Waverley Council v Mooney

DETERMINATION OF APPEAL PANEL
CITATION:	Waverley Council v Mooney [2021] NSWPICMP 171
APPELLANT:	Waverley Council
RESPONDENT:	Wayne Robert Mooney
APPEAL PANEL:	Member Richard J Perrignon Dr Margaret Gibson Dr Roger Pillemer
DATE OF DECISION:	17 September 2021
CATCHWORDS:	WORKERS COMPENSATION- Appeal from assessment of whole person impairment (left lower extremity - knee); whether medical assessor erred in assessing a ‘fair’ result from left total knee replacement surgery; whether assessor erred in declining to make a deduction for pre-existing arthritis; Held - Medical Assessment Certificate confirmed.

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

BACKGROUND TO THE APPLICATION TO APPEAL

The appellant Council appeals from the Medical Assessment Certificate of Medical Assessor Dr McGroder dated 26 May 2021.
The respondent worker Mr Mooney injured his left knee on 14 February 2012 and 26 July 2018 in the course of his duties as a parking officer. The condition of his right hip resulted from injury to the left knee. He came to arthroscopy of the left knee on 23 May 2012, and to total left knee replacement surgery on 11 June 2019.
Dr McGroder assessed a 21% whole person impairment (20% left lower extremity - knee; 2% right lower extremity - hip) as a result of injury on 14 February 20212 and 26 July 2018. In respect of the left knee, he assessed a ‘fair’ result in accordance with Table 17-33 AMA5, yielding a 20% whole person impairment. He made that assessment after according 30 points for pain while walking and using stairs, in accordance with Table 17-35, as modified by the NSW workers compensation guidelines for the evaluation of permanent impairment, 4^th edition (Guidelines).
He made no deduction for pre-existing arthritis of the left knee.
The Council appeals from the assessment of the left knee only.
It says that the Medical Assessor erred in two respects. First, by according 30 points for pain, in circumstances where there was no evidence of pain while walking, except for when using stairs. The Council says that 40 points should have been selected, for pain on use of stairs only, which would have amounted to a ‘good’ result from surgery, yielding a 15% whole person impairment. Secondly, it says the Medical Assessor erred by failing to make a deduction for pre-existing arthritis of the left knee, which was evident at arthroscopy on 23 May 2012. It says the evidence required a deduction of at least 1/10^th, yielding a 14% whole person impairment (left lower extremity - knee).
On 15 July 2021, the President’s delegate was satisfied that there was an arguable case of demonstrable error, and referred the matter to this Appeal Panel for determination.

PRELIMINARY REVIEW

The Appeal Panel has conducted a preliminary review of the original medical assessment in the absence of the parties and in accordance with the Guidelines.

SUBMISSIONS

Both parties made written submissions. They are not repeated in full, but have been considered by the Appeal Panel.
In respect of left knee pain, the Council submits that the Medical Assessor took a history that pain was mild and occasional, and experienced predominantly while using stairs. There was mention of walking the dog, but no reference to pain while doing so.
In respect of a pre-existing condition, the Council submits that there was persuasive evidence of pre-existing arthritis. It points to:
(a)    reports of gastroenterologist Dr Talley in February 2003 which refer to arthritis of the knees;
(b)    the operation of Dr Solomon on 23 May 2012 which noted grade 2 to grade 3 chrondral wear over the medial femoral condyle and grade 2 chondral wear in the patella femoral compartment, and
(c)    the view expressed by independent medical expert Dr Oates, who had been qualified by the worker, in his report of 22 January 2019, that the 2012 injury had accelerated left knee arthritis, rather than caused it.
In summary, the respondent worker submits as follows.
(a) the Medical Assessor took a history that pain was experienced ‘predominantly’ when using stairs. That implies there was pain during other activity. Though not specified by Dr McGroder, it is to be found in the evidence that was before him. That was the worker’s supplementary statement of 14 August 2020, in which the worker said he experienced knee pain during prolonged standing, sitting or walking, and the history taken by Dr Oates that knee pain ‘comes on again shortly after recommencement of standing and walking’, and
(b) there is no radiological or other evidence to support the opinion of Dr Talley in 2003 that arthritis was present in the knees, and no other evidence to support the existing of a pre-existing condition prior to injury in 2012.

