New South Wales Court of Appeal CITATION : Expokin Pty Limited v Graham [2000] NSWCA 267 FILE NUMBER(S) : CA 40481/99 HEARING DATE(S) : 18 September 2000 JUDGMENT DATE : 29 September 2000 PARTIES : Expokin Pty Limited t/as Festival IGA Supermarket (Appellant) Marilyn Ann Graham (Respondent) JUDGMENT OF : Fitzgerald JA at 1; O'Keefe AJA at 10; Santow AJA at 11 LOWER COURT JURISDICTION : District Court LOWER COURT FILE NUMBER(S) : DC 110/98 LOWER COURT Judge Delaney JUDICIAL OFFICER : COUNSEL : A Ogborne (Appellant) A S Morrison/C Locke (Respondent) SOLICITORS : Blake Dawson Waldron (Appellant) David Velleley (Respondent) CATCHWORDS : TORTS — Negligence — Damages — Causation — Medical retirement leading to future economic loss not attributable to pre-existing condition but to Appellant's negligence which aggravated that condition — Tortfeasor gets no allowance for frailty of victim — Test in Purkess v Crittenden not satisfied but ample allowance for likelihood that Respondent's pre-existing problems may come against her — Allowance in 25% discount rather than usual 15% for vicissitudes and in working life of 60 years rather than 65 years. Australian Telecommunications Commission v Parsons (1985) 59 ALR 535 Bennett v Minister for Community Welfare (1992) 176 CLR 408 Chappel v Hart (1998) 72 ALJR 1344 Faulkner v Keffalinos (1971) 45 ALJR 80 Johnston v Cowra Shire Council [2000] NSWCA 117 Johnson v Perez (1988) 82 ALR 587 CASES CITED: March v E&MH Stramare Pty Ltd (1991) 171 CLR 506 Purkess v Crittenden (1965) 114 CLR 164 Ruby v Marsh (1975) 132 CLR 642 Smith v Leech Brain & Co Ltd (1962) 2 QB 405 State Government Insurance Commission v Oakley (1990) Aust Tort Reports 81-003 Thompson v Faraonio (1979) 24 ALR 1 (PC) Watts v Rake (1960) 108 CLR 158 DECISION : Appeal dismissed with costs. THE SUPREME COURT OF NEW SOUTH WALES COURT OF APPEAL CA 40481/99 DC 110/98 FITZGERALD JA O'KEEFE AJA SANTOW AJA Friday, 29 September 2000 EXPOKIN PTY LIMITED t/as FESTIVAL IGA SUPERMARKET v MARILYN ANN GRAHAM JUDGMENT 1 FITZGERALD JA: The circumstances giving rise to this appeal are set out in the reasons for judgment of Santow AJA. 2 The respondent was a nurse at Kyogle Hospital. Prior to her accident in the appellant's shopping centre on 22 March 1996, she had degenerative arthritic changes in her right knee and lumbar spine. She had had an arthroscopy on her right knee on 15 February 1996, a little more than a month before her accident, but had recovered and was back at work. She had experienced no symptoms from the arthritic condition in her back prior to her accident. 3 After her accident, the respondent had a second arthroscopy on her right knee on 11 October 1996. She first experienced lower back symptoms in March or April 1997. The trial judge's finding that those symptoms were not "causally connected" to her accident was not challenged. In October 1997, when the respondent was pulling a stroke patient forward on her bed, she injured her back. Although she retained a residual earning capacity, she was unable to continue with general nursing duties. A CT scan on 20 November 1997 revealed previously unknown arthritic changes in her lumbar spine and disc lesions. She ceased employment on 24 November 1997. Her condition was substantially unchanged at trial. 4 The trial judge found that the lower back symptoms which the respondent experienced in March or April 1997 "were not a material cause of her ceasing her employment". His Honour held that the injury which the respondent suffered in her accident on 22 March 1996 had caused a permanent aggravation of the pre-existing degenerative changes in her right knee which resulted in instability in her knee, and the instability in her knee was a material cause of the injury which she sustained to her back when she moved the stroke patient. 5 The appellant abandoned its appeal against the trial judge's conclusion that it is liable to the respondent and a number of grounds of appeal, including ground E, which was in the following terms: "E. That Delaney J erred in finding that the negligence of the [appellant] was causative of the loss of the [respondent] (if his Honour made any such finding, which is denied)". 6 The appellant's grounds of appeal did not include a ground that the trial judge had failed to discharge his duty to give adequate reasons for his decision. Nonetheless, many of the appellant's complaints related to the manner in which his Honour explained his decision. It would have been better if his Honour's reasons had been more carefully and comprehensively expressed. 7 The factual situation was not complicated and the applicable principles are well-established. All grounds of appeal which were argued concerned the relationship between the respondent's inability to perform her nursing duties, her degenerative back and knee conditions and the injury which she suffered in her accident. The trial judge's findings were favourable to the respondent. Santow AJA has demonstrated in his judgment that those findings were amply supported by evidence. 8 I am also persuaded by his Honour's judgment that, on the evidence, the trial judge was correct to find that the respondent's degenerative back and knee conditions would not have prevented her from continuing with general nursing until her planned retirement age if she had not been injured in the accident and that her degenerative back and knee conditions were fully and adequately catered for in the heavy discount which the trial judge imposed on her damages. 