Chapman v Accident Compensation Corporation

IN THE DISTRICT COURT AT NELSON [2016] NZACC 189 ACR 568/12 UNDER THE ACCIDENT COMPENSATION ACT 2001 IN THE MATTER OF AN APPEAL UNDER SECTION 149 OF THE ACT BETWEEN GLENN CHAPMAN Appellant AND ACCIDENT COMPENSATION CORPORATION Respondent Hearing: 14 March 2016 Appearances: I Duncan for the appellant T G H Smith for the respondent Judgment: 12 July 2016 ____________________________________________________________________ RESERVED JUDGMENT OF JUDGE A N MACLEAN ____________________________________________________________________ [1] I heard oral submissions on this matter at Nelson on 14 March. The respondent had filed detailed written submissions and Mr Smith spoke to those. Apart from lengthy submissions on the issue of suppression, which I recognised as a standard format employed by Mr Duncan in other appeals before me, there were no detailed written submissions filed for the appellant other than identifying the issue namely : “whether the reviewer was correct in upholding ACC’s decision to decline cover and entitlements to the appellant’s knee injuries” and the observation that “the issues at appeal are largely same as those raised at the review hearing and are contained in the review submissions and the review transcript. [2] Although Mr Duncan presented wide-ranging oral submissions, because I had not had the opportunity at that stage to read the very full common bundle of documents tabled, including the transcript of the relevant review hearing, and, due to time constraints, after hearing from Mr Smith, I offered Mr Duncan the opportunity to make any appropriate rebuttal submissions and this was to be done by 24 March. [3] The Registry contacted Mr Duncan to remind him of the timeframe and received an indication on 24 March that they would be forthcoming but not until the following week. A further reminder was made by the Registry in late April and an indication received that they would be filed imminently. The Registry advise me that to date nothing has been received. In the circumstances, having now had the opportunity to carefully go through the bundle of documents including the review transcript and decision, I am left in a situation where in the interests of finality, I feel able to give appropriate consideration to the views of both parties and deliver judgment. [4] The issue in this appeal arises in the context of a gradual process work related injury claim. That means that s 30 of the Act is applicable and in particular the three step test under s 30(2) requiring an appellant to establish:  The employment task or tasks under scrutiny must have a particular causative property or characteristic.  The particular property or characteristic is not materially found in the person’s non employment activities and  Persons performing the particular employment task are known to be at significantly greater risk of suffering the injury in question. [5] In this case the injury in question is osteoarthritis to both knees against a background of a range of demanding physical activity going back to about 1977 when the appellant started work with the New Zealand Forestry Service. By the time a gradual process claim was filed in December 2011, the appellant, then aged 54, had a long claim history of nearly 40 injuries commencing in 1987 and including many sprain injuries to various parts of the body including the knees. More latterly, covered twisting knee injuries in March 2010 and May 2011. Those latter injuries will be discussed in more detail. [6] Activity tasks including planting, pruning and thinning of trees, a short period with the Conservation Department maintaining huts, clearing walking tracks and making bridges, 14 years or so of shearing work with logging work in the off season, logging work for about 11 years 1998 to 2009 then latterly dairy farm work from approximately June 2009 until recent times. [7] The appellant’s general submission is that the totality of that heavy physical activity underlies the claim, reinforced by an opinion from Mr Johnson, a physiotherapist with a working knowledge of the New Zealand Forestry sector, which the appellant submits should be the primary focus of attention. [8] The submission for the appellant is, that the undisputed knee osteoarthritis from which he suffers is strongly causally linked with that activity and which, particularly, with reference to the forestry aspect, carries an increased risk and causal link in terms of two of the three tests under s 30. It is common ground that non employment activity has no bearing on the issues in this case. [9] The respondent’s position is, that Mr Johnson’s opinion when weighed against medical evidence from Drs Strack, Obele, Walker and Hilliard does not meet a threshold of proof. [10] A brief summary of events and observations leading up to the lodging of the gradual process claim in December 2011 is :  1977 the appellant starts work with the NZ Forest Service.  23 March 2010 the appellant injured his right knee walking down a step and turning. Cover was initially accepted by the respondent.  17 May 2010 an MRI of the right knee noted a small effusion, chondral irregularity and fissuring over the weightbearing surface of the medial femoral condyle with some mild subchondral marrow signal change, fissuring of the subchondral bone marrow signal change posterior lateral tibial plateau, slight chondral irregularity of the apex of the patella, no meniscal abnormality concluding “areas of chondromalacia, evidence of previous MCL strain”.  28 May 2010 Mr Meighan, orthopaedic surgeon in a letter to the appellant’s GP after the MRI noted: This has shown some damage in the articular cartilage of the medial femoral condyle and features consistent with a sprain in the medial collateral ligament. I have discussed this with him. There is no surgical treatment here. I have not arranged for routine review.  