dr Browne's opinion, based on the apparent site of the injection, was that this was more related to the buttock area than to Mr Smith's hip. Dr Huntsdale noted complaint of hip pain in 1990 which was manageable at that time. Dr Browne noted that reference and said that the underlying constitutional condition may have demonstrated some aggravation at that time but he considered that this would not have remained latent for another seven years until 1997. His opinion was that the aggravation relevant to Mr Smith's claim was in 1997. Mr Smith saw Dr Miniter in 1997 for an injection to his hip. Dr Sambrook also recorded a history of onset in the late 1990s when Mr Smith had an injection for pain. I am satisfied that the aggravation of Mr Smith's hip osteoarthritis is a disease which, in accordance with s 7(4) of the Act, can be taken to have been sustained in 1997. 16 This paragraph of the AAT's decision stated two definite conclusions. The first was that the aggravation of the appellant's osteoarthritis was a "disease". For the purpose of s 14 of the SRC Act, such a finding involves a prior conclusion that the aggravation was consequent upon a material contribution by the appellant's employment by the Commonwealth. However, that proposition was later rejected by the AAT. Use of the word "disease" therefore should be seen as either inadvertent or non-technical. The second definite conclusion was that the disease (i.e. the aggravation of an ailment) was sustained in 1997. This finding was based on what the appellant sought medical attention for in 1990 and 1997. It does not seem to consider or answer any question about the cause of the symptoms which led to those visits to medical practitioners. 17 If the second finding was made only for the purpose of s 7(4) of the Act, it was unnecessary at that part of the AAT's analysis, and ultimately not necessary at all. If the conclusion was a more general one, then a question arises about the way in which the AAT approached the question of material contribution. 18 The appellant's hip operation was carried out by Dr Warwick Huntsdale, orthopaedic surgeon, who had treated the appellant for other conditions in 1988, 1990 and 2006. The AAT recorded (at [41]-[42]): 41 Dr Huntsdale first saw Mr Smith in 1988 in relation to a fractured patella. He then saw him in 1990 when he had pain in the right groin and low back. Dr Huntsdale had examined his hip at that time but said that it was manageable. He then saw him in 2006 for a shoulder problem. In November 2008, he saw him for his hip condition and recalled that he was limping badly and was in substantial pain. Mr Smith gave no history of a specific injury but told him that there had been a rapid deterioration over the previous six weeks which had caused him to cease playing golf. Dr Huntsdale conducted hip replacement surgery on 9 December 2008 at Wagga. In his reports in December 2008, Dr Huntsdale noted that Mr Smith was complaining of paraesthesia and, in February 2009, he noted some improvement in that regard. 42 In his report of April 2010, Dr Huntsdale wrote that he did not know that there was anything in Mr Smith's job which may have caused the hip condition to occur. Dr Huntsdale referred to a study on farmers with an increased risk of osteoarthritis hip but said that this related to heavy work on a repetitive basis. Dr Huntsdale confirmed his opinion that, in the absence of heavy work, Mr Smith's job would not contribute to Mr Smith's hip condition. 19 It might be noted that Dr Huntsdale had apparently found it necessary to examine the appellant's hip in 1990, even though no treatment was given. The appellant was later assessed by Dr Paul Miniter, another orthopaedic surgeon, in September 1997 as suffering from osteoarthritis of the right hip. 20 The medical evidence that supported the appellant's more general claim came from two specialist rheumatologists, Professor Neil Sambrook and Dr Christopher Browne. Medical evidence to the contrary came from a third specialist rheumatologist, Dr Neil McGill. 