Krivan v Accident Rehabilitation and Compensation Insurance Corporation

IN THE DISTRICT COURT HELD AT WELLINGTON Decision No. 22 9 198 IN THE MATTER of The Accident Rehabilitation and Compensation Insurance Act 1992 AND IN THE MATTER of an Appeal pursuant to Section 91 of the Act BETWEEN JULANNE MARGARET KRIVAN DCA 49/97 Appellant AND ACCIDENT REHABILITATION AND COMPENSATION INSURANCE CORPORATION a body corporate duly constituted under the provisions of the said Act Respondent HEARD on the 29th September and 7th October 1998 APPEARANCES: Ms S Callanan counsel for appellant Mr D Tui counsel for respondent Mr C Eggleston counsel for Waitemata Health Ltd RESERVED JUDGMENT OF JUDGE M J BEATTIE The issue in this appeal is whether the onset of osteoarthritis in both the appellant's thumbs has occurred in circumstances which give rise to an entitlement to cover under 2 section 7 of the Act, being a gradual process injury arising from her employment as a Dental Therapist with Waitemata Health Limited. BACKGROUND The appellant is now aged 60 years. In 1958, she obtained a Dental Nurse Practising Certificate and subsequently a Diploma in Advanced Dental Nursing Studies in 1979. From 1958 to 1963 she practised as a Dental Therapist for the Department of Health in Hamilton, Palmerston and Wellington. From 1963 until 1971 she was on parental leave having her family. From 1971 until January 1995 she has again been employed as a Dental Therapist both in Wellington and latterly on the North Shore in Auckland, her last employer being the CHE known as Waitemata Health Limited. Throughout her career her work has been that of a Dental Therapist in primary schools. In February 1991 the appellant first noticed that she was getting pain in her thumbs, it being more pronounced in her right thumb. Initially, she sought relief by acupuncture. At about the time that she began experiencing this pain her work load was increased by the addition of another school in her area of practise, the work load more or less doubling. By 1993 the appellant said she was continually using anti-inflammatory ointment in order to ease the pain which was experiencing in her thumbs. The appellant believed that in addition to the particular type of work she was doing, the cause of pain was being exacerbated by the particular type of surgical glove that she was required to wear. The pain was more extreme when she was required to use that particular brand rather than when she was not wearing gloves or when she had been wearing another brand of glove, previously supplied, which was more user friendly. In June 1994 she was required to take some time off work because of the severe pain in her thumbs. It was at this time that she was first referred by her GP to Dr Stuart, Rheumatologist. Dr Stuart's report to her GP notes that she had complained of intermittent pain affecting the first CMC joints for the past three years and which had flared up in recent weeks. It was Dr Stuart's assessment that she had osteoarthritis of the first CMC joints. Dr Stuart injected her thumbs with cortisone and referred her on to have some moulded splints for her hands which could be worn when she was not operating. She was also recommended to continue with anti-inflammatory medication. In order that she be able to continue with her work tasks, the appellant was required to continue taking anti-inflammatory medication and cortisone injections but by the time of the last term of 1994 she had come to the realisation that the pain and physical discomfort was affecting her ability to carry out her duties as a Dental Therapist and she ceased her employment on health grounds on 15 January 1995. In November 1995 the appellant lodged a claim for cover under the Act. The claim form stated "RSI to thumbs caused by working 32 years as school dental nurse. Now unable to work due to osteoarthritis in thumbs from RSI". Her GP gave as the diagnosis "Osteoarthritis to right and left thumbs Occupational Overuse Syndrome." The claim was considered as a gradual process claim under section 7 of the Act and questionnaires were completed by the appellant and her employer and reports were provided by her GP and Dr Stuart. The claim was then considered by the Corporation's Branch Medical Advisor who took the view that bilateral CMC joint osteoarthritis is a condition which is a degenerative disease which occurs commonly in the general population and can therefore not be said to have arisen out of the appellant's employment as required by section 7. Her claim for cover was therefore declined. The appellant sought a review of that decision and a review hearing took place on 29 October 1996. However, at that hearing there was effectively no new medical evidence provided and the appellant appeared at this hearing without any " medical support". In her decision, the Review Officer found that the appellant had satisfied section 7(1)(a) in that the constant use of her thumbs as a Dental Therapist constituted a particular property or characteristic which caused or contributed to her arthritis. It also seems that the Review Officer accepted that the property or characteristic causing the problem was not found in her non-employment activities. However, in terms of section 7(1)(c) she ruled that the risk of contracting osteoarthritis is not significantly greater than for persons not performing her employment task, osteoarthritis being an extremely widespread condition which can be aggravated by a range of occupations involving manual work. In those-circumstances, the Review Officer upheld the Corporation's decision to decline cover. For the purposes of this appeal both the appellant and the former employer obtained leave of the Court to adduce further expert medical evidence and the Court has received reports from Mr Chris Taylor, Hand Surgeon, Dr Raoul Stuart, Rheumatologist, and it has heard evidence from two Occupational Medicine experts, Dr Evan Dryson, and Dr