27 May 2011 whilst recovering from a shoulder operation the appellant turned on his right knee and reinjured it. Although cover was initially provided on 5 November 2011, the respondent declined a funding application for an arthroscopy and medial meniscectomy which was upheld at review.  On 15 November 2011, in a post operation report, Mr Wilson noted that in the course of the arthroscopy he carried out there was no effusion but the knee joint itself had fluid debris particularly through the suprapatellar pouch. There was a minor change over the distal pole of the patella and in the medial compartment significant weightbearing articular cartilage damage over an extensive portion of the femoral condyle and reciprocal change over the tibial surface centrally and intact meniscus. He debrided a minor insertional tear posterior horn and his final diagnosis was “predominantly medial compartment changes indicating imminent medial compartment failure”. He concluded with a recommendation that “a high tibial osteotomy would be appropriate.  17 November 2011 the respondent advised the appellant that it had reconsidered its decision to accept a claim for the 23 March 2010 accident. It seems that while decision was not reviewed, it appears to have been then the catalyst for the appellant’s issues to be addressed through a gradual process work related injury claim, which was lodged on 5 December 2011 with an injury diagnosis recorded as “acute meniscal tear, medial right and sprain knee/leg left – suspected gradual process degenerative changes both knees”.  Through December 2011 three separate questionnaires were completed including an employer questionnaire referring to the appellant’s occupation as a dairy farm worker and work injury details as “twisting in shed heavy work load. Climbing in and out of machines with an employment commencement date of 29 June 2009”. Dr Henry completed a medical practitioner questionnaire recording a diagnosis of “degenerative changes both knees” with a cause “many years heavy work forestry and farming” and a first consultation date of 31 March 2000. He referred back to the arthroscopy mentioned earlier referring to “meniscal tear – scan arthroscopy shows degenerative change”. A cover questionnaire completed by the appellant referred back to 27 May 2011 “sudden pain in right knee – turning and twisting”. The work tasks were described as “milking, fencing, tractor work, weed grabbing, general farm work, hill work, calves, stock work” with an average of 8 to 11 hours per day over the prior two and a half years. There was also reference back to the working history over the previous five years including “bell operator – logging, forestry – logging” with a further note “most of my earlier work was in forestry which was very physical work and often placed stress on my knees”. [11] The matter was referred by the respondent to Dr Strack, a specialist occupational physician and in a detailed report of 18 May 2012, after referring to the history supplied to him and other information, referred to medical literature and general epidemiological evidence as to industry risk factors and the linkage between the described work tasks and environment, to the osteoarthritis in particular the right knee. [12] Key extracts from that include the following:  Whilst the appellant was unable to recall clearly the actual dates of the onsets of his problems predominantly right knee: It appears that on or about the 23rd of March 2010 he was walking down concrete steps into a cow shed pit. … as he was walking down he got to the bottom and turned. He was uncertain whether he turned to the left or right. There was no fall or slip that he could recall but there was a sudden onset of pain in the right knee … a sprained knee was apparently diagnosed. He had a week off work and then was able to return to work without any specific treatment. From here the right knee seemed to improve but did not entirely resolve. It improved enough for him to be able to continue with his work although he occasionally experienced flareups of symptoms.  He also noted the further injury in 2011 whilst recovering from a shoulder operation: He walked outside his house and then stopped. He then turned while standing on his right leg and heard a crack coming from his knee. He experienced significant pain about the right knee which lasted for about 30 minutes … he saw his orthopaedic surgeon a week or so later when he went to have his shoulder reviewed post operatively. At this stage the right knee was clicking when he worked. A diagnosis of meniscal cartilage tear was made on or about 20 July 2011.  He noted the operative outcome from the notes of Mr Wilson and that a high tibial osteotomy was proposed. He noted: Post operatively Mr Chapman feels that his right knee has improved but is not totally fixed. He still experiences some aching of the right knee.  He noted ACC records have shown previous right knee problems in or about 1988 and 1993. But with no history of major left knee problems.  He traversed the previous work history as noted earlier and specifically with regard to logging work said: Logging work from 1998 through to about 2009 (approximately). The logging work involved driving of machinery as well as cutting trees with chainsaws. Mr Chapman was also involved in breaking logs out once they were cut. This would involve taking hitching chains and putting them onto the logs for a hauler. He could be accessing very steep hills when working on this. There would be some crouching and kneeling when cutting trees, and on occasions when making a hole for a chain to go around a log. He notes there was a lot of slipping and sliding in wet conditions. There was a lot of walking about and this could be on slopes.  He summarised the matter this way: There was some palpable grating of the right patella on movement of the right knee. There was a modest effusion of the right knee and modest wasting of the right quadriceps muscle. The left knee showed no obvious abnormality.  