Plaintiff v Defendants

1 The plaintiff, Dr Chua, is a general practitioner who treated the third defendant, Helen Campbell ('the claimant') for difficulties with respect to her left ankle and foot over a period of approximately two years before referring her on for specialist treatment.

2 The claimant has issued proceedings in the County Court, claiming that if Dr Chua had properly diagnosed a tendon condition from which she suffered and/or referred her to a specialist more speedily, the condition of her left ankle could and would have been more simply addressed than by the serious surgery which was ultimately necessary. In turn, her current level of impairment would have been avoided.

3 The Wrongs Act 1958 ('the Act') provisions with which this case is concerned operate as a gateway with respect to the claimant's right to recover non-economic loss damages for personal injury.

4 In cases where a plaintiff wishes to recover such damages and the seriousness of the injury is in issue, the Act requires a Medical Panel to assess the injury claimed by the injured person and to determine whether it results in a threshold level of permanent impairment.

5 In the present case, the Panel was asked the statutory medical question:

Does the degree of impairment resulting from the injury to the claimant alleged in the claim satisfy the threshold level?

6 The Panel determined that the claimant has suffered impairment of the requisite level in consequence of the condition of her left ankle following a triple fusion arthrodesis.

7 Dr Chua contends that the Panel misdirected itself in four fundamental respects. It is submitted:

(a) the Panel undertook an assessment of the claimant's present left ankle dysfunction at large as constituting relevant impairment;

(b) the Panel failed to disregard pre-existing impairment of the left ankle in accordance with s 28LL(3) of the Act;

(c) the Panel equated the ascertainment of pre-existing injury with assessment of such injury in accordance with the American Medical Association's Guides to the Assessment of Permanent Impairment (4th Edition) ('the Guides');

(d) the Panel wrongly assumed that it was required to disregard the possibility or likelihood that the impairment assessed by it might be due only to the ordinary course of a pre-existing condition and/or the ordinary course of its reasonable treatment.

8 Dr Chua seeks orders in the nature of certiorari quashing the determination of the Panel and in the nature of mandamus remitting the medical question for reconsideration in accordance with law by a differently constituted Panel.

9 I am not persuaded the Panel misdirected itself as to the nature of the injury it was required to assess. It did not simply assess the claimant's present impairment at large.

10 Likewise, I am satisfied that the Panel considered and gave effect to the provisions of s 28LL(3).

11 Unfortunately, however, the Panel erred in the reasoning by which it justified its conclusions. The Panel based its conclusions on a finding that it could not assess pre-existing impairment in accordance with the Guides. I accept that the Panel was bound to disregard unrelated impairment resulting from a pre-existing condition, whether or not it could be assessed in accordance with the Guides, provided there was an evidentiary basis for finding there was such an unrelated impairment.

12 The Panel further concluded that, at the time of treatment by Dr Chua, the claimant's left ankle had not stabilised and that for this reason no positive determination of pre-existing impairment was possible at the time of the alleged negligence. I have considered whether this finding is a sufficient basis on which to sustain the Panel's ultimate conclusion concerning level of impairment, but I have come to the view that it is not. There is ambiguity in its terms and it does not necessarily compel the ultimate conclusion to which the Panel came.

13 This said, the evidence before the Panel did not justify, let alone compel, the conclusion that the complainant would have suffered a triple fusion arthrodesis in the ordinary course of the pre-existing condition of her left ankle even if she had received appropriate treatment from Dr Chua. Such a conclusion would destroy the necessary link between the delay in diagnosis and treatment complained of and the subsequent arthrodesis. In the absence of such evidence, however, the risk of vicissitudes that confronted the claimant at the time of the alleged negligence included the potential consequences of her then medical condition. That risk was a matter which went to the damages the claimant might ultimately recover, but was not a matter for the Panel to assess. In the present case it is plain the Panel concluded it could identify a potentially compensable injury which was not simply the result of the claimant's pre-existing condition.

14 In summary, having regard to the Panel's reasons, I do not accept that the Panel misdirected itself:

(a) simply by reason that it assessed the claimant's current impairment in entirety as constituting potentially compensable injury;

(b) by failing to have regard to the requirements of s 28LL(3) of the Act; or

(c) by failing to consider whether the claimant's current impairment is the ordinary consequence of some pre-existing impairment.

15 On the other hand, I do accept that the Panel misdirected itself by equating the ascertainment of pre-existing impairment with assessment of that impairment in accordance with the Guides.

16 In order to explain these conclusions, it is necessary to say something in turn about the common law context in which the relevant statutory provisions operate, the nature of those provisions, the history of the claimant's claim, the Panel's reasons for determination and the basis on which Dr Chua contends the Panel fell into error.

17 Before examining the provisions of the Act in detail, it is necessary to first say something about the conceptual framework within which the type of common law claim in issue is formulated. I shall do so in the first instance principally by reference to the propositions summarised in the judgment of Kiefel J in Tabet v Gett,[1] secondly by reference to general propositions of law relating to the assessment of damages in cases of this type and thirdly by reference to the notion of injury by aggravation.

(a) A claim in negligence requires proof of damage. The common law requires proof by the claimant that the negligent act or omission complained of caused the loss or injury constituting the damage.[2]

(b) In medical negligence claims, the loss or damage claimed is ordinarily physical or mental injury.

The issue whether damage has been caused by a negligent act invites a comparison between a plaintiff's present position and what would have been the position in the absence of the defendant's negligence.[3] Such an inquiry directs attention to all the circumstances pertaining to the plaintiff's condition at the time he or she sought the medical treatment which was not properly provided. The question of whether harm or damage has been suffered is bound up in the question of causation.[4]

(d) A conclusion that earlier or different treatment would have altered the actual outcome may or may not be possible.[5]

(e) The causal requirement is not to be resolved by reference to notions of loss of chance:

Expressing what is said to have been lost as the loss of a chance was said by Gonthier J in Laferrière v Lawson to divert attention from the proper connection between fault and damage. It is artificial and breaks the causal link.[6] I respectfully agree. One commentator to whom his Honour referred[7] suggests that in cases of the kind in question what is involved is in truth not a loss of a chance. The factors present in that chance have played themselves out when physical injury or death occurs. What is in issue is a past event. It was to this opinion that Gaudron J referred, with approval, in Naxakis v Western General Hospital.[8]

(f) A mere possibility of a better outcome is not sufficient to found a claim for medical negligence.[9]

(g) If the causal requirement is satisfied, there may nevertheless be a discount of the damages payable to reflect the chance of a pre-existing condition producing similar symptoms. As was stated by Deane, Gaudron and McHugh JJ in Malec v J.C.H Hutton Pty Ltd:

When liability has been established and a common law court has to assess damages, its approach to events that allegedly would have occurred, but cannot now occur, or that allegedly might occur, is different from its approach to events which allegedly have occurred. A common law court determines on the balance of probabilities whether an event has occurred. If the probability of the event having occurred is greater than it not having occurred, the occurrence of the event is treated as certain; if the probability of it having occurred is less than it not having occurred, it is treated as not having occurred. Hence, in respect of events which have or have not occurred, damages are assessed on an all or nothing approach. But in the case of an event which it is alleged would or would not have occurred, or might or might not yet occur, the approach of the court is different. The future may be predicted and the hypothetical may be conjectured. But questions as to the future or hypothetical effect of physical injury or degeneration are not commonly susceptible of scientific demonstration or proof. If the law is to take account of future or hypothetical events in assessing damages, it can only do so in terms of the degree of probability of those events occurring. The probability may be very high - 99.9 per cent - or very low - 0.1 per cent. But unless the chance is so low as to be regarded as speculative - say less than 1 per cent - or so high as to be practically certain - say over 99 per cent - the court will take that chance into account in assessing the damages. Where proof is necessarily unattainable, it would be unfair to treat as certain a prediction which has a 51 per cent probability of occurring, but to ignore altogether a prediction which has a 49 per cent probability of occurring. Thus, the court assesses the degree of probability that an event would have occurred, or might occur, and adjusts its award of damages to reflect the degree of probability. The adjustment may increase or decrease the amount of damages otherwise to be awarded. See Mallett v. McMonagle; Davies v. Taylor; McIntosh v. Williams. The approach is the same whether it is alleged that the event would have occurred before or might occur after the assessment of damages takes place. [10]

(h) Damages must be discounted to reflect the plaintiff's state of health prior to the negligent act which caused compensable injury. In General Motors-Holden's Pty Ltd v Moularas,[11] Menzies J observed:

Neither in the passage just quoted nor in any other part of the direction did his Honour point out to the jury that if the accident for which the respondent was seeking damages had not happened, nevertheless other circumstances might have happened to prevent or hinder the respondent, a man predisposed to hysterical paralysis, from earning his living. The first question is whether, in the circumstances of this case, that omission amounts to a mis-direction.

I agree with Dean and Gowans JJ that it does because in the result the jury were not adequately instructed that, in considering loss of future earnings or of earning capacity, they should arrive at a figure which in their judgment represented the present value of wages which the plaintiff could have been expected to earn in the future had this accident not occurred, having regard inter alia to his own condition of health prior to the accident and the vicissitudes of life such as early death, sickness, accident and unemployment, the occurrence of which would affect the estimate.[12]

The same principles apply to compensation for non-economic loss.[13]

18 The injury compensable at common law may be constituted by the aggravation of a pre-existing condition or the acceleration of a condition that would otherwise have eventuated more slowly:

The true position is, we believe, that if an accident makes a condition worse by aggravation, or brings on earlier a condition which would have come about in any event, the defendant is liable to compensate the plaintiff for the worsening or the acceleration or both, as the case may be.[14]

19 A fundamental notion underlying the above principles is the proposition that a plaintiff is to be compensated for, but only for, such disabilities as are proved to have resulted from the relevant breach of duty by the tortfeasor.

20 This notion underlies the approach this Court has taken to the construction of the 'serious injury' provisions contained in s 93 of the Transcript Accident Act ('the TAC Act') in aggravation cases. In the recent case of De Agostino, Tate JA stated:[15]

In the context of aggravation to a pre-existing injury, Southwell and Teague JJ in Petkovski v Galletti[16] made it plain that the task of the court is to analyse the extent of the impairment of the body function before and after the relevant injury. In referring to the submissions that had been rejected by the trial judge below in that case, they said:[17]

The question of the relevance of the existence of a pre-existing degenerative condition in the applicant's spine was raised both in the court below and in this court. It was submitted in both courts for the respondent that a comparison must be made of the condition of the applicant immediately before the accident with his condition thereafter and an assessment made of the extent of the additional impairment; if that additional impairment was not 'serious', so it was said, then leave must be refused.

The learned County Court judge rejected this principal submission of the respondent. ... He said: 'In my opinion, the Act simply requires me as an assessing judge to be "affirmatively satisfied" that the applicant as at the date of the application is suffering from a "serious injury" within the meaning of the Act.'

...