FINDINGS AND REASONS

1. Pain score, Table 17-35

The Medical Assessor found at [4] under the heading ‘Present treatment’:
“He takes Celebrex occasionally. He walks his dog daily. He had hydrotherapy and exercise physiology at one stage but not recently.”
Under the heading, ‘Present symptoms’, he recorded - emphasis added:
“With regard to his left knee, he said that his pain is mild and occasional and is predominantly when he walks up and down stairs.”
On physical examination, the Medical Assessor noted at [5]:
“He had a wide-based waddling gait but did not walk with a limp favouring either leg.”
As the Council rightly submits, the Medical Assessor did not take a history of pain while walking the dog, he did take a history of mild and occasional pain predominantly while using stairs, and he noted a waddling gait without a limp. However, we agree with the respondent that the use of the word ‘predominantly’ necessarily implies that pain was experienced during some other activity, not specified by the Medical Assessor.
Before Dr McGroder were the worker’s supplementary statement of 14 August 2020 and the reports of Dr Oates. In his supplementary statement, the worker gave unequivocal evidence of bilateral knee pain during prolonged walking. In his report of 7 July 2020, Dr Oates recorded:
“He has intermittent pain in the left knee. The knee is comfortable at rest but [pain] comes on again shortly after recommencement of standing and walking.”
It is not submitted that Dr McGroder ignored this evidence, and there is no evidence to suggest that he did. It is an available inference that it is this evidence he had in mind when recording that left knee pain was predominantly experienced when using stairs. We draw that evidence, and interpret him to mean that pain was experienced both while walking and predominantly while using stairs.
In our view, a pain score of 30 points was appropriate in accordance with Table 17-35.
We can identify no error, or the application of incorrect criteria. This ground of appeal fails.