21 Professor Sambrook relied on a history given by the appellant, and research studies concerned with "heavy manual work" (which also included lifting light objects) to suggest that the appellant's work as a meat inspector contributed to the appellant's hip osteoarthritis, of which he became aware through pain in his right hip and buttock region in the late 1990's. 22 Dr Browne also offered the opinion that the appellant's work aggravated his hip osteoarthritis, although it did not cause it. Dr Browne thought the apparent onset of osteoarthritis was probably in the late 1990's also. 23 Dr McGill, on the other hand, gave an opinion that the appellant's work was not likely to have increased the likelihood of developing osteoarthritis of the hip. The AAT recorded (at [60]-[61]): 60 … Dr McGill agreed with Professor Sambrook that there was good evidence that physically demanding work continued over many years was associated with increased prevalence of hip osteoarthritis. However, his opinion was that the studies showed that hard physical work involving heavy lifting was needed over a prolonged period. He also concluded that mere repetitive work was not so associated. 61 Dr McGill's opinion was that the nature of the abattoir work by Mr Smith was not of a type that would increase the likelihood of developing osteoarthritis of the hip. … and (at [62]): 62 Dr McGill referred to the report of Dr Browne and his evidence that heavy lifting was not a requirement for the development of osteoarthritis in the hip. He said that there was no study that confirmed that opinion. He also noted Dr Browne's reference to the greater impact on the hip joint if weight was carried while the hip was in the flexed position, as Mr Smith was from time to time, while bending forward to complete his inspections. He rejected that suggestion on the basis that, when flexed, there would be no greater impact on the hip joint because the surrounding muscles would compensate by taking the additional strain. Dr McGill also dismissed the repetitive turning by Mr Smith to sterilise his knife as being causally associated with hip osteoarthritis. 24 In its discussion about the significance of the medical evidence for the claim that the appellant's work had materially contributed to the aggravation of his osteoarthritis, the AAT concluded that it would need to be shown that the appellant had been involved in "heavy lifting". The AAT then assessed whether the appellant's duties "at Wagga" involved him in heavy lifting and (at [79]) found they did not: 79 … I am satisfied that Mr Smith's meat inspection duties at Wagga did not involve him in heavy lifting and that the only lifting of any moment was in relation to the turning of items at the viscera table. Even in that regard, the motion was more one of quickly flipping the item over rather than of lifting. I am satisfied that Mr Smith's inspection duties at Wagga did not make a material contribution to the aggravation of his hip osteoarthritis. 25 Other references made by the AAT (at [80] and [82]) to the appellant's duties also concerned the period he was at Wagga. The appellant had been employed at the Forbes abattoir in the New South Wales public service from 1981, and by the Commonwealth at Forbes from 1983, before he went to Wagga in 1987. The AAT's conclusions make no reference to this earlier period of employment by the Commonwealth which was a part of the appellant's case. 26 On the present appeal, the appellant emphasised the following passage in the AAT's final conclusions (at [81]): 81 On Mr Smith's evidence, the work at Wagga was more onerous prior to 1993 when he was involved in mutton as well as beef inspections. However, the evidence of Dr Browne and Professor Sambrook was that the aggravation of Mr Smith's hip osteoarthritis in 1997 was related to his activity in the years immediately preceding that onset. 27 This passage was said to betray an erroneous approach by the AAT, whereby the AAT concentrated on its earlier conclusion (reached for the purpose of s 7(4)) about when the appellant's condition was notionally "sustained" rather than, as it was required to do, giving attention to the appellant's case about his working conditions over the whole of the period from 1983. 28 The criticism is certainly contestable. On the face of its conclusions, the AAT made an evaluation of at least the whole of the period at Wagga from 1987, even if not from 1983. It did not appear to confine its attention to the period shortly before 1997. 29 The analysis by the AAT of the impact of the appellant's working conditions involves findings of fact. Those findings are not open to challenge in their own right. If, however, they reveal, or appear to proceed upon, an error of law, the findings may be found to be insufficiently reliable to be allowed to stand. The first question to be resolved is whether an error of law was made. If it was, a further question arises about whether it renders the findings of fact potentially unsafe or incomplete.

