Robbins v Accident Compensation Corporation

IN THE DISTRICT COURT HELD AT CHRISTCHURCH Decision No. 29/2002 No. AI 240/99 UNDER the Accident Insurance Act 1998 IN THE MATTER of an appeal pursuant to s.152 of the Act BETWEEN WAYNE DOUGLAS ROBBINS Appellant AND ACCIDENT REHABILITATION AND COMPENSATION INSURANCE CORPORATION Respondent HEARD at CHRISTCHURCH on 4 October 2001 DATE OF THIS DECISION 28 January 2002 COUNSEL Mr A Cadenhead for Appellant Mr C J Hlavac for Respondent DECISION OF JUDGE P F BARBER The Issue [1] On 23 October 1998 the respondent Corporation wrote to the appellant purporting to revoke "cover" for injury to his right ankle sustained on 17 September 1996. This was in reliance on section 67A of the 1992 Act. It is accepted that the effect of the respondent's decision is not to revoke cover, but to cancel or suspend on going entitlements pursuant to section 73 of the 1992 Act. [2] The issue before me is whether the appellant's ongoing condition is causally connected with the original injury by accident for which cover was granted. In this case the relevant injury is that sustained on 14 July 1992 when the appellant's ankle was caught between a cow catcher and ballast, but in 1996 the appellant had sought further entitlements flowing from that 1992 injury. 2 [3] In short the question is: are the difficulties that Mr Robbins now suffers with respect to his ankles, effects that flow from his compensatable accidents? Also, if there are any age related difficulties, disease or gradual process causative factors involved with Mr Robbins' ongoing ankle difficulties, are they the substantial cause of his ongoing problems? Background [4] On 14 July 1992 the appellant suffered injury to his right ankle when it was caught between a cow catcher and ballast. Medical notes at the time record "grazed medially (right) ankle. FROM (full range of movement) bones okay." A week later (21/7/92) medical notes record "ankle good – slight pain on medial ridge … FROM and no effusion." [5] A claim lodged with ACC in relation to the injury was accepted. The respondent's records in relation to the claim indicate that the file was closed on 17 July 1992 with no further follow up. [6] In 1996 the appellant lodged a further claim for cover with the Corporation in relation to his right ankle. The respondent's claim records detail the date of the accident as being 14 July 1996; however, subsequent reports detail a gradual onset of relevant conditions. [7] On 16 October 1996 the appellant's GP, Dr R Turner, provided a medical certificate which diagnosed "tendinitis right tibialis posterior tendon" This noted that the appellant was only able to work six hours per day on light duties when he had previously worked a 12 hour day. On 6 November 1996 the appellant advised the Corporation that: "He said it had been sore at times but had ignored it as he couldn't have time off as was too busy. However, working in the concrete milking sheds he feels the ankle has been aggravated as the ground does not give obviously and his ankle is what is taking the shocks. His ankle has now swelled up and he is hobbling around … " [8] Accordingly the appellant was referred by his GP to Mr Rick Wilson, orthopaedic surgeon. He reported on 6 November 1996 that: "As Rod has outlined the problem may stem from an injury sustained some years ago in a railway accident. His foot was stressed for a considerable period of time in this accident but he seemed to recover quite quickly. Against this however is the fact that the symptoms seem very much bilateral and are primarily located around the medial aspect of the ankle bilaterally." [9] Mr Wilson queried the diagnosis of tendinitis and noted that the appellant: " … still has tenderness over the tib post tendon acutely so at the distal end of it just prior to the insertion into the tarsal bones. He was painful with eversion stressing the tendon and was unable to walk on tip toes which is a pretty good 3 test of this tendon. The other ankle however was more laterally based pain although there was no evidence of tenderness at all." [10] In July 1997 Mr Maxwell performed exploratory surgery of the posterior tibia tendon and a release of the tarsal tunnel right ankle. In his report of 28 July 1997 Mr Maxwell noted that: "At operation it was found there had been previous injury to the attachment of the tibialus posterior tendon but that it had healed quite satisfactorily although with a significant amount of adhesion to the surrounding tendon sheath." [11] In May 1998 Mr Maxwell reported further and noted that, while the tendon decompression had initially shown good results, the appellant" " … then