David Black. The Statutory Provisions which are relevant for this appeal are sections 7 and 10(2), and these states as follows: "7. Personal injury caused by gradual process, disease, or infection arising out of and in the course of employment --- (1) Personal injury shall be regarded as being caused by gradual process, disease, or infection arising out of and in the course of employment only if --- (a) In respect of a period that ended on or after the Ist day of April 1974, the employment task performed by the affected person, or the environment in which it was performed, had a particular property or characteristic which caused or contributed to that personal injury by gradual process, disease, or infection; and (6 ) The property or characteristic is not found to any material extent in the non-employment activities or environment of that person; and (c) The risk of suffering that personal injury is significantly greater for persons performing that employment task in that environment than for persons who do not perform that task in that environment." Section 10(2) of the 1992 Act: "(2) For the avoidance of doubt it is hereby declared that - (a) Personal injury caused wholly or substantially by the ageing process; and (6) Personal injury to teeth that is caused by the natural use of those teeth - is not covered by this Act." It is accepted by both counsel for the respondent and counsel for the employer that the evidence, both medical and from the appellant herself, satisfies the test required of section 7(1)(a) and that the appellant's employment tasks as a Dental Therapist did have particular properties or characteristics which contributed to her personal injury. However, the battle lines are drawn between the appellant and the respondent on one side and the former employer on the other insofar as whether or not the appellant can satisfy the requirements of section 7(1)(b) and (1)(c) and, the employer further contends that the appellant's claim is excluded from cover by the provisions of section 10(2) of the Act. It is in relation to section 10(2) that this Court heard extensive viva voce evidence from both Dr Dryson and Dr Black and, in relation to their evidence, each has referred 6 to published research on this question of osteoarthritis and in particular the distinction between Occupational Osteoarthritis and Generalised Osteoarthritis brought on by the ageing process. It is Dr Dryson's opinion that the appellant does not have Generalised Osteoarthritis and therefore the Osteoarthritis that she does have in her CMC joints has been caused by occupational factors. Dr Black on the other hand is of the opinion that whilst occupational factors have promoted the Osteoarthritis, nevertheless the appellant does have Generalised Osteoarthritis which occurs naturally with ageing in a large percentage of the population, particularly women and is not occupational in cause. These two experts agree that if the appellant has Generalised Osteoarthritis then cover would be excluded by virtue of the provisions of section 10(2) and it is axiomatic that if it be found that she does not have Generalised Osteoarthritis then section 10(2) would not apply to disentitle her. Because briefs of evidence had been exchanged between the appellant and the employer some little time prior to the hearing, the parties did as a first step to try and resolve the differences of opinion which had arisen, seek further advise from Dr Stuart, Rheumatologist, who had previously examined the appellant in 1994 and was aware of her history. Dr Stuart had also seen the appellant in November 1995. Dr Stuart's report dated 25 September 1998 to Dr Black states as follows: "I saw Mrs Krivan on 25.9.98. I have had the opportunity to read your correspondence dated 21.9.98, Dr Dryson's letter of 22.9.98, the report of Mr Chris Taylor of 25.9.97, your report to the District Court at Wellington in 1997 and that of Dr Dryson made at the same time. I have had an opportunity to review the recent blood results and the x-rays taken of hands and feet. From a purely symptomatic point of view Mrs Krivan remains troubled only by the first CMC joints of her thumbs. She does not have symptomatic joints 7 elsewhere. The pain she experiences is in general less than it used to be because of avoidance of aggravating activities and certainly retiring from her dental work made a major difference. However her enjoyment of life is significantly hampered by the need to avoid aggravating activities. Examination Once again the finding was one of squaring and some tenderness of the first CMC joints bilaterally. She found it hurtful to resist thumb movements including abduction, flexion-and extension. The joints were not notably crepitant and there was no soft tissue swelling. I found early Heberden's node formation in the index DIP joints bilaterally, a little bit more notable on the right side. Clinically osteoarthritis was not evident in any other peripheral joint sight and this was after a careful examination of all joints including in particular the toes, hips, knees. In the axial skeleton the cervical spine is mildly restricted on side flexion and rotation as I would expect to find in most women of this age. The lumbar spine on the contrary was extremely mobile. Investigation You will have copies of her blood test results which have returned a normal full blood count and ESR, alkaline phosphatase, CRP, rheumatoid factor. The anti -nuclear antibody was positive at 1:80 with a diffuse pattern of staining. I can see from my records that previous blood results have usually indicated a very low level positively of rheumatoid factor but this has been with the Med Lab. ANA has been weakly positive. There was a fairly consistent abnormality of alkaline phosphatase. The x-rays taken on this occasion confirm osteoarthritis change in the first carpometacarpal joints of thumbs with some progression obvious since the films were taken in June 