9 I agree that the appeal should be dismissed with costs. 10 O'KEEFE AJA: For the reasons given by Santow AJA, I agree that the appeal should be dismissed and that the appellant should pay the costs. 11 SANTOW AJA: Introduction 12 This is an appeal by the Appellant against the quantum of damages awarded by Delaney DCJ in relation to injury suffered by the Respondent, when she slipped in the Appellant's shopping centre. The Appellant does not now appeal on liability. The remaining grounds of appeal (F to M) predominantly concern causation as affecting damages. 13 The appeal is brought from a judgment in an amount of $316,948 given by Delaney DCJ in favour of the Respondent for injury suffered to her right knee in a fall which occurred in a supermarket owned by the Appellant. The medical experts for both sides gave their evidence in the form of reports but were not tested in cross-examination. The Respondent was however cross-examined. What follows is a summation of events surrounding the accident and its aftermath so far as relevant to these remaining issues. Summation of Events 14 The Respondent was working as a nurse at Kyogle Hospital in a northern New South Wales town of that name. She had a pre-existing degenerative arthritic condition in her right knee which first manifested itself in May 1994. It caused some pain, giving rise to a constant history of discomfort by November 1995. Nonetheless she was able to continue to work taking only two days sick leave, as a result of her right knee locking at work. However, after seeing her local doctor in August 1995 because of pain in the right knee especially walking up and down hill on the road home, she was referred to an orthopaedic surgeon, Dr Ashwell. Dr Ashwell told her she had a medial cartilage problem and he performed an arthroscopy on the Respondent on 15 February 1996. This was a month prior to her fall. 15 After this first arthroscopy, the Respondent improved and was back at work on normal nursing duties when she suffered the fall in the Appellant's supermarket on 22 March 1996. 16 After consulting Dr Perry on her swollen and painful right knee, she returned to work a week later but experienced little improvement. 17 Painful symptoms recurred leading to a second arthroscopy on 11 October 1996 by Dr Ashwell on the right knee. Dr Ashwell wrote a report recording that the Respondent had a recurrence of chondral damage on the medial femoral condyle and patella and a synovitis in her joint. His pre-accident report indicated there was grade 2 chondral damage on the femur and the patella and a medial flap tear. 18 Not long after, she twisted her knee in an incident at work in December 1996 ("the twisting injury"). 19 The Appellant does not dispute evidence from Dr Searle (Combined Appeal Book, 212-3) that a CT scan on 20 November 1997 revealed disc lesions and arthritic changes in the lumbar spine. I return to the significance of that finding in the context of the various grounds of appeal. 20 The Respondent then had an incident ("the pulling incident) where she was pulling a stroke patient forward on her bed when she suffered a sudden pain in her lower back in October 1997. She commenced twenty-one day's sick leave on 22 October 1997 for what was described in the record of sick leave as "acute back pain related to knee injury" (Combined Appeal Book, 61 K). She finally ceased employment on 24 November 1997. Dr Gapper, the NSW Government Medical Officer at Health Quest described her as "currently unfit for unrestricted general nursing duties" and that it appeared "unlikely that her condition will resolve to a sufficient degree to permit her to resume these duties in the foreseeable future"; Combined appeal Book, 198 F. Trial Judge's Conclusions 21 The trial judge's conclusions can be summarised as follows: (i) The Respondent was a truthful and honest witness (Red Book, 19 I; (ii) The facts and circumstances surrounding her ceasing work were recounted by the Respondent and are accepted (Red Book, 20 U) (iii) The twisting injury of December 1996 did not represent a novus actus interveniens . Rather it was caused by the Respondent's fall of 22 March 1996 leading to an instability of her knee. It is thus within the situation in State Government Insurance Commission v Oakley (1990) Aust Tort Reports 81-003 "where the further injury results from a subsequent accident which would not have occurred had the plaintiff not been in the physical condition caused by the defendant's negligence" (Red Book, 34 I-T). (iv) The Respondent as a result of the Appellant's negligence has had a permanent aggravation of pre-existing degenerative changes in her right knee which have led, as a direct cause or result, to her inability to be able to carry out the present work that she was doing as a nurse (Red Book, 34 V to 35 B); (v) "I am satisfied that the lower back symptoms came on in March or April 1997. I am not satisfied that they are causally connected with the fall but I am satisfied that they were not a [the] material cause of her ceasing her employment in October 1997. I am of the view that the material cause of that occurring was the pain, discomfort, restriction of movement and inability to be able to stand and walk to the degree in which she was previously able to do following the fall in the supermarket of the defendant." (Red Book, 35 C to I). (vi) Damages were awarded on the basis that the Respondent does have a residual earning capacity. Damages for future economic loss were allowed to the age of 60 rather than 65, being a period of sixteen years. A sum of only $400 per week was allowed for reduced earning capacity as against what she was earning of $650 per week net (Red Book, 37 M-R). (The difference of $250 per week can be taken to represent residual earning capacity.) (vii) However, the percentage reduction for the usual vicissitudes of life of 15% was increased to 25% because of her pre-existing problems and the likelihood that they may come against her, notwithstanding the fact that there is no evidence that satisfies the Purkess v Crittenden test (Red Book, 37U-Z). 