Walsh v DHS & Ors [2014] VSCA 244

1 I have had the advantage of reading in draft the reasons for judgment of Tate JA and I agree with her Honour that the appeal should be dismissed.

2 The question of principle which arises in this appeal may arise in any case where a worker suffers current incapacity for work as a result of a workplace injury, later recovers some capacity to work, and then suffers an unrelated unconnected non-workplace injury to another part of his or her body which annihilates the residual capacity to work.

3 More precisely stated: if the effects of the latter injury taken in conjunction with any residual effects of the earlier workplace injury are such as to leave the worker with 'no current work capacity', does that state of 'no work capacity' 'result from' or is it 'materially contributed to' by 'an injury which entitles the worker to compensation' within the meaning of s 93 of the Accident Compensation Act 1985?

4 The judge below answered that question in the negative, and I agree with his Honour.

5 Authority makes clear that, where a worker suffers a workplace injury which exacerbates a pre-existing injury or condition, and thereby incapacitates the worker, the worker's state of incapacity is properly described as one which 'results from' the workplace injury. That is both logical and in accordance with principle. It is logical because, judged as a common sense question of fact, the workplace injury is a sufficiently substantial or proximate cause of the incapacity to say that the incapacity results from the workplace injury. It is in accordance with principle because, just as a tortfeasor must take his or her victim as he finds them, so must an employer take his or her employees as he finds them.

6 Authority also makes clear that, where a workplace injury is so much exacerbated by a subsequent non-workplace injury as to leave the worker incapacitated, the incapacity 'results from' from the workplace injury. Possibly, that

is less logical but it might be understood on the basis that the workplace injury renders the employee susceptible to an exacerbation of the injury by the subsequent non-workplace injury. Thus, the ultimate incapacity results from the workplace injury because it is that injury, albeit as subsequently exacerbated, which results in the incapacity.

7 To date, however, there is no authority that, where a worker suffers a workplace injury from which the worker recovers some diminished capacity to work, and then suffers an unrelated unconnected non-workplace injury which annihilates his or her residual capacity to work, the consequent incapacity results from the workplace injury.

8 Logically it might be supposed that, because the workplace injury results in a degree of incapacity that contributes to the ultimate state of total incapacity, there is enough connection between the workplace injury and the ultimate state of incapacity to say that the ultimate state of incapacity 'results from' the workplace injury. But logic is not the only consideration. There are also issues of policy. There is a lesser degree of connection between the workplace injury and the ultimate state of incapacity in the latter circumstances than between a workplace injury and an exacerbation of that injury by subsequent injury in the manner previously referred to. Thus far, courts have taken the view that any decision to recognise such a lesser degree of connexion as sufficient to attract an entitlement to compensation is a decision which should be left to Parliament.

9 In her judgment, Tate JA deals at length and in detail with the relevant authorities and shows that, so far as they go, there is no warrant for this court to make that decision in place of Parliament. Whether it is to be made otherwise than by Parliament, therefore, is something for the High Court to decide.

10 I have had the considerable advantage of reading in draft the reasons for

judgment of Tate JA. I agree with her Honour that for the reasons she gives the appeal should be dismissed.

11 This appeal raises the following question of law: Where a worker suffers total incapacity by reason of a workplace injury combined with a subsequent independent injury that is not work-related, is not caused by the workplace injury, and where there is no nexus between the two injuries, does the total incapacity 'arise from' the workplace injury? In my view, for the reasons set out below, the answer is 'No'.

12 The question arises in the following circumstances.

13 In May 2008, the appellant, Denise Walsh ('Walsh'), twisted her right knee in the course of her employment as a casual disability carer with the first respondent, the Department of Human Services ('DHS').

14 DHS accepted Walsh's claim under the Accident Compensation Act 1985 ('the Act') for weekly payments of compensation in respect of the right knee injury. The right knee injury was thus a compensable injury. She suffered anxiety and depression as a consequence of the right knee injury. Weekly compensation payments commenced on 16 July 2008. Walsh has not worked in any capacity since January 2010.

15 DHS terminated the weekly payments to Walsh with effect from 8 January 2011 on the basis that such payments had been made to her for 130 weeks and that she had a current work capacity.[1]

16 In April 2011, Walsh sustained a right shoulder injury and in November 2011 she sustained a left shoulder injury. Subsequently, she also developed low back pain. On 2 May 2011, Walsh made a claim on DHS for a right shoulder arthroscopy. On 13 July 2011, DHS rejected the claim on the basis that the surgery was needed for a condition that was not work-related.

17 On 29 June 2011, Walsh commenced a proceeding in the Magistrates' Court in which she sought to challenge the decision to terminate her weekly payments. Her challenge was put on the basis that she had no current work capacity. The Magistrates' Court proceeding was expanded also to challenge the decision rejecting her claim for a right shoulder arthroscopy.

18 On 19 July 2012, the Magistrates' Court referred six medical questions to a medical panel ('the panel').[2] The panel answered the medical questions in a certificate of opinion ('the opinion') with supporting reasons. In summary, the panel determined that Walsh had no current work capacity. It arrived at that determination on the basis of all of Walsh's injuries: the injury to Walsh's right knee; the anxiety and depression Walsh had suffered consequent upon the right knee injury; her right and left shoulder injuries; and her lower back pain. It acknowledged that the shoulder injuries and lower back pain were unrelated to the right knee injury and, implicitly, that they did not involve an aggravation or exacerbation of the compensable injury. The effect of the panel's determination was that DHS was obliged to continue to make weekly compensation payments to Walsh.

19 On an application by DHS for judicial review under Order 56 of the Supreme Court (General Civil Procedure) Rules 2005, a judge of the Trial Division of the Supreme Court found that the panel had made a jurisdictional error by failing to confine itself to the right knee injury and its consequences in deciding that Walsh had no current work capacity.[3] On the appeal, the primary challenge Walsh makes to the judge's reasons is that the judge erred in concluding that it is impermissible to aggregate the consequences of a compensable injury with the consequences of a subsequent non-compensable injury when determining whether a worker has no current work capacity.

20 Section 82(1) of the Act provides that a worker is entitled to compensation in accordance with the Act, '[i]f there is caused to a worker an injury arising out of or in the course of any employment'.

21 Section 93 contains an entitlement to compensation in the form of weekly payments where 'a worker's incapacity for work results from, or is materially contributed to by, an injury which entitles the worker to compensation', 'subject to and in accordance with this Part'.

22 Section 93C relevantly provides that a worker's entitlement to compensation in the form of weekly payments ceases after the worker has received such payments for 130 weeks[4] unless the worker has 'no current work capacity' and is likely to continue indefinitely to have 'no current work capacity'.

23 Section 5(1) defines 'current work capacity' and 'no current work capacity' as follows:

current work capacity, in relation to a worker, means a present inability arising from an injury such that the worker is not able to return to his or her pre-injury employment but is able to return to work in suitable employment.

no current work capacity, in relation to a worker, means a present inability arising from an injury such that the worker is not able to return to work, either in the worker's pre-injury employment or in suitable employment.[5]

24 Both definitions make reference to 'suitable employment'. That phrase is defined in s 5(1) as follows:

suitable employment, in relation to a worker, means employment in work for which the worker is currently suited -

(a) having regard to -

(i) the nature of the worker's incapacity and the details provided in medical information including, but not limited to, the certificate of capacity supplied by the worker; and

(ii) the nature of the worker's pre-injury employment; and

(iii) the worker's age, education, skills and work experience; and

(iv) the worker's place of residence; and

(v) any plan or document prepared as part of the return to work planning process; and

(vi) any occupation rehabilitation services that are being, or have been, provided to or for the worker; and

(b) regardless of whether -

(i) the work or the employment is available; and

(ii) the work or employment is of a type or nature that is generally available in the employment market.

25 The relevant questions submitted to the panel and the opinion are set out below, with Question 3 raising the critical issue of whether Walsh had no current work capacity:

Question 1)

What is the nature of the medical condition(s) (including any sequelae) resulting from:

(a) the accepted injuries to the right knee suffered by [Walsh] in an incident on or about 20 May 2008 in the course of her employment with [DHS];

(b) the alleged injuries (rejected by [DHS]) to:

(i) the right shoulder;

(ii) the left shoulder;

...

(iv) anxiety and depression.

Answer:

(a) In the Panel's opinion, [Walsh] is suffering from an aggravation of degenerative osteoarthritis of the right knee and from a medial meniscal injury, treated by medial meniscectomy, relevant to the accepted right knee injury.

(b) (i & ii) The Panel is of the opinion that [Walsh] is suffering from bilateral shoulder dysfunction, as a consequence of bilateral rotator cuff disease, which is not relevant to the alleged injuries.

...

(iv) The Panel is of the opinion that [Walsh] is suffering from a chronic adjustment disorder with depressed mood and some features of pain amplification, which has arisen as a consequence of, and is relevant to, the accepted right knee injury.

Question 2)

(a) Was [Walsh's] employment in fact; or

(b) Could [Walsh's] employment possibly have been -

a significant contributing factor to

(i) the accepted injuries to the right knee identified in question 1(a);

(ii) the alleged injuries (but rejected by [DHS]) identified in question 1(b)?

Answer:

The Panel is of the opinion that [Walsh's] employment could possibly have been and was in fact, a significant contributing factor to the accepted injury to the right knee and to the development of a chronic adjustment disorder with depressed mood, but not to any alleged injuries to the right shoulder [or] left shoulder ... nor to the recurrence, aggravation, acceleration, exacerbation or deterioration of any pre-existing injury or condition of the right shoulder [or] left shoulder ..., in any way.

Question 3)

Does [Walsh] have:

(a) a current work capacity;

(b) no current work capacity?

Answer:

In the Panel's opinion, [Walsh] has no current work capacity.

Question 4)

If yes to question 3(b), is [Walsh] likely to continue indefinitely to have no current work capacity?

Answer:

The Panel is of the opinion that [Walsh] has no current work capacity and this situation is likely to continue indefinitely.[6]

26 Walsh explained to the panel that her right shoulder symptoms had arisen when she was attempting to lift herself up from a chair and she attributed those symptoms to the injury to the right knee. This explanation was rejected by the panel:

The Panel took account of the nature of the incident on 20 May 2008, the nature and extent of [Walsh's] right knee condition and the subsequent development of a psychiatric condition, her persisting right knee symptoms since that time, the development of symptoms in the ... right shoulder and left shoulder, ... the worker's explanation of the development of the right shoulder symptoms, which she attributed to lifting herself up from her chair and the current findings on physical examination and on medical imaging.

In particular, the Panel noted normal muscle bulk and strength around the worker's shoulder girdles, normal power in her left and right buttock and lower extremity muscles, thus not compromising her ability to stand from a sitting position. The Panel also noted that the pathology in her right knee is mild to moderate, not severe, there is no instability in her right knee, she is able to fully extend her right knee, with only mild reduction in her range of flexion, and she was able to stand from the sitting position from a chair without arms, in the course of examination by the Panel, without obvious difficulty. ... Based on this information, the Panel concluded that lifting herself up from her chair did not have any effect on her right shoulder condition.

27 The panel considered the statutory criteria for suitable employment and concluded that there was no work for which Walsh was currently suited and, as her 'condition' was unlikely to change in the foreseeable future, she was likely to continue indefinitely to have no current work capacity.

The Panel concluded that the nature of the worker's right knee condition is such that she is not capable of performing her pre-injury duties as a casual personal carer.