Error of law 30 The respondent argued that any error of law in the present case (if one was made) did not affect the AAT's conclusions on the merits of the appellant's claims, which conclusions should be allowed to stand. That was also the view taken by the primary judge. 31 Before dealing with the respondent's contention, and the primary judge's approval of it, the question of law which arises for consideration should first be identified. The questions of law relied on by the appellant were stated as follows: 1. In determining whether an employee's ailment is a disease and thereby an injury, for the purpose of the definitions of "disease" and "injury" in s.4 of the SRC Act: (a) is it necessary for the Tribunal to determine whether the ailment or aggravation of that ailment suffered by the employee was contributed to in a material degree by the employee's employment? (b) and, if so, is it necessary to make that finding prior to considering when the employee first sustained the injury? 32 The grounds in support of the appeal about those questions were stated as follows: Question of law 1(a): 1. The Tribunal failed to make a finding as to whether the Applicant's ailment, osteoarthritis, was contributed to in a material degree by the Applicant's employment by the Commonwealth or a licensed corporation and thereby failed to make a finding as to whether the Applicant had a "disease" within the meaning of the Act. Question of law 1(b): 2. The Tribunal misconstrued and misapplied s 74(4) to conclude that the Applicant's "disease" was sustained in 1997, whereas the Tribunal should have asked itself: (a) whether the Applicant's ailment, osteoarthritis, was contributed to in a material degree by the Applicant's employment by the Commonwealth or a licensed corporation; and thereby (b) whether the Applicant suffered a "disease" or "aggravation of a disease" within the meaning of s 4(1) of the Act; and if so (c) when the Applicant was to be taken to have sustained an injury under the Act. 33 In my view, the first of those grounds cannot be sustained. The AAT did make a finding about the question of material contribution. The finding was adverse to the appellant. 34 However, it involves no mere procedural criticism of the AAT in the present case to suggest that it should have said nothing about the potential operation of s 7(4) before addressing and concluding (at least in its own mind) the question of liability under s 14. In a case where no liability under s 14 is found to exist, that does not mean necessarily that it will never be necessary to address the question under s 7(4). In some cases it might be prudent to do so in case a different view is later taken of the question of liability under s 14. That said, as the AAT is the final decision maker, that form of conditional answer may not be necessary in many cases, if any. In a case where such an approach was necessary, the AAT would be bound to proceed upon the basis of assumptions contrary to its prior conclusions about liability under s 14. There is no difficulty in principle about such an approach in an appropriate case and it is an approach taken by courts all the time. Nevertheless the nature of the exercise should be fully disclosed so that its conditional nature may be readily appreciated. That will usually be difficult unless the primary finding about liability is first made, and the AAT goes on to assume, nevertheless, a contrary outcome for the purpose of giving a theoretical answer to the question in s 7(4) in case its view does not prevail. 35 In my view, the second ground set out above, and the question of law to which it is directed, does serve to identify an error of law. The error was making a finding about a matter which arose under s 7(4) of the Act without any foundation upon which to do so, whether by way of prior finding for the purpose of s 14 or by way of assumption. 36 The conclusion that an error of law was made does not mean, necessarily, that it is necessary for the matter to be remitted to the AAT for further attention. There would be no utility in such a procedure if it was sufficiently apparent that the AAT's findings of fact, and ultimate conclusion on liability, were not affected by the error. 