22 Thus the trial judge essentially held that the Plaintiff's negligence caused permanent aggravation of pre-existing degenerative changes in the Respondent's right knee which was the material cause of her physical disabilities; they in turn were the material cause of her ceasing employment with reduced earning capacity thereafter. Damages were awarded accordingly. LEGAL PRINCIPLES 23 In terms of principle, it must be emphasised that all the Respondent has to establish by way of causation is that the Appellant's negligence "materially contributed" to the loss suffered. This is in the sense explained by McHugh J in Chappel v Hart (1998) 72 ALJR 1344 at 1350: "If a wrongful act or omission results in an increased risk of injury to the plaintiff and that risk eventuates, the defendant's conduct has materially contributed to the injury that the plaintiff suffers whether or not other factors also contributed to that injury occurring. If, however, the defendant's conduct does not increase the risk of injury to the plaintiff, the defendant cannot be said to have materially contributed to the injury suffered by the plaintiff." To displace legal liability on causation grounds, the Appellant has the heavier onus of establishing that there was another wholly sufficient cause of the Appellant's loss entirely unrelated to the Appellant's negligence. That is to say, there was a cause related to the Respondent's condition sufficient by itself to bring about the loss suffered or the event leading up to it, and which was not "the very kind of thing likely to happen as a result of the defendant's negligence". (Mason CJ in March v E&MH Stramare Pty Ltd (1991) 171 CLR 506 at 518-9 in relation to superseding causes.) 24 I turn now to the Appellant's grounds of appeal. They can conveniently be grouped collectively under the issue of causation as affecting damages. Causation as affecting damages 25 The common thread running through each of these grounds of appeal is a challenge to the trial judge's conclusions on causation as affecting damages. It is said that the trial judge, for insufficient reason, or by failing to consider relevant matters, or against the weight of evidence, erred in finding that none of the following factors were a material cause of the Respondent's retirement. They are: (a) the Respondent's back condition, (b) The Respondent's pre-existing arthritic knee, or (c) The twisting injury. 26 It is not in dispute that the first factor, the back condition, pre-existed the fall but did so without symptoms. After the fall, it manifested itself in back pain later, it appears, aggravated by the pulling incident. The Appellant contends this factor caused the Respondent's medical retirement in November 1997, or would otherwise have caused her early retirement shortly after November 1997 in any event. 27 The second factor is the pre-existing arthritic knee. This is said either to have caused her medical retirement in November 1997 or would have caused her early retirement shortly after November 1997 in any event. 28 The third is the twisting injury. The Appellant relies on it as a novus actus interveniens. That is to say it was: (a) not causally connected to the fall, and (b) would have caused, either by itself, or in conjunction with the other two factors, the Respondent's medical retirement in November 1997 or shortly after November 1997 in any event. 29 The Appellant's Notice of Appeal did not expressly refer to lack of sufficient reasons, failure to consider relevant matters or findings against the weight of evidence. Nonetheless I shall deal with the Appellant's case on that basis. The back condition 30 On the back condition the Appellant's contention starts with the conclusion of the trial judge quoted in para 11(v) above. He treats this as a finding that all of the lower back symptoms, not just those in March and April 1996, were (a) not causally connected with the fall, and (b) not "a material cause" of the Appellant's medical retirement. 31 The Appellant then relies on that part of Dr Searle's report of 19 March 1998 which identifies the pre-fall symptomless lumber disc lesions and spondylosis observed in a CT scan of 20 November 1997 (Combined Appeal Book, 199) as establishing that that back condition pre-existed. However, the Appellant rejects the next part of Dr Searle's report. In so doing, he picks and chooses, but does so on the basis that the trial judge in that respect does so also. He rejects Dr Searle's conclusion that the back condition was "aggravated by the knee injury which caused her to limp". This is dealt with in the Combined Appeal Book, 213 K-Q where appears the further report of Dr Searle of 1 July 1998 in which he concludes: "The accident on 22/3/96 materially contributed to her ongoing disabilities in the low back and right knee. The injury suffered in that accident materially contributed to her being unable to continue with her employment as a nurse as and from the actual date of cessation of her employment." See Combined Appeal Book, 215D-F. Dr Searle then adds: "She would probably have been unable to continue in her employment as a nurse beyond the actual date of cessation of such employment even if the December 1996 injury had not occurred." 