returned with more generalised discomfort around the right ankle and he now returns with bilateral hind-foot discomfort. In fact his complaint is essentially one of morning stiffness in the ankle and hind-feet with pain around the anterior aspect of the ankles, the sub-malleolar area and plantar facia pain. He has recently also noticed swelling and pain of the left fourth toe … On examination, there is generalised thickening of the tissues around both ankles and sub-talar regions. The left fourth toe is very tender but there is no significant erythema. There is a generalised reduction of range of movement in his sub-talar, ankle and transverse tarsal joints. There was mild scalp psoriasis, but no other lesions in the limbs or trunk." [12] Mr Maxell considered a diagnosis of psoriatic arthropathy but referred the appellant to Dr Paul Trolove, a rheumatologist, for a second opinion. [13] The appellant saw Dr Trolove in July 1998 who reported by letter of 31 July 1998. Dr Trolove also noted that while the tendon decompression had initially given good results: " … over the next few years he became aware of a more defuse pain, particularly about the ankle on the right side and under the sole of the foot particularly about the heel and the MTP joints. He then developed pain in similar sites under the left foot and at the present time is troubled particularly by pain under the soles with marked swelling and pain of the left fourth toe. The pain is present both at rest and with activity and has caused a significant degree of dislocation of his work." [14] Dr Trolove also noted that: "Of significance, and as noted in your letter, he is known to suffer psoriasis and has done so for about 20 years." [15] Accordingly, Dr Trolove diagnosed psoriatic arthritis involving the feet and entheses about the feet. Dr Trolove also noted that: "The degree of involvement of his psoriasis is quite marked … " 4 [16] In February 1998 the appellant was seen by Dr Sue Rudge. She reported in a letter dated 2 February 1998 and reviewed the appellant's medical history and current condition, and noted the current symptoms of skin psoriasis. She concurred with Dr Trolove that the appellant suffers from psoriatic arthritis and recorded that: "Mr Robbins is obviously concerned whether the injury in 1992 has a significant bearing on his current symptoms, certainly the right foot and ankle is more severely involved than the left and this may well be related to the previous trauma on that side." [17] In July 1999 the appellant was seen by Dr J L O'Donnell, a rheumatologist. Dr O'Donnell also concurred that the appellant was suffering from psoriatic arthritis and provided recommendations as to treatment. Dr O'Donnell offered no opinion as to causation. [18] On 16 March 1999 Dr Rudge provided a further opinion in which she noted that: " … The fact that Mr Robbins is experiencing more severe symptoms from his right foot and ankle as compared with the left, may well relate to the combined effect of the psoriatic arthritis and his previous trauma on that side and are certainly sufficient to prevent him from participating in his normal activities including his work as a farmer." [19] On 23 October 1998 the respondent Corporation wrote to the appellant advising that: "I am writing to advise you that ACC has reconsidered your claim for cover for the injury sustained on 17 September 1996, based on additional information you have given us. Unfortunately your claim for cover under the Accident Rehabilitation & Compensation Insurance Act 1992 has been declined because your continued incapacity is attributable to psoriatic arthritis and not your original injury. The decision has been revised in accordance with Section 67A Revision of Decisions. This means that you will not be entitled to receive further compensation or rehabilitation services … " [20] In April 2001 the appellant was seen by Dr R D Wigley, a rheumatologist, who reported on 6 April 2001. Dr Wigley extensively reviewed the previous medical reports and the appellant's medical history. By way of diagnosis he stated that: "He has had a major injury to his foot with damage to the tibialis posticus tendon which preceded the development of the arthritis. There is general agreement that he has had psoriatic arthritis since the accident. There is some indication that the skin psoriasis proceeded the accident." And further: "It is well known that injury to the skin can bring out psoriasis of the skin in the injured area (Koebner's phenomenon). There is persuasive evidence 5 (enclosure 3) that the same mechanism may explain the onset of arthritis following injury in those with psoriasis. Under