After reviewing the material available to him including orthopaedic reports, medical practitioner notes, x-rays and operation notes he expressed the following opinion: I believe the most likely explanation of Mr Chapman’s medial compartment articular cartilage abnormalities is likely to be that of early osteoarthritis. I note the x-ray of 2 June 2011 identified minor osteoarthritis present in the medial and patellofemoral joint. The MRI of 17 May 2010 identified chondral irregularity and fissuring over the weightbearing surface of the medial femoral condyle with some subchondral bone marrow signal change. … there was mild thickening of the proximal fibres of the medial collateral ligament and it was felt this was consistent with previous medial collateral ligament stain. Although the MRI has identified changes consistent with previous medial collateral ligament strain the extent to which the relatively innocuous incident of about 31 March 2010 has contributed that this is in my opinion uncertain. … I do note that at the time of the subsequent review (Mr Wilson, 2 June 2011) there was no discomfort with varus or valgus stress testing of the right knee. This would suggest that medial collateral ligament injury was not contributing to the symptoms at that stage. I believe the more likely explanation of these changes is that of early osteoarthritis affecting the right knee joint. I am not of the opinion that the simple relatively traumatic incident described would have caused reasonably extensive medial compartment (and to a lesser extent lateral compartment) articular cartilage changes. I suspect that the initial incident described in or about March 2010 may represent a triggering of symptoms in a predisposed knee with a pre-existing osteoarthritic change. You ask regarding the causal factors and their relative significance – primary osteoarthritis is characterised by destruction of the articular cartilage with subsequent alterations of the subchondral and surrounding bone. Whilst there has been much research into this area our understanding of what initiates osteoarthritis is limited as is our understanding of the natural history of osteoarthritis. It is important to note that factors that may be associated with progression of osteoarthritis are not necessarily the factors which have initiated or caused the disease. There are a number of biochemical and biomechanical factors that are linked to osteoarthritis and the aetiology of osteoarthritis is presumed to be multifactorial. (he referred there to an article Gregory D et al Management of Elbow Osteoarthritis – The Journal of Bone and Joint Surgery 2006). Factors which have been considered by various authors as being important aetiological factors with respect to osteoarthritis include genetics, ethnicity, aging, bone mineral density, joint loading, joint malalignment and obesity. Although aging and repetitive microtrauma have been shown to alter articular cartilage, normal joint use has not been found to induce degeneration, and the changes in osteoarthritic cartilage do not reflect the changes in normal aging cartilage. Development of osteoarthritis following an injury can be difficult to predict and depends on many factors including the nature of the injury or fracture as well as the continuity of the articular surface of the joint following the surgery. Development of work related osteoarthritis is even more difficult to ascertain with any certainty. [13] Dr Strack then referred to a study (Maetzel et al) – An Analysis of 123 Original Studies on Risk Factors for Osteoarthritis. J Rheumatol 1997 which concluded: There was a consistently positive but small relationship between work involving knee bending and osteoarthritis of the knees in men. There was a consistently positive but weak relationship between work related exposure (particularly farming) and hip osteoarthritis in men. [14] Dr Strack further noted: Osteoarthritis is a multifactorial condition. Age is perhaps the most important risk factor with respect to osteoarthritis with radiological evidence of osteoarthritis becoming extremely frequent with increasing age. … a range of other risk factors have been identified for osteoarthritis. In Mr Chapman’s case I note that a degree of genuvarum deformity has been identified by his treating orthopaedic surgeon (Mr Wilson’s report of 20 July 2011). Genuvarum is a condition which can be associated with osteoarthritis of the knee. It is felt that patients with genuvarum malalignment may develop severe medial compartment osteoarthritis. The treatment often proposed for this is high tibial (inaudible). The presence of genuvarum may have contributed to Mr Chapman’s right knee osteoarthritis. There is epidemiological evidence that certain occupations may place individuals at a greater risk of developing osteoarthritis, however much of the epidemiology in relation to this is either poor or lacking. A recent study by Holmberg et al “Is there an Increased Risk of Knee Osteoarthritis Amongst Farmer – Int Arch Occup Environ Health 2004” questioned subjects who had x-ray verified osteoarthritis of the femorotibial joints and controls … the authors concluded that men who work for 11 to 30 years in the building of construction industry had 3.7 times increased risk of knee osteoarthritis … farm work was not related to an increased risk of osteoarthritis of the knee for men … no increased risk for osteoarthritis of the knee was identified in forestry workers … excess weight hereditary and previous knee injuries were strong risk factors. The overall conclusion is that:  Work in the building and construction industry is associated with increased risk of osteoarthritis of the knees.  Farming work, forestry work … are not at increased risk of developing osteoarthritis of the knees.  A study by Jensen L K (2008 knee osteoarthritis influence of work involving heavy lifting, kneeling, climbing stairs or ladders of kneeling/squatting combined with heavy lifting (Occup Environ Med 2008 265) looked at epidemiological studies that had investigated the relationship between knee osteoarthritis and heavy lifting, kneeling and climbing of stairs … conclusions included:  There is moderate evidence for a relationship between kneeling, heavy lifting and knee osteoarthritis. The association for kneeling, squatting and heavy lifting appear to be stronger but only a few studies specifically looked at this relationship.  