Kelly v Simmonds Plastering Pty Ltd

DETERMINATION OF APPEAL PANEL
CITATION:	Kelly v Simmonds Plastering Pty Ltd [2021] NSWPICMP 216
APPELLANT:	Adam Kelly
RESPONDENT:	Simmonds Plastering Pty Ltd
APPEAL PANEL:	Member Paul Sweeney Dr Brian Noll Dr David Crocker
DATE OF DECISION:	12 November 2021
CATCHWORDS:	WORKERS COMPENSATION- Medical dispute referred for assessment on basis of a frank injury to right knee and disease injuries to both knees caused or materially aggravated by the nature of the applicant’s employment as a plasterer; Medical Assessor only assesses frank injury and makes a deduction of 50% pursuant to section 323 of the Workplace Injury Management and Workers Compensation Act 1998; Medical Assessment Certificate revoked; section 323 reassessed on basis of a frank injury and disease injuries to both knees; Cullen v. Woodbrae Holdings Pty Ltd considered and distinguished; Held - a “pre-existing injury or condition” is one that existed before the deemed date of injury.

STATEMENT OF REASONS FOR DECISION OF THE APPEAL PANEL IN RELATION TO A MEDICAL DISPUTE

BACKGROUND TO THE APPLICATION TO APPEAL

On 9 September 2021, Adam Kelly (the appellant) lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Dr Tim Anderson, a Medical Assessor (MA), who issued a Medical Assessment Certificate (MAC) on 12 August 2021.
The appellant relies on the following ground of appeal under s 327(3) of the Workplace Injury Management and Workers Compensation Act 1998 (1998 Act):
· the MAC contains a demonstrable error.
The delegate is satisfied that, on the face of the application, at least one ground of appeal has been made out. The appeal panel has conducted a review of the original medical assessment but limited to the grounds of appeal on which the appeal is made.
The WorkCover Medical Assessment Guidelines 2006 set out the practice and procedure in relation to the medical appeal process under s 328 of the 1998 Act. An Appeal Panel determines its own procedures in accordance with the WorkCover Medical Assessment Guidelines 2006.
The assessment of permanent impairment is conducted in accordance with the NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4^th ed 1 April 2016 (the Guidelines) and the American Medical Association Guides to the Evaluation of Permanent Impairment, 5^th ed (AMA 5).