the circumstances of his case, I believe this to be the explanation. It has been suggested that injury causation no longer applies In other words that he would have had his present arthritis whether or not he had had the injury. I consider that the injury continues to have an effect. It was shown at the time of operation that the tendon had actually been damaged and had healed with adherence to the tendon sheath of the tendon that was released by surgery. The surgery would only have partly cleared that damage. There is still evidence of persisting damage eight years following the accident. So it cannot be said that the injury was only a trigger and should have healed and so should not have a continuing effect because it has not healed. The operation showed permanent injury. It is quite likely that the subtalar joint cartilage surfaces were also damaged in the accident." [21] Dr Wigley then went on to deal with specific legal questions raised advising: "He probably had psoriasis before the initial accident and this gave him a susceptibility to have arthritis triggered by the accident. The initial arthritic symptoms affected both the joints and the tendons and their sheaths. The latter were shown at operation to be injured. The injury would be regarded as a trigger to his continuing arthritis which is typical of the arthritis which goes with psoriasis (psoriatic arthritis)" "The skin psoriasis was an underlying condition but the arthritis could be accepted as compensible if brought on by the injury. The presumed pre-existing psoriasis would not have been compensatable "I believe that the psoriasis contributes less than 80% of his continuing disability." [22] On 13 August 2001 Dr Wigley reported further in response to additional questions posed by the appellant's counsel: "In your conclusion at page 8 you note that Mr Robbins’ psoriasis gave him a susceptibility to have his arthritis triggered by his accident. Are you indicating that the arthritis was post-traumatic in nature and was not pre-existing but asymptomatic? Yes. I did not find any evidence that the arthritis preceded the injury so I conclude that the arthritis was post-traumatic. The psoriasis was considered to have preceded the injury so may have provided a susceptibility to the arthritis which followed the accident. You indicate "the latter was shown at operation to be injured". I would be grateful if you could describe anatomically and physiologically the nature of the injury. It was shown at the time of the operation that the tibialis posticus tendon had been damaged and had only partly healed. Scar tissue was binding the tendon to its sheath. The surgery would have only partly released the damaged tendon. I consider that the injury would still contribute to the loss of 6 function of his ankle as this muscle maintains the longitudinal and arch of the foot." [23] On 1 September 2001 Dr Trolove provided a further report in which he advised: " … There is little doubt about the current diagnosis of psoriatic arthritis. The issue in question is the part played by the significant injury to Mr Robbins right foot and ankle … It is my understanding that Mr Robbins had no evidence of arthritis of any type prior to the accident. He stated to me he had been known to suffer skin psoriasis for approximately 20 years prior to 1998. I note from Dr Wigley's report that psoriatic arthritis is occasionally believed to be precipitated by injury. He quotes cases and I have enclosed additional reports describing psoriatic arthritis cases attributable to injury and the mechanism believed to be the so-called Deep Koebner phenomenon." "From the more recent reports and, certainly at the time of my examinations, Mr Robbins suffers more pain in the right side than the left. I can only assume there is an element of injury-related pain in this. My reasoning along these lines are mainly due to the findings of Mr Rod Maxwell at the time of the tendon surgery. I understand there were features of previous trauma and scarring found. As stated above, my understanding was that there was no hint of arthritis of any type prior to the injury." "My comments can only be made from the reports sent to me and from my own observations which were made nearly three years ago. I believe that Mr Robbins suffers significant psoriatic arthritis. The issue is, whether this has been precipitated by the injury (Deep Koebner's phenomenon). There is no way of proving this one way or the other. Reports from the Medical Literature had been made available and tend to support this in occasional cases." [24] Finally Dr Trolove reported again on 17 September 2001. In that report he