The evidence in relation to knee osteoarthritis and climbing of stairs or ladders is limited. Few studies have looked into this and dose response relationship has not been investigated  . I believe the study by Holmberg … is relevant as it has specifically looked at farm workers and forestry workers. These appear to be the primary vocational activities Mr Chapman has undertaken over the years. Looking at the overall picture I am not convinced that there is any clear epidemiological evidence that would indicate Mr Chapman is necessarily at significantly increased risk of developing osteoarthritis of the knee when compared with those who do not undertake this type of work. I suspect that his right knee problems are probably more likely related to age related degenerative changes. The presence of genovarum may also have contributed to these changes. [15] After commenting on the fact that Mr Chapman had been a previous smoker and studies looking into this had actually concluded that smoking may have a modest protective effect against development of osteoarthritis of the knee, he observed that osteoarthritis of the knee is associated with increased body mass index but that also appeared not to be relevant, as Mr Chapman was not significantly overweight. He also opined that the right knee problems being exhibited were not caused by any specific event and even if the incident on March 2010 in the cowshed was looked at there was no significant force involved and no slip or blow. He regarded that as a “relatively innocuous incident” which “represents the triggering of symptoms in a predisposed knee”. [16] Dr Strack then turned to the question of whether the work tasks of the appellant or his work environment had a particular property or characteristic that has caused or contributed to the right knee osteoarthritis and concluded: I believe the answer to this is probably no, not to any significant extent. Mr Chapman’s work over the years has primarily involved forestry and farming type activities. As previously discussed, the epidemiology in relation to osteoarthritis of the knee and work is poor. I believe that there is epidemiological evidence that would suggest that forestry workers and farm workers are not likely to be at increased risk of developing osteoarthritis of the knee. As previously discussed however the epidemiology in relation to osteoarthritis of the knee and work is imperfect. On assessing the information that is currently available, I am not of the opinion that Mr Chapman’s work has specific characteristics or properties that are likely to have significantly contributed to the osteoarthritis of his right knee. I am not of the opinion that Mr Chapman and his work as a farm worker or forestry worker (in the absence of significant acute injury) is at significantly greater risk of developing osteoarthritis of the right knee than those who do not undertake this type of work. [17] Dr Strack’s opinion was followed up by the Branch Medical Advisor Dr Obele who on 23 May 2012 commented: The cause of osteoarthritis (OA) for a given individual is generally not well understood. It may be primary occurring in the absence of any pre-existing recognised joint incongruity or instability or may be secondary when such pre-existing factors are present (e.g. congenital abnormalities, joint disease, or joint injury). From Apley (Apley’s System or Orthopaedic and Fractures Solomon L ed 8th edition London 1 – the most obvious thing about OA is that it increases in frequency with age. This does not mean that OA is simply an expression of senescence … perhaps primary, generalised factors (genetic, metabolic or endocrine) alter the physical properties of cartilage and thereby determine who is likely to develop OA while secondary factors such as anatomical defects or trauma specify when and where it will occur … The case for OA having an occupational basis is weak. There is weak evidence that cleaners, construction workers, farmers, firefighters and floor layers may be at significantly greater risk of OA of the knee but the studies are limited by methodological issues such as confounding, reporting bias, selection bias, recall bias. The best evidence of any relationship probably comes from the Framingham study … the results show that men whose job required knee bending in at least medium physical demands had higher rates of later knee OA seen on x-rays than men whose job required neither …however it must be noted that the x- ray changes noted were only osteophytes and not cartilage loss. … however the study did not identify any occupational physical demands as being a risk factor for symptomatic or disabling knee disease … in terms of applying s 30 criteria for Mr Chapman who is forestry and farming worker I would have thought that significantly greater risk implies the presence of at least moderate strength, supportive evidence based on medical studies rather than weak evidence to support a claim. Regardless of the strength of such studies Mr Chapman’s forestry and farming duties would have been varied and his exposure to knee bending cannot be considered to be significantly similar in terms of intensity to that of carpet and floor layers and the like. There is no doubt that forestry and farming work is very heavy work, with a lot of heavy lifting, carrying and physically intensive work. Mr Chapman would have had some knee bending and kneeling but this would have been interspersed with other tasks. Consequently in my opinion Mr Chapman’s work is not contributed to the cause of his right knee osteoarthritis or placed him at significantly greater risk of developing knee osteoarthritis. It is also unlikely that his work tasks or work environment placed Mr Chapman