37 The primary judge, from whose decision the present appeal has been brought, did not find it necessary to decide whether an error of law had been made. That is because his Honour thought the appellant could not succeed in any event. His Honour said (at [21]-[23]): 21 … It was not explored by either party why, in this case, the s 7(4) question needed to be asked (or answered). Without drawing a final conclusion on that matter, I would imagine that the time at which the injury was taken to have occurred may well have impacted upon which version of the Act was to apply. Whatever the answer to that question, however, the Tribunal correctly approached the issue of aggravation by looking at the whole period form [sic] 1977 to 2008. Even if it was incorrect to consider the issues posed by s 7(4) before the disease in question had been identified that error had no impact on the manner in which the Tribunal approached the issue of material aggravation. 22 Pointedly, it was not suggested in this Court that the Tribunal had erred in concluding that the injury should be taken to have occurred in 1997; that is, although it was argued that the question had been answered out of order it was not suggested it had been answered incorrectly. So viewed, the only relevance advanced for the notion that it had been answered prematurely was the argument, which I have rejected, that the Tribunal had thereby mishandled the issue of material aggravation. 23 What this means is that the issue which Mr Smith seeks to ventilate has no relevance to the outcome of the proceedings. … 38 In my respectful view, it is not sufficiently clear that the AAT did, in fact, assess the whole period from 1977 to 2008 (more precisely, 1983 to 2008). Perhaps it was deflected from doing so by a view of the medical evidence that the aggravation of the appellant's hip osteoarthritis was likely to be found in events no more than a few years prior to 1997, rather than potentially in the whole period from at least 1983. If so, that is hard to reconcile with reference to the various studies suggesting a relationship between a history of heavy lifting over many years, followed by a later onset of osteoarthritis. That evidence suggests that consideration would need to be given to the whole of the relevant period of employment, and that it may not be the case that symptoms would emerge within a few years of the relevant activity beginning. 39 I cannot exclude from my own mind the reasonable possibility, for which the appellant contended, that the AAT's premature and unnecessary attention to the question in s 7(4) might have sent it on the wrong line of enquiry about the issues arising under s 14. The conclusions by the AAT stated in [81] of its decision (set out earlier) give sufficient (even if not decisive) support for that thesis.

Conclusion 40 In those circumstances, in my view, the question of law does not lack relevance. Furthermore, I am not satisfied that there need not be further attention to the question of whether the provisions of s 14 were satisfied, having regard to the employment of the appellant from 1983 to 2008. It would be a matter for the AAT to determine, but I cannot see why further evidence would be necessary or appropriate. 41 I would uphold the appeal and remit the matter to the AAT for further consideration and determination according to law. The appellant should have his costs of the present appeal. I certify that the preceding forty (40) numbered paragraphs are a true copy of the Reasons for Judgment herein of the Honourable Justice Buchanan.

Associate: Dated: 28 June 2013 IN THE FEDERAL COURT OF AUSTRALIA AUSTRALIAN CAPITAL TERRITORY DISTRICT REGISTRY GENERAL DIVISION ACD 43 of 2012

JUDGES: GREENWOOD, BUCHANAN AND BROMBERG JJ DATE: 28 JUNE 2013 PLACE: SYDNEY (VIA VIDEO LINK TO CANBERRA)

REASONS FOR JUDGMENT BROMBERG J: 42 Between 1977 and 2008, the appellant ("Mr Smith") worked as a meat inspector. From 1983, he was engaged by a Commonwealth service now known as the Quarantine and Inspection Service. In November 2008, Mr Smith stopped work due to severe pain in his right hip. He was operated on and his hip was replaced. On 14 March 2010, he was medically retired from his employment with the Commonwealth. 43 Mr Smith applied to the Respondent ("Comcare") for worker's compensation. His application came to be dealt with by the Administrative Appeals Tribunal ("the AAT") (Smith v Comcare [2011] AATA 662). The AAT affirmed Comcare's decision to reject Mr Smith's claim. Mr Smith's challenge to the AAT's decision was dismissed by the primary judge (Smith v Comcare [2012] FCA 502). 44 There is no issue that Mr Smith suffers from hip osteoarthritis. The main issue before the AAT was whether Mr Smith's hip condition was a degenerative condition which had been aggravated by Mr Smith's work as a meat inspector. If Mr Smith's condition was aggravated by his employment, Comcare would be liable to pay Mr Smith compensation in accordance with s 14(1) of the Safety, Rehabilitation and Compensation Act (1988) (Cth) ("the Act"). 