stated: "As mentioned above, injury as a causative factor for psoriatic arthritis is by no means proven. I agree that almost all cases arise in the absence of injury. i. I am unable to give a percentage figure in those cases associated with injury. In my experience, the overwhelming majority are not associated with injury. ii Relationship between skin psoriasis and psoriatic arthritis – There is a strong link. Usually, but not always, the skin involvement pre-dates the arthritis. Various figures are given for the chance of a person with psoriasis developing psoriatic arthritis. The most common figures quoted are 5 to 8%." [25] Dr Trolove then goes on to note other non-injury related factors identified as causing or contributing to the development of psoriasis into psoriatic arthritis. He notes that he could find no other cause of the factors in Mr Robbins' case. 7 A Summary of the Submissions for the Appellant [26] Mr Cadenhead for the appellant very helpfully took me through the salient passages of the series of medical reports and then through relevant case law. He then set out his arguments as follows: "5.1 That Mr Robbin's ongoing incapacity is caused wholly or at least in part by psoriatic arthritis which flows from his compensatable accidents. 5.2 That if his incapacity and/or ongoing medical difficulties in any way flows from psoriasis simpliciter then this is not the substantial cause of his ongoing incapacity or medical difficulties. 5.3 Mr Robbins may well have been beset by psoriasis prior to his accident but this provided him with a susceptibility to develop post traumatic psoriatic arthritis as a result of trauma." [27] I also appreciated receiving ancillary submissions from Mr Cadenhead as follows: "1. It is accepted that the appellant now suffers from psoriatic arthritis in his left and right ankle, his right knee and his neck. Secondly, it is accepted that for approximately 20 years prior to 1998 the appellant had suffered from psoriasis simpliciter. 2. It is submitted that matters largely turn on the consideration of the medical situation by Dr Wigley and Dr Trolove. 3. Dr Wigley in his report indicates: " … injury to the skin can bring out psoriasis of the skin in the injured area (Koebners phenomenon). There is persuasive evidence …that the same mechanism may explain the onset of arthritis following injury in those with psoriasis…" 4. Dr Trolove in his report of 1st September 2001 concurs with Dr Wigley's explanation of the deep Koebner phenomena and goes on to state that the issue to be considered is whether the psoriatic arthritis has been precipitated by the injury. Dr Trolove in finalising his opinion indicated: "There is no way of proving this one way or the other. Reports from the medical literature had been made available and tend to support this in occasional cases." 5. In a second report (17 September 2001) Dr Trolove expands on his opinion and says: " … almost all cases arise in the absence of injury." He also says: " … the overwhelming majority are not associated with injury." 8 Further, Dr Trolove, amongst other things, indicates that persons with skin psoriasis developing psoriatic arthritis have a probability of approximately 5-8%. 6. It is submitted, looking in isolation at Dr Trolove's report, that while his figures and conclusions tend to suggest that only in occasional instances will skin psoriasis develop into psoriatic arthritis and it is only in rare or occasional cases that it will happen as a result of injury – the short point is that it can and does occur. 7. Further, Dr Trolove does not discount the possibility that Mr Robbins' psoriatic arthritis did occur by way of the trauma that beset him; he simply indicates that it cannot be proved. Dr Trolove goes to the extent in the second report of clearing off a number of non-injury related factors that can cause arthritis. Mr Robbins does not appear from this analysis to be predisposed to arthritis. Additionally it is to be noted from Dr Trolove's two reports that it is accepted that Mr Robbins had no pre-traumatic arthritis. Further, in terms of the fact that the psoriatic arthritis is affecting more than one aspect of his body, Dr Trolove does not place any importance on this factor, and in fact indicates that arthritis is often migratory. 8. Dr Wigley in his report does take the step of indicating that he believes that the trauma in question activated the susceptibility of Mr Robbins to contracting psoriatic arthritis. In short, these are the only two specialists who deal with this question and for that matter the deep Koebner phenomenon. Dr Trolove is "neutral"; Dr Wigley is affirmative. 