1994. There is now heterotopic bone around the medical aspect of the joints. Early degenerative changes are shown in proximal interphalangeal joints and distal interphalangeal joints but I must emphasise that the changes are minimal. They are most notable in the index finger DIP joints where there are clinical findings to correlate. The feet are said to show early degenerative changes in the interphalangeal joints and I note that relatively easily in one or two joints but otherwise it is rather difficult to be conclusive. Certainly absent from both hands and feet is any evidence of an erosive synovial arthropathy. Assessment I think it can be very fairly stated that there is no evidence to support an inflammatory arthritis in this patient The absence of rheumatoid factor or any inflammatory change, the clinical findings and the radiological appearances certainly point us away from any problem in that regard. She remains clinically troubled by the osteoarthritis in her first CMC joints. Although there is minimal radiological evidence of some osteoarthritis in interphalangeal joints it is not notable on a clinical basis. The larger joints that are often afflicted by the osteoarthritis in the cases of generalised disease are notably normal and by that I mean the hips and knees. The lumbar spine is certainly free of any obvious clinical disease and I would expect that the cervical spine will reflect some change if we are bothered to x-ray. If I go through your questions in order then: 1. Given that osteoarthritis of the first carpometacarpal joints is extremely common (perhaps the most common site in women) are the findings in Mrs Krivan outside those expected in a percentage of the normal population of New Zealand women of her age? I agree that a large number of women of Mrs Krivan's age would have osteoarthritis in the thumbs and in other joints. 9 2. If so, is there documented, objective evidence of lack of, or lesser disease in other joints which would point to exceptional circumstances sin the causation of the arthritis in her CMC joints? What is very notable in Mrs Krivan's case is the fact that the osteoarthritis is markedly predominant in the first CMC joints and notably clinically absent in other joint areas although minimally evident now on x-ray in some fingers. You would have to say that this degree of clinical and radiological involvement is out of keeping with the general pattern of experience. One could take that to raise some support for the argument that her occupational activities as a dental nurse have contributed in a significant way to the causation or the promotion of osteoarthritis prematurely in her CMC joints. 3. Given that osteoarthritis is, at least to some extent, caused by normal use and wear and tear, is it your opinion that the extent of the arthritis in her CMC joints is more likely than not to have been caused by wear and tear and use of and loading of these joints above and beyond normal? I think in essence that is my opinion. 4. What is the current status of her rheumatoid serology and other serological indicators for inflammatory joint disease? I have given that above. Basically there is no evidence to indicate inflammatory joint disease or other inflammatory joint problems. 5. Can the date from blood tests be taken to either: a. reasonably exclude systemic inflammatory joint disease, or b. confirm the existence of likelihood of an underlying inflammatory condition, or 10 c. be accepted as an artefact of the tests and having no relevance at all to the condition in her CMC joint? I think that the data clearly points us away from systemic inflammatory joint disease. In my experience if those blood test results were portents of rheumatoid disease or something similar one would have expected to have seen the emergence of that at this stage. A more likely explanation is she had weakly positive serology as we do see in a small percentage of the population. I therefore think the test results have no relevance to the condition of her CMC joints. 6. The latter point (c) is particularly important in that whilst it is accepted that perhaps 30% of normal people may have weakly positive rheumatoid factors at some time, it seems to me that the sub- group of those who have both these findings and also active joint disease must be more significant. Your views on this would be helpful. I believe that issue has been covered in the previous question." I now consider in detail the evidence of Dr Dryson and Dr Black. As a preface to their evidence I note that each is well qualified in general medical terms and each has specialist qualifications in Occupational Medicinal, both being Fellows of the Australiasian of Faculty of Occupational of Medicine and both are members of the establishment known as the NZ Institute of Occupational and Environmental Medicine. Dr Dryson has conducted a clinical examination of the appellant whereas Dr Black has not. 11 Dr Dryson's Evidence 1. On examination on 16 June 1997, the appellant was found to have Osteoarthritis of the Carpometacarpal (CMC joints) and to a lessor extent at the Metacarpophalangeal (MCP) joints of the thumbs on both sides. She also had some evidence of tenderness of the forearm muscles and adverse neural tension in the median nerve. 2. Osteoarthritis is considered to be work related when it is confined to one or two joints and these joints are those which are specifically loaded in the occupation. 3. The fact that there were activities involving pressure on her thumbs in her job and that her osteoarthritis is predominantly confined to these particular joints indicates work causation. 4. Dr Stuart's report confirms the presence of significant Osteoarthritis of the CMC joints of the thumbs only. There is no clinical evidence of Osteoarthritis in any other joints including toes, hips and knees. 