[I]t is clear that the submission for the respondent ought not to have been rejected by the judge ... We are of that opinion for these reasons. One should commence with the acknowledgement that it has for long been the law that an injured person is to be compensated for, but only for, such disabilities as are proved to have resulted from the relevant accident. While the wrongdoer must take the victim as he finds him, he must compensate only for the damage he has wrought.

The Act does not affect that long-established principle.

21 In the present case, the claimant's claim is, in substance, that she has suffered a condition requiring a triple fusion arthrodesis of her left ankle, when such arthrodesis would have been unnecessary if a pre-existing tendon condition had been properly diagnosed by Dr Chua during the course of his treatment of her.

22 The pre-existing tendon condition was left-sided posterior tibial tendon dysfunction of the tibialis posterior tendon ('PTTD').

23 The statement of claim particularises the injury as follows:

Injury to lower left leg and ankle requiring multiple surgical procedures but resulting in persisting pain, weakness, stiffness, instability and limitation of movement; pain and shock; nervousness, nervous and psychological upset; anxiety and depression.

24 The referral to the Panel pursuant to s 28LW(b) of the Act also particularises the injury that the Panel was to consider:

Injury to the left lower leg and ankle requiring multiple surgical procedures, [t]riple arthrodesis of the left foot with painful deformity of the left ankle and foot. Resultant persistent pain, weakness, stiffness, instability and limitation of movement.

25 The claim was supported in documentation supplied to the Panel, including medical reports from Mr Khan and Dr Patel. In his report dated 11 December 2006, Dr Patel states:

Mrs Campbell has been a patient of mine since January 2006 when she first presented to me with significant problems relating to bilateral posterior tibial tendon dysfunction (PTTD). This had resulted in quite severe adult acquired flat feet.

Helen is a rather tall and slightly large 61 year old non insulin dependant diabetic who works as a law clerk. She presented with a 18 month history of left foot progressive pain and deformity which had significantly worsened after a fracture of the right ankle which had resulted [in] her depending on her left ankle for weight bearing. The right ankle fracture had been treated conservatively and even though the right ankle had signs of early deformity developing as a result of PTTD it did not seem to bother her.

Helen's left ankle however caused severe pain and when she first presented to me, she could barely walk a couple of steps without significant pain. Helen's diabetes was well controlled and she had been diligent in foot management with visits to her podiatrist who had reported normal 2 point discrimination in her foot.

Helen had very severe PTTD with the foot in a significant plano-valgus[18] position requiring her to bear weight along the anterior and anterior medial aspect of the foot. She also found it much more comfortable to walk bare foot than with shoes. She was highly dependant on her stick which she used in her right hand to help unload the left foot and ankle.

Examination revealed that the left ankle had 15 degrees of dorsi flexion and 25 degrees of plantar flexion. The subtalar joint was in valgus[19] which could not be corrected fully to the neutral position. Mobility in the subtalar joint surprisingly did not cause much pain however the mobility was considerably decreased compared to the opposite side. There was tenderness along the head of the talus which was considerably worse when Helen was weight bearing since the head of the talus was the load bearing bone. The tibialis posterior tendon was nonfunctional though the perioneii were normal. Helen was graded as having Grade IV PTTD i.e. end stage, requiring corrective foot surgery and mid foot and hind foot fusion.

Helen's case was presented at the clinical case conference at the teaching orthopaedic unit at Monash Medical Centre where the consensus was that the deformities would not be correctable either by simple osteotomies[20] or manually and would therefore require gradual correction using an external fixation Ilizarov frame prior to performing formal subtalar and midtalar fusions.

Helen had an Ilizarov frame applied to her lower extremity on 24th February. The deformity was gradually corrected to the neutral position. The Ilizarov frame was in place for 6 weeks. On the 7th of April the Ilizarov frame was removed and a triple fusion performed. This involved the subtalar joint and the talar navicular joint. The calcano-cuboid joint had a distraction bone grafting (per MOSCA) with a bone graft. Unfortunately it was this bone grafting that caused Helen difficulty with wound irritation and low grade infection which was easily controlled with regular dressings and antibiotics. Helen had one of her screws in the foot back out probably as a result of loosening of the fusion between calcano-cuboid joint. The screw was removed and the calcano-cuboid fusion revised using bone graft substitute wedges. The foot has healed in good position and importantly Helen has very little pain on weight bearing which is a significant improvement for her. Helen has intermittent ooze from the lateral aspect of the foot. Latest x-rays show that one of the bone graft wedges has failed to be integrated and has indeed dislodged and will require removal. The fusion however is relatively solid and the correction has been maintained and therefore the fusion does not need to be revised.

Helen has had a difficult treatment period because of ongoing problems with her right ankle which has also been intermittently painful as well as her relatively large size which has not been helped by the period of inactivity. She has been quite diligent in following her physiotherapy and has remained motivated throughout her treatment.

I envisage that in the next 3-6 months Helen will have made a complete recovery and would be able to walk on the left foot without any aids. [She] may ultimately require surgery on her right foot and ankle albeit to a lesser extent to correct early PTTD type acquired flat foot. At this stage the right side is being treated conservatively.

It is my understanding that Helen had complained to Dr Chua about her progressively worsening foot deformity and pain about 18 to 24 months prior to her presenting to me.

I can only speculate on what deformity was when Helen presented to Dr Chua. PTTD can be difficult to diagnose and indeed early features are commonly missed. That said, PTTD is now a recognized entity and certainly does better when treated earlier in the piece. For example if Helen's right ankle were to be treated at this stage she would only require a debridement of the tibialis posterior tendon with or without augmentation using the FDS tendon[21] with a calcaneal shift osteotomy. This is a much smaller undertaking than the one Helen had to undergo.

... In conclusion I can state that like with any other medical condition, PTTD treatment is easier and simpler if diagnosed in time. That said, we still have a large percentage of our patients presenting in Grade III or Grade IV PTTD for a variety of reasons.[22]

27 In his report dated 26 August 2008, Dr Patel states the following:

It is very difficult to assess the extent of permanent impairment that would have resulted had the above mentioned procedure[23] proceeded when performed at the optimum time. Helen unfortunately has other ongoing issues with her diabetes and her weight. Unfortunately it is these very problems that made the more extensive foot osteotomy surgery even more difficult in Helen's case, and ultimately contributed to the level of impairment.

I apologise for not being able to answer these questions with a greater degree of certainty but you would understand that at this stage we are talking in terms of hypothetical's.

She started seeing her general practitioner, Dr K S Chua, since 2002 or 2003 for her right ankle. From the statement, Dr Chua had started her on acupuncture treatment and painkillers on a weekly basis over a long period of time. Later in 2004 she was developing pain in the left ankle and had noticed swelling of the ankle. The pain was becoming unbearable at times. When she mentioned this to Dr Chua he did not do any investigations or x-rays. He suggested that she had been putting extra strain on the left ankle on account of the fracture of the right ankle and she had now developed osteoarthritis in the left ankle. She recalls telling him in June 2005 that the pain in the left ankle was severe. At that time he did some blood tests for her and carried on with acupuncture and painkilling medication.

Eventually she wanted to have something done and asked her doctor to send her to a rheumatologist. She even looked up the name of the clinic which was an arthritis clinic in Blackburn. Dr Chua then referred her to see Dr Roy Karna who saw her on 30 November 2005. After arranging x-rays and ultrasound of the left ankle he (Dr. Karna) came to the conclusion that she had a suspected rupture of the tibialis posterior tendon and that it was posterior tibial tendon dysfunction condition and apparently did not have any direct relationship to the arthritis.

By the time she saw Dr Minoo Patel in the first week of January 2006 this condition had reached such an advanced stage of degeneration that simple tendon operation on the medial side of her left ankle was no longer indicated. Advanced changes had occurred in the bones of the left ankle and foot and she was walking on the bone in the inner side of the left ankle (head of talus).

Her heel was severely everted.

She was in considerable pain and could hardly weight bear on the affected left leg. As she already had a problem with her right ankle, which continued to do so, she was between the devil and the deep sea as there was some discomfort in the right ankle, although minimal on weight bearing.

...

However, I can confidently say that if the condition was diagnosed at an earlier stage as indicated above in my report, when she saw her general practitioner, she was most likely not to require arthrodesis surgery and extensive procedures involving destruction of the joints, stiffening below ankle level and exposing her to infections due to the extensive nature of the surgery. Hence, the impairment would have been expected to be far less in percentage than it is likely to be now.[24]

29 There was no medical evidence before the Panel contradicting the opinions of Dr Patel and Mr Khan that if PTTD had been correctly diagnosed by Dr Chua, the probability is:

(a) the PTTD would have done better if treated earlier;

(b) the PTTD would have been capable of treatment with substantially simpler surgery; and

30 If it were accepted at trial that the claimant could and should reasonably have received earlier and substantially less traumatic and more effective treatment than was ultimately necessary, then at common law the injury constituted by the condition requiring arthrodesis and the consequences of that arthrodesis are potentially compensable.

31 The damages payable in respect of such injury would, however, be discounted for vicissitudes relating specifically to the claimant's health, including her pre-existing tendon condition, her diabetes, her weight and any other relevant aspects of her health.

The Wrongs Act 1958

32 Part VBA of the Act provides for the ascertainment of threshold levels of impairment as a preliminary requirement to claims for the recovery of damages for non-economic loss resulting from personal injury.

33 Section 28LC provides that pt VBA applies to claims for non-economic loss except for those which are specifically excluded by sub-ss 2 or 3. The exclusions include claims to which pts 3, 6 or 10 of the TAC Act and pt IV of the Accident Compensation Act 1985 ('the ACA') apply.

34 Section 28LD entrenches the substantive provisions of pt VBA by providing:

For the avoidance of doubt it is declared that all the provisions of this Part contain matters that are substantive law and are not procedural in nature.

A person is not entitled to recover damages for non-economic loss in any proceeding in a court in respect of an injury to a person caused by the fault of another person unless the person injured has suffered significant injury.

36 Section 28LB defines injury to include psychological or psychiatric injury and includes aggravation, acceleration or recurrence of an injury or disease.

37 The claimant's case is not an aggravation case. It is in substance a claim that she has suffered an injury, namely a triple fusion arthrodesis, which she would not have suffered but for Dr Chua's negligence.

38 Likewise, this is not an acceleration case. The evidence of Dr Patel and Mr Khan is not that the claimant would inevitably have required an arthrodesis and the need for such surgery was accelerated by mis-diagnosis and delay in intervening treatment. Their opinions support the view that the arthrodesis was avoidable if the claimant's condition was properly diagnosed and treated by Dr Chua.

39 Section 28LF(1) provides that an injury is a significant injury if

(a) the degree of impairment of the whole person resulting from the injury has been assessed by an approved medical practitioner in accordance with this Part as satisfying the threshold level, unless a Medical Panel has made a determination as to the threshold level under Division 5;

...

(b) a Medical Panel has determined under Division 5 that the degree of impairment of the whole person resulting from the injury satisfies the threshold level...

40 Section 28LB defines impairment to mean 'permanent impairment'. It follows that pt VBA is fundamentally concerned with the ascertainment of permanent impairment.