32 The next step in the Appellant's attack, is to identify the basis for the trial judge's earlier conclusion rejecting any causal connection between the lower back symptoms and the Respondent's medical retirement. That basis is the trial judge's acceptance of the Respondent's "evidence about the nature and extent of her problems" (Red Book, 32N-O) and of "the facts and circumstances surrounding … [the Respondent] … ceasing work … recounted by the [the Respondent]" (Red Book, 20U-W). 33 The Appellant then contends that an examination of the transcript of Respondent's evidence (Combined Appeal Book, 27 P-28 H) shows that it cannot be reconciled with the trial judge's acceptance of her evidence. According to the Appellant she there concedes that lower back symptoms were a material cause of her medical retirement. The passage of the cross-examination of the Respondent relied upon by the Appellant for that supposed concession is as follows: "Q. Isn't it the case that there was a specific incident relating to your back in October 1997 that was the immediate cause of your work — your employment terminating? A. Yes, but I was told that it wasn't workers' compensation because it was — because of my knee. Q. All right. Well, let's not worry about whether it's workers' compensation or not for the moment but it's the case, isn't it, that you were trying to lift a stroke patient on a bed and suffered severe pain in your lower back when trying to do that? A. I was leaning the patient forward to put the lifter behind her when it happened. Q. Were you bearing weight when this occurred? A. No, I was — the lady was sitting in the chair and we were just pulling her forward to put the straps behind her to put the mechanical lifter on her. Q. And when you were bending forward to put her into the lift, you got a sudden pain in your lower back preventing you from lifting the patient? A. That's right. Q. That's correct, isn't it? A. Yes. Q. And it was immediately as a result of this pain in your lower back that you then contacted your work supervisors and said that you were unable to continue to work? A. That's right. Q. So it wasn't as a result of the pain in your knee, it was as a result of the pain in your back, you say? A. Yes. Q. that led you to stop working. Is that correct? A. Yes." [emphasis added] 34 However, it is important to note the emphasised references to "immediate" and "immediately" and to place that passage in context, identifying what she was precisely asked, and not asked. In the earlier passage of cross-examination, the Respondent was asked about the twisting injury. Then immediately before the passage quoted appear the following questions and answers: "Q. And after you had turned and you felt your kneecap dislocate, it is only after that incident that the pain in your knee increased to the levels that you complained of that ultimately led you to stop work. Is that correct? A. Yes, I saw Work Directions after that and they — Commonwealth Rehab it was, and they put me off work for two months. Q. Now, when I heard you give your evidence about you leaving work, you talked about in giving notice in October 1997 and mentioned factors relating to your knee but you didn't give any evidence in relation to your back. Do you recall that? A. Yes." Clearly enough she was not giving an account of her medical retirement that treated the knee as other than central to it. 35 And earlier in examination in chief the Respondent gave a much fuller account why she had had to give up work which reinforces that centrality. A fair reading of that evidence shows that she attributes her medical retirement to disability in performing her nursing functions stemming from pain and restricted movement which she experienced with her knee. These were precisely the trial judge's findings (Red Book, 35 F to I). Thus after the twisting injury she went back to work on restricted duties, limited initially to paper work. She then progressed to night duty soon interspersed with day duty. She explains that she suffered a lot more pain in her knee than immediately after the second arthroscopy (Combined Appeal Book, 11 W to 12 E). She could not carry out functions such as wiping the patients' bottoms when they were sitting on colludes and lifting anything that was low on the ground and the nurses had to help her (Combined Appeal Book, 12 P-T and again 14M-V). She was eventually flown down to Sydney where Health Quest "suggested medical retirement because of my condition", meaning the condition she had previously described; see Combined Appeal Book, 12 Y-13 E) 36 She gave evidence that the worse her knee was the worse her back was. Thus Combined Appeal Book, 13 W-14 H: "Q. Let me ask you about something else. At some point did you have any pain in your back? A. Yes. Q. When did you first get that? A. About six months before I finished