The Panel took into account all aspects of the definitions of 'suitable employment', 'current work capacity' and 'no current work capacity' in the [Act] and in particular, her age of 55 years, (which limits her employment options); the nature of her right knee condition (which limits her degree of mobility) combined with her bilateral shoulder condition and low back pain (which further affects her capacity to undertake physically demanding work); the mild nature of her psychiatric condition (which limits her work capacity); her education to year 9; her transferrable skills, including a Certificate IV in disability care at TAFE Bendigo in 2008/2009, and previous work experience (involving working in a café for a few months, as a seasonal dried fruit packer and citrus packer and as a personal carer); her place of residence in rural NSW, 20 minutes from Mildura, (which would not limit her capacity for work); the medical information in the referral material from those doctors who have treated or examined the worker; and the absence of a return to work plan.

The Panel noted the vocational assessment reports from Konekt Australia ... in the referral material, which contain suggested job options for the worker. Based on its analysis of the criteria for suitable employment set out in the previous paragraph the Panel concluded that the suggested job options of outside of school assistance, disability support worker, employment consultant, customer services assistant, café worker, pharmacy assistant and aged care worker, would not constitute suitable employment for the worker.

The Panel considered that there is no work for which the worker is currently suited and which she could perform on a consistent basis. The Panel therefore concluded that the worker has no current work capacity.

The Panel considers the worker's condition is unlikely to change in the foreseeable future and therefore concluded that she is likely to continue indefinitely to have no current work capacity.

28 In arriving at its conclusions, the panel considered that Walsh's right knee injury limited her employment options because of its impact on her mobility.

29 The judge concluded that the panel had fallen into error largely on the basis that its approach to the statutory question it had been invited to answer was inconsistent with the principles enunciated by the High Court in Ward v Corrimal-Balgownie Collieries Ltd[7] which he took to be the definitive authority in the area. Walsh maintains on the appeal that Ward has been implicitly by-passed, or effectively overruled, by the Privy Council in Bushby v Morris,[8] and by the High Court in Conkey v Miller[9] and Calman v Commissioner of Police.[10] The judge considered that Ward was consistent with later authority.

30 In Ward the Workers' Compensation Commission of New South Wales ('the Commission') found that a worker, employed as a coal miner at the Corrimal-Balgownie Collieries, was totally and permanently disabled because he suffered from lung disease due to his exposure to dust in the course of his employment which caused him partial incapacity for work (assessed as 20 per cent) as well as suffering from arteriosclerosis and myocardial degeneration which was not due to the nature of his work but caused him partial incapacity for work (assessed at 80 per cent).[11] It held that the two conditions were not causally related and that the compensable injury itself did not result in the worker's total and permanent disablement.[12]

31 The finding of total and permanent disability was relevant because of a monetary limit that was imposed under statute on the grant of compensation except in the case of total and permanent disablement. Section 9(3) of the Workers Compensation Act 1926-27 (NSW) provided that:

[T]he total liability of an employer in respect of compensation under this section shall not, except in the case of a worker whose injury results in total and permanent disablement, exceed one thousand pounds in any one case.[13]

32 The Court held that a worker is not entitled to the benefit of the exception to the monetary limit where he or she suffers a compensable injury that results in partial incapacity and other causes, not associated with the compensable injury, later bring about total disablement.

33 Walsh, in seeking to distinguish Ward on the appeal, made much of the difference in statutory language between s 9(3) of the Workers Compensation Act 1926-27, where the required connection between the injury and the total disablement was described by the words 'results in' by contrast with the words 'arising from' used in the definition of 'no current work capacity' in s 5 of the Act. It was submitted that the words 'results in' might appear to call for a proximate or direct cause whereas 'arising from' can accommodate multiple causes or pre-conditions, including causes that are unrelated to each other and occur at different times to different body parts.[14]

34 The judge below acknowledged that, for the purposes of workers' compensation legislation, a single incapacity may be attributable to more than one injury (one compensable and one not work-related) but this will be so only in accordance with the following principles he identified as flowing from Ward:

(a) The proposition that a compensable injury need not be the sole cause of total and permanent incapacity only applies in accordance with the principles in (b) to (e) below.

(b) If a worker suffers from a medical condition which does not result in incapacity for work and then suffers a workplace injury which, acting on the underlying condition, renders the worker totally and permanently incapable of working, the total and permanent incapacity results from the workplace injury. An example is where the workplace injury aggravates an underlying condition. The workplace injury is regarded as the cause of the total and permanent incapacity even if the injury would not have resulted in another worker who did not suffer the underlying condition, becoming totally and permanently incapacitated.

(c) Where a workplace injury initially does not cause total and permanent incapacity but over time, without the intervention of a new cause, the injury worsens and eventually causes total and permanent incapacity, that incapacity results from the injury. The position is the same where the workplace injury is part of a chain of causation culminating in a single condition which amounts to total and permanent incapacity.

(d) If a worker suffers partial incapacity due to a workplace injury and, after suffering an independent injury which is unrelated to the workplace injury, the worker becomes totally and permanently incapacitated, the total and permanent incapacity does not result from the workplace injury; it results from 'the concurrent action' of both injuries. In other words, where a workplace injury and an independent cause produce independent consequences, distinct bodily conditions, which amount to total and permanent incapacity only because they must be added together, the total and permanent incapacity does not result from the workplace injury. For example, where a workplace injury causes partial incapacity and subsequently, through advancing age or other natural causes, the worker becomes totally and permanently incapacitated, the worker's employer is not liable for the total and permanent incapacity.

(e) If a workplace injury results in total and permanent incapacity and a subsequent independent and unrelated event, such as an illness, occurs which is sufficient to cause total and permanent incapacity, the workplace injury is still regarded as having resulted in the total and permanent incapacity.[15]

35 Importantly, principle (d) stands for the proposition that where a worker suffers a partial incapacity because of compensable injury, and is subsequently rendered totally incapacitated by reason of an unrelated and supervening cause (that is, because of a further or additional incapacity), the worker is only entitled to compensation for partial incapacity; it cannot be said that the total incapacity 'resulted from' the compensable injury.

36 In summary, the judge held that the panel was obliged to apply the principles he identified from Ward,[16] most especially principle (d),[17] and that it had failed to do so. He held that, given the findings of a lack of causal relationship between the compensable injury and the bilateral shoulder condition and low back pain, the panel was wrong to have taken into account the non-work related injuries and to have aggregated them with the compensable injury in assessing whether Walsh had no current work capacity. In doing so it had erred by taking into account considerations that it was obliged not to take into account and had misconstrued the nature of its statutory task.

37 The challenge on the appeal related particularly to the following passages of the judge's reasons, where he said:

What is important for present purposes are the following considerations:

(a) The Medical Panel did not make a factual finding that Ms Walsh's 'no current work capacity' arose from, or resulted from or was materially contributed to by her right knee injury and anxiety and depression.

(b) The Medical Panel made a factual finding that attributed Ms Walsh's 'no work capacity' to the nature of her right knee injury 'combined with' her bilateral shoulder condition, low back pain, anxiety and depression, and other factors.

In order for Ms Walsh to be entitled to continue to receive weekly compensation payments it was necessary for her to satisfy the definition of 'no current work capacity' in s 5(1) of the ... Act. To do so, she had to establish that she had 'a present inability arising from [her right knee injury and anxiety and depression] such that [she] is not able to return to work, either in [her] pre-injury employment or in suitable employment'.

In deciding whether Ms Walsh had satisfied the above statutory requirement for the purposes of answering medical question 3, the Medical Panel was obliged to apply the principles summarised [as flowing from Ward].

I reject Ms Walsh's submission that there is such a fundamental difference between the phrases 'results in' and 'arising from' that the principles in Ward do not apply to the present case. I also reject Ms Walsh's submission that Ward has been 'bypassed' by Bushby and Calman. ... the principles in those cases are consistent with Ward. However, I agree that in the light of the wording of s 93 of the ... Act, the phrase 'arising from' in the definition of 'no work capacity' in s 5(1) includes situations where a compensable injury materially contributes to a worker's inability to return to his or her pre-injury employment or to suitable employment. It also follows that the phrase does not require that a compensable injury be the sole cause of such an inability. In the discussion that follows, I will use the phrases 'arising from' and 'arose from' as including 'materially contributed to by'.

The analysis in the Medical Panel's Reasons is not consistent with the principles set out [in Ward]. ... The Medical Panel's finding that there was no causal relationship between Ms Walsh's compensable injuries (the right knee injury and the anxiety and depression) and her bilateral shoulder condition and low back pain means that principles (b) and (c) in Ward ... were not engaged. The Medical Panel's failure to find that Ms Walsh's 'no current work capacity' arose from her compensable injuries means that principle (e) in Ward was not engaged. ...[18]

38 The judge went on to hold that the panel had not concluded that Walsh suffered from a single incapacity and that the aggregation of compensable and non-compensable injuries was inconsistent with Ward:

Ms Walsh relied heavily on the principle that a single incapacity may result from independent injuries. However, the Medical Panel in the present case did not make a factual finding that Ms Walsh had a single incapacity that arose from the compensable injuries and the non-compensable injuries. There was no finding that the separate injuries affected only one set of work-related acts which Ms Walsh can no longer perform. Rather, as the Department pointed out in its submissions, the Medical Panel concluded that Ms Walsh's right knee injury affected her mobility whereas her bilateral shoulder condition and lower back pain affected her capacity to undertake physically demanding work.

None of the cases in which a single incapacity was held to arise from different injuries involved injuries to different body parts. ...

In my opinion, the second sentence of principle (d) in Ward ... would have applied to the present case if the Medical Panel had concluded that Ms Walsh's compensable injuries were insufficient to satisfy the definition of 'no current work capacity' and that that definition was only satisfied by adding to the consequences of those injuries the consequences of the bilateral shoulder condition and the low back pain. ... where there is no causal relationship between a compensable injury and a non-compensable injury and a medical panel decides that the definition of 'no work capacity' is satisfied only by aggregating the consequences of the compensable injury with the consequences of the non-compensable injury, the medical panel's opinion is vitiated by error of law.

In the present case, although the Medical Panel decided that Ms Walsh had 'no current work capacity' it did not do so by asking itself whether Ms Walsh's inability to return to work either in her pre-injury employment or in suitable employment arose from her right knee injury and anxiety and depression. Rather, the Medical Panel decided that Ms Walsh had no current work capacity based on a consideration of her compensable injuries and her bilateral shoulder condition and low back pain, notwithstanding the factual context ... . In doing so, the Medical Panel misconstrued the nature of its statutory task in answering medical question 3 and took into account considerations that it was obliged not to take into account. Accordingly, it made an error of law which is apparent on the face of the record of the Opinion. It is not necessary for me to decide whether the Medical Panel's error of law is jurisdictional in nature.[19]

39 The judge went on to reject the submission that the panel's reasons were inadequate. He ordered that the opinion be quashed and remitted the medical questions for redetermination.

40 The contest on the appeal was primarily directed to the issue of whether the panel had been obliged to apply the principles in Ward or whether Ward had been over-ruled by Conkey, Bushby and Calman. The question arose whether, if Conkey, Bushby and Calman established a new test, the circumstances of Walsh's injuries met that test. In any event, Walsh submitted that Ward was distinguishable, the statutory context being based on a different relevant causal relationship. The third issue Walsh raised on the appeal is whether the panel, in expressing the reasons it did, concluded that Walsh had a single incapacity, the judge having held that the panel did not make such a finding.[20]

41 Walsh emphasised the importance of recognising that total incapacity can have concurrent causes and there is no requirement under the Act, informed by modern views on causation, for a compensable injury to be the sole, proximate or direct cause of the total incapacity. She relied on what she described as the simple proposition that if the combined effect of a compensable injury and a non-compensable injury produces a total incapacity then the total incapacity 'arises out' of each injury, combined together. The alternative would be to conclude, absurdly, that the total incapacity arose out of neither injury because the incapacity could not be solely attributable to either injury. Walsh submitted that an incapacity that arises from both injuries gives rise to a single incapacity, in which case the first injury as well as the second must be an injury from which the total incapacity arose.