at significantly greater risk of developing this condition compared with other persons not performing these work tasks or not employed in this work environment. [18] On 31 May 2012 Dr Walker, a specialist in occupational and environment medicine reviewed the opinions of Drs Strack and Obele and their highlighting of relevant literature. Essentially he agreed with their views noting that: Osteoarthritis is a chronic degenerative disease that starts in the cartilage and diagnostic features include joint space narrowing, increased bone formation around the joint (subchondral sclerosis) cyst formation and osteophytes. And: In consideration of our client I note that the client’s work history is outlined in Dr Strack’s report … I do not think that such work place exposure would have entailed exceptional amounts of knee bending or knee demands in order to mount an exceptional case for work place causation. I also note the client’s condition of genuvarum (bow-leggedness) which would have loaded the medial component of the client’s knees and this would be consistent with the client’s OA which was predominantly in the medial compartment. It is also important to note that knee OA is a very common condition. There is nothing unusual about a person of about 50 years having knee OA without obvious cause. I note knee OA prevalence is quoted as affecting 28% of the population over age 45 and 37% of the population over age 60 years (he cited reference to articles in J Rheumataol) in support of this. [19] He concluded in summary: It is doubtful that the client’s work task has contributed to the cause of his knee OA and there is no good evidence to indicate that the client’s work history involved an exposure that placed him at significantly greater risk of developing knee OA compared to those not faced with such exposures. Hence in my view neither the cause nor risk criteria of section 30 are satisfied. [20] Accordingly, on 1 June 2012 the respondent advised the appellant that the claim had been declined because: There is no work task or factor in your work environment that can be identified as having caused your condition – the work you do and/or your work environment is not recognised as placing workers at significantly greater risk of developing your medical condition. [21] On 23 July 2012, in a letter to the appellant’s advocate, Mr Johnson an occupational therapist set out a contrary view. Extracts from that include the following: It is clear that Glen has sustained multiple injuries to his knees over his working life. The ACC records show five injuries since 1998 but from talking with Glen it is clear that he sustained a significantly greater number of knocks to his knees during his years doing silviculture forestry work, sheep shearing, logging and farming. Glen advises that Mr Rick Wilson has told him he will need further surgery to his right knee and that he will do well if he can last six months without the surgery. Glen advises that he also has problems with his left knee but this is not as bad as the right. [22] Mr Johnson then set out a very detailed “task analysis”. He described how there are three distinct areas of silviculture namely planting, pruning and thinning. Also two types of pruning – first lift and second lift. He described in detail his perception of the various work tasks based on a visit to silviculture locations on many occasions which he summed up as: Every time I have gained the picture that the work is very physically demanding due to steep slopes highly over grown areas where the workers have to use a chainsaw to cut themselves a path through gorse or use a ladder to climb over the gorse to get to each tree. Workers repetitively trip over the rough ground and so knocks to the body happen multiple times on a daily basis.  He described a: Work culture where there is a lot of mana to be gained from being the fastest worker, the one who can plant, prune or cut down the most trees in a day. Added to this is that workers are paid solely on the number of trees they work on each day. So workers race each other over the work day”.  When describing planting, he noted that: Planters carry large bags of trees which weigh 30 plus kgs. They work over the hills and plant the trees. The ground is often hard and stony so they have to use a lot of force to drive the shovel into the ground … they are in a stooped position for a lot of the day … over each day Glen would walk for many kilometres on the rough terrain. All aspects of the work required repetitive bending at the knees. Tripping and slipping … was very common.  He described a similar slipping and tripping issue with the Department of Conservation work and with respect to shearing that: Involves repetitive bending and shearing … repetitive bending at the knees with this work.  With respect to the logging work he described “repetitive bending” when felling, constantly bending and kneeling when breaking up. [23] Mr Johnson in a “biochemical summary” noted: Glen has undertaken very physically demanding jobs all of his working life. When doing logging and silviculture work he has been on slippery hillsides for long periods. This work has involved: Repetitive deep knee bending. Repetitive kneeling. Respectively slipping and sliding. Repetitive jumping. Repetitive climbing and clambering over objects. Moving quickly over obstacles in steep, slippery areas. A lot of walking in rough conditions.  