work I started to get muscle spasms in my back and I went to Dr Perry and he gave me Valium which didn't help a lot and when my knee was really playing up my back was really tight. Q. Was this the situation that the worse your knee was the worse your back was? A. Yes. Q. Is that still the situation now? A. Yes. Q. Prior to that first onset which I think would've been about March/April 97, about six months before you finished work, had you had any back problems? A. No." 37 That provides context for the cross-examination so strongly relied upon by the Appellant quoted in para 23 above. It becomes quite clear both from that context and from the use of the word "immediate" before "cause" in the passage itself as well as the later reference to "immediately" that the evidence given by the Respondent certainly did not preclude a finding that her knee remained the operative or substantive cause of her ceasing permanently to work. Rather the pulling incident relating to her back simply precipitated her contacting her work supervisors to say that she was "unable to continue to work" (Combined Appeal Book, 28D). That, it should be remembered, did not lead then and there to medical retirement, but to her twenty-one day sick leave. It was not till a month later (24 November 1997) that her employment actually terminated following Dr Gapper's report of 13 November 1997. If the Appellant wanted to rely on the Respondent's evidence as a concession that the real cause of her medical retirement was her back problems exacerbated by the pulling incident and wholly independent of any effect of the fall, that in fairness should have been put to her squarely. It was not. 38 I understand the trial judge to be saying, albeit with some understandable imprecision, that the lower back symptoms firstly of March or April 1997 were not "a material cause" of her ceasing her employment in October 1997. 39 By necessary implication, the trial judge is to be understood as saying that back symptoms generally, and thus also those which followed the pulling incident, were not "a" material cause of the medical retirement either; I interpolate that they may well have precipitated her taking sick leave but should not be considered the sufficient cause of her medical retirement. It might have been clearer had the trial judge in rejecting those circumstances as a material cause used the definite article "the" instead in conveying rejection of those circumstances as being sufficient in themselves and irrespective of the Appellant's negligence, to bring about medical retirement. Clearly enough use of that expression "the material cause" of medical retirement in the following sentence where he refers to the pain, discomfort, etc. following the fall, indicates that he saw those rather as the operative cause. That was a conclusion properly open to him on the medical evidence as well as the Respondent's own account. 40 I should interpose here that terminological inexactitude about causation is not uncommon in negligence cases. It simply reflects that causation in the law is not a matter of scientific precision. It has been said often enough that causation is a question of fact, to be resolved as a matter of common sense, by reference to the correct legal principles operating in the particular context and where policy issues play a now acknowledged part; see for example Bennett v Minister for Community Welfare (1992) 176 CLR 408. What the trial judge was really doing was explaining what happened in a commonsense way, just as authority requires; see the discussion on this in Jane Stapleton "Perspectives on Causation" in Oxford Essays in Jurisprudence (OUP, 1999). 41 The trial judge relied substantially on the Appellant's own account. The Appellant's own account is important for two reasons. First, the Respondent is the best witness of her own symptoms, including experience of pain. Second, she can express her attitude to her continued working, and the trial judge assess its genuineness. It was an attitude which the trial judge described as stoical (Red Book, 35U). It is for these reasons that the trial judge would have derived some advantage from seeing the witness. I should add that it might have been preferable had the conflicting medical evidence been tested by some limited cross-examination. Of course this was not primarily a decision for the judge but the parties. Nonetheless issues such as the extent the back condition was affected by the knee might have been probed. In saying this, I make no criticism of the trial judge, who is largely in the hands of the parties and operates with a busy list. 42 This appeal has proceeded on the basis that neither party challenged the trial judge's earlier finding that he was not satisfied that the lower back symptoms were causally connected with the fall. That too was a conclusion open to the trial judge, who in that regard did not accept Dr Searle's evidence though he did accept it as to the right knee. As to the latter the trial judge confirms that he does accept the following quoted passage from Dr Searle's report of 1 July 1998: "the injury suffered in the accident materially contributed to her being unable to continue with her employment as a nurse as and from the actual date of cessation of her employment"; see Red Book, 35 O-R and Combined Appeal Book, 215D-F). 