41 It also follows, as Mr Nash submitted for the claimant, that a pre-existing injury or condition is not necessarily to be equated with pre-existing 'impairment', as a pre-existing injury or condition does not necessarily lead to permanent impairment. This distinction is of substantial significance in the present case. A pre-existing tendon condition is not to be automatically equated with permanent impairment.

(1) Subject to this Division, an approved medical practitioner must make an assessment of degree of impairment under this Part -

(a) in accordance with -

(i) the A.M.A. Guides; or

(ii) the methods prescribed for the purposes of this Part; and

(b) in accordance with operational guidelines (if any) as to the use of those Guides or methods issued by the Minister.

(2) Nothing in subsection (1) prevents an assessment being made in respect of a degree of impairment of a person even if not all of the injuries to the person have stabilised.

43 The opening words make clear that the provisions of the Guides are subordinate to the other provisions of the Division,[25] which relevantly include s 28LL(3) to which I shall shortly come.

44 The Guides are adopted as the basis of assessment of serious injury for different purposes, not only pursuant to the Act, but also pursuant to the ACA and the TAC Act.

45 In the context of the ACA, Bongiorno J has said with respect to the Guides:

The Accident Compensation Act 1985 requires the Medical Panel to assess impairment using the AMA Guides. This attempt by the legislature to introduce some degree of objectivity into the assessment of impairment for compensation purposes represents a significant application of the rule of law in an area where one of the fundamental principles of justice - that like cases should be treated alike - has particular importance. Nothing would discredit a compensation system more quickly than the idiosyncratic application of criteria to the determination of an injured person's impairment and hence their entitlement to compensation at a particular level. Although the efficacy of the application of the AMA Guides to achieve a just result for injured people may be debated, as the law stands they must be applied regardless of any personal view of the assessor called upon to make the assessment. Whilst the interpretation of medical matters referred to in the Guides and the exercise of clinical judgment must be left to the medical examiner who is applying them, it is not within that medical examiner's remit to ignore an express direction contained in the Guides as to how a particular objective fact is to be treated in making an assessment. Thus it was not within the power of the Medical Panel in this case to reach its assessment of Mr Taylor's impairment after taking into account the effects of surgery performed on his cervical spine.[26]

46 In H J Heinz Company Limited v Kotzman, Kyrou J set out general principles for interpreting the Guides which were adopted by J Forrest J in Alcoa:[27]

The interpretation of the Guides is a question of law. The determination of a level of impairment is a question of fact.

It has been said that to the extent that an Act requires determinations of impairment to be made in accordance with the Guides, the Guides has the force of law and is a legislative document.

However, the Guides is, as its title suggests, a guide. It was written by expert medical practitioners and not by statutory draftspeople, and should not be overlaid with legalistic - or a lawyer's precise - interpretation. It is of paramount importance to be faithful to the Guides' plain words. The Guides should not be interpreted as if it was a statute.

The use of the Guides is designed to promote precision, certainty and consistency. Its purpose is to make as objective as possible the process of estimating impairment by reference to sufficient medical and non-medical information to justify the estimate.

If there is any inconsistency between the AC Act and the Guides, the AC Act will prevail. If there is any inconsistency between the text in the Guides and an example which seeks to illustrate what is said in the text, the text will prevail.[28]

47 In H J Heinz, Kyrou J went on to say as to the use of the Guides by a Medical Panel:

In order for a medical Panel to assess impairment 'in accordance with the [Guides]' as required by s 91 of the AC Act, it must act in conformity with the Guides. This means that it must apply the methodologies, processes and criteria set out in the Guides for the relevant condition, body part or system and adhere to any minimum or maximum values set out in the Guides for that condition, body part or system. Where the Guides contains a table that is applicable to a condition, body part or system, an assessment based on that table will not be in accordance with the Guides unless the categories, descriptions, criteria, ranges, adjustments and other elements of the table that are relevant to the condition, body part or system are adhered to and complied with.

Some provisions of the Guides, including some tables, provide alternative methodologies or set out ranges, and require the exercise of professional judgment in selecting the most appropriate methodology or in determining where in the range the relevant condition or body part falls. However, the Guides does not permit the exercise of professional judgment at large, unconstrained by the specific requirements of each methodology or table that it sets out. Once a particular methodology or table is selected, its requirements, including any limitations, must be applied in the manner set out by the Guides even if the outcome may appear sub-optimal. This is so because the role conferred by the AC Act on a Panel is not to arrive at a correct or fair assessment, but rather to arrive at an assessment that is the product of the application of the Guides.

The Guides itself makes it clear that the protocols and methodologies it sets out are intended to be standardised processes which produce similar outcomes irrespective of who conducts the assessment. In particular, the statement in s 1.2 of the Guides which I have set out in [11] highlights that in order for an assessment to be in accordance with the Guides, the Panel must follow the protocols and tables in the Guides.[29]

48 The Guides contain s 2.3 which is headed 'General Comments on Evaluation'. The approach identified in s 2.3 was referred to in part by the Panel in the present case and gives rise to some issues of contention between the parties. It is appropriate to set out the full section:

The Guides attempts to take into account all relevant considerations in estimating or rating the severity and extent of permanent impairment and the effects of the impairment in terms of the individual's every day activities. An impairment should not be considered 'permanent' until the clinical findings, determined during a period of months, indicate that the medical condition is static and well stabilized.

A physician who is asked to reevaluate an individual's impairment must realize that change may have occurred, even though a previous evaluator considered the impairment to be permanent. For instance, the condition may have become worse as a result of aggravation or clinical progression, or it may have improved. The physician should assess the current state of the impairment according to the criteria in the Guides.

Valid assessment of a change in the impairment estimate would depend on the reliability of the previous estimate and the reliability of the evidence on which it was based. If there were no valid previous evaluation, information gathered earlier could be used to estimate impairment according to Guides criteria. However, if there were insufficient information to document the change accurately, then the evaluator ought not attempt to estimate the change but should explain that decision.

If 'apportionment' is needed, the analysis must consider the nature of the impairment and its possible relationship to each alleged factor, and it must provide an explanation of the medical basis for all conclusions and opinions. Apportionment and causation are considered more fully in the Glossary (p.315).

For example, in apportioning a spine impairment, first the current spine impairment would be estimated, and then impairment from any pre-existing spine problem would be estimated. The estimate for the pre-existing impairment would be subtracted from that for the present impairment to account for the effects of the former. Using this approach to apportionment would require accurate information and data on both impairments.

Even when the impairment is well localized, its consequences cannot be understood without taking an individual's activities into account. Attention to full and complete reporting will provide the best opportunity for physicians to explain the health status of patients and the nature of their impairments to reviewers, claims examiners, and hearing officials; for attorneys to understand impairments; and for individuals to pursue any benefits to which they are entitled.[30]

49 Section 28LL(3) states that, for the purposes of pt VBA, impairments 'from unrelated injuries or causes' are to be disregarded in making an assessment. In the present case, the Panel was thus confronted with the need to disaggregate any pre-existing impairment from the injuries the subject of the claim. It is this requirement which is central to the principal issues Dr Chua seeks to agitate in this proceeding.

50 The Panel was required to disregard any pre-existing impairment which reduced the net degree of impairment which could be said to flow from the subsequent injury.

51 Section 28LN provides that, subject to s 28LNA (governing cases in which the assessor is unable to determine the degree of impairment because the injury has not stabilised), an approved medical practitioner who makes an assessment of degree of impairment under pt VBA must provide a certificate of assessment to the person seeking the assessment.

(3) If not all the injuries to a person have stabilised, a certificate of assessment can only be provided under this section in respect of the person if the injuries that have stabilised are sufficient to determine a degree of impairment that satisfies the threshold level.

(1) This section applies if, after making an assessment of degree of impairment under this Part, an approved medical practitioner is unable to determine the degree of impairment because the injury has not stabilised.

(2) If, at the end of 6 months after that first assessment, an approved medical practitioner is unable to determine the degree of impairment but is satisfied that the degree of impairment resulting from the injury will satisfy the threshold level once the injury has stabilised, that approved medical practitioner may issue a certificate of assessment under this section.

(3) The certificate of assessment must state that the approved medical practitioner is unable to determine the degree of impairment but is satisfied that the degree of impairment resulting from the injury will satisfy the threshold level once the injury has stabilised.

54 The sections which follow provide for a series of alternative procedures. Section 28LT relevantly requires that a certificate of assessment on which a claimant intends to rely must be served on the respondent to the claim.

55 In turn, s 28LWE provides that the respondent may refer a medical question in relation to the assessment to a medical panel for determination. This occurred in the present case.

56 'Medical question' is defined by s 28LB to mean 'a question as to whether the degree of impairment resulting from the injury to the claimant alleged in the claim satisfies the threshold level'. The question concerns the actual degree of impairment. The words 'alleged in the claim' relate to the phrase 'injury to the claimant' not the degree of impairment.

57 'Threshold level' is defined to mean impairment of more than 5 per cent in the case of injury other than psychiatric injury.[31] In the present case, the question referred to the Panel was thus whether the claimant was suffering a permanent impairment of more than 5 per cent resulting from the injury alleged in the claim.

58 As Pagone J observed in a case concerned with an alleged failure to treat a hereditary condition properly, Melbourne Health v Lloyd & Ors,[32] there is a need:

... to ensure that there is a match between the question determined by a medical panel and the entitlement which may be enlivened through s 28LE. That section prevents recovery except to the extent that a person has suffered a 'significant injury'. For present purposes a 'significant injury' is defined by s 28LF as an injury which 'a Medical Panel has determined under Division 5 that the degree of impairment of the whole person resulting from the injury satisfies the threshold level'. In other words, it is the medical panel's determination of an injury that enlivens, and effectively defines, the entitlement to recover damages for non-economic loss. It is important, if not essential, that there be identity between the injury determined by the medical panel and that in respect of which a claim for non-economic loss is made.[33]

59 The medical question in the present case thus required the Panel to first identify a potentially compensable injury and then to assess whether that injury caused the threshold level of impairment.

60 It was not for the Panel to determine whether in fact the injury was caused by the negligence alleged in the common law proceeding. Nevertheless, it must ascertain the existence of an injury as the starting point of its inquiry.