42 The challenge to the continuing application of Ward to the Act, and in particular to the definition of 'no current work capacity' under s 5(1) of the Act, included the claim that even in Ward Dixon J considered that a different view was available but that he was bound to follow a prior decision of the House of Lords.

43 In Ward Dixon J recognised that the Commission had found that the worker's total and permanent disablement 'was due to two causes operating concurrently'[21] but that there was no causal connection between them and that in the absence of the later condition, the arteriosclerotic and myocardial degenerative condition, the worker would not have experienced total incapacity or disablement. He distinguished between a single incapacity and an incapacity based on multiple or aggregated injuries; that is, where total incapacity originates from two independent causes. He considered circumstances where there is a 'chain of causation consisting of links representing different factors or events all terminating in a single conclusion, that is to say, in one condition amounting, as the case may be, to total or to partial incapacity'.[22] Such circumstances are different from those where total incapacity depended upon an aggregation of injuries, that is, where there are

... independent causes producing independent consequences, distinct bodily conditions which amount to total incapacity only because they must be added together. Cases of the latter description appear to me to be governed by the decisions relating to the loss or impairment of the sight of both eyes. The loss of the sight of one eye may or may not mean lasting incapacity, but usually it will mean no more than partial incapacity. If it is caused by an accident arising out of and in the course of the employment, the employer will, of course, be responsible to the full extent of the resulting incapacity. But if, from causes independent of the accident, the vision of the second eye is lost or impaired so that the worker becomes totally incapacitated, or his incapacity is greatly increased, then the employer is not responsible for this additional consequence. The total incapacity or increased incapacity is not considered to 'result' from the accident.[23]

44 The decisions relating to the loss or impairment of the sight of both eyes, to which Dixon J referred, included Hargreave v Haughhead Coal Co Ltd,[24] Lomax v Sutton Heath and Lea Green Collieries Ltd,[25] and Birch Brothers Ltd v Brown.[26] In Hargreave's Case a worker sustained an injury to his right eye arising out of or in the course of his employment as a miner and the right eye had to be removed. He received compensation for total incapacity until the employers ceased payments on 15 September 1910 and instituted proceedings for a review by the sheriff. At the date of the hearing by the sheriff in February 1911 it was proved or admitted that: (1) the worker was fit to resume his former work as a miner; (2) he had an incipient cataract in his left eye that was not due to the accident; (3) incapacity for work would result gradually from the cataract; (4) his condition was the same on 15 September as on 12 November 1910; (5) he had in fact resumed his work as a miner in December 1910; and (6) his wage-earning capacity was not diminished by the loss of his right eye. The sheriff-substitute ended the compensation as at 15 September 1910. The House of Lords held that he was right to do so and that the liability of an employer to pay compensation for an accident to a worker's right eye could not be extended to include liability for an injury not inflicted by the accident but owing to some supervening event such as a disease that destroyed the sight of the worker's left eye.

45 The Court in Hargreave's Case rejected the submission that the total incapacity 'resulted' from the injury because the incapacity was due to the combination of two concurrent causes, one of which was the injury due to the workplace accident. The appellant had submitted as follows:

The accident is the cause of the [total] incapacity to some extent because if the natural cause alone had operated the [total] incapacity would not arise; it does produce the resultant incapacity along with some other cause. The provision in the schedule says nothing about causa proxima and causa sine qua non, and it is submitted that the incapacity in this case does result from the injury within the meaning of that provision.[27]

46 While the statutory context was different,[28] the submissions rejected were substantially similar to those relied on by Walsh.

47 Lord Macnaghten took the view that to set aside the sheriff-substitute's decision would involve imposing an endless liability on an employer premised on speculation as to the chance of further diminished capacity. He emphasised the need for a connection between an accident and a later disease before an employer could be held liable. He said:

There is nothing to connect the accident with the disease. That being so, it seems to me that it is impossible to say that the award ought to have been kept open, unless your Lordships are prepared to hold that when a man being gifted by nature with two organs of vision loses one, the award ought always to be kept open on the chance of his losing the other before he becomes unfit to work or is unable to earn his livelihood.[29]

48 He thus rejected the theory of the 'stand-by eye', the theory that when a worker loses one eye he or she not only loses vision from that eye but also loses the attribute of having a stand-by eye; the worker becomes 'a one-eyed man, dependent upon the other eye remaining efficient'[30] and should be compensated accordingly.

49 Lord Atkinson was also concerned to avoid imposing an indefinite liability for compensation upon an employer based upon speculative external contingencies unconnected with the workplace. In focusing upon the lack of causation between the workplace accident and the cataract, he considered that attribution of liability ought reflect causal connection. He said:

[T]his cataract is not due to the accident - that is, that it is not caused by the accident. Now the compensation is given where the injury is caused by an accident arising out and in the course of a man's employment, and it is in respect of that injury, and of that alone, that the workman is entitled to receive compensation. The function of the schedule is to supply a measure of damages for that compensation; but a man is not entitled to compensation for an injury not inflicted upon him by the accident with which he meets.

If the argument of the appellant were well founded, then if a man loses one eye, inasmuch as if anything happens to the other eye he would become totally blind, the award must be for ever kept open in order to see whether that misfortune will ever befall him. If that were so, there would be no finality in such a case.[31]

50 Nevertheless he acknowledged, on grounds of fairness, a worker's entitlement to compensation from an employer for a workplace accident that accelerated or exacerbated a pre-existing injury when he said:

It is, on the other hand, quite understandable that, if a man is in a diseased condition at the time he meets with an accident, and the accident accelerates in any way his disease, that, as well as the actual physical injury directly caused by the accident, may be fairly taken into account. And if this cataract was in an incipient stage at the time when the injury to the right eye was sustained, and if that injury to the right eye accelerated the disease in the left eye, it might possibly be that the award should be kept open to meet further developments. But it appears to me - taking the finding here to be that this cataract did not exist at the time the man sustained the injury to his right eye, but that it developed subsequently, coupled with the ... finding, 'that the cataract in the left eye is not due to the accident' - that the award should not be kept open to meet the possibility of the consequences which may hereafter ensue.[32]

51 Lord Shaw also regarded the absence of a causal connection as decisive:

I think that the finding ... 'that the cataract in the left eye is not due to the accident,' destroys all causal link of connection between that ailment and any accident arising out of and in the course of the employment. The causal connection having been thus destroyed, it appears to me that it would be straining the statute and contrary to its provisions to apply it to a case like the present.[33]

52 Hargreave's Case was applied in Lomax where the worker's total incapacity was also due to the operation of two concurrent causes. The worker had lost his right eye in a workplace accident and later his left eye from a cause unconnected to his workplace. He could no longer work as a collier but could work as a dataller. Lord Hanworth MR limited the employer's liability so that it did not extend to an injury 'for which his employers were in no sense responsible; [the injury] arose from some cause wholly outside the employment'.[34] He identified the policy basis for limiting an employer's liability as recognising that an employer was not a worker's insurer. He said:

The Act deals with the liability and the responsibility of the employers for their workmen. It lays down certain limitations to that liability but the Act does not make the employers insurers, so that after one accident has happened they are to be responsible for all misfortunes which may arise to the workmen wholly independently of the employment given to the workman by the employers, and wholly outside the range of the Act.[35]

53 Lord Hanworth MR treated the proposition for which Hargreave's Case stands as based on what is fair and, despite the legislation using the language of 'results'[36] he made his observations on liability in terms of what could permissibly be said to 'arise' out of the workplace accident:

It appears to me ... that that case [Hargreave's Case] is a clear authority for this, that one must impute to the employers responsibility for the act for which they are liable, and no more, and that although some supervening event may put the workman in a much worse position, still, it would be unfair to the employers to keep the matter open in order that, later on, some responsibility might then be imputed to them which does not arise out of the accident.[37]

54 Scrutton LJ also applied Hargreave's Case but, if left to himself, would have embraced the stand-by eye theory.[38] He pointed to the anomaly which arose in the circumstances of the case that although a dataller was a lower paid employment than that of a collier, the worker's earnings after the accident were always more than his earnings before the accident due to a rise in wages and the worker therefore received no compensation. The injury to the worker's second eye rendered him blind and he continued to have no entitlement to compensation. The relevant legislation, which failed to compare earnings as at the date of the accident, had been repealed but the compensable injury was bound by the earlier Act.[39]

55 In Birch Brothers Ltd v Brown[40] Scrutton LJ raised the question why there should be any difference in principle between the compensation to which a worker is entitled if he or she suffers from a pre-existing disease which is aggravated by a workplace injury and that applicable if the workplace injury comes first and the unrelated disease comes later. In both instances, the incapacity results from two matters, only one of which is related to the workplace. In effect he asked the question: 'Why should the sequence be relevant?' In repeating the stand-by eye theory, he said:

A man with two eyes has each eye as a stand-by to the other; if he loses either, his condition is materially impaired, for he is deprived of a stand-by eye. It does not seem to me to make much difference whether he first loses an eye by disease and then loses the other eye by accident within the Act, in which case I understand it is agreed he would recover compensation for total incapacity; or whether he first loses an eye by accident, and then loses the other by unconnected disease. In the second case, I should have thought, the effect of the accident is that he becomes totally blind, whereas if there had been no accident but only disease, he would be able to see. In other words, the resultant blindness is caused by two combined causes, neither of which would produce it alone, the disease in one eye and the accident to the other.[41]

56 On appeal,[42] the House of Lords considered Hargreave's Case. Lord Tomlin described Hargreave's Case as 'having disposed of what may be called the theory of the "stand-by eye"'.[43] He said: 'The employer cannot be made responsible for the consequence of the loss of a second eye where there is no causal link between the accident and such loss'.[44] Lord Atkin went on to say, in a passage extracted by Dixon J in Ward:[45]

I think the case, however, is an authority for the proposition that in an ordinary case if a man loses one eye by accident in the course of his employment and afterwards loses his second eye by a cause unconnected with his employment the arising total blindness is not caused by the accident. Many people have thought this a hard saying, and that the accident would be in such a case at least half the cause of the blindness. But if this decision fails to give to the workman the full relief which the Act intended him to have, the Legislature alone can correct it ... Greer L.J. adopts the attractive view that a distinction should be drawn between a supervenient and an antevenient disability in the uninjured eye: and suggests that an injury to a sound eye when the other eye has incipient cataract should be treated as analogous to an accident to a man suffering from heart disease the full consequences of which must be attributed to the accident. However much one might be disposed to accept this view unfettered by authority, I think that the decision in Hargreave's Case too definitely dissociates from the results of the accident any infirmity in the uninjured eye to enable me to reconcile the decision with the distinction proposed.[46]

57 When Dixon J referred in Ward to those cases relating to the loss or impairment of the sight of both eyes, he was thus adverting to a line of authority under workers' compensation legislation that:

(1) understood that an impairment, including a total incapacity, could arise from concurrent causes: a compensable injury need not be the sole cause of a worker's impairment;

(2) accepted that fairness requires that where a workplace injury accelerates or aggravates a pre-existing impairment, or combines with a vulnerability or pre-disposition, the worker is entitled to compensation for the whole of the incapacity;

(3) concluded that subject to the exception for fairness identified in (2), attribution of liability of an employer should be based upon a causal connection between the workplace injury and the impairment suffered;

(4) understood that to make an employer liable for any additional impairment arising after a compensable injury, unrelated to the injury or the workplace, would be to render an employer a general insurer of its employees with indefinite liability that lacked any finality;

(5) accepted that it would be necessary for the Parliament to enact further legislation if it wished to impose such a burden on employers.