He concluded: Having been into the bush on many occasions with silvicultural cress and logging crews. I personally find it very hard to believe that the study that Dr Christopher Strack “showing no increased risk of knee osteoarthritis for forestry workers” would reflect the extreme conditions of New Zealand forestry workers. For such a study to be relevant in this case it would have to reflect the unique work tasks and working condition of New Zealand silviculture industry. I would also be very surprised if ACC and other agencies involved in assessing occupational hazards in silviculture have not already collected data which confirms the biomedical risks inherent in New Zealand silviculture – including the increased risk of knee injury. Indeed it is my understanding that the ACC levy for workers in silviculture is higher than almost any other occupation in New Zealand. In that way it would seem that ACC has already acknowledged the risks inherent in a New Zealand forest are greater than other work. [24] That report was referred to Dr Andrew Hilliard, Branch Medical Advisor who on 26 July 2012 in a file review noted amongst other things: I have reviewed BMA comment from Dr Obele and comment from the director of Workwise. Dr Strack’s report is comprehensive, well referenced and with appropriate evidence in the medical literature. It reflects the current consensus in the literature with respect to the work causation of degenerative knee disease. Given the nature of my role for the WRGPI team I am very familiar with the evidence and the literature with respect to the work-relatedness of degenerative knee disease and like Dr Strack I am not familiar with any relevant evidence indicating individuals undertaking the client’s type of work are at increased risk of developing degenerative knee disease. A report from Mr Johnson, an occupational therapist … has been reviewed. It is not clear from Mr Johnson’s report whether he has actually visited the client’s specific work or whether the conclusions of the report are based solely on the client’s self reported exposures, work types and tasks. There is evidence in the occupational medicine literature that self reported exposures can be biased. Although the report comprehensively details the client’s reported work tasks this information was already on file and was available to Dr Strack. Occupational therapists do not undertake any specific training with respect to causation or work-relatedness of disease, where this is an integral part of the training and ongoing work of occupational physicians. Mr Johnson has not provided any evidence with respect to the work- relatedness of knee problems whereas Dr Strack has demonstrated that he is aware of the evidence base for degenerative disease of the knee. Although Mr Johnson’s opinion is to be respected, he has provided no indication that this is based on evidence from the literature and clearly in this case Dr Strack’s conclusions must be preferred over those of Mr Johnson as he is a specialist in occupational medicine with huge experience in assessing WRGPI claims. In part Mr Johnson bases his opinion on the fact that the silviculture industry pays higher ACC levies. Although this may be correct this would be for all injuries (including spinal, upper limb and lower limb injuries) and provides no evidence that individuals in the silviculture industry have a higher risk of developing slow onset knee problems. A higher degree of overall risk in any occupational group does not equate with the increased risk of injury for all body areas and I doubt very much that any higher levels paid by the industry (if this is indeed the case) is specifically due to a higher level of work related degenerative disease of the knee. Without any specific condition, it is very possible for a specific occupational group to have an overall higher inherent risk of injury, but not to have a quality that could be causative of knee problems. I have reviewed Mr Johnson’s report in detail. There is no evidence in this report that the client is exposed to a level of activities and work that could have been causative of the degenerative disease of the knee and there is only very weak evidence for an association between OA of the knee and any job or role. [25] The matter went to review on 9 August 2012. The reviewer had the same evidence as the Court does. Perusal of the transcript displays a number of features including:  Mr Duncan asserted that one of the reasons for the matter changing to a gradual process degeneration claim when earlier specific injury claims were declined was “because ACC’s destroyed critical information”.  That Mr Duncan took Mr Chapman through the specific work tasks of the appellant, but in the process the reviewer remonstrated with him that in effect he was leading to some extent.  At an early stage in the transcript it notes, that Mr Duncan spoke of the environment having “one of the highest mortality rates of the industry”.  Mr Duncan addressed criticism at Dr Hilliard, with particular reference to his observation when critiquing Mr Johnson’s report as to whether that was based on actual visits to specific work sites or generally saying: I have some difficulty when these assessors get on their high horse, because at some point, particularly when we talk about self assessment, I’d like to know how much ACC paid Dr Hilliard over the last 12 months, how much they paid Dr Strack, that when we start to question people’s integrity, that puts everyone’s integrity on the table. Then, with respect to Dr Hilliard’s observation that occupational therapists do not undertake specific training with relation to causation and work related issues: Has Dr Hilliard been to any of these sites. Did Dr Strack go. Has he actually ever worked in the forestry. Occupational therapists are trained. They spend a lot of time at work sites, interviewing people in the work place, trying to evaluate how they’re actually working and would know the difference between generalised trends in the industry and best practice in the industry … so the occupational therapists have that front end exposure and I thought it was quite a condescending comment because the value here of what Mr Johnson has done is looking at the specific tasks involved in the industry.  