45 At the time relevant to this litigation, the expression "injury" was defined by the Act to include, inter alia, a "disease suffered by an employee" and the definition of "disease" encompassed the aggravation of any ailment, being an ailment or aggravation that "was contributed to in a material degree by the employee's employment": s 4(1) of the Act and the Safety, Rehabilitation and Compensation and Other Legislation Amendment Act (2007) (Cth), Sch 1, s 42. By reference to the definition of "disease", the critical question before the AAT was whether Mr Smith's employment had contributed in a material degree to the aggravation of his osteoarthritis. 46 Before the primary judge, Mr Smith's counsel argued that as well as determining whether the aggravation of Mr Smith's osteoarthritis had been contributed to in a material degree by his employment, it was also incumbent upon the AAT to determine when the aggravation had occurred. A deeming provision contained in s 7(4) of the Act governed that latter question. It provided: For the purposes of this Act, an employee shall be taken to have sustained an injury, being a disease, or an aggravation of a disease, on the day when: (a) the employee first sought medical treatment for the disease, or aggravation; or (b) the disease or aggravation resulted in the death of the employee or first resulted in the incapacity for work, or impairment of the employee; whichever happens first. 47 Mr Smith contended before the AAT that the scheme of the Act demanded a particular order for the resolution by the AAT of the material contribution and the s 7(4) issues. First, the AAT had to identify an ailment which had been contributed to in a material degree by the employment and second, and only when that first step had been completed, the AAT needed to ask the question posed by s 7(4) as to when the injury had been sustained. It was contended for Mr Smith before the primary judge that the reasons of the AAT showed that it had determined the s 7(4) question at an earlier point in its reasons (at [63]) than when it determined the issue of material contribution (at [72]-[82]). This was said to be not a matter of mere technicality, because by inverting the correct order in which the two questions were to be asked, the Tribunal had misled itself. Particular reliance was placed on [81] of the AAT's reasons because the contents of that paragraph, so it was argued, showed that the Tribunal had been misled into thinking that the question it had to consider was whether Mr Smith's employment in 1997 alone (the year that the AAT determined the injury occurred under s 7(4)) had contributed to the aggravation of Mr Smith's osteoarthritis in a material degree. Mr Smith contended that that was not the proper question at all, the correct question being whether Mr Smith's employment over the whole period of his employment had contributed to the aggravation of his osteoarthritis. 48 The primary judge was prepared to assume that the order in which those questions needed to be dealt with was as contended for by Mr Smith and that the AAT had inverted the correct order by determining the issue raised by s 7(4) before determining whether there was a disease by reason of the aggravation of Mr Smith's ailment. However, the primary judge rejected Mr Smith's contention that the consequence of the AAT inverting the correct order was that the AAT had only considered Mr Smith's employment in the year 1997, rather than considered the whole period of Mr Smith's employment, in determining whether that employment had contributed to the aggravation of Mr Smith's osteoarthritis in a material degree. The primary judge reasoned that when [81] of the AAT's reasons is read in the full context of those reasons, and particularly [79]-[82], the meaning that was sought to be ascribed by Mr Smith to [81] was not made out. The primary judge concluded that Mr Smith's reading of [81] was "antithetical to the surrounding context and the balance of the Tribunal's reasons". The primary judge was satisfied that the Tribunal's reasons demonstrated that its focus was not limited to Mr Smith's employment in 1997 and that the AAT correctly approached the issue of aggravation by looking at Mr Smith's employment over the whole period from 1977 to 2008. 49 The primary judge concluded that once that was accepted, no material error could arise from the AAT having considered the s 7(4) issue in advance of the material contribution question. Even if it had been incorrect for the AAT to consider the issue posed by s 7(4) before the existence of the disease in question had been assessed, that error had no impact on the manner in which the AAT approached the issue of material aggravation. The issue which Mr Smith sought to ventilate was therefore regarded as having no relevance to the outcome of the proceeding and, in those circumstances, the primary judge dismissed Mr Smith's application. 