58 The line of authority thus supported the proposition that the sequence of a compensable injury and a non-compensable injury is relevant and is so because without that limitation the employer would be obliged to assume an on-going and indefinite responsibility for every injured employee from all extraneous future contingencies of accident, disease or injury. By contrast with the safeguards an employer could take against preventing injury in the workplace, including to those workers who have pre-existing conditions, the employer would have no capacity to guard against the risk of future contingencies unrelated to the workplace. The breadth of the potential liability spoke strongly against Scrutton LJ's view.

59 Dixon J concluded that the authorities relied on by Lord Atkin left no room for an employer to be liable for the total incapacity of a worker where that incapacity depended upon the combination of a compensable injury and a later independent and unrelated injury. He said:

When the total disablement of the worker is made up of a partial incapacity due to the injury for which the employer is liable and of a later disability or disabilities due to independent causes, it is, in my opinion, impossible, consistently with these decisions, to hold that the total disablement results from the injury.[47]

60 He did not indicate what view he would embrace if he was unburdened by authority.

61 In Ward Rich J also took the view that as Ward's total incapacity was due to injuries which were unconnected and independent, and 'between which there is no "causal link of connections"',[48] he was precluded by the authority of Birch Brothers Ltd v Brown and Hargreave's Case from holding that the total incapacity resulted from the pulmonary fibrosis.[49]

62 By contrast, the reasons of Latham CJ in Ward did not focus upon the pre-existing House of Lords authority. Rather, they analysed the legal doctrine of causation and implicitly distinguished between legal causation and non-legal or factual causation.[50] As he said:

The legal doctrine may be illustrated by considering the case of a worker who has a condition of heart disease which is not an injury within the meaning of the Act and which has not produced any incapacity. Although the worker has heart disease, he is able to earn full wages and, as his earning capacity is not diminished, he is suffering from no incapacity within the meaning of the Act ... If such a worker then receives an injury within the meaning of the Act and suffers incapacity as the consequence of the injury added to his heart disease, then the incapacity (total or partial as the case may be) in those circumstances results from the injury. The injury is an element which only completes the tale of circumstances which constitutes the cause of the incapacity in the non-legal sense: but in the legal sense it is itself the cause of the incapacity which therefore is said to 'result' from it.[51]

63 Latham CJ thus acknowledged that the determination of the legal cause of an injury will involve what the High Court has described more recently in Wallace v Kam[52] as 'a normative question as to whether legal responsibility for that particular harm occurring in that way should be attributed to a particular person' by contrast with 'a question of historical fact as to how particular harm occurred'.[53] He went on to say:

A partial incapacity which, in the sense stated, results from an injury may itself, without the intervention of any new cause, result in total incapacity; for example, a man whose eye is injured may be only partially incapacitated for a time, but the injury may, without any new cause operating, so develop as to produce complete blindness in both eyes. In such a case first the partial incapacity, and next the total incapacity, would have resulted from the injury. The position is the same if the injury aggravates an already existing disease so as to bring about incapacity, partial or total.[54]

64 He then focused upon whether legal responsibility should be attributed to an employer for a worker's total incapacity where the incapacity is due to the combination of a workplace injury and a subsequent unrelated accident or injury, and held that the employer should be held liable only for the partial incapacity attributable to the workplace injury:

[T]here may already be partial incapacity resulting from an injury, and other causes, quite independent of and not associated with the injury in any way, may afterwards bring about further or total incapacity. In such a case the worker is still entitled to compensation, but it is only the incapacity which is the result of the injury (and not the added incapacity which is the result of other causes) for which there is any liability under the Act. Thus if a man was suffering from an injury consisting in lung disease which produced partial incapacity he would be entitled to compensation in respect of that incapacity. If he subsequently became subject to a form of heart disease which was quite unconnected with his lung disease and by reason thereof became totally incapacitated, he would still be entitled under the Act to payment in respect of the partial incapacity which resulted from the injury, but only to payment for partial incapacity.[55]

65 He held that where two causes operate concurrently, only one of which is a compensable injury, and it is only in combination that they produce total incapacity, 'the total and permanent disablement of the applicant cannot be described as a disablement which resulted from the injury'.[56]

66 In my opinion, it is clear that, if Ward applies to the Act, the judge was correct in finding that the panel had erred in failing to apply the principles in Ward and had thereby misconstrued its statutory function and taken into account considerations it was obliged to ignore.

67 Walsh submits, however, that the principles in Ward do not apply to the Act. She argues that the statements of principle enunciated in Conkey, Bushby and Calman are not subject to the limitations identified in Ward.[57]

68 In Conkey[58] the worker had a heart attack at work and later died from a second heart attack a year later which was a month after he had ceased working. The second heart attack was certified as due to coronary artery disease said to be current for some two years. The first infarction was severe and the evidence was that it 'indicates, as a basis for such infarction, [that] you must have coronary atherosclerosis, so that he [Conkey] has got degenerative arterial disease of the heart'.[59] Conkey thus suffered from a pre-existing and progressive coronary disease.

69 There was evidence given by a medical practitioner that although the first heart attack did not cause the second, the first had a contributing effect in respect of the worker's death. This was because following the first myocardial infarction the damaged muscle would have been replaced by scar tissue reducing the amount of available cardiac muscle, rendering it more likely that a second myocardial infarction would cause death. In referring to this evidence, Barwick CJ said:

The evidence did not establish that the second infarction was caused by the first. Thus it may be said, and it was said, though perhaps in a qualified way, that the fatal infarction was 'an independent event'. But the Commissioner found that the deceased did not recover from the first infarction. His cardiac condition resulting from the infarction of August 1974 thus remained with him ... the effect of the medical evidence ... would seem to be that the work-caused injury to the heart at the time of the first infarction was so great that, there being no recovery, another infarction, no matter what its immediate cause, would most probably, if indeed not certainly, be fatal. In my opinion, such a statement warrants the conclusion that death by reason of myocardial infarction when it did ultimately occur, 'resulted' from the work-caused injury of the first infarction, even if it could not be said that the final infarction was itself caused by work-caused injury.[60]

70 Walsh emphasised that the High Court made no reference to Ward and that, contrary to Ward, the death was held to result from the earlier compensable injury, although it only came about by the contribution of a later non work-related injury.

71 In my view, the circumstances in Conkey were not addressed in Ward and this may explain the lack of reliance on Ward. The second infarction was not caused by the first and there was thus no single chain of causation that would otherwise have been sufficient, on an application of Ward, to conclude that the total incapacity was the result of the workplace injury. In that sense Conkey goes beyond Ward and was not an application of Ward.[61]

72 Nevertheless, the focus for the Court was on the connection between the workplace injury and the non work-related injury in the context of a progressive coronary artery disease. The connection was apparent from the fact that the first infarction caused damage to the heart muscle that weakened its reserves and thus rendered it more probable that a second infarction would be fatal. The Court's concern with the connection between the two injuries is evident from the basis on which the Court distinguished Commonwealth v Butler,[62] namely, that the Court there concluded, as a question of fact, that 'a fatal occlusion was unrelated to an earlier occlusion'.[63] It is also apparent from Barwick CJ's description of the second infarction as 'an independent event' 'perhaps in a qualified way' and the emphasis upon the cardiac condition from the first infarction having 'remained' with the worker and there having been 'no recovery' from the first infarction.[64]

73 In my view, Conkey could only be held to have implicitly overruled Ward if it is read as suggesting that the relevant question to ask is whether a workplace injury renders it more probable that a total incapacity will result if the worker suffers an additional non work-related injury than if the worker had suffered only the non work-related injury and there had been no workplace injury in the first place. Read in this way, the focus is not upon the connection between the two injuries (as part of a single chain of causation or otherwise) or the resulting incapacity from their aggregation, but solely upon the connection between the workplace injury and the total incapacity regardless of other circumstances of the case. The problem is that the answer to the question will almost invariably be 'yes' because the combination of a workplace injury, no matter how small, to whatever additional independent injury is experienced is more likely to result in total incapacity than would arise from the independent injury alone. But this is only to say that the workplace injury makes some contribution towards the total incapacity.

74 To conclude that an employer whose worker has suffered a workplace injury is liable for the whole of any incapacity to which the workplace injury makes some contribution would lead to absurdity, and I do not consider that Conkey should be read in that way. As DHS submitted on the appeal, one can consider circumstances in which an elite pianist suffers a compensable injury to his or her little finger which is medically minor in nature but which permanently precludes work as a professional pianist thereafter, without otherwise affecting the capacity for work. It would be anomalous if the effects of such an injury could be aggregated with the incapacitating effects of an unrelated and supervening condition (for example, paraplegia) to bring about a situation of 'no current work capacity' attributable to the pianist's employer.

75 In response, Walsh submitted that it was necessary to take a common sense approach and that a de minimis contribution made by a workplace injury to a total incapacity could be excluded on that basis.

76 However, such a response invites the prospect of serious contests over whether any particular workplace injury makes only a de minimis contribution to a total incapacity with no principled basis for resolution. Not only would the accompanying uncertainty invite speculative litigation but also there is nothing in the language of the statute to guide the evaluation of when the contribution made by a workplace injury to a worker's total incapacity has reached the relevant threshold.

77 Furthermore, the common sense approach does not resolve the difficulty arising from the combination of workplace injury and natural causes. DHS invited consideration of another example where a worker had suffered a permanent partially incapacitating physical injury but remained capable of sedentary duties on a full-time basis. As the worker ages and develops age-related medical conditions, the combined effect of the compensable injury and age would prevent him or her from working. The approach adopted by Walsh would mean that the worker would meet the definition of 'no current work capacity' notwithstanding that the compensable injury rendered the worker only partially unfit and the effects of age were necessary to bring about a situation of total incapacity.

78 In my opinion, to read Conkey in the manner submitted by Walsh would be to regard it not so much as bypassing, or impliedly overruling Ward, but rather as a wholesale rejection of the principles in Ward.[65] The variety of circumstances which Ward sought to grapple with, and the articulation of principles which the judge below carefully identified, would be swept away by a general rule attaching liability to an employer for a worker's total incapacity whenever a workplace injury has made some contribution to that incapacity. In other words, the normative question of legal causation, that of determining whether legal responsibility for particular harm should be attributed to an employer, would be answered by reference only to whether the employer had responsibility for a workplace injury which contributed to the worker's total incapacity. On this reading, Conkey would endorse an unlimited breadth of the scope of an employer's liability contrary to all the policy reasons supporting the earlier House of Lords authority applied in Ward.

79 I do not consider that Conkey can be properly read as intending the momentous step of sweeping away all the limitations previously understood as applying in the context of workers' compensation legislation. Rather, the tenor of the case was that it was a modest determination that focused upon the evidence. For example, in distinguishing Commonwealth v Butler for the reason mentioned above,[66] Barwick CJ said:

The case does not decide any principle of law. The statute requires the death to result from work-caused injury: whether it does or does not is a matter of fact. ...