61 As Kaye J stated in Amendola v Coles Supermarkets Australia Pty Ltd & Ors:[34]

It is important to bear in mind that the role of the Panel, as identified in the Act, is to determine whether the degree of impairment of the whole person 'resulting from the injury' is above the threshold level. A number of provisions make express reference to the assessment, first by the approved medical practitioner, and then by the Panel, of the degree of impairment 'resulting from the injury'.[35] Section 28LZG(4) requires that the determination of the Medical Panel must (where appropriate) 'state whether the degree of impairment resulting from the injury satisfies the threshold level ... '. Axiomatically, an impairment cannot result from an injury, where there is no injury. It would, in my view, be inconceivable that the legislation contemplated that a Medical Panel was required to assess an impairment, notwithstanding that the Panel could not elicit any evidence of injury.[36]

62 In Melbourne Health, Pagone J further stated:[37]

... Its role is essentially to determine something about the nature of the injury to permit a category of compensation to be sought in an appropriate forum. That accords with what was said in the second reading speech and the explanatory memorandum relevant to the amending provisions. In the second reading speech the Treasurer said:

Concern has been expressed that the current wording of the 'medical question' under the Act could still require the medical panel to consider issues of causation - that is, to advise on whether particular injuries were caused by the alleged incident that gave rise to the claim. The medical question has been revised to make it clear that the panel's [determination] [sic] is based on the injuries that the claimant has cited in his or her claim, and that issues relating to causation are therefore to be left to the parties or a court to determine.[38]

In the explanatory memorandum it was said that by the amending provisions the medical panel ought not 'determine issues of causation'.[39]

63 Section 28LZ governs the procedures of Medical Panels and provides in part:

(1) A Medical Panel is not bound by rules or practices as to evidence, but may inform itself on any matter relating to a reference in any manner it thinks fit.

(2) A Medical Panel must act informally, without regard to technicalities or legal forms and as speedily as a proper consideration of the reference allows.

64 Section 28LZG provides for the determination of a Panel in the following terms:

(1) A Medical Panel must not determine the degree of impairment of a person unless it has made an assessment of the degree of impairment in accordance with Division 3.

(2) After making the assessment, the Medical Panel must give the claimant and the respondent -

(a) its determination of the medical question in accordance with subsection (4); or

(b) its certificate, in accordance with subsection (5), that it is unable to determine the medical question but that it is satisfied that the degree of impairment will satisfy the threshold level when the injury has stabilised; or

(c) its certificate that it is unable to determine the medical question and a statement of the time fixed for further assessment of the person under subsection (6).

(3) The Medical Panel must give the determination or certificate -

(a) within 30 days after the last of the following to occur -

(i) the last date on which the claimant complies with a request under section 28LZC;

(ii) the last date on which a registered health practitioner complies with a request under section 28LZE or if a request is made to more than one registered health practitioner, the last date on which the last of the registered health practitioners to comply, complies with the request; or

(b) within such longer period as is agreed by the claimant and the respondent.

(4) If, after making the assessment, the Medical Panel determines the degree of impairment, the determination of the medical question must state whether the degree of impairment resulting from the injury satisfies the threshold level but must not state the specific degree of impairment.

(5) If, after making an assessment, the Medical Panel is unable to determine the medical question because an injury has not stabilised, but the Medical Panel is satisfied that the degree of impairment resulting from injury will satisfy the threshold level once the injury has stabilised, the Medical Panel may certify in writing to that effect.

(6) If, after making an assessment, the Medical Panel is unable to determine the medical question because an injury has not stabilised and subsection (5) does not apply, the Medical Panel must in writing -

(a) certify that it is unable to determine the medical question; and

(b) fix a time (not being later than 12 months after the first assessment) for a further assessment of the degree of impairment of the person to be made under this section.

(7) The time fixed under subsection (6) must be the earliest time by which the Medical Panel considers that the injury will have stabilised.

(8) More than one further assessment may be made under this section but each further assessment must be made within the period of 12 months following the first assessment.

(9) A determination of the Medical Panel under subsection (4) must be given in writing and be certified by the Medical Panel.

(10) If the Medical Panel gives a certificate under subsection (5) in relation to an injury, the injury is deemed to be significant injury.

(1) A determination by the Medical Panel under this Division that the degree of impairment resulting from an injury satisfies the threshold level must be accepted by a court in any proceeding on the claim as a determination of significant injury for the purposes of this Part.

(2) A determination by the Medical Panel under this Division that the degree of impairment resulting from an injury does not satisfy the threshold level must be accepted by a court in any proceeding on the claim as a determination that the injury is not significant injury for the purposes of this Part.

(1) No appeal on the merits may be made to a court from an assessment or determination of a Medical Panel under this Division.

(2) Nothing in subsection (1) affects any right of a court to grant any other relief or remedy in relation to an assessment or determination of a Medical Panel under this Division.

67 The initial referral of the medical question relating to the degree of impairment resulting from the injury to the claimant alleged in her claim was made on 12 December 2008. In turn, a Panel determined on 19 March 2009 that the degree of whole person impairment resulting from the physical injuries to the claimant alleged in the claim did satisfy the threshold level.

68 The Panel also issued a four page statement of reasons. The Panel referred to a submission on behalf of Dr Chua that the relevant impairment was limited to impairment consequential upon the claimant not being referred at an earlier stage for specialist opinion and radiological examination. The Panel stated:

The Panel does not accept this proposition. Such a proposition would involve the Panel embarking on an analysis of causation and liability. The respondent (Dr Chua) itself submits that the '... question of negligence and matters relating thereto ... are not matters for the consideration or determination of the Panel.'[40]

69 Emerton J subsequently set aside the Panel's determination and directed that the matter be remitted for re-determination in accordance with law. In so doing, her Honour held in part:

1. It is clear from its statement of reasons that the Panel assessed the claimant's impairment having regard to the claimant's injury 'at large'. The Panel assessed impairment arising from the physical condition of the claimant's left lower leg and ankle at the time of examination, not impairment arising from the injury allegedly caused by the plaintiff's delay in diagnosis and treatment. The Panel noted and expressly rejected the plaintiff's submission that the Panel restrict its assessment to the 'impairment consequential on the Claimant not being referred at an earlier stage for specialist opinion and radiological examination'.

1. ... In the present case, however, the claimant has brought proceedings against the plaintiff alleging that she suffered injury because of specific acts or omissions by the plaintiff, and that the relevant injury is the injury arising from the plaintiff's delay in diagnosis and treatment of an existing condition. The injury that is the subject of that claim is not the injury 'at large'.
2. It is true that a new definition of 'medical question' was inserted in the Wrongs Act in 2003 to make clear that a medical panel does not have to determine questions of causation. The explanatory memorandum to clause 13 of the Wrongs and Other Acts (Law of Negligence Bill) 2003 states that the new definition was included to make it clear that the role of the medical panel is to assess the degree of impairment resulting from the injury or injuries that a claimant alleges in his or her claim. The panel does not determine issues of causation, that is, 'whether or not those injuries could have been sustained in the incident on which the claim is based.'
3. This does not support an argument that the medical panel can only consider injuries 'at large'. To the contrary, it makes plain that the panel is concerned with the injury or injuries alleged in the claim. The panel must consider the injury allegedly caused by the tortfeasor and assume that it was caused by the tortfeasor as alleged. However, that does not absolve the panel of responsibility to correctly identify - for the purposes of assessing the degree of impairment - the injury which is alleged to have been caused by the tortfeasor.
4. The requirement that the Panel assess impairment arising from the injury that occurred as a result of the incident which is the basis for the claim does not require the Panel to determine whether the plaintiff caused the injury in respect of which damages are sought. Rather, it requires the Panel to assess the degree of impairment resulting from a particular injury - the injury in respect of which damages are sought. In this case, it is the injury suffered by the plaintiff as a result of delay in the treatment and diagnosis of a pre-existing dysfunction of the lower left leg and ankle.

1. Most importantly, the medical question itself required the Panel to assess whether the degree of impairment resulting from 'the injury alleged in the claim' satisfied the threshold level. The injury alleged in the claim is not coextensive with the injury 'at large'.

1. In this case, the Panel assessed impairment resulting from the injury that is the subject of the claim and from a pre-existing dysfunction of the left lower leg and ankle. In so doing, it took into account considerations which it was bound not to take into account and fell into error.
2. The plaintiff further complains that the Panel fell into error by answering a question other than the medical question referred to it. It follows from what I have said that the Panel did not answer the medical question that it was required to answer. In assessing impairment from the injury 'at large', the Panel did not assess the degree of impairment from the injury that was alleged in the claim.[41]

70 The determination with which I am now concerned was made following the reconsideration of the medical question by a new Panel constituted by the first and second defendants. The Panel had the benefit of documentary evidence including the clinical notes of Dr Chua and the medical reports of Dr Patel and Mr Khan. It also took a history directly from the claimant and medically examined her.

71 The Panel's reasons record the history taken by it in extended detail. It is sufficient for present purposes to refer to the following:

The claimant said that in [or] about August 2004 she noted the acute onset of pain in the front and outer side of her left ankle when walking back from lunch one day. She said that she thinks there was also a little swelling at the time. She said that within a few weeks she became aware that when walking her foot and hindfoot seemed to be 'going out' and her back was sore.

The Panel discussed with the claimant her symptoms before the onset of these symptoms in August 2004. She said that her left foot/hindfoot was definitely not going out, she did not experience pain or swelling, and she wore normal shoes. She said that she was not aware of any uneven wear on her shoe heels, and her shoes were not twisted.

The claimant said that she attended her local doctor on 2 August 2004, and was told that she had arthritis due to weakness in her right ankle. She said that she was treated with acupuncture and with Codalgin Forte analgesic medication. She said that radiological investigations were not performed at that time.

The claimant told the Panel that over the next few months, she noted increased pain in the left ankle, which would stop her walking, and she was unable to walk downstairs because of her symptoms.

The claimant said that by late 2005 she was experiencing constant pain in the front and outer side of the left ankle, the twisting of the left hindfoot was worse and she had been forced to change from wearing shoes to wearing clogs and sandals because of the left foot deformity, there was swelling over the front of the left ankle and she was having to use a stick constantly. She said that she was not aware of pain in her right ankle and foot at that time.

The claimant said that she asked her local doctor for a referral to a specialist in November 2005, and was referred to a rheumatologist, who she attended in early December 2005. She said that she was referred for an ultrasound examination and was referred to an orthopaedic surgeon.

The claimant told the Panel that she subsequently underwent three surgical procedures on her left ankle.

72 The Panel also recorded the results of its findings upon physical examination of the claimant. It noted in part:

There was a fixed deformity of the left hindfoot, with the hindfoot externally rotated and in inversion. There was minimal movement of the left ankle, and no movement of the subtalar or midtarsal joints. The left toes were mobile. There were callosities present under the first metatarsophalangeal joint and over some of the toe joints. Left knee flexion was reduced in range. There was a small patch of reduced sensation over the dorsal aspect of the left foot.

73 The Panel also reviewed the medical imaging of the claimant's left ankle and foot. A report of x-rays of both ankles made on 7 December 2005 described similar appearance on the left and right sides 'with degenerative changes within the talus and navicular bone and possible talar coalition. The talar dome appears intact.' An ultrasound of the same day produced the conclusion 'the appearances are highly suggestive of rupture of the tibialis posterior tendon. There are certainly features of tendonopathy present.' Medical images from February, April and July 2006 recorded the subsequent fixing and fusion of the left ankle and foot.

The Panel concluded that the claimant has left ankle dysfunction, and left hindfoot and midfoot fusion as a result of multiple surgical procedures. The Panel considers that the claimant's medical conditions of the left ankle and foot have stabilised.[42]

The Panel thus expressly concluded that the dysfunction it assessed resulted from the multiple surgical procedures which the claimant claims resulted from Dr Chua's negligence.