2. Deduction for pre-existing condition

As indicated, Dr McGroder declined to make a deduction for a pre-existing condition of the left knee. He explained at [11]:
“There is no evidence of any condition that was present involving the lower extremities prior to 2012 that would suggest that a deduction is required for a pre-existing condition.”
He took the following history at [4]:
“Mr Mooney said that he had no problem with his left knee prior to 14 February 2012. Working as a parking officer he was stepping up a gutter when he stumbled and twisted his left knee. There was pain and swelling at the time. He saw his GP, Dr Prasad. An x-ray was performed and this was normal.”
He noted the results of a left knee MRI scan performed on 22 March 2012, which demonstrated:
“Contusion medial tibial plateau. Tear of body of medial meniscus with likely flap tear of posterior body and a flip fragment into the inferior recess. Sprain of the ACL, lateral collateral ligament and gastrocnemius tendon. Partial thickness cartilage loss at the medial trochlea.”
He also noted a subsequent MRI of 9 August 2018, taken after the injury of 26 July of that year, which relevantly demonstrated
“… Marked ACL and PCL sprain with possible partial thickness ACL tear. Patellofemoral and medial joint compartment degeneration. …”
Dr McGroder offered the following summary at [7] - emphasis added:
“Mr Mooney originally injured his right [sic, left] knee in an incident on 14 February 2012. This resulted in a medial meniscal tear and chondral damage and he had an arthroscopic partial medial meniscectomy. He further aggravated the condition on 26 July 2018 when he twisted his knee and investigations demonstrated progressive arthritis in the knee joint along with further pathology that required a total knee replacement that occurred on 11 June 2019. He has had a fair result from the replacement.”
At [10c], he noted the views of treating orthopaedic surgeons:
(a) Dr Solomon, that there were ‘no prior problems with Mr Mooney’s left knee before the injury on 14 February 2012’ and that the x-ray was normal, and
(b) Dr Viswanath, ‘that Mr Mooney originally injured his knee in 2012 and subsequently developed increasing degenerative changes to the extent that he required a total knee replacement’.
Dr McGroder noted that Dr Oates had not made a deduction for a pre-existing condition and agreed with that approach.
With respect to Dr Rimmer’s assessment, he observed:
“Dr Rimmer made a deduction for a pre-existing condition but I note that the referred date of injury that he was given was 26 July 2018 and under these circumstances it is not unreasonable to make a deduction but as the referral I had was dating from the injury in 2012 I did not feel that a deduction was justified.”
This amounted to a finding that, even though there was likely to have been degeneration prior to the 2018 injury, there was none prior to the 2012 injury. Having made that finding, a deduction pursuant to section 323 was not available to the Medical Assessor. It is that finding which the appellant says was in error.
Dr McGroder did not refer to the reports of Dr Talley in 2003, though that does not necessarily mean that he failed to take them into account, and as they were before him attached to the Reply, we consider it likely that he did take them into account. In his report to Dr Sarich of 10 February 2003, gastroenterologist Dr Talley said:
“Thank you for asking me to see Mr Mooney. Unfortunately, his whole situation is a disaster. He started off with his genetic disability, in other words he has the X syndrome, of obesity, insulin resistance, gout and hypertension. He also has asthma, which doesn't help. He has also developed significant osteoarthritic changes, which I didn't go into too much, but it affects his shoulder, his knees and his feet.”
He makes no mention of the basis on which he draws the conclusion that there were significant osteoarthritis changes affecting the knees. As there is no evidence that he conducted an orthopaedic examination, and the purposes of the referral was for gastrointestinal complaints, we are not persuaded that he did so. It is highly likely that he was there reporting the history given by the worker. The basis for the worker’s opinion is neither stated nor known.
In his report of 24 February 2003, Dr Talley said that if medications were adjusted in a certain way:
“… maybe a lot of his arthritic phenomena will be a bit better, although his weight is causing him enough osteoarthritic problems, which we won’t be able to help.”
For the same reasons, this does not appear to be a finding of arthritis based on an examination, but rather a restatement of the history taken from the worker. In the circumstances, these reports are not persuasive evidence of the presence of osteoarthritis in 2003.
In our view, even if it was not the only possible finding, it was reasonably open to
Dr McGroder to find, as he did, that the degenerative condition of the left knee was not present prior to injury in 2012. We can identify no error. This ground also fails.
Even if Dr McGroder had been persuaded that arthritis was present prior to injury in 2012 - for instance, because of the extent of chondral wear noted by Dr Solomon at arthroscopy on 23 May 2012 - a deduction would not have been available.
In order to make a deduction, a Medical Assessor must be satisfied, not only that a condition or abnormality was present prior to injury, but also that a proportion of the impairment is due to that condition or abnormality. To do that, the assessor must find that the impairment is greater than it would otherwise have been as a result of the injury. As Campbell J found in Ryder v Sundance Bakehouse [2015] NSWSC 526 at [45] - emphasis added:
"What s 323 requires is an inquiry into whether there are other causes, (previous injury, or pre-existing abnormality), of an impairment caused by a work injury. A proportion of the impairment would be due to the pre-existing abnormality (even if that proportion cannot be precisely identified without difficulty or expense) only if it can be said that the pre-existing abnormality made a difference to the outcome in terms of the degree of impairment resulting from the work injury. If there is no difference in outcome, that is to say, if the degree of impairment is not greater than it would otherwise have been as a result of the injury, it is impossible to say that a proportion of it is due to the pre-existing abnormality. To put it another way, the Panel must be satisfied that but for the pre-existing abnormality, the degree of impairment resulting from the work injury would not have been as great.”
Mr Mooney’s current permanent impairment is measured by reference to the results of his total left knee replacement surgery. That surgery has replaced the knee, and eliminated any arthritis, pre-existing or otherwise. Whether or not a pre-existing arthritis contributed to the need for surgery, the result is the same. It cannot be said, in our view, that the impairment is any greater than it would otherwise have been as a result of injury in 2012 and 2018. Nor, using the converse formulation in Ryder, can it be said that, but for the pre-existing arthritis, the impairment following total knee replacement would not have been as great.
For the reasons given, the Medical Assessment Certificate of Medical Assessor Dr McGroder is confirmed.

[2021] NSWPICMP 171

17 September 2021