However, in this case we have evidence of a much more positive kind ... .[67]

80 Furthermore, Walsh's submission that the circumstances of this case are analogous to those in Conkey cannot be made out. Walsh argued that Conkey 'directly translates to the present case, in which [Walsh] was injured at work, and this injury made her later incapacity (the compensable matter) from a second injury (not at work) more likely (as indeed happened)'. There was no evidence in this case that the injury Walsh suffered to her right knee was part of a progressive disease which diminished her body's resources to deal with the later injury to her right and left shoulders and her lower back pain. The later injury was wholly independent of the workplace injury, and not merely independent in a qualified way. Indeed, the suggestion that the workplace injury and the later injury were related was expressly rejected by the panel when it did not accept Walsh's evidence that the pain in her right shoulder developed by reason of her pushing herself up with her right arm out of a chair. The opinion set out Walsh's evidence:

[Walsh] said that in April 2011, she developed pain in the right shoulder, which she attributed to pushing up with her right arm to get out of her chair. She said that the onset of her right shoulder symptoms was not associated with the use of crutches, as she only briefly used crutches after each of her right knee operations. With respect to the cause of her right shoulder symptoms, she said that 'The only thing I can think of is getting up from my chair'.

81 The opinion went on to explain the panel's conclusion that the right shoulder condition was not connected to Walsh's ability to lift herself out of a chair and the workplace was not a significant contributing factor to the shoulder injuries.[68]

82 As set out above,[69] the panel answered the questions posed to it by certifying that Walsh is suffering from 'bilateral shoulder dysfunction, as a consequence of bilateral rotator cuff disease, which is not relevant to the alleged injuries'.[70] It also certified that Walsh's employment was a significant contributing factor to the right knee injury and consequence adjustment disorder it 'but not to any alleged injuries to the right shoulder [or] left shoulder ... nor to the recurrence, aggravation, acceleration, exacerbation or deterioration of any pre-existing injury or condition of the right shoulder [or] left shoulder, in any way'.[71] The evidence here is starkly different from that relied on in Conkey and, in my opinion, the circumstances are clearly not analogous.

83 Nor is it tenable to suggest that the right knee injury rendered the total incapacity more likely in anything other than the sense which I have rejected, namely that the impairment it caused made some contribution to Walsh's condition by rendering it more probable that the right and left shoulder injuries, and lower back pain, would leave Walsh totally incapacitated by comparison with the circumstance in which the later injuries had been experienced alone. The anomalies that flow from this approach justify its rejection.

84 In Bushby the worker, a bricklayer, had suffered spinal injuries on separate occasions and with different employers, first in 1964, when employed by George & McKern ('George'), and secondly in 1966 when employed by T H Bushby. He was found to have become totally incapacitated for work in 1973 and also in 1974-5, with different employers, as a result of the effects of each of the injuries and their treatment. The Privy Council held that an incapacity may be attributable to more than one cause and the finding by the Workers' Compensation Commission that the worker's incapacity resulted both from the accident of 1964 and from that of 1966 concluded the matter. It also held that there was no room for an artificial rule of law that one or other accident must necessarily be selected as the cause of the incapacity and that the existence of such a rule is unsupported by principle or authority.[72]

85 Walsh submitted that Bushby held contrary to Ward that the total incapacity resulted from the earlier compensable injury, although it only came about by the contribution of a later injury. It was argued that, with respect to the liability of the employer at the time of the first injury, the circumstances of Bushby directly translate into the present case.

86 The first injury suffered was a lumbar disc strain and the second injury was an aggravation and exacerbation of the pre-existing lumbar spinal condition.

87 The Privy Council did not refer to Ward. However, there was an extensive discussion of Ward in the New South Wales Court of Appeal, in Morris v George,[73] from which the appeal was brought to the Privy Council. The Privy Council affirmed the decision of the Court of Appeal.

88 In Morris v George there were two questions of law before the Court. One concerned the liability of a principal under the relevant legislation[74] given that George was a contractor and Glenmore Pty Ltd, another party to the proceedings, was the principal. The second question was whether the legislation contemplated that in respect of a given period of incapacity there can be an award against more than one respondent. The trial judge found that the incapacity upon which the awards were based resulted from the first and second injuries. It was argued that an incapacity cannot in law be the result of two injuries received in the service of two employers. In the Court of Appeal, Glass JA referred to Dixon J's analysis of causation in Ward, as quoted above,[75] and identified the following propositions as ones that he could 'extract without loss of meaning' from Dixon J's analysis:

(1) A worker may suffer from a double disability due to two independent injuries which equally incapacitate him. Although neither injury is the only cause, his incapacity for work is, nevertheless, the result of each of them.

(2) A worker may suffer from a single disabling condition which has been produced by the combined operation of two independent injuries. His incapacity may be treated as the result of both.

(3) A worker may suffer from an overall incapacity resulting from the combined effect of two disabilities independently caused by two injuries. The employer responsible for part of that incapacity is not responsible for the whole incapacity resulting from the addition to it of the other part.[76]

89 He held that, in the circumstances of the case, 'the second of the above propositions is alone relevant';[77] that is, he characterised Morris's lumbar spinal condition as 'a single disabling condition ... produced by the combination of two independent injuries' rather than 'an overall incapacity resulting from the combined effect of two disabilities independently caused by two injuries' as was the case in Ward. Thus, far from bypassing or implicitly over-ruling Ward, Glass JA reasoned in terms that applied Ward.[78] Importantly, Glass JA, while viewing the two injuries as independent rather than the first being the cause of the second, distinguished between the two circumstances, a single disabling condition and an overall incapacity, just as Dixon J had done in Ward.[79] The single disabling condition was the degenerative condition of Morris's lumbar spine.[80] Thus, he attached importance to the impact of the injuries on the same body part; it was this that gave rise to the single disabling condition of which Glass JA spoke.

90 Hope JA, who largely agreed with Glass JA, also treated the two injuries as independent rather than causally related. Relying on Conkey he observed that it 'leads to the conclusion that a tribunal can find that a particular incapacity resulted from each of two injuries, and make awards against two different employers, even though those injuries are independent injuries'.[81] However, he recognised that, while there might not be a requirement for a causal connection, there is a requirement for a nexus between the injuries, which nexus can be satisfied by both injuries occurring to the same bodily part. A nexus between the injuries thus provides a real connection between the first injury and the total incapacity. In this context he referred to Pyrmont Publishing Co Pty Ltd v Peters[82] and said:

There the applicant injured his neck at work, and suffered a second injury to his neck while rockfishing. His slipping and striking his head and back on a rock while fishing had no causal connection with the first injury. Nonetheless, an award in respect of his incapacity following his second injury, but based on his first injury, was upheld. The nexus between the first injury and the incapacity was the neck condition caused by the first injury. In relation to this nexus, Jacobs JA ... said 'There must be a real connection between the pre-existing condition and the incapacity which was immediately caused by the later injury'.[83]

91 Moffitt P emphasised the causal connection between the injuries, the first involving a narrowing of the intervertebral disc space at the L5-S1 level and the later involving an intervertebral disc protrusion at the L4-5 level which was surgically excised. He noted that because of the different disc space involved, the medical question arose whether the protrusion could be related to the original injury in 1964. He observed that 'there was medical opinion that the first accident did damage the disc the subject of the operation, that accident [where the worker tripped and fell] "causing the chain of events that led to its eventual protrusion which required surgical removal"'.[84] In finding that 'one incapacity may result from two causally interrelated work injuries'[85] with the effect that two employers are each liable, he relied upon a judgment of Bray CJ in Bratovich v Rheem (Aust) Pty Ltd[86] which he considered was 'considerably influenced'[87] by a passage which he italicised from the judgment of Dixon J in Ward, where Dixon J referred to the statement that an incapacity need not be solely caused by the injury and said:

The statement may contemplate also a chain of causation consisting of links representing different factors or events all terminating in a single conclusion, that is to say, in one condition amounting, as the case may be, to total or partial incapacity.[88]

92 This observation by Dixon J was made immediately before the further remark:

But it is not concerned with independent causes producing independent consequences, distinct bodily conditions which amount to total incapacity only because they must be added together.[89]

93 Thus Moffit P based his conclusion precisely on the distinction made in Ward, between a single disabling condition produced from multiple injuries in a chain of causation and an overall incapacity arising from the aggregation of impairments to distinct bodily conditions. He further contrasted the circumstances where there are two causally independent injuries from those where there is a causal relationship between an initial and a later injury:

[W]here nothing more appears than that there are two independent i.e. causally unconnected successive injuries, the incapacity, if any, which follows the first results from it, and the further incapacity which follows the second results from it. In the simplest example if one eye is lost in one accident and, quite unconnectedly, the other eye is lost in a second accident, then the incapacity, if any, from being one-eyed results from the first accident, and the additional incapacity from being blind, as against one-eyed, results from the second accident. On these simple facts, there would be no evidence to find incapacity due to blindness resulted from the first accident.[90]

94 In the present case, there is neither a causal connection between the injuries nor is there a nexus between the knee injury with its consequent anxiety and depression and the later injuries to the right and left shoulders and the lower back pain, in the form of successive injuries to a single bodily part. As the panel found, the knee injury was 'not relevant' to the later injuries.[91] The ultimate incapacity depends on adding together unrelated distinct bodily conditions. These matters preclude Bushby being directly translated to Walsh.

95 In Calman, a police officer had an underlying work-related anxiety disorder and he became incapacitated after he received notice of a transfer. Receiving the notice exacerbated the underlying anxiety disorder and gave rise to an incapacity. A claim for compensation was rejected and the officer appealed to the Government and Related Employees Appeal Tribunal which found that his anxiety disorder was contracted in the course of his employment and to which his employment as a police officer was a contributing factor. It was thus a compensable injury. However, it also found that the officer's incapacity for work was the result of the exacerbation of his anxiety disorder and that the officer's employment was not a contributing factor to the exacerbation. It found that the sole factor which contributed to the exacerbation was the decision to transfer the officer to perform duties in the Sydney metropolitan area and the consequential effect the communication of that decision had upon him. It also found that the decision to transfer was not made in the course of his employment as a police officer, the decision being one of a number of decisions to transfer officers.

96 The tribunal considered that had the decision to transfer the officer not been made, the underlying anxiety disorder would not have progressed to the stage of incapacity for work. It thus found that the incapacity did not 'result from' the anxiety disorder. The High Court held that this was wrong, relying on Conkey for the proposition that an incapacity may result from a compensable injury even though it also results from other causes, including later causes. The Court said:

Once the appellant established that his underlying anxiety disorder was an injury within the meaning of the Workers Compensation Act, he was entitled 'to compensation ... under [that] Act' upon proof that his total or partial incapacity for work resulted from that injury. The question then for the tribunal was whether the appellant's incapacity was causally connected to the underlying anxiety disorder. It has long been settled that incapacity may result from an injury for the purposes of workers' compensation legislation even though the incapacity is also the product of other - even later - causes.[[92]] Indeed, death or incapacity may result from a work injury even though the death or incapacity also results from a later, non-employment cause. Thus, in Conkey & Sons Ltd v Miller, Barwick CJ, with whose judgment Gibbs, Stephen, Jacobs and Murphy JJ agreed, held that it was open to the Worker's Compensation Commission to find from the medical evidence in that case 'that the death by reason of myocardial infarction when it did ultimately occur, "resulted" from the work-caused injury of the first infarction, even if it could not be said that the final infarction was itself caused by work-caused injury'.[93]

97 The Court went on to emphasise that the decision to transfer had exacerbated the underlying anxiety disorder:

Whether incapacity results from injury is a question of fact. Upon the findings in this case, however, the answer to that question could admit of only one answer. As a matter of law, the tribunal was bound to find that the incapacity of the appellant resulted from injury within the meaning of s 33 of the Workers Compensation Act. Although the incapacity would not have arisen but for the appellant being told that he was to be transferred, there would have been no incapacity but for the existence of his underlying anxiety disorder. The incident, which was the immediate cause of his incapacity, merely exacerbated the underlying anxiety disorder which continued to exist, notwithstanding that immediately before the incident it manifested no symptoms. In those circumstances, the injury was a contributing cause to the incapacity. As Jordan CJ pointed out in Salisbury v Australian Iron and Steel Ltd:

It is not necessary that the employment injury should be the sole cause of disability. It is sufficient if it is a contributing cause. It may be the catalyst which precipitates disability in a medium of disease. But when the stage is reached at which the employment injury ceases to produce effects and could therefore no longer be a contributing cause to any incapacity which may then exist, the right to compensation ceases.