75 The Panel next referred to photographs taken of the claimant's ankle by Dr Patel immediately before he conducted surgery. It considered such photographs were confirmatory of the fact that at the time they were taken the claimant had an apparent greater degree of hindfoot valgus deformity on the left side than on the right and that both feet had flattening in the arches of the feet. The Panel noted that it requested photographs of the claimant's lower legs and feet taken earlier than when she attended Dr Patel and in particular prior to 2004, but was advised that the claimant does not have any photographs of her left ankle taken prior to the complaint of left ankle symptoms in 2004.

76 The Panel's reasons also record that the Panel reviewed the clinical notes of Dr Chua. The Panel noted references to:

• Post-traumatic arthritis and pain in the right ankle, first documented in the note dated 20 December 2000,
• Recurrent pain in the right and left ankles first documented in the note dated 25 March 2002,
• Bilateral ankle swelling first documented in the note dated 3 December 2002,
• Painful swollen left ankle for two weeks which was diagnosed as osteoarthritis in the note dated 2 August 2004,
• acupuncture treatment for both ankles from August 2004 onwards with most of the initial entries referring to the right ankle although some referred to the left as well, and
• referral to a rheumatologist on 10 November 2005.

77 The Panel's reasons record that it considered that the clinical notes did not contain any information which would provide assistance to the Panel in determining what, if any, impairment of the claimant's lower limbs existed in 2004 or 2005. The Panel then recorded the reports of Dr Patel and quoted from parts of the passages I have already set out above.

78 The Panel then summarised the submissions made on behalf of Dr Chua:

The submission of the respondent dated 12 December 2008 questions the validity of the Certificate of Assessment of Degree of Impairment arising from the Stabilised Injury, and raises the claimant's diabetes and osteoarthritis as causes of significant degenerative changes and tendon dysfunction which would have been present at the time the claimant first presented to the respondent on 2 August 2004 complaining of left ankle pain. The submission also contends that surgery and its outcome was inevitable even if the claimant had been referred for surgery at an earlier stage, and that the subsequent multiple surgical procedures were due to aspects of the initial surgical procedure on the claimant's left ankle 'apparently failing and requiring correction.' The submission also identifies that the claimant 'also developed septic arthritis.'

This submission and subsequent submissions also raises various issues including the Panel's need to ensure that:

• regard must not be had to unrelated injuries or causes of impairment
• it identifies the degree of impairment 'resulting from the injury'.

The submission dated 2 September 2010 also addresses the Judgment of Her Honour Justice Emerton.

79 The Panel then summarised the submissions made on behalf of the claimant and in particular the submission that the specific injury which is compensable is the left ankle condition in its entirety. It was the claimant's submission that had the left ankle condition been diagnosed and treated in a timely fashion, it could have been corrected with simple surgery without any resultant impairment.

80 The Panel then went on to quote from relevant parts of the judgment of Emerton J, including paras 34, 36 and 37. The Panel referred to its responsibility to identify the injury which is alleged to have been caused by the tortfeasor assuming that it was caused as alleged. The Panel expressly referred to the statement in para 37 of Emerton J's judgment that the Panel is required to 'assess the degree of impairment resulting from a particular injury - the injury in respect of which damages are sought. In this case, it is the injury suffered by the plaintiff as a result of delay in the treatment and diagnosis of a pre-existing dysfunction of the lower left leg and ankle.'[43] The Panel went on to state:

The particular injuries to be assessed are the injuries described in the statement of claim by reason that the claimant's allegation is that, had the condition been promptly diagnosed and treated, the condition 'could, and would, have been easily corrected.'

The Panel considers itself bound by Her Honour's reasoning, and by the definition of medical question in section 28LB of the Wrongs Act 1958, to assess the impairment resulting from the injury as described in the claimant's statement of claim.

81 The Panel then made reference to part of section 2.3 of the Guides headed 'General Comments on Evaluation' which I have already quoted in the course of dealing with the scheme of the relevant provisions of the Act.

82 The Panel stated that it was required to conduct an impairment assessment in accordance with the Guides as required by s 28LH of the Act. It then stated the basis of its impairment assessment in summary as follows:

The Panel has considered the history obtained from the claimant at the time of its examination, its findings at examination, has reviewed the medical imaging and reports on such imaging and has reviewed the contemporaneous medical records and available medical reports relevant to the claimant and has concluded that it has sufficient information to conduct an impairment assessment of the claimant's left lower leg and ankle.

The Panel assessed the claimant's lower left leg and ankle in accordance with Section 3.2 of Chapter Three of the Guides. The Panel used a goniometer, where necessary, to measure the range of motion in accordance with the instructions in the Guides.

The Panel concluded that the most appropriate method of assessment was to use Section 3.2f for joint ankylosis of the left hind foot and Section 3.2e for restricted range of motion of the left ankle as they were clinically the most appropriate to use.

The Panel assessed the appropriate whole person impairment due to ankylosis of the left hind foot pursuant to Table 57 and the instructions on page 81 of Section 3.2f of Chapter Three of the Guides.

The Panel assessed the appropriate whole person impairment due to moderately impaired range of motion of the left ankle pursuant to Table 42 of Section 3.2e of Chapter Three of the Guides.

83 There is no dispute that the assessment carried out by the Panel accorded with the Guides insofar as it assessed the claimant's degree of impairment at the time she came before the Panel. There is, however, a dispute as to whether such an assessment was a proper basis for the Panel's conclusions. I pause only to note that it was conceded by counsel for Dr Chua that it can be inferred that the assessment of current impairment demonstrated an impairment in excess of 10 per cent.

84 The Panel then returned to the question of pre-existing impairment. It stated:

The Panel gave consideration to whether any impairment may have existed prior to the claimant's visit to Dr Chua in August 2004 and during the period to January 2006 when the claimant's medical condition was diagnosed and arrangements made for surgical treatment to commence. This was done for the purposes of section 28LL(3) of the Wrongs Act 1958 which provides that impairments from unrelated injuries or causes are to be disregarded in making an assessment.

The Panel has considered the history obtained from the claimant at the time of its examination, reviewed the medical imaging and reports on such imaging, the contemporaneous medical records and available medical records relevant to the claimant and considers that there is unlikely to exist any additional relevant contemporaneous medical records to assist it to make a retrospective impairment assessment under the Guides.

85 The Panel then expressed two critical conclusions. The first conclusion was that there was insufficient information available to permit it to validly assess any impairment existing during the period August 2004 to January 2006 of the claimant's left lower leg and ankle. The second critical conclusion was that it considered in any event that it is likely that during the period between August 2004 and January 2006 the claimant's condition had not stabilised, which would have precluded the making of an impairment assessment in respect of the claimant's condition at the time of the alleged negligence.

86 The Panel also concluded that it was unable to make an impairment assessment as at January 2006 when the claimant first consulted Dr Patel. This finding is of contextual relevance only to the principal issues between the parties. Likewise, the Panel considered that it is likely that at the time of the consultation with Dr Patel the claimant's condition had not stabilised. Once again, this is a finding of contextual relevance only.

87 It is the first critical conclusion relating to the insufficiency of information enabling a valid assessment of any impairment existing during the period between August 2004 and January 2006 which is the factual finding central to the principal attacks Dr Chua now seeks to make upon the Panel's reasoning.

As noted above, the Guides are specific in Section 2.3 headed 'General Comments on Evaluation' that, in seeking to assess a change in impairment where there is no valid previous evaluation, and there is insufficient information to document the change accurately, the evaluator ought not attempt to estimate the change.

The Panel has therefore concluded that, in accordance with the Guides, and specifically Section 2.3, it is unable to and therefore has not made an impairment assessment of the claimant's pre-operative condition of the left lower leg and ankle during the period between approximately August 2004 and January 2006.

89 It went on to reject the proposition that the claimant's diabetes was in any way related to the impairment assessment of the left lower leg and ankle injuries. It noted that there was no medical evidence which supported the view that the diabetes was relevant. This conclusion was open to it as a matter of fact.

On the basis of the insufficient information available, the Panel concluded that it has insufficient verifiable or complete evidence to assess the degree of impairment of the lower left leg and ankle attributable to any pre-existing condition (that is prior to the claimant's visit to the respondent in August 2004 and in 2005) as required by the Guides.

The Panel therefore concluded that it has insufficient information to estimate an impairment that pre-existed the claimant's first consultation with the respondent in August 2004 and in 2005 which can be disregarded in accordance with Section 28LL(3) of the Wrongs Act 1958.

The Panel therefore considers that it is unable to make a valid assessment of any change in impairment estimate (from around the time of the claimant's visit to the respondent in August 2004 and in 2005, and, as at the time of the claimant's first visit to treating surgeon) for the reasons that there is no reliable evidence or gathered information to enable the Panel to determine any previous estimate of impairment (which existed prior to the claimant's visit to the respondent in August 2004 and in 2005).

On the basis of the Panel's assessment (at its examination of the claimant on 28 May 2010) of whole person impairment resulting from injury which the Panel considers to be potentially compensable injury, the Panel concluded that the degree of whole person impairment resulting from the physical injury to the claimant alleged in the claim is more than 5% and is permanent.

92 The Panel then recorded its view that it was not required to make a finding in relation to the issue of whether or not the claimant's current medical condition was caused by the circumstances of the incident alleged to have given rise to the claim. The Panel stated that it had assessed impairment arising from the injuries to the claimant 'that are potentially compensable' in accordance with the referral.

Did the Panel misdirect itself by undertaking an assessment of the impairment of the claimant's left ankle 'at large'?

93 The Panel's reasons demonstrate that it did not misdirect itself as to its fundamental task, namely the assessment of the impairment constituted by the injury alleged in the claim. The Panel expressly acknowledged that it was required to take account of and disregard, for the purposes of its assessment, any relevant prior impairment.

94 The Panel expressly acknowledged the terms of the decision of Emerton J relating to the previous assessment of the claimant. The Panel's reasons demonstrate that it understood that it was required to assess the degree of impairment resulting from the particular injury in respect of which damages are sought.

95 It is true that an impairment of the type in issue will necessarily raise a question of a before and after comparison. It is also true that, as is normally the case in medical negligence cases, the claimant suffered from an existing condition at the time of the alleged failure to diagnose and treat her properly.

96 Nevertheless, as counsel for Dr Chua acknowledged, this is not an aggravation case. The injury alleged is not, in terms, an aggravation of a pre-existing impairment. The nature of the injury alleged does not itself imply a pre-existing impairment. This does not mean that the claimant did not in fact suffer from pre-existing impairment, but it is not implicit in her case that she did so.

97 The claimant is not alleging impairment analogous to aggravation of a pre-existing degenerative condition of the spine. Such an allegation postulates pre-existing impairment as the starting point for the compensable injury.

98 The claimant had not suffered a triple fusion arthrodesis at the time of the alleged negligence by Dr Chua. The condition identified as causing impairment at the date of the Panel's assessment did not exist at the time of treatment by Dr Chua. The assessment of the before situation required the Panel to assess whether the claimant suffered from other impairment of the left leg, and more particularly the left ankle, at the time of the alleged negligence.