Further he noted: I suspect from what Glen’s saying (the appellant having expressed his own critical views of Dr Strack), because Dr Strack didn’t have any objective view of the value of the information from Glen that they then come out with a report that’s less correct. It lacks objectivity. But where these guys are supposed to be the experts is in the terms of their own discipline so what does Dr Hilliard say? – he says that like Dr Strack I’m not familiar with any relevant evidence indicating individuals undertaking the client’s type of work are at an increased risk of developing degenerative knee disease. He went on: Now what I would provide are a couple of studies that – including some quite substantial studies that show that they are. So in that case since these two experts say they’re not aware of any studies and I’ve shown that there are studies, they’ve then put forward a one eyed view and because if he had said and Dr Strack said look there are a number of studies that indicate or suggest there is some risk here but there are some other studies that show that there isn’t and I prefer the other studies and for these reason well that would be fine. [26] The reviewer sought clarification on what studies he was referring to and Mr Duncan indicated that there was a Forestry Industry Contracts Association analysis of cost which indicates “that they are recognising that knees are a major problem in the industry” and “my understanding is that forestry is pretty much at the top of the list in terms of serious injuries. And that’s recognised by the levies charged”. And later when discussing the levy: Now again Dr Hilliard is quite dismissive of that saying well that’s got nothing to do with gradual process knee injuries. That’s highly relevant because this is a dangerous job which means that the focus for the workers is on not getting killed or losing a limb. Small injuries everyone takes in their stride so that the threshold for making reports about individual small bumps and bruises and repetitive stresses on the body is a lot higher in forestry because the expectation is that if you get out for a year without being killed you’ve done reasonably well.  The reviewer was then referred to a Department of Labour forestry sector action pamphlet which “notes the high risk of sprains and dislocations to the knees” and Mr Duncan added: What Dr Hilliard seems to be suggesting extrapolating from Dr Strack is well this isn’t about dislocation, but for every dislocation and sprain you’ve got an almost or lots more almosts. And it’s not – for every time you’ve got someone killed you’ve got lots that are having lesser injuries as well. That’s the nature of forestry … you have a higher threshold with reporting injuries.  He then referred to an International Journal of Logging study in Louisiana, and then in particular, to the report from the National Occupational Health and Safety Advisory Committee of New Zealand,(NOHSAC) observing: Interesting one of the things they noted is that we haven’t had a lot of studies in this area and suggesting that we need to and I’d be saying as a multi million dollar work place insurer, ACC’s negligent in not producing such study. Or that either they produced the studies and they’ve got them and they haven’t disclosed them to this hearing or they haven’t produced them. But what we’re saying here in NOHSAC … is quite important because it’s saying that it goes through that it says, occupations and tasks associated with an increased risk of developing osteoarthritis are common in New Zealand. So that if the National Occupational Health and Safety Advisory Committee … is saying that those are the things in a significant report now at least there is some fairly substantial New Zealand based information that sits not just from one person’s opinion but from a whole group from the multidisciplinary approach based on researchers coming to that view, who the hell is Dr Hilliard to say there’s nothing there.  Further on he said: The thing that concerns me most is that I’ve pulled out information and this is just a quick across the board. ACC is the premier workplace insurer. They’re involved in NOHSACS, they’re involved in a lot of these committees. They have this information and they’re saying is all we’ve got is Hilliard and Strack. Actually ACC has got all this information. Their library will be chock full of this and they’ve got an obligation to disclose it and what they’ve done here I think is very naughty and it’s concerning that an industry like horticulture, forestry, agriculture, shearing, I’m facing the same thing over and over again and I’m having to justify to our premier work place insurer that actually this is, these are the tasks involved. Analysis and Discussion [27] This appeal, as with any appeal in the jurisdiction is a rehearing and it is open to the Court to disregard the conclusions of a reviewer and make its own assessment on the evidence available. To conclude that the appeal should be allowed would necessarily involve the conclusion that the reviewer’s decision was wrong. That is particularly so here, where there is no additional evidence available to the Court that was not available to the reviewer. [28] The general approach to a gradual process claim is outlined in B v Accident Rehabilitation and Compensation Insurance Corporation 20001 where Pankhurst J said after outlining the three stage step under the present s 30 (then s 7 of the 1992 Act): It follows that the onus upon a claimant is a particularly heavy one. No doubt the intention of Parliament was to ensure that personal injury, said to be caused by employment-related gradual process, disease or infection would only be compensated in clear cases. … unless there was a known significant risk to persons performing the employment task, the case will not be recognised. [29] That case, and many other cases in the District Court emphasise the focus is on a causative link between the employment activities and the injury that is claimed to result. [30] In this case the injury is osteoarthritis to both knees, particularly the right knee. [31] Literature references, including any applicable epidemiological studies, are often a feature of a gradual process claim such as this. While the lack of epidemiological studies is not necessarily fatal to a successful claim particularly with regard to establishing a “significantly greater risk”, usually that involves consideration of whatever evidence is available. [32] In Phillips v Accident Compensation Corporation2 His Honour Judge Beattie observed: It cannot be that the mere fact that there is no research into the particular employment tasks under consideration that it should mean that a worthy claimant must fail when the specialist medical evidence in a particular case identifies that there is a significantly greater risk for persons who carry out the particular work tasks in question. 