43 The medical evidence further supports the trial judge's rejection of the lower back symptoms as the operative cause of her ceasing employment. Thus the Respondent had never complained of back pain in isolation before its exacerbation in October 1997 from the pulling incident. The sick leave record (Combined Appeal Book, 60) shows that there was no time off for back pain prior to October 1997. Three periods of 9, 10 and 2 days off in October and November 1997 were all for back pain "related to knee injury"; see Combined Appeal Book, 61 K-M. 44 Moreover, the history of back pain was minor compared to the knee. Thus Dr Opie in a report dated 16 March 1998 recorded, "back pain is now intermittent and mainly comes when the knee pain is severe" (Combined Appeal Book, 106 P). He noted, "right knee pain", "right knee swelling", and "minor low back pain". That in turn explains his conclusion that "back pain and right knee pain contributed to her invalidity and made her incapable of full-time work"; see Combined Appeal Book, 109. The evidence of the Respondent was that when her knee was worse her back was worse; see Combined Appeal Book, 13 Y-14 F. 45 Significantly in the Health Quest report which finally led to her medical retirement, dated 13 November 1997, the history of knee problems is set out (Combined Appeal Book, 197 P-R). Significantly, the report refers to a combination of lower back pain and right knee problems (Combined Appeal Book, 197S). 46 Finally, the risk that the back (or indeed her pre-existing arthritic knee) might have caused the Plaintiff problems anyway is fully and adequately catered for in the heavy discount the trial judge imposed on future economic loss. In so doing, he had basis in authority: see for example the judgment of Windeyer J in Faulkner v Keffalinos (1971) 45 ALJR 80 at 85-6. While her residual earning capacity may have been the reason for the first element of discount, namely reducing her working age from 65 to 60 and her net weekly earnings from $650 per week to $400 per week, clearly increasing the percentage for the usual vicissitudes of life from 15% to 25% was directed to "her pre-existing problems". I am satisfied that I may infer that these would have included not only the arthritic condition in her knee but also her as yet symptomless back problem at the time of the accident; see Red Book, 37 M-38 D. Indeed the reduction in her working age is also recognition of these factors. 47 The foregoing analysis of the evidence disposes of any appeal based on there being either insufficient reasons or failure to consider relevant matters or finding against the evidence and weight of evidence in relation to the Respondent's back condition. Moreover, the trial judge's approach to the back condition as also to the pre-existing knee condition is in accordance with the principles applicable to pre-existing conditions to which I now turn. The pre-existing knee injury and pre-existing conditions generally 48 Both the back and arthritic knee were pre-existing conditions. The Appellant contends that either separately or in combination both caused her medical retirement in November 1997 or would have caused her early retirement shortly thereafter in any event. The trial judge concluded in relation to those pre-existing conditions that the Appellant had failed to satisfy the evidential burden placed on it by reference to the High Court's reasoning in Purkess v Crittenden (1965) 114 CLR 164. There Barwick CJ and Kitto and Taylor JJ described (at 168) what was required of the defendant to meet the evidential burden: "… the pre-existing condition and its future probable effects or its actual relationship to that incapacity must be the subject of evidence (i.e. either substantive evidence in the defendant's case or evidence extracted by cross-examination in the plaintiff's case) which, if accepted, would establish with some reasonable measure of precision, what the pre-existing condition was and what its future effects, both as to their nature and their future development and progress, were likely to be." 49 It can readily be accepted that the Appellant did provide with some "reasonable measure of precision", evidence which, if accepted, would identify what the pre-existing condition was. Thus Dr Thompson's evidence in the form of his three reports of 12 August 1998 and in particular his first one, identifies as pre-existing conditions, the arthritic right knee with its experienced pain. He also describes "minor degenerative changes" at various disc points as revealed by a CT scan of the lumbar spine dated 20 November 1997, following the accident. These, as Dr Searle's evidence affirms, were a symptomless pre-existing condition manifesting itself only after the fall. 50 The deficiency in the Appellant's evidence lies in its inadequate treatment of the future effects of those pre-existing conditions. That evidence did not satisfy a reasonable measure of precision. One may accept, as Heydon JA did in Johnston v Cowra Shire Council [2000] NSWCA 117 [46] that a defendant is not expected to attain a standard of near perfection in adducing evidence to meet that evidentiary burden. However, in Johnston (supra) while there was no precise statement of when the pre-existing condition would manifest itself in an inability to work, there was nonetheless a conclusion, assisted by other evidence, that the lifting injury was "more likely to occur" with the spine anomaly of the plaintiff; see para 42. It is dangerous to extrapolate from