5. For the appellant to develop only the fourth most common joint at onset of her symptoms and who has not developed any clinical evidence of OA in any other joint of the body means that she does not have Generalised OA. 6. The presence of radiographic changes on the recent x-rays, slight as they are, in other joints of the hand and toes are no more than would be expected in someone of the appellant's present age and are not associated with any clinical symptoms of OA. 7. OA as a disease is characterised by pain and discomfort and inability to use the joints. When one looks at x-ray changes and the presence of Hebedens Nodes 12 without any such symptoms, a diagnosis of OA becomes very subtle and has little basis in reality. Many people have Hebedens nodes without any symptoms of OA. 8. The OA in the thumb joints exceeds the degree of subtle radiological changes in other joints of the hand by a factor of many times. 9. For a person to be diagnosed as having Generalised OA, Clinical OA must be present in three or more of the hands, feet, knees, hips and spine. This is the definition established by the Diagnostic and Criteria Committee of the American College of Rheumatology. 10. For the purposes of that diagnostic criteria clinical evidence of OA must be established. The criteria does not include asymptomatic OA or OA established only by radiographic change. Radiographs cannot be used to define clinical OA. 11. As the appellant has OA only in one area of the five listed, she cannot be said to have Generalised OA. Radiological evidence of OA in hands and feet does not come within the diagnostic criteria. If one considers the recent study by Dr C Cooper and others, if the appellant were to have generalised OA she ought, at present age at 60, to have clinical evidence in all five joint groups. 12. For the appellant to have developed only the fourth most common joint at onset of her symptoms and to have subsequently not developed any clinical evidence of OA in any other joint of the body establishes that she definitely does not have generalised OA. Dr Black's Evidence 13 1. In order to sustain an argument that the OA seen in the appellant is more likely to be secondary OA due to work than primary OA due to ageing, it is necessary to demonstrate that the disease be shown to be at an unusually advanced stage, or present to a greater extent than would be expected on the basis of the age of the patient, than the status of other joints. 2. An exacerbation of existing disease at a level which would be expected for the age of the patient occurring during work tasks would not be regarded as an occupational disease unless the work had an adverse effect on progression of the disorder. As a result of Dr Stuart's examination and report, the appellant must be accepted as having Generalised OA as radiologically it is shown to exist in other joints in her hands, the proximal interphalangeal joints (P.I.P)and the distal interphalangeal joints (D.I.P) of both hands and there are similar changes present in the interphalangeal joints (the toes of both feet). This evidence establishes the criteria for generalised OA as specified by the subcommittee of the American College of Rheumatology. 2 . The American College of Rheumatology Criteria for Generalised OA is characterised by the involvement of three or more joints or groups of joints, DIP and PIP joints are counted as one group each. The radiological report of Dr Benson-Cooper supports the findings of changes in those joints and that the appellant's distribution of OA meets the American College of Rheumatology Criteria. 3. The appellant has Generalised OA to an extent which is relatively common on the basis of the degenerative processes for a woman of her age. 4. It is accepted that anybody working with joints which are affected by underlying OA will notice an exacerbation of symptoms in these joints, given the manual tasks required of a dental nurse. 14 5. Work was not the primary cause of the disease and neither was it the sole cause of the progression of the disease as can be shown by the report of Dr Benson-Cooper from x-rays taken in September 1998 in comparison with those taken in June 1994. This finding of progression after retirement is consistent with the naturally expected progression with ageing of Osteoarthritis joints. 6. The primary cause of the appellant's generalised OA is age related change in combination with all activities involving her hands both at work and in daily life. Other Medical Evidence The report of Dr Benson-Cooper, Radiologist, has been referred to. His report was made for the purposes of Dr Stuart's examination and opinion and there is a report of the x-rays taken by him on 23 September 1998. It states as follows: "BOTH HANDS Comparison is made with previous radiographs dated 29/6/94 of both thumbs. Degenerative changes are shown in the IST carpometacarpal joints with progression evident when comparison is made with the films of June 1994. There is heteroptopic bone shown around the medial aspect of the joints. Elsewhere bone density and alignment is normal. Early degenerative changes are shown in the proximal interphalangeal joints and distal interphalangeal joints of both hands. There are no synovial type erosions and there is no evidence of soft tissue calcification related to the phalanges. BOTH FEET 15 Bone density and alignment is normal. The intertarsal joints have normal appearance. No abnormality is shown in the MTP joints. Early degenerative changes are evident in the interphalangeal joints. There are again no synovial type erosions. CONCLUSION: The appearances are consistent with osteoarthritis which is most pronounced at the IST CMC joint of both hands." The final report of relevance is that of Mr Taylor, Hand Surgeon, which was commissioned by the respondent. Mr Taylor carried out an examination of the appellant on 24 September 1997 and in his report to the respondent he confirmed that the appellant had bi-lateral thumb CMC joint osteoarthritis. He went on to note: "With respect to the