In the present case, the underlying anxiety disorder continued and was capable of producing serious effects if exacerbated or aggravated, as the tribunal's findings showed. That being so, the tribunal was bound to find as a matter of law that the appellant's incapacity resulted from injury within the meaning of s 33 of the Workers Compensation Act.[94]

98 Walsh relies on Calman for a general principle that she submitted was contrary to Ward, namely, an incapacity can result from an earlier compensable injury even if there has been a subsequent event contributing to the incapacity, which was not compensable. Implicit in the principle is the recognition that, as in Calman, the later injury was not caused by the earlier compensable injury. If the later injury had been caused by the earlier injury the incapacity would have resulted from the compensable injury on orthodox grounds, as recognised in Ward,[95] because of the causal connection. The proposition for which Walsh contended was rather that Calman, as well as Bushby and Conkey, stand for the principle that an incapacity can result from an earlier compensable injury even if there has been a subsequent independent non-compensable injury which contributed to the incapacity. Walsh submitted that these modern authorities establish that, contrary to previous views, for the purposes of workers' compensation legislation an incapacity to return to work may result from more than one injury, and such an incapacity may result from a work injury even though the death or incapacity also results from a later, non-employment cause. The circumstances of Walsh's injuries fit neatly into this approach. If the approach was correct, Walsh's total incapacity would clearly result from her right knee injury, and consequent anxiety and depression, even though it also resulted from her right and left shoulder injuries, and lower back pain, which were not employment-related and were independent of her right knee injury. For the total incapacity to result from the right knee injury, it would be sufficient that the right knee injury was a contributing cause of that incapacity.

99 If Walsh was correct in identifying the principle for which Calman stood, Calman would indeed have implicitly over-ruled Ward because Ward expressly rejected the view that a worker's total incapacity can be said to result from a compensable injury when the total and permanent disablement is only experienced after the occurrence of a later non work-related injury not associated with the compensable injury. However, I do not consider that Walsh has correctly identified the principle for which Calman stands.

100 In my opinion, Calman recognises the need for a nexus to exist between a compensable injury that causes partial incapacity and a later independent non-employment injury, after which a worker suffers total incapacity, before it can be held that the total incapacity resulted from the compensable injury. On the facts of Calman the nexus consisted in the continuation of the anxiety disorder and its aggravation or exacerbation from the communication to the police officer of the decision to transfer him. Thus, although the later injury was 'independent' in the sense that it was not caused by the earlier compensable injury, it remained the case that a nexus existed between the two injuries. This is supported by the repeated references in the passage extracted above[96] to the later injury 'merely exacerbat[ing]' the underlying anxiety disorder which remained 'capable of producing serious effects if exacerbated or aggravated'. It is also supported by the basis on which the Court concluded that the tribunal was bound to find that the incapacity resulted from the early injury; namely that it lay in 'that being so', referring to the exacerbation of the underlying disorder. The Court did not indicate that it was sufficient for an incapacity to result from an early compensable injury providing only that the injury was a contributing factor to the incapacity, as Walsh would have it.

101 There is further support for the view that the Court in Calman recognised the need for a nexus between an early compensable injury and a later non work-related injury by the reliance placed upon Salisbury v Australian Iron and Steel Ltd[97] where the example was given of an employment injury being a contributing cause to a disability by means of 'precipitat[ing] disability in a medium of disease'. Moreover, the Court also relied upon Conkey and Bushby and I have already explained why I consider that in each of those cases the incapacity was considered to have resulted from the early compensable injury because of the recognition of a connection (albeit not causal) between the compensable injury and the later non work-related injury. In Conkey the connection between the workplace injury and the non work-related injury was that both occurred in the context of an underlying progressive coronary artery disease so that the compensable injury had the effect of reducing the heart muscle's reserves to resist a second infarction being fatal. In Bushby the connection was that both injuries occurred in the context of a single disabling condition, namely, the degenerative condition of Morris's lumbar spine; the nexus was satisfied by both injuries occurring to the same bodily part.[98]

102 The judge below considered that Conkey and Bushby were both consistent with principle (c) derived from Ward[99] and that Calman was consistent with principles (b), (c), and (e) derived from Ward.[100] Principle (b) is concerned with a workplace injury acting on an underlying condition which renders a worker totally incapacitated. It does not address a subsequent non work-related injury. Principle (c) is concerned with a workplace injury that ultimately causes total incapacity, without the intervention of a new cause and, relevantly, where the workplace injury is part of a chain of causation culminating in a single condition which amounts to total and permanent incapacity. It does not address the circumstance where the work-related injury does not cause the subsequent non work-related injury. Principle (e) applies where a workplace injury results in total incapacity and an independent event occurs which also causes total incapacity. This principle does not address the circumstance where the workplace injury causes only partial incapacity and it is only after the later non work-related injury that the worker experiences total incapacity. With great respect to the judge below, I do not consider that the circumstances in Conkey, Bushby and Calman are adequately explained by principles (b), (c) and (e) from Ward although there is no inconsistency between the modern authorities and those principles.

103 In my view, the relevant principle arising from Conkey, Bushby and Calman is a principle that is implicit in principle (d) as formulated by the judge but should be expressed positively. Principle (d) was expressed negatively, in terms which state when a total incapacity will not be held to result from a workplace injury. It was expressed as follows:

If a worker suffers partial incapacity due to a workplace injury and, after suffering an independent injury which is unrelated to the workplace injury, the worker becomes totally and permanently incapacitated, the total and permanent incapacity does not result from the workplace injury; it results from 'the concurrent action' of both injuries. In other words, where a workplace injury and an independent cause produce independent consequences, distinct bodily conditions, which amount to total and permanent incapacity only because they must be added together, the total and permanent incapacity does not result from the workplace injury. For example, where a workplace injury causes partial incapacity and subsequently, through advancing age or other natural causes, the worker becomes totally and permanently incapacitated, the worker's employer is not liable for the total and permanent incapacity.

104 The negative formulation of the principle was understandable given that it sought to express a principle derived from Ward and the result in Ward was that the total incapacity was held not to be the result of the workplace injury. It was principle (d) which served as the basis upon which the Court in Ward refused to recognise that the total incapacity resulted from the workplace injury.

105 However, there is a need for a positively expressed principle to explain why it is that in Conkey, Bushby and Calman the total incapacity was held to result from an earlier workplace injury, in circumstances where the worker suffered a subsequent independent non work-related injury, not caused by the workplace injury, and where the workplace injury alone would have caused only a partial incapacity. In my view, that positive principle is nevertheless implicit in principle (d), which can be recast as follows:

If a worker suffers partial incapacity due to a workplace injury and, after suffering an independent injury which is related to the workplace injury, the worker becomes totally and permanently incapacitated, the total and permanent incapacity results from the workplace injury; it results from 'the concurrent action' of both injuries. In other words, where a workplace injury and an independent cause produce consequences by reason of aggravating or accelerating a single underlying condition or disease, or impact upon the same bodily part, the total and permanent incapacity results from the workplace injury. For example, where a workplace injury causes partial incapacity and subsequently, through an independently caused but nevertheless connected non-workplace injury, the worker becomes totally and permanently incapacitated, the worker's employer is liable for the total and permanent incapacity.

106 This principle, which can be called principle (f), is consistent with Ward. It is the complement of principle (d). In particular, it is consistent with the observation made by Dixon J, extracted above,[101] that total incapacity does not result from a compensable injury if the independent causes produce independent consequences in respect of distinct bodily conditions which amount to total incapacity only because they must be added together. I do not consider that Conkey, Bushby or Calman have by-passed or implicitly overruled Ward; rather, the modern authorities have drawn out the positive implications of Ward.

107 Importantly, the requirement for a nexus between the compensable and non-compensable injuries, recognised in Conkey, Bushby and Calman, respects the history and the policy that lie behind the line of authority upon which Dixon J relied in Ward. It ensures that an employer is not faced with an indefinite liability for any injury suffered by a worker who had earlier experienced a workplace injury, no matter how unrelated the injuries are. It ensures that the normative question asked about the appropriate scope of the liability of an employer at law, the legal doctrine of causation, adverted to by Latham CJ in Ward, is answered without placing an employer in the position of a worker's insurer. It avoids the anomalies that would result if there were no requirement for a connection between the injuries.

108 In my opinion, Conkey, Bushby and Calman, while they do not involve an application of Ward, are compatible with Ward and the English authorities that preceded it.

109 Walsh relied on two decisions of the New South Wales Court of Appeal, in Switzerland Insurance Workers Compensation (NSW) Ltd v Burley[102] and in Medcalf v Perry,[103] as supporting her case.

110 In Switzerland Insurance the worker had suffered four injuries to his back over time while employed by two different employers. All of the injuries were employment-related.[104] There were three different insurers and questions of the apportionment of liability arose, most especially whether the Compensation Court had the power under the relevant legislation[105] to order apportionment. It was found at first instance that the totality of the injuries suffered by the worker had a cumulative effect on his capacity for work and, in particular, the last injury 'made a causative contribution to the incapacity which resulted'.[106] On the remittal of a cross-appeal,[107] one insurer, QBE, argued that the trial judge ought to have found that the insurer on risk at the time of the last injury was wholly responsible for any compensation payable. Priestley JA, with whom Meagher JA agreed, held that subsequent legislation had had the effect of making the question raised by QBE of no continuing relevance and he did not decide it.[108] Mahoney P held that the ground was unarguable as the judge had ordered compensation by reference to all of the injuries and held the first injury to be mainly responsible. Those findings stood as QBE had abandoned the grounds of appeal in the cross-appeal that suggested they were wrong. The findings sought in the cross-appeal that QBE was not liable at all could only be made if the first injury, when QBE was the insurer of the relevant employer, could not be taken into account in determining compensation. This would have been inconsistent with the findings made at trial that were not contested on the appeal. In the course of a general discussion about the power of a court to apportion liability between employers and between insurers, Mahoney P noted that, contrary to some earlier views, 'as the result of the Morris v George litigation, it was authoritatively determined that an incapacity could result from more than one injury'.[109] That proposition is not in contest in the present case.

111 Medcalf v Perry was concerned with a statutory defence that an employer could rely upon in proceedings brought by a worker independently of the Workers' Compensation Act 1926 (NSW) where the employer had made payments of compensation under the Act. The defence was limited to the extent of compensation paid. The Court of Appeal held that where a worker suffered a single incapacity for work that had resulted from two injuries both of which were sustained during the course of employment with the one employer, but the worker's right to recover damages differed in respect of each injury, it was proper to apportion the benefit of the statutory defence as between the two injuries. The worker had injured her back twice while employed by a district hospital. It was found that each injury had made an equal contribution to the worker's permanent incapacity. Bushby v Morris was relied upon for the proposition that a single incapacity could be attributable to more than one injury.[110] Again, the proposition is not in contest in the present case.

112 There is thus no need to qualify the conclusion I have reached by reason of either Switzerland Insurance or Medcalf v Perry.

113 An application of principle (f) to the circumstances of the present case is clear. The panel found not only was there no causal relationship between the compensable injury and the later injuries, but there was no nexus or connection between them. The shoulder injuries were 'a consequence of constitutional bilateral rotator cuff disease', unrelated to the injury to the right knee. As the panel certified in response to Question 2) (b) (i)&(ii),[111] and as mentioned above,[112] the shoulder injuries were 'not relevant' to the compensable injury. This was not an instance of the non work-related injuries aggravating or accelerating an underlying condition or disease (such as a progressive coronary disease, or an anxiety disorder) or acting upon the same bodily part (such as the lumbar spine).