the evidentiary matrix of one case to another, in making generalisations about what should be sufficient to satisfy the shifting evidentiary onus. 51 In the present case, Dr Thompson as the Appellant's expert simply states after examining the Respondent that, "I consider her unfitness for nursing duties is as a result of the degenerative changes in her right knee, left knee and low back degenerative conditions." (Combined Appeal Book, 92 R) Earlier he says, "These changes can only be managed by general measures such as loss of weight and improvement of general health with a restriction of activities which place strain on the knee, prolonged standing, crouching, squatting, running and lifting from ground level." There is no real analysis as to why that management, without the effect of the fall, would have been unavailing in preventing the early medical retirement he predicts for the Respondent. He gives no prediction, even the vaguest, as to when the natural progression to which he refers would culminate in medical retirement. 52 It was open to the trial judge to conclude that this evidence, in its present context, did not satisfy the evidential onus on the Appellant in answering what is essentially a hypothetical question. That question is whether, without the accident, the pre-existing conditions would have led to the Respondent being in any event unfit for nursing duties by November 1997 or soon thereafter The trial judge though concluding that there was no evidence that satisfied him on the Purkess v Crittenden test, did reduce the sum for future economic loss by a factor of 10% over and above the usual 15% for vicissitudes. He also took into account a working life to 60 not 65 years. Though he did so in the context of residual earning capacity, it clearly was relevant also in the context of future vicissitudes. It could not be said that conclusion was not properly open to the trial judge. 53 Nor indeed did the actual fact of medical termination provide the contemporaneous evidence that would of necessity lead a trial judge to conclude that medical termination had in fact occurred as a result of pre-existing conditions, as distinct from the fall. It was open to the trial judge to conclude, as he did, that the fall caused a "permanent aggravation of pre-existing degenerative changes in right knee" leading as a direct causal result to her inability to carry out her pre-accident work as a nurse. 54 Windeyer J in Purkess v Crittenden draws a distinction which clearly underlies the reasoning of the trial judge: "The evidence may not show that the conduct of the defendant did more than accelerate misfortune. But of course it will not avail the defendant to show that but for the plaintiff being in some way ailing when he was hurt, his injuries would have been less serious than they were. A tortfeasor gets no allowance because of the frailty of his victim." (at 170) 55 The frailty of the victim is not treated as a cause of the injury. Rather, that vulnerability is treated as part of the pre-existing circumstances, upon which the wrongdoer's negligence has wrought its aggravated effect. The wrongdoer takes his victim as he finds him. 56 The words of Dixon CJ in Watts v Rake (1960) 108 CLR 158 at 160 are also apt in pointing to what the Appellant has failed to do: "If the disabilities of the plaintiff can be disentangled and one or more traced to causes in which the injuries he sustained through the accident play no part, it is the defendant who should be required to do the disentangling and to exclude the operation of the accident as a contributory cause. If it be the case that at some future date the plaintiff would in any event have reached his present pitiable state, the defendant should be called upon to prove that satisfactorily and moreover to show the period at the close of which it would have occurred. For myself I do not think that he has proved more than that at an earlier time than other men the plaintiff would have reached a stage of disability but not the same disability." 57 Clearly enough, the trial judge was not satisfied that the Appellant had satisfied the evidentiary onus inherent in such disentanglement. That was a conclusion properly open to him after taking into account, as a court properly should, evidence of the Respondent's current medical condition right up to the date of hearing when any actual incapacity may be ascertained: Thompson v Faraonio (1979) 24 ALR 1 (PC); Ruby v Marsh (1975) 132 CLR 642 per Barwick CJ at 647 and per Gibbs J at 658; Johnson v Perez (1988) 82 ALR 587; and Australian Telecommunications Commission v Parsons (1985) 59 ALR 535 at 542. The twisting injury — novus actus interveniens? 58 That leaves the Appellant's third causal candidate, namely the twisting injury. Essentially, the Appellant invokes the twisting injury in December 1996 as a novus actus interveniens. 59 The trial judge rejected the contention that the twisting injury was in no way connected with the original injury suffered by the Respondent in the supermarket; Red Book, 33 W-34 B. He treated that injury as resulting from a subsequent accident which would not have occurred had the Respondent not been in the physical condition caused by the Appellant's negligence. This has the legal consequence that the added damage should be treated as caused by that negligence. In so concluding he adopted the earlier quoted reasoning in State Government Insurance Commission v Oakley. 