question as to the cause of Mrs Krivan's thumb CMC joint osteoarthritis, it is my opinion that her occupation significantly contributed to the onset and deterioration of her osteoarthritis in these joints. The specific activities that she performed on a daily basis for over 30 years at her work involving forced pinch grip must have significantly contributed to the degenerative change within the basal thumb joint. In reference specifically to section 7(b), while her thumbs were used outside of the workplace, they were not used to the extent or degree that was occurring at work. She denies having made significant contributions to the house cleaning, gardening, or being involved in other sporting activities during her working life. In relation to section 7(c) the thumb CMC joint is the most commonly affected joint in the hand with osteoarthritis. This is due predominantly to its mobility and its extensive use. Any occupation that increases the force across the joint in the use of this joint must increase the risk of osteoarthritis. There is little 16 doubt that Mrs Krivan's occupation has significantly contributed to the osteoarthritis in her thumb CMC joint." SUBMISSIONS Ms Callanan, counsel for the appellant, submitted that the clinical and opinion evidence of Dr Stuart and Dr Dryson is to be preferred to that of Dr Black, and that in any event the factual basis of the extent of OA in the appellant's hands was questionable and therefore the appellant did not fall into the criteria specified by the American College of Rheumatology for Generalised OA. She further submitted that there was published material, even that relied on by Dr Black, which stated that major trauma and repetitive joint use are both risk, factors for Osteoarthritis and examples given were of ballet dancers and prize fighters. Insofar as section 7(1)(b) and 1 (c) is concerned counsel submitted that the evidence of Dr Dryson and Dr Taylor establish that the criteria of those two subsections are satisfied. Mr Tui, counsel for the respondent, submitted that the evidence of Dr Dryson and Dr Taylor satisfied the criteria necessary for section 7(1)(b) and (c). He further submitted that for the purposes of 7(1)(b) the property or characteristic must be found in the non- employment environment or activities to a material extent. In this context the word material means causative and he submits that the evidence establishes that her non- work activities, whilst of course involving use of the thumbs on a regular basis do not involve their use in the same way as are used in her employment activities and their use is not material in non-employment activity. Counsel also relies on the evidence of Dr Dryson and Mr Taylor insofar as 7(1)(c) is concerned and positively asserts that, contrary to the finding made by the Review Officer, the criteria for section 7 have been satisfied. 17 Insofar as section 10(2) is concerned counsel submits that the opinions of Mr Taylor and Dr Stuart, without even considering that of Dr Dryson, are such that the appellant's condition was caused by work tasks in her employment to a significant extent and that such a finding is inimical to finding that the appellant's personal injury was caused wholly or substantially by the ageing process. Mr Eggleston, counsel for the employer, Waitemata Health Limited, submitted that the central issue is the applicability of section 10(2) as disentitling the appellant to cover. In that regard he relies upon the evidence of Dr Black and of the fact that Dr Black's view of the criteria for Generalised OA as he stated was correct, it rather than that which was propounded by Dr Dryson and the written material which he relied on. He further submitted that age is highly significant in the development of Osteoarthritis and that the appellant has not established on balance of probabilities that age is not at the root cause of her development of OA. Counsel further submitted that although the appellant may not have shown clinical signs of OA at any other site, the fact is that x- rays of those sites were not taken so there is no evidence that she does not have underlying asymptomatic OA in those joints. Counsel accepts that it is reasonable to conclude that the degree of osteoarthritis would not have occurred if it had not been for the particular occupational activity of the appellant. However, he submits that it does not follow that osteoarthritis is occupational in origin. He submits that Dr Black's evidence should be accepted that the cause and onset of osteoarthritis is still due wholly or substantially to factors such as age and hereditary susceptibility rather than occupational trauma. Finally counsel submitted that unless the Court is satisfied that the occupational activities caused the osteoarthritis quite independently of the ageing process then cover must be denied. 18 In respect of section 7 (1)(b) and (c) counsel submitted that every day use of her thumbs support the conclusion that the property or characteristic is found to a material extent in her non-employment activities. He submits that the fact that there has been further degeneration in the CMC joints since she has given up work is evidence of that. Insofar as 7(1)(c) is concerned counsel submits that neither Dr Dryson nor Dr Taylor, who are being relied upon for support by the appellant, have stated that the risk was significantly greater. Furthermore, he submits that there is no evidence, statistical or otherwise, which links osteoarthritis-of the thumb joint to the employment of dental therapists. He submits that the evidence does not satisfy the test of 7(1)(c) on balance of probabilities. DECISION This Court notes that the respondent now supports the appellant in all facets of this appeal and without the opposition of the appellant's former employer, Waitemata Health Limited, cover for the appellant would now be accepted by the respondent. The employer's principal contention is that the appellant is simply one of a substantial body of women who at her age shows signs of osteoarthritis by virtue of degenerative changes occurring as part of the ageing process, and that she has and would have had osteoarthritis in her thumbs as an inevitability and that the most her occupational tasks have done is to promote it more swiftly than would otherwise have been the case. It is to be noted that the appellant was 53 years of age when she first identified symptoms of osteoarthritis in her thumbs and she was aged 56 years 5 months when she ceased her employment because of her inability to continue with her work as a result of the arthritic conditions in her thumbs. 