9. Judge Beattie in Walker v ARCIC DCA 152/2000 (while not dealing with psoriatic arthritis) dealt with regional pain syndromes and the fact that a small proportion of the population appears to have a susceptibility to contracting these on a chronic basis. At the base of page 16 of the decision Judge Beattie indicated: "That I find is a cross the Accident Compensation regime must bear and that small group of people who have the misfortune to have that propensity and suffer the type of injury which triggers regional pain syndrome that has been identified." 10. It is submitted that a similar situation exists in this case. Mr Robbins, unfortunately, is in the small proportion of persons who have been afflicted with skin prosiasis, have had a trauma and have then developed psoriatic arthritis." [28] Accordingly, Mr Cadenhead submits that appropriate causation exists in this case. 9 Reasons for Decision [29] Essentially, for the reasons advanced by Mr Hlavac for the respondent, this appeal cannot succeed. Accordingly, my following reasoning relies heavily on his very helpful submissions. [30] The decision in Burke (198/98) clarifies that section 10 of the 1992 Act establishes a fundamental concept, which needs to be addressed on an ongoing basis throughout the time that a claimant is continuing to seek entitlements under the Act, that where a claimant's ongoing problems are no longer causally connected to the injury for which he or she has cover, then entitlements can be suspended pursuant to section 73(1). [31] The test is whether the appellant can establish, on a balance of probabilities, that his present condition is directly attributable to, or causally connected with, the injury he sustained in the accident and in respect of which he was granted cover. In this case the relevant injury is that sustained on 14 July 1992. [32] As has been observed by this Court on numerous occasions, such an issue must be determined on a consideration of the medical evidence. Here, the medical evidence is clear that the appellant now suffers from generalised psoriatic arthritis in both ankles, in his right knee, his neck and in his ability to forward bend. [33] The primary issue is whether this psoriatic arthritis is directly attributable to, or causally connected with, the injury sustained on 14 July 1992. [34] The medical evidence is also clear that: (a) For about 20 years prior to 1998 and, certainly, prior to the accident in 1992, the appellant has suffered from psoriasis simplicita, i.e. a long standing skin condition. (b) That following the accident in 1992 the appellant recovered fairly quickly; and at the time of the operation carried out by Mr Maxwell in July 1997 it was noted that while " …there has been previous injury to the attachment of the tibialus posterior tendon but that it had healed quite satisfactorily although with a significant amount of adhesion to the surrounding tendon sheath." [35] It seems to me that the situation is one where the actual injury sustained in 1992 has largely healed, yet the appellant continues to suffer ongoing effects as a result of psoriatic arthritis which has now become generalised throughout his body. The question is whether the arthritis is causally connected with the injury. [36] The evidence of Dr Wigley is that: " … Injury to the skin can bring out psoriasis of the skin in the injured area (Koebner's phenomenon). There is persuasive evidence … that the same mechanism may explain the onset of arthritis following injury in those with psoriasis". 10 [37] In his report of 1 September 2001 Dr Trolove confirms Dr Wigley's opinion regarding the "so-called" Deep Koebner phenomenon and identifies that the issue is whether the psoriatic arthritis has been precipitated by the injury. Dr Trolove's view in his first report is that: "There is no way of proving this one way or the other. Reports from the medical literature have been made available and tend to support this in occasional cases." [38] In his second report (17 September 2001) Dr Trolove clarifies his earlier opinion noting that injury as a causative factor of psoriatic arthritis is by no means proven and that: " … almost all cases arise in the absence of injury." Further, that " … the overwhelming majority are not associated with injury." Dr Trolove also goes on to recognise the strong link between skin psoriasis and psoriatic arthritis, noting that usually the skin condition involved pre-dates the arthritis. Further, that the chance of a person with skin psoriasis developing psoriatic arthritis is in the area of 5% to 8%. [39] On the basis of that analysis (which is not challenged by other medical evidence) it is clear that: (a) there is a 5% to 8% chance of a person with skin psoriasis going on to develop psoriatic arthritis; and (b) of those cases where skin psoriasis does develop into psoriatic arthritis: (i) It is only in rare or occasional cases that this will happen as a result of injury; (ii) In the "overwhelming majority" of cases this change will take place spontaneously, in the absence of injury. [40] On the basis of that analysis, the appellant cannot show that, on the balance of probabilities, his psoriatic arthritis has arisen as a result of injury, and that it has not arisen spontaneously as will occur in the "overwhelming majority" of cases. [41] Finally, because I accept on the balance of probabilities that the appellant's psoriatic arthritis was not caused by the injury, consideration needs to be given to whether any other aspect of the appellant's condition continues to be causally connected with his original injury. The symptoms in his right foot and ankle are more severe than those in his left. This is likely to relate to the combined effect of the psoriatic arthritis and his previous trauma on that side. Dr Wigley notes that, at the time of the appellant's operation, it was clear that the tendon had actually been damaged and had healed with adherence to the tendon sheath of the tendon. That was released by surgery which would only have partly cleared the damage. There was still evidence of persisting damage eight years following the accident. [42] However, while there is continuing evidence of damage, the medical evidence does not adequately distinguish between those ongoing effects which are directly attributable to the original injury per se and those which are attributable to the psoriatic arthritis. 11 [43] After the original injury in July 1992, the appellant's ankle appeared to have healed within a week in that he had full range of movement and no effusion, and was subsequently able to return to work. He continued to work up until 1996, by which stage his arthritis had developed. Several of the specialists, including the appellant's treating surgeon Mr Wilson, refer to him having recovered from that injury. [44] Having said all that it does concern me that the appellant's case fails because he is unable to discharge his onus of proof. It also troubles me that the medical evidence relating to causation largely rests on that of Dr Wigley, who is very supportive of the appellant's case, and that of Dr Trolove who cannot support the appellant's case. For all the medical evidence one way or another, one's instinct suggests that, perhaps, the appellant's ongoing problems with his right ankle flow from the said injury to it which was sustained on 14 July 1992 and again on 17 September 1996. The evidence is that there was the said accident on 14 July 1992 but that, perhaps, in mid-1996 there was simply a gradual onset of aggravation of effects from the accident of 14 July 1992 due to the type of work undertaken by the appellant as a farmer. [45] Much store has been placed by Dr Trolove on the appellant having suffered psoriasis since about 1978 and that having developed into psoriatic arthritis in both feet and ankles and, particularly, in the right foot and ankle (and in the right knee and in the neck). One can understand Dr Rudge's view that the fact that the appellant experiences more severe symptoms from his right foot and ankle, as compared with the left, could relate to the combined effect of the psoriatic arthritis and his previous trauma on that side in terms of the 1992 accident. [46] Inter alia, Dr Wigley addressed the issue whether the 1992 injury causation still applied in April 2001, i.e. whether the appellant would have had his present arthritis in his feet and ankles (and knee and neck) whether or not he had had the 1992 injury and, apparently, the accident aggravation of it in 1996. Dr Wigley considers that the injury continues to have an effect and, for reasons which he gives, is a permanent injury from the 1992 accident. Dr Wigley accepts that the appellant probably had psoriasis before the 1992 accident which would give him a susceptibility to have arthritis triggered by that accident. It is, of course, accepted by all concerned that the presumed pre-existing psoriasis is not compensatable, but the present arthritis would be if it can be proved to have been brought on by the 1992 (or 1996) injury. [47] Rather puzzlingly, it seems to me, Dr Wigley states in his report of 6 April 2001; "I believe that the psoriasis contributes less than 80% of his continuing disability." [48] As indicated above, by his letter of 13 August 2001 Dr Wigley confirms that his view is that the arthritis