60 The trial judge, having accepted earlier the Respondent's evidence including the circumstances of the twisting injury concluded "there is no novus actus, this is a question of the plaintiff's condition which was I find caused by her fall of 22 March 1996 leading to an instability of her knee which then led to the further difficulties occurring in December 1996." (Red Book, 34 Q) 61 To this the Appellant argues that there was simply no medical evidence that the Respondent's right knee was unstable in December 1996 or that any instability present in December 1996 was caused by the condition of the Respondent as a result of the fall on 22 March 1996. It was further submitted that the weight of the evidence established that any instability caused by the fall on 22 March 1996 had been rectified by the second arthroscopy on 11 October 1996. 62 However, the latter proposition is clearly contrary to the conclusions of Dr Searle earlier cited. His conclusion was rather that the injury suffered in the earlier accident materially contributed to her being unable to continue with her employment as a nurse. That much the trial judge also accepted. He referred to there being "a material contribution to her ongoing disabilities in both the low back and right knee"; see Combined Appeal Book, 215 D-G. This in relation to the low back the trial judge did not accept — but he clearly did accept the knee injury as alone causative of the medical retirement. Moreover, and in no way inconsistently with the trial judge's findings, Dr Searle did deal with the twisting injury in his second report of 1 July 1998 in referring to Dr Perry's notes. Dr Searle concluded that, "I believe that this injury caused only a temporary aggravation of her problem and no additional damage to the right knee." Combined Appeal Book, 214 X. 63 It is well settled that it is not possible to establish a novus actus unless it can be shown that the earlier breach had no causative effect, even of the "but for" kind. The onus is on the wrongdoer to show that the injury would have occurred, or the same risk of it, even if the relevant duty of care had been performed; compare Chappel v Hart (supra) where the minority would have concluded that a surgeon's failure to warn did not materially contribute to the plaintiff's injury. The Appellant has not satisfied that onus. 64 Thus having accepted the Respondent's account of the pain she suffered after the twisting injury, it was open to the trial judge consistently with Dr Searle's evidence, to reject that aggravation as a novus actus. It was also open to him to conclude as he did that the knee was unstable judging simply by the Respondent's account of how the accident occurred. As to the questionnaires completed by the Respondent on 27 November 1995 (Combined Appeal Book, 46 W) and 12 March 1997 (Combined Appeal Book, 50 X), while it is true that the Respondent indicated under the heading "Instability" that there was "no giving way" in her right knee, under the heading "Locking" she refers to there being "no locking but catching sensations". While the trial judge did not rely on that evidence, it negates the suggestion that the questionnaires form such a weight of evidence as in the circumstances to require this Court to set aside the trial judge's conclusion. Conclusions 65 It was open to the trial judge to reject, either singly or in combination, symptomless pre-existing back condition, the pre-existing arthritic right knee and the twisting injury as a sufficient cause of the Respondent's ceasing to work. By sufficient cause, I mean, using more precise language than "a material cause", a cause sufficient by itself to bring about that medical termination without any contribution from the Appellant's negligence; as where the incidents leading to termination are the very kind of thing likely to happen as a result of that negligence. It follows that it was open to him to conclude, as he did, that none of these factors displaced the material contribution of the Appellant's negligence to the Respondent's medical termination.. 66 It follows that none of the damage suffered should be reduced. It was open to the trial judge to conclude, as he did, that the Appellant has failed to satisfy the shifting evidentiary onus upon it to establish, in circumstances of admitted negligence, that the damage suffered was the result of some pre-existing condition or incapacity on the part of the Respondent. In truth, the present case is simply one where the Appellant is liable for additional damage of a foreseeable kind suffered by a Respondent who has some special vulnerability; compare Smith v Leech Brain & Co Ltd (1962) 2 QB 405. In any event the trial judge, though unsatisfied on the Purkess v Crittenden test, nonetheless made ample allowance for the likelihood that any of the Respondent's pre-existing problems may come against her. ORDERS 67 I propose the following orders. 68 Appeal dismissed with costs. ********** DISCLAIMER - Every effort has been made to comply with suppression orders or statutory provisions prohibiting publication that may apply to this judgment or decision. The onus remains on any person using material in the judgment or decision to ensure that the intended use of that material does not breach any such order or provision. Further enquiries may be directed to the Registry of the Court or Tribunal in which it was generated.