19 At this point I think it is helpful to record the definition of osteoarthritis. In the August 1997 volume of the Lancet at page 503, it is stated: "A single definition of osteoarthritis remains elusive. A workshop held in 1995 proposed the following consensus definition: Osteoarthritis diseases are a result of both mechanical and biologic events that destabilise the normal coupling of degradation and synthesis of articular cartilage chondrocytes and extracellular matrix, and subchondral bone. Although they may be initiated by multiple factors, including genetic, developmental, metabolic, and traumatic, osteoarthritis diseases involve all of the tissues of the diarthrodial joint. Ultimately, osteoarthritis diseases are manifested by morphologic, biochemical, molecular, and biomechanical changes of both cells and matrix which lead to a softening, fibrillation, ulceration, loss of articular carilage, sclerosis and eburnation of subchondral bone, osteophytes, and subchondral cysts. When clinically evident, osteoarthritis diseases are characterised by joint pain, tenderness, limitation of movement, crepitus, occasional effusion, and variable degrees of inflammation without systemic effects." In the present case it is the contention of the appellant that the cause of her OA is traumatic, that is the repetitive loading that her work tasks as a Dental Therapist have placed on her thumbs over a 32 year period and which have caused a loss of the central load bearing area of Articular Hyaline Cartilage by a process of fibrillation, fissuring and fragmentation. Further on in the same Lancet article it is stated that: "Age is the strongest determinant of osteoarthritis with prevalence rates for all joints rising with increasing age. Incidence rates also arise with age but there is some evidence that this reaches a plateau in the seventh decade. The mechanism by which age predisposes to osteoarthritis is unclear. It is tempting to speculate that biochemical changes within ageing cartilage render 20 it more susceptible to damage and degradation but evidence to support this is lacking. Women are at a higher risk of developing osteoarthritis than men, particular after menopause." As has been noted the appellant began experiencing clinical signs of osteoarthritis at age 53, after some 30 odd years of working as a dental therapist and during the last few years working under an ever increasing load. The initial diagnosis by Dr Stuart in July 1994, confirmed by x-rays, showed osteoarthritis changes affecting the first CMC joints. At that time she was not displaying any signs of osteoarthritis in any other joints. This fact was confirmed when Dr Stuart examined her again in November 1995 where he said "She has not developed any symptoms of arthritis elsewhere". When she was examined by Dr Dryson in June 1997 he similarly diagnosed osteoarthritis at the first CMC joints in both thumbs. This caused Dr Dryson to advise that osteoarthritis can be considered to be work related when it is confined to one or two joints and these joints are those which are specially loaded in the occupation. In the appellant's case he found that because there were activities involving pressure on her thumbs in her employment and that her osteoarthritis was predominantly confined to those particular joints, it indicated work causation. He discounted Generalised Osteoarthritis. When Dr Stuart examined the appellant in September 1998 he noted that clinical osteoarthritis was not evident in any other peripheral joint sites and this was after a careful examination of all joints including in particular the toes, hips and knees. It is noted that Dr Black accepts that osteoarthritis can be secondary arthritis due to work rather than primary arthritis due to ageing, but for the former to be accepted it would have to be demonstrated that the disease is shown to be at an unusually advanced stage than would be expected on the basis of the age of the patient and the status of other joints. 21 The age of the patient when she developed osteoarthritis was 53 and if one accepts the evidence produced by Dr Dryson, being the study of Dr Cooper and others into Generalised Osteoarthritis in women set out in the Journal of Rheumatology 1996 where it says that that group's findings were that osteoarthritis in the CMC joints was only the fourth most common site in women at aged 53. Further, that same journal indicated that by the time of age 60 Generalised Osteoarthritis would be said to have been evident in all five joint groups. According to Dr Stuart the appellant cannot be said to have osteoarthritis in all five joint groups, be it as a result of radiological examination or clinical examination.