was post-traumatic in nature and was not pre-existing but asymptomatic. He said that he did not find any evidence that the arthritis preceded the injury so he concluded that it was post-traumatic. He added: "The psoriasis was considered to have preceded the injury so may have provided a susceptibility to the arthritis which followed the accident". [49] Also in that letter, he said that he considered that the 1992 injury is still contributing to the loss of function of the appellant's right ankle. [50] In his report of 1 September 2001 Dr Trolove, inter alia, emphasised that the appellant had been known to suffer skin psoriasis since about 1978 and there had 12 been no hint of arthritis of any type prior to the 1992 injury. He concludes that the issue whether the significant psoriatic arthritis, from which the appellant suffered as at 1 September 2001, has been precipitated by the 1992 injury (or presumably by whatever happened in 1996) simply cannot be proved one way or the other. In his report of 17 September 2001, Dr Trolove seems to be saying that there is a 5 to 8% chance of skin psoriasis developing into psoriatic arthritis. [51] I have often thought that in these ACC cases, there are frequently far too many medical reports which have been obtained over too long a period of time. All that must create unnecessary expense. It can certainly create confusion in terms of what medical evidence should tell the Court. However, - although there are about 14 medical reports from 6 November 1996 to 17 September 2001 in this case it is a pity that there is not one more independent specialist medical report on the issues upon which I have focused, especially causation. On that theme, I accept, of course, that the medical witnesses are professional persons acting independently and with complete integrity. Nevertheless, when it is left to me to make a decision based on conflicting medical evidence, I must be permitted to wonder whether the fact that a particular medical practitioner was instructed by one party or the other could have some unconscious effect on the presentation of the medical report. Perhaps, it would be more helpful to this Court if there was a diminution in numbers of medical reports obtained, but if the briefing for those reports came from some independent committee rather than one side or the other. Certainly, in this case I would have found a third independent specialist report very helpful if it were to deal with the issue of causation of the appellant's ongoing condition. [52] On that note, I refer further to some of Mr Cadenhead's submissions. In terms of Mr Cadenhead's submission that the appellant's ongoing incapacity is caused wholly, or at least in part, by psoriatic arthritis which flows from his compensatable accidents, the appellant's problem is that (in terms of the medical evidence) this cannot be proved on the balance of probabilities and it would be guesswork to come to that conclusion – even though that could well be the case. Similarly, it may well be that the appellant's pre-accident psoriasis has made him susceptible to post- traumatic psoriatic arthritis as a result of the trauma of the accidents, but causation cannot be proved on the balance of probabilities. [53] Dr Trolove seems to be saying that, generally, cases of psoriatic arthritis are not associated with injury but simply develop and, frequently, from the condition of psoriasis of the skin. He also seems to be saying that not infrequently skin psoriasis will develop into psoriatic arthritis. I accept that the evidence seems to be that the appellant had no pre-traumatic arthritis. I am interested to note that arthritis is often migratory, which could explain why it is in both feet and ankles and, to some degree, in the appellant's right knee and neck. [54] I appreciate that Dr Wigley seems to be saying that he believes that the trauma in question activated the appellant's susceptibility to contracting psoriatic arthritis but, of course, this cannot be proven and could not be regarded as conclusive medical opinion. [55] Despite the misgivings I have expressed about this case in these concluding paragraphs, on the balance of probabilities, I find that the psoriatic arthritis now suffered by the appellant was not caused by the accidents of 1992 or 1996 described above. Also, the evidence shows that if there are any continuing effects of those 13 accident injuries then, in themselves, they must only be minimal and are insufficient to justify receipt of ongoing entitlements. [56] Accordingly, I hereby dismiss this appeal. ________________________ Judge P F Barber District Court Judge Wellington robbins.rl