RELEVANT FACTUAL BACKGROUND

The appellant is a plasterer having completed his apprenticeship in 1990. During most of the ensuing 28 years, he performed the work of a plasterer for Simmonds Plastering Pty Ltd (the respondent). By his statement of 5 February 2021, he describes his work as follows:
“My duties involve substantial amounts of climbing up and down scaffolding, and also using ladders. I was required to carry sheets of plaster over rough terrain on building sites. My duties involved carrying, bending, squatting and long periods of weight bearing on my lower limbs. I was required to use wheelbarrows to remove waste or rubbish from worksites and other manual tasks required of myself on building sites. My employment duties often involved stress, strain and load on both my left and right knees.”
The appellant suffered an injury to his left knee when he twisted it while descending from a platform in the course of his employment on 14 March 2018. Following this incident, he experienced difficulty walking and was unable to perform his duties. He attended the Tamworth Base Hospital where it is recorded that he had “ongoing concerns about his left knee” for three years. He was then examined by his general practitioner, Dr Niroj Khanal of Tamworth, who referred him for an MRI scan which demonstrated moderate patellofemoral degenerative changes and marked degenerative changes in the lateral compartment of the tibiofemoral joint. It also revealed a large degenerative tear of the posterior horn of the lateral meniscus with bone bruising in the proximal tibia.
The respondent’s workers compensation insurer accepted liability in respect of the injury and the applicant has been paid weekly compensation pursuant to the provisions of the Workers Compensation Act 1987 (the 1987 Act).
The appellant had experienced symptoms in his knees for some time before the incident in 2018. By his statement, he says that he recalls experiencing pain in his right knee prior to 2007. In January 2007, however, he fell in his backyard “causing increasing pain to my knee”. He came under the care of Dr Doig, an orthopaedic surgeon, who performed an arthroscopic “wash-out” of the right knee.
In 2016, the appellant came under the care of another orthopaedic surgeon in respect of the condition of his knees, Dr Ben Gooden. He had a further “wash-out” and debridement of his right knee under Dr Sudhahar, an orthopaedic surgeon, at Tamworth on 19 September 2018. According to the history recorded by Dr Hopcroft in his report of 12 May 2020, Dr Gooden “advised that he would ultimately come to surgery for both knee joints”. Dr Hopcroft also states in his report that the appellant is to be “reviewed again by Dr Ben Gooden regarding the possibility of proceeding to surgery”.
Dr Hopcroft expressed the opinion that the appellant suffered 20% whole person impairment (WPI) of each lower extremity as a result of the condition of his knees. However, he deducted one tenth from his assessment of each knee “due to pre-existent changes” presumably pursuant to s 323(2) of the 1998 Act. He also found that the appellant had 1% WPI of each knee on the TEMSKI scale as a result of “significant scarring of both knee joints”.
Dr Hopcroft attributed the applicant’s left knee condition to the injury of 14 March 2018 and to the nature of his work as a plasterer over the years. He attributed the condition of the applicant’s right knee to the nature of his work. He said this:
“It is my opinion that the nature and conditions of this patient’s employment as a plasterer, undertaken on a full-time basis over a 30 year period of time, caused stresses, strains and loads on his left and right knees, and his employment duties caused a slow evolution of accumulated post-traumatic osteoarthritic disease of both left and right knees, and that his duties were the main contributing factor to the evolution of his post-traumatic osteoarthritic condition of both knee joints.
There is no other cause outside of his work that could rationally explain his very significant and advanced pathology.”
By these proceedings, the appellant claimed permanent impairment compensation pursuant to s 66 of the 1987 Act in respect of injuries to both knees. The claim is based on the assessment of WPI formulated by Dr Hopcroft. Presumably, the respondent did not accept this assessment. As this gave rise to a medical dispute as that phrase is defined in s 319 of the 1998 Act, the President referred the issue of WPI to a medical assessor.
On 4 August 2021, Dr Anderson assessed the appellant as suffering from 20% WPI of his left leg and 10% WPI of his right leg. In each case, he deducted one half pursuant to s 323 in respect of a pre-existing injury or condition. He certified that the appellant suffered 15% WPI. It is from that certification that the appellant brings this appeal.

PRELIMINARY REVIEW

The appeal panel conducted a preliminary review of the original medical assessment in the absence of the parties and in accordance with the WorkCover Medical Assessment Guidelines 2006.
As a result of that preliminary review, the appeal panel determined that it was unnecessary for the worker to undergo a further medical examination. Neither party sought a further examination by a medical practitioner who is a member of the appeal panel. Importantly, the panel noted that the appellant did not criticise the clinical examination and findings of the MA. The sole ground of appeal related to the deduction made in respect of s 323 of the 1988 Act. A further medical examination would not have assisted the panel in determining this issue.

EVIDENCE

The appeal panel has before it all the documents which were sent to the MA for the original medical assessment and has taken them into account in making this determination.

Medical Assessment Certificate

The parts of the medical assessment certificate given by the MA which are relevant to the appeal are set out in the body of this decision.

SUBMISSIONS

Both parties made written submissions. They are not repeated in full but have been considered by the appeal panel.
The appellant alleges that the deduction of 50% made by the MA was erroneous. In particular, the appellant asserts that:
“Dr Anderson does not take into account or explain that the Appellant’s degenerative knee condition is attributable to his plastering duties extending over 3 decades or more.
The appellant is 49 years of age and in the event that the s 323 discount is to be 50%, the AMS needs to explain a pathway of reasoning that his work did not cause such degeneration to such a significant extent. There is no such pathway or reasoning in any way expressed in his report.”
The appellant then refers to the report of Dr Hopcroft dated 12 May 2020 where the doctor asserted that the appellant’s plastering duties over a period of 30 years had either caused or significantly aggravated the osteoarthritis in both knees. He argues, correctly, that the MA does not address this aspect of Dr Hopcroft’s report.
The MA’s failure to address the possible causal nexus between the appellant’s employment over the years and the condition of his knees is to be contrasted with the opinion of
Dr Hopcroft which deals with the issue directly and concludes that there is a causal connection between the appellant’s work and the osteoarthritis in his knees. The appellant continues:
“It is entirely inadequate for the AMS to simply advise of a long history of degenerative changes without explaining or taking into account the arduous nature of his employment extending over 30 years or more as a plasterer causative of degenerative changes to both knee joints.”