99 Although the opinions of Dr Patel and Mr Khan were consistent with the existence of some pre-existing permanent impairment, the evidence before the Panel did not require a finding of pre-existing impairment. It was open to it to find that at the relevant time, the claimant's pre-existing condition had not stabilised in permanent impairment.

100 There was no medical opinion evidence positively identifying pre-existing impairment. There was no evidence from Dr Chua himself specifically recording symptoms of permanent impairment. This is perhaps not surprising if in fact Dr Chua misdiagnosed the claimant's condition. Nevertheless, he was the medical practitioner who carried out clinical examinations of her at the relevant time.

101 It follows that it cannot be said the Panel misdirected itself as to its task, either by reference to its statements formulating such task, or by necessary inference having regard to its findings of fact. I accept the claimant's submission that it is appropriate to recall the observations of McHugh J in Re Minister for Immigration and Multicultural Affairs & Ors; Ex Parte Cohen:[44]

If an administrative tribunal applies a wrong legal test or asks itself or decides a wrong legal question, it may be a short step to concluding that it did not decide the question that it had to decide. But questions of fact are ordinarily for an administrative tribunal to determine and so are the reasoning processes employed to make such findings. Disagreement with a finding of fact or the reasoning process used to find it is usually a slender ground for concluding that a tribunal misconceived its duty.[45]

102 Dr Chua's originating motion gives a series of particulars of alleged taking into account of considerations the Panel was bound to ignore. The first particular[46] is:

When coming to its Determination, the Medical Panel's reasons show that the reconvened Medical Panel had regard to, and included in its assessment of impairment resulting from the claimed injury, all the impairment attributable to the claimant's 'left ankle dysfunction' (including impairment to the left lower leg, left ankle and left foot due to multiple surgical fusion procedures to treat the said dysfunction);

103 I do not accept this ground establishes error as particularised. The extent of the relevant impairment was a question of fact. The Panel cannot be said to have misdirected itself simply because it attributed all the claimant's current impairment to the alleged injury. It was neither necessarily implicit in the claimant's claim nor a necessary conclusion from the evidence that there was pre-existing impairment in the sense of permanent impairment.

104 The next allegation particularised is: [47]

The said left ankle dysfunction condition is long standing and predated the acts or omissions alleged by the claimant to have caused her personal injury;

105 In terms, this ground raises a question of fact. It raises neither a jurisdictional error nor an error of law. Moreover, it is plainly incorrect in that the claimant's current condition results from a triple fusion arthrodesis and is not 'longstanding'. The fact that the claimant suffered from pre-existing PTTD and osteoarthritis does not necessarily establish of itself that she suffered a condition of permanent impairment relevant to the Panel's assessment of impairment as a result of the alleged negligence.

106 The Guides state the following with respect to permanent impairment:

Permanent impairment is impairment that has become static or well stabilised with or without medical treatment and is not likely to remit despite medical treatment.

A permanent impairment is considered to be unlikely to change substantially and by more than 3% in the next year with or without medical treatment. If an impairment is not permanent, it is inappropriate to characterise it as such and evaluate it according to Guides criteria.[48]

107 The evidence before the Panel did not compel the conclusion that the claimant suffered from pre-existing permanent impairment either in the sense stated in the Guides or in the ordinary sense of that term.

Did the Panel fail to disregard pre-existing impairment of the left ankle in accordance with s 28LL(3) of the Act?

108 As I have said, I accept that the assessment of impairment in accordance with the Guides pursuant to s 28LH of the Act is subject to the other provisions of the division of the Act concerning the assessment of serious injuries.

109 It follows that the provisions of the Guides relating to the assessment of impairment must be read subject to the provisions of s 28LL(3), which state that, for the purposes of pt VBA, impairments from unrelated injuries or causes are to be disregarded in making an assessment.

110 Once again it is necessary to bring squarely to mind that this is not an aggravation case. The impairment which resulted from the triple fusion arthrodesis did not pre-date Dr Chua's treatment. It was the result of subsequent events allegedly necessitated by his negligence.

111 Put another way, the impairment which the Panel assessed arose from circumstances arising after (and allegedly as a result of) treatment of the claimant by Dr Chua.

112 Particulars 11(iii), (iv) and (v) in Dr Chua's originating motion allege as follows:

(iii) The Panel failed to limit its impairment assessment to '...the injury in respect of which damages are sought. In this case it is the injury suffered by the [claimant] as a result of delay in the treatment and diagnosis of a pre-existing condition of the lower left leg and ankle', as adjured by her Honour Justice Emerton in her reasons for judgment dated 11 December 2009 at paragraph [37] thereof;

(iv) The Panel was bound to disregard any left lower leg, left ankle or left foot impairment that resulted from circumstances which pre-dated Dr Chua's treatment or did not result from Dr Chua's alleged failure to give a timely diagnosis and/or referral, in that such impairment, being due to an unrelated injury or cause, was to be excluded from assessment because of the provisions of sub-section 28LL(3) of the Act;

(v) Contrary to its said statutory obligation, and contrary to the said direction in her Honour's reasons for judgment, the Panel failed to so disregard any left lower leg, left ankle or left foot impairment that resulted from circumstances which pre-dated Dr Chua's treatment or did not result from Dr Chua's alleged failure to give a timely diagnosis and/or referral, but instead has included such impairment in its assessment of impairment resulting from the claimed injury.[49]

113 These particulars assume that the claimant was suffering from impairment which pre-dated Dr Chua's treatment. The evidentiary basis for this assumption has not been made out. I am not satisfied that the Panel's reasons or the evidence before it compel the assumption. It is one thing to say the claimant had a pre-existing tendon condition at the time Dr Chua treated her. It is quite another to say that she suffered from pre-existing permanent impairment of her left lower leg, ankle or foot. The material before the Panel raised this possibility but does not demonstrate the Panel was bound to so conclude. It is not sufficient for Dr Chua to suggest that this is possible. He must demonstrate that there was an impairment which the Panel was bound to disregard and failed to do so in order to demonstrate error in the terms particularised above.

114 Ground 12(ii) of the originating motion further states:

... the Panel misunderstood its jurisdiction such that it wrongly assumed that it was required to treat any increase in lower left leg, ankle and foot impairment measured in accordance with the AMA Guides between the date of the claimant's first treatment by Dr Chua and the date of the Panel's assessment (should it be capable of calculation) as constituting, a priori, the result of Dr Chua's alleged failure to give a timely diagnosis and/or referral, and it further reveals that the Panel misunderstood its jurisdiction in this respect such that it wrongly assumed that it was required to disregard the possibility or likelihood that any such increase in impairment might be due only to the ordinary course of the pre-existing condition, and/or the ordinary course of its reasonable treatment.[50]

115 In my opinion this ground is also misconceived.

116 The Panel's reasons demonstrate that it correctly identified its obligation to disregard pre-existing impairment and then examined the evidence concerning such pre-existing impairment. The real question is thus whether the Panel misdirected itself in the manner in which it assessed that evidence.

Did the Panel misdirect itself in the manner in which it applied s 28LL(3)?

117 Dr Chua contends that the Panel misdirected itself by wrongly assuming that it must not disregard impairment due to a pre-existing condition in accordance with s 28LL(3) unless there was 'sufficient information' within the meaning of the Guides to properly reconstruct an impairment assessment in accordance with the Guides, as though it had been performed at the time.

118 The existence or absence of pre-existing impairment must logically be relevant in a case such as the present case where the current impairment suffered by the claimant results from a supervening cause, namely the triple fusion arthrodesis she has suffered. The Panel must assess the net impairment caused by the injury the subject of the claim.

119 As I have previously said, the impairment to which s 28LL(3) refers is by definition permanent impairment. The general comments on evidence contained in the Guides which I have previously quoted commence with reference to assessment of 'permanence'.

An impairment should not be considered 'permanent' until the clinical findings, determined during a period of months, indicate that the medical condition is static and well stabilized.[51]

120 In the present case, the Panel did not merely find that it could not be satisfied that the claimant's pre-existing condition was permanent; the Panel found positively that the probability was the claimant's condition had not stabilised at the time she was seen by Dr Chua.

121 In making what I have referred to as the second critical finding, the Panel made a finding which was directly responsive to the scheme of the Act. Section 28LNA expressly contemplates that the medical assessor may be unable to determine a degree of impairment because an injury has not stabilised (see also s 28LZG(5)-(8)).

122 It must be open to a Panel to find that a claimant's pre-existing condition had not stabilised so as to constitute permanent impairment of any ascertainable extent. This is a situation contemplated by the Act itself.

123 If that finding be made, it may be open to characterise a subsequent supervening injury (such as that here alleged) as giving rise to the whole of the permanent impairment which occurs as a result of the supervening incident.

124 In my view, the Act does not require the Panel to assume that a pre-existing condition caused a permanent impairment when the evidence does not demonstrate that it did so. It does not require the Panel to speculate. It requires the Panel to disregard pre-existing impairment which is established by evidence to have resulted from a cause other than the relevant injury.

125 It was submitted on behalf of Dr Chua that even if a claimant was very seriously injured, if the extent of a possible pre-existing impairment could not be ascertained then a Panel could not certify the level of the existing impairment. I do not accept this is the effect of s 28LL(3). If the evidence enables pre-existing impairment to be ascertained, that pre-existing impairment must be disregarded as irrelevant. If, however, the Panel can positively identify a current impairment potentially caused as alleged in the claim (as in the present case) and there is no evidence establishing a pre-existing impairment, then there is nothing to be disregarded.

126 Counsel for Dr Chua placed significant reliance upon the decision of J Forrest J in Alcoa. That decision concerned the provisions of the ACA relating to the assessment of serious injuries by a Panel.

127 There is a significant threshold difference between those provisions and those with which I am concerned. The ACA provisions require the assessment of an actual level of impairment and not merely an assessment of a threshold level of impairment.

128 There is a further fundamental difference on the facts between the present case and that with which J Forrest J was concerned. The worker's injury in issue in the Alcoa case was aggravation of an acknowledged pre-existing back impairment. As I have been at some pains to stress, the present case is not such a case.

129 Nevertheless, s 98(c) of the ACA mirrors s 28LL(3) of the Act and requires that 'impairments from unrelated injuries or causes are to be disregarded in making an assessment'. His Honour relevantly held that:

(a) The evaluation of unrelated impairment under the provisions of the ACA is not required to be carried out in accordance with the tests stated in the Guides.

(b) The ACA requires previous impairment from an unrelated injury to be disregarded for the purpose of assessing the compensable injury.

(c) The evidence may enable the assessment of pre-existing impairment in accordance with the two step approach contemplated by the Guides. First, an assessment is to be made of the pre-existing impairment. The determination is to be made from historical information and previously compiled medical data which 'can be verified as being accurate'. Second, it is implicit that an assessment of the pre-existing impairment be subtracted from that of the current impairment assessment.[52]

(d) There may also be cases where the evidence is insufficient to enable the utilisation of the two step process but is sufficient to enable the Panel to apply the provisions of the Act and disregard any relevant pre-existing impairment.