114 In my opinion, the panel was wrong to conclude that, for the purpose of the definition of 'no current work capacity' in s 5(1) of the Act, an injury that is supervening and unrelated can be aggregated with a compensable injury so as to give rise to an indivisible state of no work capacity. The panel thus misconstrued its statutory function and took into account irrelevant considerations in arriving at its conclusion. In determining whether Walsh had no current work capacity, within the meaning of the Act, the panel ought to have confined itself to the incapacity that flowed from the compensable injury alone.

115 Walsh submitted that, even if Ward has not been implicitly over-ruled by the later authorities, it can be distinguished because of the difference in the statutory language between the legislation at issue in Ward and the Act, as mentioned above, [113] with the former requiring that an injury 'results in' total disability and the latter requiring that the condition of no current work capacity be one 'arising from' an injury. DHS conceded, on the hearing of the appeal, that Ward would not have direct application to the Act because it concerned a different statute.

116 In light of the conclusion I have reached above, namely, that Conkey, Bushby and Calman require for their explanation an additional principle beyond that recognised in Ward, although consistent with Ward, it may seem unnecessary to examine this additional submission. However, the legislation under consideration in all of these authorities used the language of 'results in' rather than 'arising from' and, with that in mind, I will consider what relevance might attach to the use of different statutory language.

117 It was submitted by Walsh that the language of 'results in' may suggest a need to identify a sole proximate cause. By contrast the words 'arise from' have a wider connotation than 'caused by' or 'as a result of' and are satisfied by a consequential relationship. The relevant causal relationship is not required to be immediate, direct, proximate, real, sole or dominant.[114] In support of this proposition Walsh relied on the judgment of Newnes AJA (with whom McLure and Buss JJA agreed) in Butler v St John of God Health Care Inc[115] who said, in the context of the construction of a deed of release:

The releases and discharges are expressed to be 'in connection with', 'arising out of' or 'in respect of' allegations of vilification, victimisation and discrimination previously made by the appellant ... While their meaning must, of course, depend upon their particular context, in their ordinary usage each of the expressions 'in connection with', 'arising out of' and 'in respect of' is of wide connotation.

...

While there is no easy test for the nature or extent of the causal or consequential relationship involved in the words 'arising out of', the relationship is less than that required by words such as 'caused by' or 'as a result of': beyond that it is a question of judgment on the particular facts.[116]

118 So too Osborn J in McCann v Roads Corporation observed, in the context of a disputed valuation under the Land Acquisition and Compensation Act 1986 (Vic) that the words 'arising from' are broad words.[117] Within the context of the Repatriation Act 1920 (Cth) the Full Court of the Federal Court in Repatriation Commission v Law[118] distinguished between the requirement that incapacity or death 'resulted from' war service and death or incapacity that 'has arisen out of' war service. Bowen CJ, Brennan and Lockhart JJ said:

The Act does not say death which is 'caused by' or 'results from' his war service - phrases which might connote a proximate causal relationship. The expression 'arisen out of' is satisfied if some less proximate causal relationship is established. Of course, a suggested relationship which is fanciful is not sufficient; and a suggested relationship may be so tenuous as to preclude its consideration as answering the description of 'arising out of'.[119]

119 Even if it be accepted that the words 'arising from' in the definition of 'no current work capacity' in the Act are broader than a requirement of causation, in my opinion this can make no difference to my conclusions. The question of whether a non work-related injury, sustained subsequently to a compensable injury, is to be included in an assessment of whether a worker has no current work capacity, with the effect of continuing indefinitely the liability an employer has for weekly payments of compensation, involves normative issues about the appropriate scope of liability, as I have endeavoured to explain. These are not issues that are resolved simply by the replacement of words of causation, 'results from', by words with a somewhat broader connotation such as 'arising from'. If the Legislature intended that an employer's liability was to extend not only beyond that recognised in Ward but also beyond that recognised in Conkey, Bushby and Calman, it would be expected to have made that intention unequivocally plain. It has not done so.

120 I consider that the change in statutory language cannot bear the weight that Walsh seeks to place upon it.[120]

121 Walsh submitted that the judge was wrong to find that the panel did not make a factual finding that she suffered from a 'single incapacity' that arose from the compensable injuries and the non-compensable injuries. It was submitted that the panel did so find and that, furthermore, the judge also acknowledged that the panel had decided that Walsh had no current work capacity based on a consideration of her compensable injuries and her bilateral shoulder condition and low back pain. The lack of current work capacity was thus a singular state based on a combination of compensable and non-compensable injuries.

122 In response DHS accepted that multiple injuries could give rise to a single incapacity, as, for example, when the Privy Council described Morris's condition in Bushby as 'one and the same incapacity'.[121] However, it argued that whether multiple injuries do give rise to a single incapacity is a question of fact, to be guided by the considerations identified by Mahoney P in Switzerland Insurance, and that the injuries suffered by Walsh do not indicate that she bore a single incapacity.

123 In Switzerland Insurance, Mahoney P identified an incapacity as characterised by an inability to do work related acts.[122] There may be discrete inabilities, for example, when arising from injuries to distinct body parts, or there may be multiple injuries which preclude a worker from doing the same set of work related acts. He said:

[T]here may be various combinations of injury and incapacity and, in my opinion, each may support a proceeding for compensation. Thus, there may be one or more injuries. The injury or injuries in question may result in one or several forms of or combinations of incapacity. Sometimes it involves incapacity for work which results from a single injury ... Sometimes it involves two or more discrete injuries, each of which produces a discrete incapacity, ie, a discrete inability to do work related acts. Thus, one injury may affect the arm and the other the leg; each injury may result in an inability to do, respectively, things which formerly the worker did by his arm and by his leg and each may produce an incapacity for work. In such a case, the separate incapacities may be able to be identified and separately assessed.

...

Sometimes, a proceeding may involve two or more separate physical injuries, each of which is separate from the other but (I use a neutral term) each of which goes to the same thing. Back injuries often are of this kind. Thus, the first injury may cause a spinal disc to protrude from its place, to cause pain, and to incapacitate the worker from doing some work related acts. The next injury may cause the disc to protrude further or otherwise increase the pain so that the number or kind of thing which the worker cannot do is increased. In such a case, there is a single incapacity, in the sense of only one set of work related acts which the worker can no longer do and by reference to which his incapacity is seen to exist.[123]

124 The cases relied on by Walsh identify a single incapacity as arising from multiple injuries where only one body function was affected: Conkey (heart condition); Bushby (lumbar spine); Calman (psychiatric disorder); Medcalf v Perry (back); and Switzerland Insurance (back).

125 Here, the compensable and non work-related injuries affect separate and distinct body parts and functions. The panel determined that the right knee injury affected Walsh's mobility, whereas her bilateral shoulder condition and lower back pain further affected her capacity to perform physically demanding duties.[124] In my view, the panel did not make a finding that Walsh had a single incapacity; but if it did, it was wrong to do so.

126 The injuries affected discrete abilities to do work related acts. Had she sustained the right knee injury alone, and attendant psychological consequences, the set of work related acts that Walsh would be inhibited from performing would be different from those she would be unable to perform had she sustained the bilateral shoulder condition and lower back pain injury alone, although there may be some overlap. It is only if the incapacitating effects of Walsh's compensable injury could be aggregated with the supervening and unrelated conditions of Walsh's shoulder and back injuries that Walsh could be assessed as sustaining a single incapacity. In my view, this is precisely what cannot be done as it contradicts the approach adopted in Ward and receives no support from Conkey, Bushby or Calman. Far from a single incapacity, Walsh suffers from what was described by Glass JA in Morris v George as an 'overall incapacity resulting from the combined effect of two disabilities independently caused by two injuries',[125] or as Dixon J said in Ward, as the experience of 'distinct bodily conditions which amount to total incapacity only because they [impermissibly] must be added together'.[126]

127 Walsh's submission that she suffers from a single incapacity must be rejected.

[1] DHS relied on s 93C of the Act which, when read together with s 91E, provides that a worker's entitlement to weekly compensation payments ceases after the worker has received such payments for 130 weeks unless the worker has 'no current work capacity' and is likely to continue indefinitely to have 'no current work capacity'. This is discussed further below.

[2] The referral was made pursuant to s 45 of the Act. The panel was made up of David Kotzman, Brendan Hayman, Jennifer Harmer, John Lloyd and Keith Elsner. The panel was named as the second respondent to the appeal but did not participate in the proceedings, either at first instance or on appeal, in accordance with R v Australian Broadcasting Tribunal; Ex parte Hardiman [1980] HCA 13; (1980) 144 CLR 13, 35-6.

[3] Department of Human Services v Kotzman [2013] VSC 360 ('Reasons').

[4] Section 93C is cast in terms of weekly payments ceasing 'upon the expiry of the second entitlement period' which is relevantly a period of 117 weeks 'after the expiry of the first entitlement period' which is relevantly a period of 13 weeks (see s 91E).

[6] Certificate of Opinion, dated 5 October 2012 (emphasis added).

[7] [1938] HCA 70; (1938) 61 CLR 120 ('Ward').

[8] [1980] 1 NSWLR 81 ('Bushby').

[9] (1977) 16 ALR 479 ('Conkey').

[10] [1999] HCA 60; (1999) 167 ALR 91 ('Calman').

[11] Ward [1938] HCA 70; (1938) 61 CLR 120, 136.

[14] The same submission was raised and rejected below: see Reasons [47], [58]. See [37] below.

[15] Reasons, [25] (citations omitted).

[20] These were the issues on which the parties made submissions in writing and orally. I propose to analyse the parties' submissions in the manner presented on the hearing of the appeal.

[21] Ward [1938] HCA 70; (1938) 61 CLR 120, 139.

[24] [1912] AC 319 ('Hargreave's Case').

[25] (1926) 135 LT 564 ('Lomax').

[26] [1931] AC 605.

[27] Hargreave's Case [1912] AC 319, 320.

[28] The relevant legislation was the Workmen's Compensation Act 1906 (UK), sch I, paragraph 1(b) of which provided that in every case 'where total or partial incapacity for work results from the injury' a weekly payment shall be made during the incapacity.

[29] Hargreave's Case [1912] AC 319, 321 (emphasis added).

[30] Lomax (1926) 135 LT 564, 567 (Scrutton LJ).

[31] Hargreave's Case [1912] AC 319, 321 (emphasis added).

[33] Ibid 322. Lord Robson and Lord Loreburn LC concurred.

[34] Lomax (1926) 135 LT 564, 565. He also stated (at 567) that the 'supervening events did not arise out of or in the course of the employment, and were not connected with the employment, and were not attributable to the conduct of the employers'.

[36] The Workmen's Compensation Act 1906 applied.

[37] Lomax (1926) 135 LT 564, 566.

[38] The third member of the bench, Russell J, agreed with the disposition of the appeal saying he was of the same opinion and did not wish to add anything to the judgments which had been delivered.

[39] The Workmen's Compensation Act 1906 had been repealed and substituted by an Act of 1923 but the 1923 Act did not apply to the matter as the accident took place in 1915.