The appellant submits that the instruction from the High Court in Wingfoot Australia Partners Pty Ltd v Kocak [2013] HCA 43 (Wingfoot) required the MA to demonstrate the pathway by which he concluded that the appellant’s employment did not materially contribute to the degenerative changes in the appellant’s knees. He submits that the MA provides no such reasoning. The MA observes that there is a long history of severe degenerative changes in the appellant’s knees but:
“does not provide reasoning or explanation relating to such degenerative changes to his employment or otherwise.”
Finally the appellant submitted that the appellant was “left guessing” as to why the MA made a deduction of one half in view of the evidence in the matter.
The respondent submitted that the MA had “explicitly” outlined his reasoning for making a 50% deduction. It also submitted that there were “substantial references” in the reasons of the MA to degenerative changes and its origins. The submission continued:
“The MA stated that the appellant was too young to be in his current situation. It is therefore evident that the degenerative changes observed was constitutional, rather than causally related to the appellant’s employment.”

FINDINGS AND REASONS

In Campbelltown City Council v Vegan [2006] NSWCA 284 the Court of Appeal held that the Appeal Panel is obliged to give reasons. Where there are disputes of fact it may be necessary to refer to evidence or other material on which findings are based, but the extent to which this is necessary will vary from case to case. Where more than one conclusion is open, it will be necessary to explain why one conclusion is preferred. On the other hand, the reasons need not be extensive or provide a detailed explanation of the criteria applied by the medical professionals in reaching a professional judgement.
Section 328(2) of the 1998 Act provides that an appeal is to be by way of review of the original medical assessment, but the review is limited to the grounds of appeal on which the appeal is made. This subsection was considered by Davies J in New South Wales Police Force v Registrar of the Workers Compensation Commission of New South Wales [2013] SC 1792 (11 December 2013). Davies J considered that the form of the words used in s 328(2) of the 1998 Act ‘the grounds of appeal on which the appeal is made’ was intended to convey that the appeal is confined to those particular demonstrable errors identified by a party in its submissions. The panel has only considered those grounds specifically raised by the appellant in the Application.
The role of the medical appeal panel was considered by the Court of Appeal in Siddik v WorkCover Authority of NSW [2008] NSWCA 116. An appeal by way of review may, depending upon the circumstances, involve either a hearing de novo or a rehearing. Such a flexible model assists the objectives of the legislation. However, in Versace vAustralia Best Tyres & Auto Pty Limited [2016] NSWSC 1540 (2 November 2016) Schmidt J, held that the 1998 Act did not permit the panel to review the determination of the MA without first identifying error.
Though the power of review is far ranging it is nonetheless confined to the matters which can be the subject of appeal. Section 327(2) of the 1998 Act restricts those matters to the matters about which the medical assessment certificate is binding.

In considering the submissions of the appellant, it is necessary to bear in mind the nature of the statutory obligation of the MA to provide reasons. It is evident from reasoning of the High Court of Australia in Wingfoot that it is only necessary for the MAC to explain the actual path of reasoning of the MA in sufficient detail to enable a court or an appeal panel to determine whether there is error in its findings. In Wingfoot, it was said that:

“The function of a medical panel is neither arbitral nor adjudicative: it is neither to choose between competing arguments, nor to opine on the correctness of other opinions on that medical question. The function is in every case to form and give its own opinion on the medical question referred to it by applying its own medical experience and its own medical expertise.”