- This leads on to the central area of difference which causes a divergence of opinion between Dr Black and Dr Dryson. This difference being what precisely is the accepted criteria as laid down by the American College of Rheumatology for the classification of Generalised Osteoarthritis. It could even be refined further to ask whether in fact that body has yet propounded a criteria rather than simply proposed one. Both Dr Dryson and Dr Black have stated that they have applied the criteria for the determination of whether Osteoarthritis can be said to be generalised or not from that which the American College of Rheumatology promulgated through its Diagnostic and Criteria Committee. In a paper published in 1991 Dr Altman, who was a member of that Criteria Committee, stated that the "American College of Rheumatology's proposed sub-classification determined that idiopathic Generalised OA was established if it could be clinically found in three or more of six sites namely hands, feet, knee, hip, spine or other single sites such as shoulder, ankle, wrist. That classification appears to have been widely accepted and is referred to in an article published in the Lancet of August 1997 where a major paper on Osteoarthritis is reproduced and the authors of that seminar refer to that classification criteria developed by the American College of Rheumatology. 22 Dr Black bases his opinion on a passage contained in the text book Harrison's Text Book of Internal Medicine and the section authored by Kenneth D Brandt, who was also a member of that same classification committee. Dr Brandt in Harrison states: 'Generalised OA is characterised by involvement of three or more joints or groups of joints (distal interphalangeal and proximal interphalangeal joints are counted as one group each.) " It is accepted that Harrison is an authoritative medical text. Dr Black's opinion that the appellant does have Generalised Osteoarthritis is based on the report of Dr Stuart of September 1998 where, in addition to Osteoarthritis in the CMC joints, he stated there was radiological evidence of degenerative changes in the proximal interphalangeal and distal interphalangeal joints. Even though Dr Stuart said that the change was minimal, Dr Black said nevertheless, OA was present and therefore the test of three or more groups was met. Dr Dryson on the other hand contends that the test requires joints of the hands to be regarded as one group and that all that a finding of osteoarthritis in several joints of the hands establishes is that indeed the person does have osteoarthritis of the hands. He said that the situation could not be that a person has Generalised Osteoarthritis in their body on the basis of having three joints in the hand affected. On a closer examination of the text of Harrison it is this Court's assessment that the passage relied on by Dr Black is in fact only a passage that pertains to the interphalangeal joints, as the statement of generalised OA is under the paragraph so entitled. Thereafter in the text the author considers OA in the thumb base, the hip, the knee and the spine. One would have thought that if the statement of Generalised OA was applicable to the whole body then that statement would occur at the end of the discussion of the individual joint sites such as it has been done in the way the 23 American College of Rheumatology Criteria has been set out in other publications, and as it has been similarly identified in the Lancet article. Thus, this Court has some doubt that the text relied on by Dr Black is describing Generalised OA in the body as opposed to Generalised OA in the hands. In addition, however, I find an important feature of the appellant's condition is that when she was examined by Dr Stuart in 1994, that is at the time when the appellant contends she was suffering her personal injury by way of gradual process, the x-rays that were taken at that time showed osteoarthritis only at the first CMC joints. When the appellant was seen in November 1995, that is after she had ceased employment because of her arthritis, he stated that she had not developed any symptoms of arthritis elsewhere. He went on to say "This is reassuring". This appellant is contending that she has suffered a gradual process injury and had done so by at the very latest January 1995, but for all intents and purposes that injury had been suffered earlier and it is that injury for which she is seeking cover. In those circumstances, I find that this Court is required to look at her physical situation as at that time and to look at the matter from that stand point and apply the criteria which the experts have said give the indication of whether the OA can be said to be generalised or not. If that be the case then the appellant had not developed any symptoms of arthritis in her distal or proximal interphalangeal joints. There was radiographic and clinical evidence to the contrary. Thus by whichever criteria the Court were to adopt, be it that relied on by Dr Dryson, or that relied on by Dr Black, the appellant could not be said to have Generalised Osteoarthritis, even though she was of an age when such a condition might have been beginning to manifest itself. It follows from that, that the contention of Dr Dryson supported as it is by Dr Stuart that it was the appellant's occupational activities as a Dental Therapist which have 24 caused the onset of OA in her CMC joints, which is claimed to be the location of the personal injury. In addition to that finding, I note that Dr Stuart states: "The larger joints that are often afflicted by osteoarthritis in the cases of generalised disease are notably normal and by that I mean hips and the knees." This I find is further support for the opinion of Dr Dryson and, I find that his opinion prevails in this particular case. I find on balance that this appellant does not have and did not have Generalised OA at the material time. Accordingly then, I rule that the provisions of section 10(2) do not apply to exclude the appellant's entitlement under the Act. It is now necessary to consider section 7(1)(b) and 7(1)(c). The appellant's evidence was that there was nothing in her non-work activities which required the same use or pressure on her thumbs as her employment tasks as a Dental Nurse. She advised that she did not play any sport, did not knit and had done little sewing in the past 25 years. She employed somebody to do her house work while she was working and preparation of meals was kept to minimum as she and her husband ate out regularly. Both Dr Dryson and Mr Taylor were firmly of the opinion that there were no activities carried on by the appellant in a non-work environment which would have her using her thumbs to the same intensity or degree as carrying out her dental therapy tasks. This Court has previously held that the word material in section 7(b) means causative and I find there is no evidence, medical or otherwise, which establishes that any non- employment activities of the appellant were causative. 