130 In the course of his reasons his Honour stated:[53]

In engaging in its statutory task the Panel must do the best it can to evaluate the extent to which impairment from the unrelated injury or cause is playing a part in the worker's current impairment.[54] If the evidence enables it to determine the extent of the present impairment and that of the pre-existing impairment, then it must make allowance for the pre-existing impairment.

In summary, the Act and the Guides require the following approach where there is evidence of a pre-existing impairment of the same body part:

(a) if the evidence is sufficient to demonstrate the existence of a pre-existing impairment from an unrelated injury or cause, then the Panel must, as best it can, determine the extent of that impairment so it can be disregarded and evaluate the impairment related solely to the compensable injury;

(b) the Panel is required to apply s 91(7)(c); this does not necessitate the application of clause 9[56] in evaluating the pre-existing impairment. Indeed, in some cases, to utilise the clause 9 criteria (and its inbuilt evidentiary requirements) would result in error; and

(c) in an appropriate case, the two-step approach provided for in clause 9 may be appropriate, provided that in conducting the evaluation the assessment complies with the obligation imposed by the Act. There is no discretion in the Panel (as clause 9 would seem to convey) to ignore any pre-existing impairment.

132 I respectfully accept that like principles substantially apply to the proper interpretation of the provisions of the Act with which I am concerned. First, s 28LL(3) does not require that unrelated impairment necessarily be assessed in accordance with the Guides, as:

(a) Section 28LH, which requires utilisation of the Guides, commences with the words 'subject to this division'.

(b) Section 28LL(3) utilises imperative words.

(c) The underlying common law notions of compensable injury support his Honour's conclusions. It is the potentially compensable injury and it alone which the Panel is intended to assess.

133 Secondly, if the evidence allows, the Panel must assess pre-existing impairment to the extent necessary to its task. (It is logically possible in cases under the Act that, because all that is required is a conclusion that impairment reaches a certain threshold, it may not be necessary to assess the degree of a pre-existing impairment. Thus, where the subsequent injury resulted in amputation of a leg, it may not be necessary to assess the level of some pre-existing functional impairment if it is plain that that impairment could not affect the decision concerning the relevant threshold.)

134 Thirdly, the tests contained in the Guides may or may not provide a satisfactory basis for assessment of pre-existing impairment and in circumstances of insufficient information they are not to be regarded as the exclusive method for such assessment.

135 Fourthly, any assessment of pre-existing impairment must be evidence based. It cannot simply be speculative. The Panel must have an evidentiary basis on which it can be positively satisfied of a pre-existing impairment which it then disregards. The Panel is not bound by rules or practices as to evidence but it must act on the basis of evidence of some sort.

136 Despite acceptance of the above propositions there are, however, two problems in the application of these principles in the present case in the manner for which Dr Chua contends. First, this is not an aggravation case and the fact of pre-existing permanent impairment is itself in issue. Secondly, Dr Chua has not satisfied me that the Panel was bound to conclude that 'the evidence is sufficient to demonstrate the existence of a pre-existing impairment from an unrelated injury or cause'. The submissions made on his behalf simply assert that because the claimant suffered from a pre-existing condition she must be regarded as having suffered from a pre-existing permanent impairment. This does not follow and I am not satisfied that the Panel was bound to conclude the claimant suffered from a pre-existing impairment of the requisite permanent nature.

Did the Panel equate the ascertainment of pre-existing impairment with assessment of such injury in accordance with the AMA Guides?

137 This said, I accept that the latter part of the Panel's reasons demonstrate that it did ultimately equate ascertainment of pre-existing impairment for the purposes of s 28LL(3) with the assessment of such impairment in accordance with the Guides.

138 In particular, as I have indicated, the Panel stated immediately before its final conclusion:

On the basis of the insufficient information available, the Panel concluded that it has insufficient verifiable or complete evidence to assess the degree of impairment of the lower left leg and ankle attributable to any pre-existing condition (that is prior to the claimant's visit to the respondent in August 2004 and in 2005) as required by the Guides.

The Panel therefore concluded that it has insufficient information to estimate an impairment that pre-existed the claimant's first consultation with the respondent in August 2004 and in 2005 which can be disregarded in accordance with Section 28LL(3)of the Wrongs Act 1958.

The Panel therefore considers that it is unable to make a valid assessment of any change in impairment estimate (from around the time of the claimant's visit to the respondent in August 2004 and in 2005, and, as at the time of the claimant's first visit to treating surgeon) for the reasons that there is no reliable evidence or gathered information to enable the Panel to determine any previous estimate of impairment (which existed prior to the claimant's visit to the respondent in August 2004 and in 2005).[57]

139 I accept that it was not open to the Panel to reason that simply because no assessment could be made in accordance with the Guides it followed that no valid estimate of pre-existing impairment could be made. The conclusion that the Panel had insufficient information to assess any pre-existing impairment of the left lower leg and ankle in accordance with the Guides did not of itself justify the conclusion that there was no pre-existing impairment to be disregarded in accordance with s 28LL(3) of the Act. I accept for the reasons I have already stated that s 28LL(3) imposed an overriding obligation upon the Panel.

140 Nevertheless, the claimant submits that the second critical finding made by the Panel that the claimant's pre-existing condition had not stabilised sufficiently to enable assessment of impairment logically precluded a conclusion that there was pre-existing impairment in the sense of permanent impairment. In effect, it is submitted that, although I may accept that the reasoning process based on the Guides which I have set out above was not open to the Panel, I should not be persuaded that the error identified constitutes a vitiating error.

141 The question is whether the Panel's finding that during the relevant period the probability was that the claimant's condition had not stabilised precluded the making of an assessment of pre-existing impairment.

142 I am not ultimately persuaded that the Panel went sufficiently far in its finding relating to the stabilisation of the claimant's condition to provide an independent basis for its ultimate conclusion. As counsel for Dr Chua submit, the notion of stabilisation is not fixed in its relationship with that of permanent impairment. A condition may already comprise a degree of permanent impairment but not be sufficiently stabilised to determine the ongoing degree of impairment which may result from the then existing condition. As I have said, the Act itself contemplates that a series of alternative consequences may result from the fact that an injury has not stabilised (see eg s 27LZG(5)-(8)).

143 In the present case, the Panel did have evidence of a pre-existing disabling tendon condition and of some degenerative osteoarthritis (including medical imaging produced when the client was referred to Dr Patel). A finding that the claimant's condition had not stabilised may or may not have precluded a further finding of impairment. Thus it may be that the tendon condition was not necessarily one resulting in permanent impairment but the osteoarthritis was. If the Panel had itself found that it was not satisfied there was a pre-existing impairment because the pre-existing condition had not stabilised, that finding would be dispositive of the issue. But the Panel did not so conclude. It simply found that the claimant's condition had not stabilised at the time of the alleged negligence (ie between August 2004 and 2006) and the probability is this would have precluded the making of an impairment assessment at this time. I take its reference to an impairment assessment in this context to be a reference to an assessment in accordance with the Guides having regard to its surrounding reasons.

144 In turn, the Panel relied specifically on the absence of sufficient information relating to the relevant period to undertake assessment in accordance with the Guides as the basis of its conclusion that there was no relevant impairment. In these circumstances the finding concerning stabilisation is equally consistent with the possibility that there was some degree of pre-existing impairment now capable of being estimated, albeit that degree of impairment had not stabilised when the claimant was treated by Dr Chua and albeit that it cannot now be assessed in accordance with the Guides.

145 It follows that I accept Dr Chua's submission that the Panel's explanation for its conclusions concerning pre-existing impairment reveals that it asked itself the wrong question. The Panel regarded the absence of sufficient information to make the assessment of pre-existing impairment in accordance with the Guides as conclusive of the absence of such impairment when it should not have.[58]

Was the Panel required to assess the claimant's impairment against the possibility that such impairment might only be due to the ordinary course of the pre-existing condition, and/or the ordinary course of its reasonable treatment?

146 Dr Chua contends that the Panel wrongly assumed that it was required to disregard the possibility or likelihood that any increase in impairment might be due only to the ordinary course of the pre-existing condition and the ordinary course of its reasonable treatment.

147 The evidence did not compel or indeed justify the conclusion the claimant would have required a triple fusion arthrodesis if properly treated by Dr Chua.

148 The Panel positively concluded that the impairment arising from the injuries claimed by the claimant was 'potentially compensable'. It both identified the existence of an injury and assessed the level of impairment flowing from that injury. In so doing, the panel necessarily rejected the proposition that there was no evidence the claimant's impairment was other than consequence of the ordinary course of her pre-existing condition and / or its reasonable treatment.

149 It is not the Panel's function to do other than identify and assess the impairment in fact resulting from the injury alleged in the claim. It will be the function of a court to determine whether that injury was caused by the negligence of Dr Chua and, if so, what quantum of damages should be assessed having regard to the surrounding circumstances including risks of vicissitudes peculiar to the claimant.

150 In summary, I accept the Panel was required to do a before and after enquiry in order to identify the degree of potentially compensable impairment resulting from the alleged injury.

151 It was also required to identify an 'injury', ie a change in circumstances other than that constituted by the ordinary progression of any pre-existing condition. In the present case it was plainly open to characterise the condition requiring triple fusion arthrodesis as such an injury.

152 The Panel was not however required to assess the difference between the hypothetical after situation (in which no injury was inflicted) and the current situation. That assessment goes to the issue of damages.[59]

153 Once positively satisfied of the fact of an identifiable potentially compensable injury, the Panel was not, as Dr Chua submits, required to assess the difference in percentage terms implicit in Mr Khan's opinion that if treated properly by Dr Chua '... the impairment would have been expected to be far less in percentage than it is now.'

154 Accordingly, the ground stated in the amended originating motion, para 12 particular (ii) fails:

... the Panel misunderstood its jurisdiction in this respect such that it wrongly assumed that it was required to disregard the possibility or likelihood that any such increase in impairment might be due only to the ordinary course of the pre-existing condition, and/or the ordinary course of its reasonable treatment.

Jurisdictional error or error of law on the face of the record

155 During the course of the hearing, counsel for the claimant submitted that the grounds articulated in the originating motion were properly characterised as allegations of error of law on the face of the record rather than as jurisdictional error. After hearing argument, I granted leave to Dr Chua to amend the grounds stated in the originating motion to rely upon the same allegations of error but characterise them in the alternative as errors of law. In turn, I directed the parties have leave to file and serve written submissions arising out of the amendment.

156 In the event, I have concluded that one substantive allegation of error on the part of the Panel can be sustained. That is the allegation that it wrongly assumed that a conclusion that there was insufficient information to assess impairment in accordance with the Guides in respect of the claimant's pre-existing condition justified, in itself, the conclusion that there was no pre-existing impairment which could be estimated and disregarded.