The reasoning in Wingfoot has been applied to medical assessments under the NSW Workers Compensation legislation: see, for example El Masri v Woolworths Ltd [2014] NSWSC 1344 (26 September 2014).
In the MAC, the MA summarised the appellant’s injuries and diagnoses as follows:
“Mr Kelly has quite a long history of severe degenerative changes of his knees. The left side has been more severely affected. This condition was aggravated in mid-March 2018. The aggravational features continue, now the right knee is subjectively just as bad as the left. His clinical management remains conservative, although in the long term future there is likely to be knee joint replacements. He is holding out for as long as he can and hopes that he will be able to last until he is at least 60 before these procedures are conducted. The extent of his condition has resulted in his incapacity to continue working as a plasterer.”
The MA referred to a “long history” of degenerative changes in the appellant’s knees, however, he did not consider whether the bilateral osteoarthritis was causally related to the nature of the appellant’s work as a plasterer over many years. In assessing WPI and in making a deduction for the purposes of s 323 of the 1998 Act, the only injury that the MA considered was the frank incident to the left knee on 14 March 2018. Thus, he only considered part of the medical dispute between the parties in this case.
The medical dispute between the parties is set out in the Application to Resolve a Dispute (ARD) under the heading “Injury Details”. After describing the frank injury on 14 March 2018, when the applicant twisted his knee when descending from a platform, the appellant pleaded a second injury related to the nature of his work. Relevantly, the ARD states:
“The applicant relies upon the provisions of s 4(b)(i) and (ii) of the Workers Compensation Act 1987. The applicant alleges the nature and conditions of his work as a plasterer/labourer over a period of 28 years placed significant stress, strain and load on both left and right knee joints causing osteoarthritic degenerative disease, and the nature of his duties caused aggravation, acceleration, exacerbation and deterioration of his degenerative/osteoarthritic disease of both knees and that the heavy labouring nature of his duties were the main contributing factor to his osteoarthritis causing chronic symptoms and pain.”
The ARD also states that the appellant relied on both ss 15 and 16 of 1987 Act “being the relevant disease provision”.
The allegation of a disease injury caused or materially aggravated by the nature of the appellant’s employment was initially raised in the letter of claim dated 15 July 2020 from the appellant’s solicitor to the respondent’s insurer, Employers Mutual Limited. The allegation is consistent with the reasoning of Dr Hopcroft in his report dated 12 May 2020 on which the claim for permanent impairment compensation was made. It is also consistent with evidence of the appellant in his written statement dated 5 February 2021.
By its Reply in these proceedings, the respondent put in issue the following matters:
“1. Whether the Applicant has suffered whole person impairment as a result of the alleged injury, pursuant to s 66.
2. The respondent has made arrangements for an independent medical examination with Dr Robin Diebold 02/06/2021 to investigate the matter.”
The respondent requested that the appellant’s appointment with the MA be scheduled at a time after it had obtained the report of Dr Diebold. It is unclear whether the appointment with Dr Diebold took place. A report from that doctor was not in evidence before the MA and is not before the appeal panel.
In Skates v Hills Industries Ltd [2021] NSWCA 142 (14 July 2021) (Skates), the New South Wales Court of Appeal emphasised the importance of the claim for compensation and the pleadings in determining the “medical dispute” between the parties. Relevantly, in this case the appellant made a claim for permanent impairment compensation in respect of both lower extremities on the basis of both a frank injury and a disease injury resulting from the nature of his employment. The respondent did not dispute this in its Reply. The failure of the MA to consider the disease injury clearly raised in the ARD is a demonstrable error.
The panel appreciates that the Referral issued by a delegate of the President on 11 May 2021 may have been ambiguous as it merely nominated a date of injury of 14 March 2018 and referred the lower extremities for assessment of WPI. However, the appellant’s case is put unambiguously in the letter of claim, in the ARD, and in the report of Dr Hopcroft, the only report from a qualified medical practitioner which was before the MA. The disease injury was, therefore, clearly raised in both the pleadings and evidence referred to the MA.
As the respondent does not dispute that the nature of the appellant’s work as a plasterer for some 28 years caused or materially aggravated the disease of osteoarthritis, the only remaining issues for the panel is to consider the nature of the injury to the appellant’s knees as a result of his work and to reassess the deduction made by the MA under s 323 of the 1998 Act on the premise that the appellant suffered a frank injury to his left knee on
14 March 2018 and disease injuries to both knees which attract the operation of either s 15 or s 16 of the 1987 Act.
The only medical evidence which specifically deals with these issues is the report of
Dr Hopcroft. The doctor’s opinion in respect of the causal relationship between the appellant’s employment as a plasterer and the development of bilateral osteoarthritis is ambiguous. On the one hand, he states that these duties were “the main contributing factor to the evolution of his post-traumatic osteoarthritic condition”. On the other, he states that the duties have “significantly aggravated the osteoarthritis” and makes a deduction of one tenth in respect of a pre-existing condition in accordance with s 323(2).