1 [2000] NZAR 385 2 ACC 237/04 [33] In Turner v ACC3 , His Honour Judge Ongley discussing the meaning of significantly greater risk observed: If there is expert opinion either that an aspect of the tasks posed a special risk or that epidemiological studies showed there is a palpably greater risk for the occupational group measured against the general population excluding persons doing that task, then the test would be satisfied without requiring proof that the difference is major or substantial. [34] Inherent in any analysis is a focus on the actual injury under consideration. [35] The general thrust of the submissions and evidence for the appellant is to the effect that the appellant has had over a long period of time, particularly in the forestry sector, involvement in very demanding physical tasks and there is a clear message coming through that amongst other things legs and arms in particular are at risk of injury simply because of the nature of the dangerous work involved. [36] Mr Johnson and the experts for the respondent are not really in material disagreement about the nature of the work tasks. The appellant is critical of the fact that the respondent’s experts may well not have the same “on the ground” experience of Mr Johnson, but that is not really the issue. The issue is whether a causal link with osteoarthritis to the knee is a development for which people engaged in the appellant’s occupation are at significantly greater risk and whether in the particular case a causative link between the appellant’s osteoarthritis and his work has been proven on the balance of probabilities. [37] There appears to be little doubt that the forestry industry is inherently quite dangerous both from an injury and mortality perspective but the issue is whether there is sufficient evidence to establish that osteoarthritis of the knee is a development that fits within that category. [38] That is where, in my view the appellant’s case fails. I note that in the review decision, reference was made to NOHSAC studies and also to ACC publications. These were not actually tabled at the hearing before me and only passing reference 3 [2007] NZACC 229 made to them in the oral submissions. Neither was the issue of destroyed or non disclosed material held by the respondent advanced save to assert that the records may not be complete and a submission that the forestry industry has a pattern of underreporting of accidents. [39] By way of contrast, the expert views from the respondent contain detailed references to literature and epidemiological studies. The clear message coming through is that osteoarthritis is multifactorial in its causation and there is not necessarily any material correlation between injury generally, whether to the knee area or elsewhere that they are causative of arthritis. The evidence is that osteoarthritis is a quite common feature in persons of the appellant’s age and, while he, understandably, feels that there must be some correlation between his knee problems and his work, that at the end of the day is simply his opinion to be weighed up in the balance with the scientific epidemiological evidence which is not supportive of that. [40] Mr Johnson’s opinion does not really assist. He does not address the same causative, epidemiological factors that the respondent’s experts do. [41] The proposition raised at review about the respondent withholding information, destroying information, was not pursued in the submissions before me. [42] A Court can only come to a conclusion based on the evidence before it. On the evidence presented before me at appeal, a causative link between the work activities described and osteoarthritis has not been established. That is particularly so in respect of the left knee upon which there is little information but very much so also for the right knee. [43] Accordingly I find the causative link to the appellant has not been established. It has also not been established that people such as the appellant against the background of the particular work tasks are at significantly greater risk of suffering osteoarthritis of the knee through the work place activity as a gradual process matter. [44] Accordingly the appeal is dismissed. Costs should fall where they lie. [45] I will address briefly the application for suppression of name. There is nothing in the detailed written submissions on this which takes the case out of the ordinary. Reference is made to intimate personal health details but the reality is nothing in the evidence really falls within that category. [46] As was observed in Clark v Attorney General (No 1)4 : The principles of open justice and the related freedom of expression create a presumption in favour of disclosure of all aspects of Court proceedings which can be overcome only in exceptional circumstances. [47] While s 60 of the Accident Compensation Act reposes a discretion in this Court to make an order “if it is of the opinion that it is necessary and appropriate to do so to protect the privacy of the person referred to … ” that needs then to be considered in the light of that Clark principle and absent, in this case any particular special reasons making it “necessary and appropriate to protect privacy”, in my view it is inappropriate to make such an order. That application is also dismissed. an mailed Judge A N Maclean District Court Judge Solicitors: Luke Cunningham Clere, Wellington for the respondent 4 [2005] NZAR 481 ACR 568-12-Chapman