[40] [1930] 2 KB 255. A workman who was employed as a wheelwright and van driver suffered a workplace injury that required the removal of his left eye. He was compensated first for partial incapacity and later, due to an inability to get work because of his disfigurement, for total incapacity. He became nearly blind due to a cataract in his right eye. The employers' insurers offered him employment as a cleaner in their office at wages that were double the market rate but the worker refused by reason of his impairment. The employers applied for a review of the worker's compensation. A County Court judge reduced the compensation. The Court of Appeal (Greer and Slesser LJJ; Scrutton LJ dissenting) held that the County Court judge was wrong in reducing the compensation. Greer LJ concluded (at 269) that the worker's inability to do any work was the result of the accident and Slesser LJ considered (at 276) that the work offered was not suitable work for the worker given his impairment. Scrutton LJ considered (at 262) that Hargreave's Case and Lomax prevented him from interfering with the judgment of the County Court judge although he considered that result unsatisfactory.

[42] Birch Brothers Ltd v Brown [1931] AC 605. The Court found that the offer made by the employers had no evidentiary value as a test of the worker's earning capacity in the open market and thus that the County Court judge was wrong to find that the worker's inability to earn wages by reason of the loss of his left eye (the compensable injury) had ceased to exist (at 617 (Lord Warrington); 619-20 (Lord Atkin); 624-5 (Lord Tomlin); 629 (Lord Macmillan); (Lord Dunedin dissenting)). It dismissed the appeal and affirmed the decision of the Court of Appeal.

[44] Ibid 626. He also said: 'The presence of incipient cataract in the right eye at the date of the accident, in the absence of evidence that the accident accentuated or accelerated the progress of the disease, does not in my opinion afford any sound ground for distinguishing this case from those in which the disease in the second eye first began after the accident' (at 626).

[45] Ward [1938] HCA 70; (1938) 61 CLR 120, 143.

[46] Birch Brothers Ltd v Brown [1931] AC 605, 622-3 (citation omitted).

[47] Ward [1938] HCA 70; (1938) 61 CLR 120, 144.

[50] See the distinction now applied within the context of s 51 of Part X (Negligence) of the Wrongs Act 1958 (Vic) between factual causation (where the negligence was a necessary condition of the harm) and legal causation (where it is appropriate for the scope of the negligent person's liability to extend to the harm so caused). See also Wallace v Kam [2013] HCA 19; (2013) 250 CLR 375 which concerned s 5D of the Civil Liability Act 2002 (NSW) which is in substantially the same terms as s 51 of the Wrongs Act. See also Powney v Kerang and District Health [2014] VSCA 221.

[51] Ward [1938] HCA 70; (1938) 61 CLR 120, 130.

[52] [2013] HCA 19; (2013) 250 CLR 375.

[53] Ibid 381 [11] (French CJ, Crennan, Kiefel, Gageler, Keane JJ). Speaking of causation in the context of negligence at common law, the High Court went on to say: 'The distinct nature of those two questions [factual causation and legal causation] has tended, by and large, to be overlooked in the articulation of the common law. In particular, the application of the first question, and the existence of the second, have been obscured by traditional expressions of causation for the purposes of the common law of negligence in the conclusory language of "directness", "reality", "effectiveness" and "proximity".' In pointing out that the Civil Liability Act 2002 (NSW) now requires that the two questions be kept distinct, the High Court said (at 385 [21]-[22]):

'Satisfaction of legal causation requires an affirmative answer to the further, normative question [in addition to that of question of factual causation] ...: is it appropriate for the scope of the negligent medical practitioner's liability to extend to the physical injury in fact sustained by the patient?

In a case falling within an established class, the normative question ... is properly answered by a court through the application of precedent. Section 5D [of the Civil Liability Act] guides but does not displace common law methodology. The common law method is that a policy choice once made is maintained unless confronted and overruled.'

[54] Ward [1938] HCA 70; (1938) 61 CLR 120, 130.

[55] Ibid 130-1. He also accepted (at 131) that if a worker suffers a total incapacity from a compensable injury and another cause (for example, heart disease) also produces total incapacity, the worker is entitled to continue to receive compensation for the total incapacity resulting from the injury. See also 132-3. He further accepted that where a workplace injury 'supervened upon a pre-existing condition of heart disease so as to produce a total incapacity, then it would follow that that incapacity resulted from the injury' (at 137).

[57] See [34] above.

[58] (1977) 16 ALR 479.

[60] Ibid 484 (emphasis added). He thus dismissed the appeal from the Supreme Court of New South Wales which had upheld the Workers' Compensation Commission's conclusion that the widow of the worker was entitled to be compensated for the worker's death. The other judges (Gibbs, Stephen, Jacobs and Murphy JJ) agreed with Barwick CJ.

[61] On this issue, I disagree, with great respect, with the analysis adopted by the judge below, who characterised the circumstances as falling within the category of a single chain of causation: Reasons [29]. See further at [102]-[108] below.

[62] [1958] HCA 56; (1958) 102 CLR 465.

[63] Conkey (1977) 16 ALR 479, 484 (emphasis added).

[64] See [69] above (emphasis added).

[65] For example, in Ward [1938] HCA 70; (1938) 61 CLR 120, 131 Latham CJ specifically rejected the scenario described in [77] above when he said: 'What are called "natural causes" bring about total incapacity with advancing age. The employer is not liable under the Act for any incapacity resulting from such natural causes'.

[66] See [72] above.

[67] Conkey (1977) 16 ALR 479, 485.

[68] See [26] above.

[69] See [25] above.

[72] In doing so, it saw no reason to doubt the correctness of Conkey or of Commonwealth v Butler [1958] HCA 56; (1958) 102 CLR 465, but stressed 'that each of them turned upon an analysis of the medical evidence': [1980] 1 NSWLR 81, 87. The Privy Council also noted (at 87) that '[n]one of the numerous decisions in the Workers' Compensation Commission and the Court of Appeal of New South Wales relied on by the appellants as affording such support [for the view that at law one or other accident must necessarily be selected as the cause of the incapacity], which their Lordships have carefully examined and which it is unnecessary to cite at length, are properly to be understood in that sense'.

[73] [1977] 2 NSWLR 552.

[74] Workers' Compensation Act 1926 (NSW), s 6(3)(a).

[75] See [43] above.

[76] Morris v George [1977] 2 NSWLR 552, 580.

[78] Glass JA applied the same passage from Dixon J as relied upon by the judge below in his articulation of principle (c): see Reasons, n 15.

[79] See [43] above.

[80] See reference to the facts and findings in the single judgment annexed to the stated case: Morris v George [1977] 2 NSWLR 552, 557.

[82] (1972) 46 WCR (NSW) 27.

[83] Morris v George [1977] 2 NSWLR 552, 573 (emphasis added, footnote omitted).

[86] (1971) 2 SASR 33 ('Rheem').

[87] Morris v George [1977] 2 NSWLR 552, 565.

[88] Ibid; Rheem (1971) 2 SASR 33, 42; Ward [1938] HCA 70; (1938) 61 CLR 120, 141. See [43] above.

[89] Ward [1938] HCA 70; (1938) 61 CLR 120, 141. See also Morris v George [1977] 2 NSWLR 552, 565; Rheem (1971) 2 SASR 33, 42. See [43] above.

[90] Morris v George [1977] 2 NSWLR 552, 567. Moffit P accepted that there would be exceptions where, eg, a first back injury is of such major proportions that incapacity is recurrent and progressive.

[91] See [25] above.

[92] For this proposition the Court relied on Conkey (1977) 16 ALR 479, as well as Bushby [1980] 1 NSWLR 81, Commonwealth v Butler [1958] HCA 56; (1958) 102 CLR 465, and Salisbury v Australian Iron and Steel Ltd [1943] NSWStRp 50; (1943) 44 SR(NSW) 157, 162.

[93] Calman [1999] HCA 60; (1999) 167 ALR 91, 100-101 [38] (Gaudron ACJ, McHugh, Gummow, Kirby and Callinan JJ) (citations and footnotes omitted).

[94] Ibid 101, [39]-[40] (emphasis added and citations omitted).

[95] In accordance with what the judge described as principle (c). See [34] above.

[96] See [97] above.

[97] [1943] NSWStRp 50; (1943) 44 SR (NSW) 157.

[99] Reasons, [29] and [32] respectively. See [34] above.

[100] Reasons, [35]. See [34] above.

[101] See [43] above.

[102] [1996] NSWCA 512. ('Switzerland Insurance').

[103] [2000] NSWCA 230; (2000) 50 NSWLR 211.

[104] Switzerland Insurance [1996] NSWCA 512, 3.

[105] Workers Compensation Act 1987 (NSW), s 22.

[106] Switzerland Insurance [1996] NSWCA 512, 20.

[107] There were also various appeals which had been dismissed and no application was made in respect of them for special leave to the High Court. The cross-appeal had also been dismissed (the dismissal was made summarily because it was thought unarguable) but the High Court allowed an appeal by QBE Insurance against the dismissal of the cross-appeal (on the basis that the point was arguable and should have been considered) and remitted the cross-appeal to be re-determined by the Court of Appeal. On the re-determination the Court of Appeal again dismissed the cross-appeal. The judgments referred to are from the re-determination of the cross-appeal.

[108] Switzerland Insurance [1996] NSWCA 512, 22. Had the Court upheld the cross-appeal it would have either had to decide the case on a rehearing or remitted it to the Compensation Court to be determined there and, in either event, the law to be applied would be the law at the time of the further determination.

[109] Ibid 13. It followed that the apportionment power would be available in such a case. See also Ilsley v Wattyl Australia Pty Ltd (1977) 75 FCR 1, 6.

[110] Medcalf v Perry [2000] NSWCA 230; (2000) 50 NSWLR 211, 215 [18], 218 [35]-[36]. The issue of the applicability of the statutory defence arose because in respect of the first injury there were only notional proceedings as the worker's solicitors had allowed her action against her employer to become statute barred.

[111] See [25] above.

[112] See [94] above.

[113] See [33] above.

[114] See Ilsley v Wattyl Australia Pty Ltd (1997) 75 FCR 1, 6.

[115] [2008] WASCA 174.

[117] [2011] VSC 96, [34] citing Hi Fert Pty Ltd v Kiukiang Maritime Carriers [1996] FCA 1914; (1996) 71 FCR 172, 179.

[118] [1980] FCA 92; (1980) 31 ALR 140.

[119] Ibid 150. See also Gilkinson v Repatriation Commission [2011] FCAFC 133; (2011) 197 FCR 102, 104-5 [6] (Perram J), 110-11 [38] (Nicholas and Roberston JJ); Telstra v Bowden [2012] FCA 576; (2012) 206 FCR 207, 213-4 [32]-[37] (Murphy J) and Ilsley v Wattyl Australia Pty Ltd (1997) 75 FCR 1, 5.

[120] This conclusion is reinforced by the legislative history of the Act. As the High Court said in Thiess v Collector of Customs [2014] HCA 12; (2014) 306 ALR 594, 599 [22]: 'Statutory construction involves attribution of meaning to statutory text. As recently reiterated: "This Court has stated on many occasions that the task of statutory construction must begin with a consideration of the [statutory] text". So must the task of statutory construction end. The statutory text must be considered in its context. That context includes legislative history and extrinsic materials. Understanding context has utility if, and in so far as, it assists in fixing the meaning of the statutory text'. The amendment to s 5 of the Act was made by the Accident Compensation (Miscellaneous Amendment) Act 1997 (Vic), the second reading speech of which gave no indication that the change in language between 'results from' and 'arising from' was intended to bring with it such a significant expansion in an employer's liability beyond that which it was historically understood to be.

[121] [1980] 1 NSWLR 81, 84 [9].

[122] As the judge below considered it to be: Reasons, [60]. See [38] above.

[123] Switzerland Insurance [1996] NSWCA 512, 10-11 (emphasis added).

[124] See [27] above.

[125] [1977] 2 NSWLR 552, 580.

[126] [1938] HCA 70; (1938) 61 CLR 120, 141.