The reference to a post-traumatic condition suggests that that the injury was a disease contracted by the worker in the course of his employment in accordance with s 4(b)(i) of the 1987 Act. The reference to aggravation of a disease suggests a disease that was aggravated or accelerated by the nature of the employment in accordance with s 4(b)(ii) of the 1987 Act. When a disease is “contracted” by a worker in the course of his employment by a gradual process it is caught by s 15 of the 1987 Act. Although the language no longer appears in the Act, these conditions were formerly referred to as “industrial diseases” to distinguish them from community diseases. If an injury “consists” in the aggravation of a disease by the nature of the employment it is caught by s 16.
If a disease is “contracted by a worker in the course of his employment” and the employment is the main contributing factor to contracting the disease, it is difficult to envisage how there can be any pre-existing condition for the purpose s323 . The disease is caused by the employment.
If the injury is found to consist in the aggravation etc of a disease within s 16, it assumes that the presence of a pre-existing condition and there is scope for a deduction to be made pursuant to s 323 of the 1987 Act. In Moran v Thomson Adsett &Partners Pty Ltd (1996) 13 NSWCCR 484 (17 September 1996) Neilson J, in the former Compensation Court of NSW said this:
“I find it difficult as a matter of logic to accept that, where the only diagnosis is of exacerbation or aggravation of a pre-existing conditionsuch as degeneration of cervical spine, that no part of the impairment of the whole of the neck can be laid at the door of the underlying condition.”
Sections 15 and 16 of the 1987 Act, insofar as they are relevant, are as follows:

“15 DISEASES OF GRADUAL PROCESS--EMPLOYER LIABLE, DATE OF INJURY ETC

(cf former ss 7 (4), (4C), (5), 16 (1A))
(1) If an injury is a disease which is of such a nature as to be contracted by a gradual process--
(a) the injury shall, for the purposes of this Act, be deemed to have happened--
(i) at the time of the worker's death or incapacity, or
(ii) if death or incapacity has not resulted from the injury--at the time the worker makes a claim for compensation with respect to the injury, and

(b) compensation is payable by the employer who last employed the worker in employment to the nature of which the disease was due.
(2) Any employers who, during the 12 months preceding a worker's death or incapacity or the date of the claim (as the case requires), employed the worker in any employment to the nature of which the disease was due shall be liable to make to the employer by whom compensation is payable such contributions as, in default of agreement, may be determined by the Commission.
(4) In this section, a reference to an injury includes a reference to a permanent impairment for which compensation is payable under Division 4 of Part 3.
(4A) In this section, a reference to employment to the nature of which a disease was due includes a reference to employment the nature of which was a contributing factor to the disease.
(5) This section does not apply to an injury to which section 17 applies.

16 AGGRAVATION ETC OF DISEASES--EMPLOYER LIABLE, DATE OF INJURY ETC

(cf former ss 7 (4A), (5), 16 (1A))
(1) If an injury consists in the aggravation, acceleration, exacerbation or deterioration of a disease--
(a) the injury shall, for the purposes of this Act, be deemed to have happened--
(i) at the time of the worker's death or incapacity, or
(ii) if death or incapacity has not resulted from the injury--at the time the worker makes a claim for compensation with respect to the injury, and

(b) compensation is payable by the employer who last employed the worker in employment that was a substantial contributing factor to the aggravation, acceleration, exacerbation or deterioration.
(2) Any employers who, during the 12 months preceding a worker's death or incapacity or the date of the claim (as the case requires), employed the worker in any such employment shall be liable to make to the employer by whom compensation is payable such contributions as, in default of agreement, may be determined by the Commission.
(3) In this section, a reference to an injury includes a reference to a permanent impairment for which compensation is payable under Division 4 of Part 3.
(4) This section does not apply to an injury to which section 17 applies.”