50 To provide a clear understanding of the issue before the primary judge and the basis for this appeal, it is necessary to set out [79] to [83] of the reasons of the AAT: 79. The majority of those studies and, indeed, the medical reports in evidence support the need for heavy lifting in employment in order to have an association with hip osteoarthritis. The Juhakoski report also implicated light objects but only in the context of "much lifting" thereof. Dr Browne, who implicated the employee's flexed position to be relevant, also required that to be done in the context of lifting. His evidence in relation to the DVD was that he observed no lifting. I am satisfied that Mr Smith's meat inspection duties at Wagga did not involve him in heavy lifting and that the only lifting of any moment was in relation to the turning of items at the viscera table. Even in that regard, the motion was more one of quickly flipping the item over rather than of lifting. I am satisfied that Mr Smith's inspection duties at Wagga did not make a material contribution to the aggravation of his hip osteoarthritis. 80. Mr Smith described a greater degree of heavy work when allocated to relieve at more remote abattoirs. However, there is no evidence specific to the nature of the work at those other abattoirs. In any event, I am satisfied that the short periods of Mr Smith's allocations to those abattoirs was not such as to make a material contribution to his hip osteoarthritis. 81. On Mr Smith's evidence, the work at Wagga was more onerous prior to 1993 when he was involved in mutton as well as beef inspections. However, the evidence of Dr Browne and Professor Sambrook was that the aggravation of Mr Smith's hip osteoarthritis in 1997 was related to his activity in the years immediately preceding that onset. 82. There was no medical evidence which supported a material contribution to Mr Smith's hip osteoarthritis from repetitive turning by Mr Smith to sterilise his knife or to any specific incident of trauma to the hip. There is no evidence that Mr Smith's hygiene inspections and load out duties involved any lifting. 83. I am satisfied that Mr Smith's employment as a meat inspector did not materially contribute to his hip osteoarthritis. Accordingly, the decision under review is affirmed. 51 It is necessary to observe by reference to the findings made by the AAT at [11] and [18]-[25], that the meat inspection duties (at Wagga and "more remote abbatoirs") to which reference is made in [79] and [80] of the AAT's reasons is a reference to work which occurred in the period 1987-2008 and not the earlier period of 1980-1986 when Mr Smith worked at Forbes and Blayney as described at [12]-[17] of the AAT's reasons. 52 It is also necessary to set out [63] of the AAT's reasons. That paragraph was headed "Onset" and concluded with the AAT's finding in relation to s 7(4) of the Act: Onset 63. Dr McGill described Mr Smith's hip condition as a constitutional and degenerative condition. Mr Smith was treated for a hip problem in 1970 but this settled in a few days. He received an injection in 1997 but Dr Browne's opinion, based on the apparent site of the injection, was that this was more related to the buttock area than to Mr Smith's hip. Dr Huntsdale noted complaint of hip pain in 1990 which was manageable at that time. Dr Browne noted that reference and said that the underlying constitutional condition may have demonstrated some aggravation at that time but he considered that this would not have remained latent for another seven years until 1997. His opinion was that the aggravation relevant to Mr Smith's claim was in 1997. Mr Smith saw Dr Miniter in 1997 for an injection to his hip. Dr Sambrook also recorded a history of onset in the late 1990s when Mr Smith had an injection for pain. I am satisfied that the aggravation of Mr Smith's hip osteoarthritis is a disease which, in accordance with s 7(4) of the Act, can be taken to have been sustained in 1997. 