25 Insofar as section 7(1)(c) is concerned, Dr Dryson stated that the employment tasks which the appellant was required to carry out and which he listed, he said were unique to dental practise and constituted and increased risk to thumb joint injury compared with persons not doing those tasks. It was his opinion that the criteria for section 7(1)(c) had been met. Mr Taylor stated that "Any occupation that increases the force across the CMC joint must increase the risk of osteoarthritis". He was of the opinion that her occupation had significantly contributed to her osteoarthritis in her thumbs CMC joints. Dr Black was of the opinion that there was no more increased risk than for normal persons not exposed to the appellant's employment tasks or environment but he did state "I think her current condition results from a combination of a predisposition caused by genetic factors and her age and the way in which she has used her hands in her work and elsewhere". He went on to state "The individual factors such as genetics, an individual factor in Mrs Krivan's make-up must be the predominant factor or else all dental nurses of her age would have the same condition. Now we have no evidence that they do have therefore it must be more related to her make-up so that activities at work are much less significant then her make-up". He then stated that work activities would the greater contributor. In answer to a question from the Court he stated "We don't have evidence that this happens to most dental nurses but we do have some persuasive evidence that it has happened to her. The variable there must be her make-up unless there is something about her tasks as a dental nurse which are different to others and in favour of that argument is the findings of at least the existence of similar or the same pathology elsewhere in her body, admittedly much less progressed". In that I find that Dr Black is accepting that if the appellant were to be predisposed to osteoarthritis then the work task as it applied to her would have a greater risk of establishing or creating osteoarthritis. 26 Section 7(1)(c) is seeking to identify risk of injury from employment tasks as opposed to the risk of injury from general life experience outside the particular identified employment tasks or environment which have caused the injury. In those circumstances, I find that it is valid to identify the particular employment tasks which are said to have caused or contributed to the injury and then look and see whether that injury is just as likely to be suffered by somebody outside the employment environment not performing those employment tasks. Imputed into that equation must be placed the principle that you must take your victim as you find him/her. This means that any predisposition or suseeptibility to a particular injury from a particular employment task is going to establish a greater risk in the particular circumstances than would apply to the general populous not performing that employment task and not having the same susceptibility. If one applies that consideration to the facts of this case and in particular the opinions which have been expressed by Mr Taylor, Dr Dryson and Dr Black, I find that the risk of personal injury is significantly greater to sustain occupational osteoarthritis from the employment tasks required of a dental therapist, particularly one who may have a predisposition or susceptibility, then for the general populous of sustaining that same injury even though they do not perform any of the tasks of a dental therapist. In regard to the test for section 7(1)(c) I find in the particular circumstances of this case, where the particular employment tasks are specific and demanding on her CMC joints, the fact that they have satisfied the test of section 7(1)(a) can be relevant for the test of section 7(1)(c) where the tasks are of sufficient particularity and are not tasks which are normally done by persons who are not dental therapist. The particular tasks themselves I find therefore can establish the significantly greater risk, thereby satisfying the test of section 7(1)(c). For the foregoing reasons therefore, I find that the appellant has satisfied the tests required of her under section 7(1)(a)(b) and (c) and is entitled to cover in respect of 27 her personal injury suffered by gradual process between 1991 and 1995. The decision of the Review Officer is accordingly revoked. As earlier noted, this was an appeal where the Corporation itself had come to the view that the appellant was entitled to cover and would have accepted her claim were it not for the contention of the former employer that the appellant was not so entitled. In those circumstances, I find that this is a case where the appellant is entitled to costs from the former employer. This appeal occupied two days of hearing and required the appellant to engage counsel and obtain expert evidence to support her claim. In the circumstances, I find that a larger figure for costs is warranted than is the normal tariff in appeals to this Court. At the same time, this Court does have regard to the normal tariff that applies. Accordingly, I fix costs in favour of the appellant payable by Waitemata Health Limited in the sum of $2,500.00 together with the costs of any medical reports and the attendance of Dr Dryson, at the hearing. DATED at WELLINGTON this day of November 1998 ithe' M J Beattie District Court Judge Krivan.doc(gm)