In Cullen v Woodbrae Holdings Pty Ltd [2015] NSWSC 146 (28 September 2015) (Cullen), Beech-Jones J in the Supreme Court of NSW set aside determinations by an MA and a MAP that a substantial deduction should be made pursuant to s 323 in respect of an osteoarthritic condition of a worker’s hips. At paragraph 57, the Judge said this:
“Overall, the approach of the MAP was to treat a pre-existing condition as a condition that existed outside the course of employment whereas in this case it had to be a condition that existed prior to Mr Cullen’s employment. As noted, Mr Blount repeatedly asserted that there was evidence to support such a finding but that contention travels nowhere as the MAP did not make such a finding. Instead the MAP concluded that once it was established that Mr Cullen had osteoarthritis that had a “constitutional pathology” then it automatically followed that it was a pre-existing condition. In this case that approach was erroneous in law and constitutes an error of law on the face of the record (and that is the case irrespective of whether the condition had to pre-date the commencement of his employment or some later time).”
It was conceded by the employer in argument that a “pre-existing injury condition or abnormality” must exist prior to the commencement of the employment in work to the nature of the disease is due. In Cullen, the worker worked as a slaughterman for his employer for some 26 years prior to the closure of the abattoir on 14 July 2004. In the several years prior to his cessation of work, the worker experienced pain in both hips. After his cessation of work, his condition worsened and he underwent a right hip replacement in 2008 and a left hip replacement in 2010. He brought proceedings in the Workers Compensation Commission claiming permanent impairment compensation as a result of an injury to his hips on 28 February 2014.
On the approach conceded by the respondent in Cullen, it would be necessary to demonstrate that the applicant suffered a condition or injury in his hips prior to the commencement of his work in the abattoir in 1978. It is, of course, difficult to prove that hypothesis.
This approach to ascertaining the deductible proportion in a s 16 case has been adopted by medical assessors and medical appeal panels in determining WPI in the years since Cullen was decided. It is not self-evident, however, that this approach is correct. The error identified by the judge was that the MA and the MAP had assumed that once a pre-existing condition was established “it automatically followed that it was a pre-existing condition”. He did not determine that a pre-existing condition must predate the commencement to the nature of which the condition is due. Thus, his reasoning and the ratio of the case is analogous to that in Cole v Wenaline Pty Ltd [2010] NSWSC 78.
Sections 15 and 16 of the 1987 Act deem an “injury” to which they apply to occur either at the first date of incapacity, or if there is no incapacity, the date on which the claim for compensation is made. Sections 15(4) and 16(3) state that a reference to “injury includes a reference to a permanent impairment for which compensation is payable”. Thus both the injury and the impairment for which compensation is payable occur at the same time.
The deeming provisions in ss 15 and 16 obviate the need to prove injury simpliciter in circumstances where there might not be evidence of disturbance of the worker’s normal physiological state. The time of onset of a disease might only be determined by hypothesis and hindsight and it may progress without symptoms or clinical signs for many years. But where there is a proven incapacity resulting from the disease or a claim for permanent impairment compensation resulting from the disease, injury is established.
It was previously accepted by medical assessors and medical appeal panels in the Workers Compensation Commission and by judges in the former Compensation Court of New South Wales that a pre-existing condition was one which pre-existed the deemed date of injury or impairment. That was probably on the basis that an injury or impairment having been deemed by the Act to occur at a certain time, it should be treated in the same way as any other injury within s 4 of the 1987 Act. That seems to be consistent with the approach of the High Court in Williams v Metropolitan Coal Co Ltd (1948) 76 CLR 431 (Williams).
To assume, in accordance with the concession made in Cullen, that a pre-existing condition or injury must be a condition that exists prior to the commencement of the worker’s employment in work to the nature of which the disease was due throws up some potentially odd consequences. A frank injury which occurred in the course of or outside of the workers employment after the date he commenced the relevant work but before the deemed date of injury could not be held to be a “pre-existing injury”. That cannot be the intention of the legislature.
If “pre-existing” means before the commencement of the relevant employment, there would have been no need for the legislature to enact s 68B of the 1987 Act. In so far as it applies to s 16, the section is as follows:
“(3) When determining the compensation payable by an employer in a case in which section 16 applies (an injury that consists in the aggravation, acceleration, exacerbation or deterioration of a disease), section 323 of the 1998 Act applies to that compensation subject to the following—
(a) there is to be no deduction under section 323 of the 1998 Act for any proportion of the impairment that is due to the worker's employment in previous relevant employment (as defined in paragraph (b)) except any such proportion for which compensation under this Division (as in force at any time) or section 16 of the former Act has been paid or is payable,
(b) for the purposes of paragraph (a),
"previous relevant employment" is employment that was a substantial contributing factor to the aggravation, acceleration, exacerbation or deterioration by a previous employer who is liable under section 16 to contribute in respect of the compensation being determined (or who would be so liable if the requirement to contribute were not limited to employers who employed the worker during a particular period),
(c)in the case of permanent impairment of the back, neck or pelvis, a reference in this subsection to previous relevant employment is limited to employment after the commencement of this Act.”
The effect of the section is to preclude a deduction being made pursuant to s 323 in respect of that proportion of the impairment that is due to work performed by the worker in relevant employment before the date of injury/impairment. Arguably, that permits a deduction to be made for any part of the impairment that results from factors extraneous to the employment including the inexorable progression of a disease such as osteoarthritis.
Accordingly, the panel does not intend to approach the matter on the basis of the respondent’s concession in Cullen. It accepts that the principles stated by the Judge are correct. However, the panel approaches the issue of a deduction pursuant to s 323 on the basis that a pre-existing injury or condition must predate the deemed date of the injury and impairment.
In the opinion of the panel, it is unlikely that the appellant “contracted” the condition in the course of his employment or that the condition is “post- traumatic” as Dr Hopcroft suggests at one part of his report. Bilateral osteoarthritis of the knees is a condition that is prevalent in the community. It is not a disease that is due to the nature of the applicant’s employment. The applicant first experienced symptoms at a young age. It is probable that he suffered from a constitutional condition of osteoarthritis which was aggravated by the nature of his work and, to a much lesser extent, by the injury in 2018.
On the history obtained by Dr Hopcroft, it may have also been aggravated by touch football which the appellant had to cease because of problems with his knees and his attendances at gym. There may have also been an aggravation of the condition of the applicant’s right knee at the time of the incident at home in 2008 which brought him to surgery under Dr Graeme Doig.
On this analysis, the injury consists in the aggravation of the disease and falls within s 16 of the 1987 Act. As the condition existed prior to the aggravation and, certainly, prior to the deemed date of injury and the date on which the impairment arose, it is necessary to make a deduction pursuant to s 323 to reflect the pre-existing condition. The only medical evidence that addresses the issue is that of Dr Hopcroft. Clearly, the appellant worked as a plasterer for a long period of time. However, the panel does not accept that a deduction pursuant to
s 323 (2) properly reflects the causal potency of the underlying osteoarthritic disease or the other aggravating factors which have resulted in the appellant’s impairment in this case.
It must be borne in mind that s 323 is a disentitling provision. While the issue of onus is rarely of importance in a medical appeal, the principles enunciated a very long time ago in Watts v Rake (1960) 108 CLR 158 and Purkess v Crittenden 114 CLR 164 have application to an evaluation under s 323. That these principles are relevant to the assessment of lump sum compensation under the Workers Compensation Act is also of ancient lineage: see Sadler v Commissioner for Railways (NSW) (1969) 123 CLR 216. It is necessary for a respondent to be able to point to appropriate evidence to support a deduction. It has not specifically addressed this issue in its submissions on appeal. Bearing in mind the matters discussed above, the panel has concluded that an appropriate deduction for pre-existing condition and injury pursuant to s 323 of the 1987 Act is 1/5th.
For these reasons, the Appeal Panel has determined that the MAC issued on 12 August 2021 should be revoked, and a new MAC should be issued. The new certificate is attached to this statement of reasons.