53 On the hearing of the appeal, Mr Smith emphasized the unnecessary and erroneous finding made by the AAT at [63] in relation to s 7(4) of the Act. From that platform Mr Smith contended that in dealing with whether Mr Smith's employment had made a material contribution to the aggravation of his ailment, the AAT's focus had been distracted by the s 7(4) question so as to limit to 1997, or shortly beforehand, the scope of its examination of the material contribution of Mr Smith's employment. The AAT's reasons at [81] were said to confirm the myopic approach which the AAT took. 54 I accept that having ultimately rejected that Comcare was liable to pay compensation to Mr Smith it was unnecessary for the AAT to determine the s 7(4) question. It is only when liability under s 14 of the Act is established that it becomes necessary for the deeming provision in s 7(4) to operate and for a finding to be made so that it can. 55 I accept also that the use by the AAT of the word "disease" in [63] is curious. If it was intended to be used by reference to its defined meaning in the Act, it raises a contradiction. The word "disease" is defined to encompass a condition which the employee's employment has contributed to in a material degree. The AAT concluded at [79] and [80] that no such material contribution was made. It is likely therefore that the AAT's use of the word was not intended to take its defined meaning. In any event, nothing turns on that curiosity. It was not Mr Smith's contention that, if meant in its defined sense, the use of the word demonstrated an error of any consequence to the disposition of the appeal. 56 The real issue that arises out of [63] of the AAT's reasons is whether it sign posts the AAT's departure from the task it was required to undertake of assessing whether the aggravation of Mr Smith's hip condition was contributed to in a material degree by his employment. 57 Although Mr Smith was employed as a meat inspector in abattoirs from 1977, his employment by the Commonwealth commenced in 1983 and concluded in 2008. To the extent that Mr Smith relied upon work performed by him in that period as making a material contribution, the AAT was required to examine and assess that work in combination with the medical evidence which dealt with the possible connection between the work and the aggravation of Mr Smith's ailment. 58 There was a rational basis for the AAT to have considered whether Mr Smith's employment contributed to the aggravation of his ailment, by identifying the date of clinical onset of that aggravation. The time at which an ailment becomes patent, in the sense that its symptomology becomes observable, may well be probative of the materially contributive event or events responsible for the ailment. That is clearly the case in circumstances where, as here, there was medical evidence before the AAT (to which the AAT referred at [56] and [63]) as to the period of time, from the date of causation, that a condition may be expected to remain latent. Dr Brown's evidence was that whilst osteoarthritis could occur spontaneously it would probably not be asymptomatic for a period as long as seven years. Dr Brown gave evidence, which the AAT appears to have accepted, that onset was likely to have occurred in 1997 and not earlier and was related to Mr Smith's duties performed from 1993-1997 (see at [56]). 59 It is apparent, however, that in addressing the issue of 'onset' the AAT did so, (at least in part) to make the unnecessary s 7(4) finding. Nevertheless, the findings made at [63] had a forensic purpose beyond the application of s 7(4) of the Act. The date of onset had, on the evidence before the AAT, a temporal connection to causation and was relevant for that purpose. For the AAT to have considered that connection does not demonstrate the AAT left the path it was required to travel. 60 In considering the relationship between Mr Smith's employment and the aggravation of his ailment, the AAT considered the medical evidence relied upon by both Mr Smith and Comcare. The AAT's reasons suggest that it understood that evidence to be based upon histories recounting the nature of Mr Smith's work as an inspector and his symptomology over the whole period of his employment. 61 The AAT dismissed Mr Smith's application because it was satisfied that his employment as a meat inspector made no material contribution to the aggravation of his hip osteoarthritis. It came to that view because the medical evidence and the evidence from studies of the causes of osteoarthritis which the AAT accepted concluded that there needed to be heavy lifting in the employment in order for that employment to have led to hip osteoarthritis. 62 The AAT was satisfied that whilst Mr Smith was engaged at Wagga his duties did not involve him in heavy lifting. That finding was made at [79]. On its face it appears to relate to the period 1987-2008 because that is the period in which Mr Smith worked at Wagga. 