157 Jurisdictional error by an administrative tribunal includes an error of law which results in the tribunal identifying the wrong issue, ignoring relevant material or relying on irrelevant material in a way that affects its decision.[60]

158 The error I have identified is an error apparent from the Panel's reasons, which in this State are to be regarded as part of the 'record'.[61]

159 In my view, the Panel either committed jurisdictional error or an error of law on the face of the record in that, as J Forrest J put it in Alcoa, the Panel misconstrued the requirements of the statute.[62] The error committed by the Panel vitiated its decision.[63]

160 The Panel has not simply made positive findings of fact, it has constrained consideration of the question of pre-existing impairment by reliance on the application of the Guides when this was not the definitive test.

161 Senior counsel for the claimant and counsel for the Panel both submitted to me that if I were to conclude the Panel had erred and remit the matter for further consideration by a Panel, then I should seek to give that Panel clear instructions. I will accordingly seek to summarise my conclusions as to the relevant principles bearing on the present case:

(1) The Panel must identify an injury potentially caused in the manner alleged in the claim.

(2) The Panel will not be able to do so if it concludes that the claimant's current impairment is the result of the ordinary progression of a pre-existing condition.

(3) In the present case, it was open to the Panel to conclude that the condition requiring triple fusion arthrodesis constituted such an injury ('the compensable injury').

(4) In order to assess the degree of impairment consequent upon the compensable injury the Panel was required to disregard impairment from unrelated injuries or causes.

(5) Such irrelevant impairment included pre-existing permanent impairment. It was necessary to disregard such impairment in order to assess the net impairment resulting from the compensable injury.

(6) A pre-existing condition or injury may or may not constitute pre-existing impairment because impairment in the relevant sense is permanent impairment.

(7) It may be that pre-existing impairment can be established and assessed in accordance with the Guides on the basis of historical evidence.

(8) Alternatively, it may be that although there is insufficient information to permit assessment in accordance with the Guides, nevertheless there is evidence which demonstrates that there was a level of pre-existing impairment. In such cases, the Panel must disregard and discount such impairment as best it can as an expert tribunal, having regard to the probabilities on the evidence available.

(9) The evidence may raise an issue of stabilisation with respect to a pre-existing condition. It may be that a condition such as PTTD had not sufficiently stabilised so as to constitute permanent impairment at the time of the compensable injury. If the Panel concludes that this was the case then there is no impairment to be disregarded as irrelevant.

(10) Conversely, although a condition such as PTTD had not stabilised at the time of the compensable injury, it may nevertheless be concluded there was already a level of permanent impairment. In such cases, the Panel must assess the level of such impairment as best it can as an expert tribunal having regard to the probabilities on the evidence available.

(11) The Panel may conclude that a component of a pre-existing condition (eg PTTD) had not resulted in permanent impairment at the date of the compensable injury but another component of a pre-existing condition (eg osteoarthritis) had resulted in permanent impairment.

(12) The Panel may be able to conclude that the level of impairment resulting from the compensable injury necessarily exceeds the threshold without concluding more than a probable potential range of pre-existing impairment. It may be clear that the potential range of pre-existing impairment could not bring the assessment of the impairment resulting from the compensable injury down below the threshold level. In such cases it will be unnecessary to make an assessment of a precise percentage of pre-existing impairment. It will be possible to conclude the threshold has been exceeded in respect of the compensable injury.

(13) Once the Panel has identified a potentially compensable injury and the current level of impairment caused by it, the Panel is not required to hypothesise what level of impairment the claimant may have suffered from as at the date of assessment if the injury had not occurred.

(14) The Panel must undertake a before and after enquiry in the context of a medical negligence claim, but is not required to undertake a comparison between the hypothetical and actual after situations. A before and after enquiry will bear on the threshold question of whether a potentially compensable injury has occurred. Once that question has been answered in the affirmative, however, the Panel's statutory task is not to inquire further. The comparison of what is and what would have been if the injury had not occurred goes to the assessment of risks which are properly resolved when considering quantum upon the trial of the common law proceeding.

(15) It is not disputed in the present case that it was open to conclude that the claimant's present impairment exceeds 10 per cent.

(16) Assuming the Panel reaches like conclusions upon the facts to those reached by the Panel in the present case, the Panel must determine whether:

(a) despite the lack of information sufficient to make an assessment in accordance with the Guides in respect of the claimant's condition at the time of the alleged injury; and

(b) the probability that the claimant's condition had not stabilised sufficiently to permit an impairment assessment at that time in any event, nevertheless;

(c) there is sufficient evidence to establish the claimant did suffer from pre-existing permanent impairment of any and what nature; and

(d) doing the best it can, determine the degree of such pre-existing impairment (if any) to the extent necessary (which may only be a range of potential impairment) for the Panel to reach a conclusion as to whether the current level of impairment resulting from the compensable injury exceeds the threshold.

162 It follows from my conclusions that this matter must be remitted for reconsideration in accordance with law. I will hear counsel as to the question whether I should direct the Panel be differently constituted and as to other ancillary orders.

[1] [2010] HCA 12; (2010) 240 CLR 537. ('Tabet')

[3] Gregg v Scott [2005] UKHL 2; [2005] 2 AC 176, 182 [9] per Lord Nicholls of Birkenhead and Harriton v Stephens [2006] HCA 15; (2006) 226 CLR 52, 104 [167] per Hayne J, cited in Tabet, [140].

[5] In Tabet the evidence did not establish the necessary link between the delay in treatment of the plaintiff and the condition from which he suffered [114].

[6] Laferrière v Lawson [1991] 1 SCR 541, 591, cited in Tabet, [142].

[7] Savatier, 'Une faute peut-elle engendrer la responsabilité d'un dommage sans l'avoir causé?', D 1970 Chron 123, at p 124, cited in Laferrière v Lawson [1991] 1 SCR 541, 574, cited in Tabet, [142].

[8] [1999] HCA 22; (1999) 197 CLR 269, 280 [36], cited in Tabet, [142].

[10] Malec v J.C. Hutton Pty Ltd [1990] HCA 20; (1990) 169 CLR 638, 642 following. Citations omitted. See also Harold Luntz, 'Assessment of Damages for Personal Injury and Death' (Butterworths Australia, 4th ed, 2002), 173-4.

[11] [1964] HCA 39; (1964) 111 CLR 234, 248.

[13] Overland Sydney Pty Ltd v Piatti (Unreported, NSW Court of Appeal, Kirby P, Priestley and Meagher JJA, 12 November 1992) 12-14; Harold Luntz, 'Assessment of Damages for Personal Injury and Death' (Butterworths Australia, 4th ed, 2002), 174.

[14] Zumeris v Testa [1972] VicRp 97; (1972) VR 839, 842.

[15] De Agostino v Leatch and TAC [2011] VSCA 249, [9].

[16] [1994] VicRp 32; [1994] 1 VR 436.

[17] Ibid 443 (emphasis added). Brooking J stated that he agreed with Southwell and Teague JJ that the appeal should fail, for substantially the reasons they had given.

[18] An abnormal turning from the level.

[20] Making a section of the bone for the purpose of correcting a deformity.

[21] The Flexor Digitorum Superficialis tendon, a tendon in the ring finger of the hand.

[23] The procedure referred to is a FDS transfer and/or tibialis posterior debridement without calcaneal medial shift osteotomy.

[25] Cf H J Heinz Company Limited v Kotzman [2009] VSC 311 ('H J Heinz'); Alcoa Holdings Ltd & Anor v Lowthian & ors and De Haas [2011] VSC 245 ('Alcoa').

[26] Taylor v Mountain Pine Furniture Pty Ltd [2006] VSC 499, [21].

[28] H J Heinz, [24]-[28] (citations omitted).

[30] Guides, section 2.3.

[31] Section 28LB.

[32] [2009] VSC 370 ('Melbourne Health'); Chua v Newman-Morris [2009] VSC 582, [42].

[34] [2008] VSC 36 ('Amendola').

[35] See for example s 28LF(1)(b), s 28LF(2)(a), s 28LL(1)(2), s 28LN(2), s 28LNA(2), s 28LZH(1), (2), cited in Amendola.

[36] Amendola, [31]. In Amendola the Panel determined there was no clinical evidence of persisting injury.

1. [38] Victoria, Parliamentary Debates, Legislative Assembly, 30 October 2003, 1425 (John Brumby), cited in Melbourne Health.

[39] Explanatory Memorandum, Wrongs and Other Acts (Law of Negligence) Bill 2003 (Vic) 17; see also Dr Cuc Thi Thu Nguyen v Wen Lu (Unreported, Supreme Court of Victoria Court of Appeal, Winneke P and Charles JA, 24 September 2004), cited in Melbourne Health.

[40] Cited in Chua v Newman-Morris [2009] VSC 582, [22].

[41] Chua v Newman-Morris [2009] VSC 582.

[43] Chua v Newman-Morris [2009] VSC 582, [37].

[44] [2001] HCA 10; (2001) 177 ALR 473.

[46] Amended originating motion dated 15 April 2011, [11(i)].

[47] Amended originating motion dated 15 April 2011, [11(ii)].

[49] Amended originating motion dated 15 April 2011, [11]. Emphasis in original.

[52] The implicit subtraction is explicitly expressed in section 2.3 of the Guides which I have quoted above.

[54] In a similar way to the evaluation of loss by a trial judge on limited evidence, he or she must 'do his or her best to quantify the loss': Wellington Shire Council v Steedman [2003] VSCA 115 [46]. See also State of New South Wales v Ross [2000] NSWCA 133; (2000) 54 NSWLR 536 [71], [87]. Footnote and citation of J Forrest J in Alcoa, [73].

[56] Clause 9 of Section 3.3f of the Guides relates to the determination of pre-existing impairment in conducting an assessment of spinal impairment. The clause provides: From historical information and previously compiled medical data, determine if there was a pre-existing impairment. If the previously compiled data can be verified as being accurate, they may be used in apportionment (see Glossary). The percent based on the previous findings would be subtracted from the percent based on the current findings. Guides, p 101.

[58] The amended originating motion, para 12 particular (iv) states:

Further, this explanation reveals that the Panel misconstrued s.28LH of the Act, which section adjures that the requirement that the Panel assess impairment 'in accordance with the AMA Guides' is 'subject to this Division', ie subject, inter alia, to s.28LL(3). The Panel's explanation of its reasoning shows that it substituted ostensible conformity with the methods set out in the AMA Guides so as to render nugatory its primary statutory obligations (a) to only assess impairment resulting from the claimed injury, and (b) to disregard 'impairments from irrelevant injuries and causes'.

[59] See the passage quoted from Malec at [17](g) above.

[60] Craig v South Australia [1995] HCA 58; (1995) 184 CLR 163, 179; Kirk v Industrial Relations Commission (New South Wales) (2010) 239 CLR 531, 572.

[61] Administrative Law Act 1978, s 10.

[63] Samad v District Court (NSW) [2002] HCA 24; (2002) 209 CLR 140, [42]-[44] per Gleeson CJ and McHugh J; Body Corporate Strata Plan No. 4166 v Sterling Properties Ltd No 2 [1984] VR 909, 913-4 per Ormiston J.