PERSONAL INJURY COMMISSION

APPEAL PANEL
MEDICAL ASSESSMENT CERTIFICATE

Injuries received after 1 January 2002

This Certificate is issued pursuant to s 328(5) of the Workplace Injury Management and Workers Compensation Act1998.

The Appeal Panel revokes the Medical Assessment Certificate of Dr Anderson and issues this new Medical Assessment Certificate as to the matters set out in the Table below:

Table - Whole Person Impairment (WPI)

Body Part or system	Date of Injury	Chapter, page and paragraph number in WorkCover Guides	Chapter, page, paragraph, figure and table numbers in AMA 5 Guides	% WPI	Proportion of permanent impairment due to pre-existing injury, abnormality or condition	Sub-total/s % WPI (after any deductions in column 6)
Left lower extremity (knee)	14 March 2018 and 14 March 2018 (deemed)	P 13 Chapter 3	P 544 T 17-31	20	1/5th	16
Right lower extremity (knee)	14 March 2018 (deemed)	P 13 Chapter 3	10	1/5th	8
Total % WPI (the Combined Table values of all sub-totals)					23

The above assessment is made in accordance with the Guidelines for the Evaluation of Permanent Impairment for injuries received after 1 January 2002

Paul Sweeney
Member

Dr Brian Noll
Medical Assessor

Dr David Crocker

Medical Assessor

[2021] NSWPICMP 216

12 November 2021