63 At [80] and [81] the AAT dealt with two aspects of Mr Smith's evidence which suggest his involvement in heavier or more onerous work than that which the AAT regarded as generally applicable to his work at Wagga. At [80] the AAT appears to accept that Mr Smith was involved in "a greater degree of heavy work" when allocated to relieve at more remote abattoirs. As the reasons elsewhere identify, this work was also performed in the period 1987-2008, whilst Mr Smith was substantively employed at Wagga. Given the short periods of Mr Smith's allocation to these abattoirs, the AAT was satisfied that the duties there performed made no material contribution to the aggravation of Mr Smith's ailment. 64 At [81], the AAT returns to Wagga and to Mr Smith's evidence that the work at Wagga was "more onerous" prior to 1993. It dismissed that evidence on the basis that the evidence of both Dr Brown and Professor Sambrook (each called by Mr Smith) "was that the aggravation of Mr Smith's hip osteoarthritis in 1997 was related to his activity in the years immediately preceding that onset." 65 It is somewhat curious that the AAT returned to consider Mr Smith's duties at Wagga given its earlier finding that the work at Wagga involved no heavy lifting and made no material contribution to the aggravation of his ailment. That curiosity is relied upon by Mr Smith to contend that by so stating, the AAT made it clear that it did not take into account Mr Smith's Commonwealth employment other than the period immediately preceding 1997 to assess the contribution made by that employment to the aggravation of Mr Smith's ailment. That submission is somewhat assisted by the fact that nowhere, in its consideration of the relationship of the employment to the aggravation of the ailment, do the AAT's reasons refer to Mr Smith's Commonwealth employment at the Forbes abattoir between 1983-1986. The evidence and the manner in which Mr Smith's case was run, confirms that Mr Smith did rely upon that earlier period. 66 Those matters do suggest that the AAT focused upon Mr Smith's employment post 1993. Taken together with the AAT's reasons at [79] and [80], I would accept that the period of employment assessed by the AAT was 1993-2008. Whilst Mr Smith contends for a narrower period, his appeal is founded on the basis that the AAT confined its assessment to a narrower period than it should have because it erroneously answered the s 7(4) question and did so prior to determining liability. 67 It is the reference in [81] to "1997", the year which (at [63]) the AAT determined to be the year that the aggravation of the ailment was notionally sustained for s 7(4) purposes, which Mr Smith relies upon to connect the content of that paragraph to the s 7(4) finding. Without that connection, Mr Smith's contention that the AAT was distracted from examining the whole period of Mr Smith's employment is hollow because the asserted distraction has no nexus to the asserted error of law. 68 In my view there is no relevant connection between the content of [81] and the s 7(4) finding. At [81], the AAT dealt with the evidence of actual (not notional) onset given by Dr Brown and Professor Sambrook. It will be recalled that Dr Brown's evidence was that the likely 1997 onset was related to duties performed by Mr Smith from 1993-1997 and not earlier. It is that evidence which the AAT is referring to when at [81] it says "Mr Smith's hip osteoarthritis in 1997 was related to his activity in the years immediately preceding that onset". Based on that evidence, the reasons at [81] suggest that the AAT came to the view that Mr Smith's duties prior to 1993 were not responsible for the aggravation. The AAT was entitled to come to that view on the evidence before it. Both Dr Brown and Professor Sambrook were called by Mr Smith and, unfortunately for Mr Smith, their evidence was not as helpful to his claim as he might have wished. 69 The fact that the AAT made the s 7(4) finding had no relevant impact on the finding made by the AAT at [81] and, in my view, no bearing upon the manner in which the AAT determined liability. 70 For those reasons, grounds 1 and 2 of Mr Smith's appeal must be dismissed. 71 Grounds 3-5 of the appeal relate to an observation made by the primary judge at [22]. His Honour there said that the appellant had not suggested that the AAT had erred in concluding that the injury should be taken to have occurred in 1997. Mr Smith contended that such a suggestion was implicitly made. However, whether or not the suggestion was made, the primary judge's observation was of no consequence to his decision to dismiss Mr Smith's application and the challenge to that observation can have no bearing on the disposition of the appeal. 72 The appeal should be dismissed with costs. I certify that the preceding thirty one (31) numbered paragraphs are a true copy of the Reasons for Judgment herein of the Honourable Justice Bromberg.