By Danny Khoshaba, Partner and Shabnam Thompson, Lawyer
When assessing permanent impairment of the lower extremities under statutory workers compensation, there are a number of different methods that can be applied based on individual circumstances in accordance with Chapter 17 of the American Medical Association Guides 5th Edition (“AMA-5”), and subject to modifications in Chapter 3 of the NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment 4th Edition (“the Guidelines”).
In particular, AMA-5 and the Guidelines provide for permanent impairment assessment of the lower extremities based on physical evaluation including, amongst other things, leg length discrepancy, gait derangement, unilateral muscle atrophy, manual muscle strength testing, and range of motion. In the assessment process, the evaluation giving the highest impairment rating is selected, however AMA-5 and the Guidelines also provide instructions that certain evaluations are not to be used depending on specific circumstances.
In the recent matter of the State of New South Wales (NSW Police Force) v Royal  NSWWCCMA 122 (“Royal”), we challenged the findings of an Approved Medical Specialist (“AMS”) where the AMS made an assessment of the left lower extremity based on manual muscle strength testing in circumstances where the measurements for muscle testing varied by more than one Grade between the two respective expert medical reports relied upon by the respondent and applicant, and the findings of the AMS.
We submitted on appeal that, amongst other things, the Medical Assessment Certificate (“MAC”) issued by the AMS was made on the basis of incorrect criteria and/or contained a demonstrable error under sections 327(3)(c) and 327(3)(d) of the Workplace Injury Management and Workers Compensation Act 1998.
Relevant to the matter is that AMA-5 provides different Grades of muscle function under Table 17-7 which range from Grade 1 to Grade 5, with Grade 5 being the lowest rating of impairment on the criteria representing active movement of muscle function against gravity with full resistance. However, Part 17.2e of AMA-5 sets out that if assessments on muscle function vary by more than one Grade between examiners, the measure should be considered invalid and impairment estimates should not be used under that form of testing. The reason for this is because AMA-5 sets out that even in a fully cooperative individual, strength may vary from one examination to another, but not by more than one Grade.
In Royal, the applicant worker’s left lower extremity was assessed by her expert doctor with Grade 3 muscle function, by the respondent’s expert doctor with Grade 5 muscle function, and by the AMS with Grade 4 muscle function. As you will observe, the Grades of muscle function differed by more than one Grade between each examiner.
Accordingly, we submitted on appeal that the MAC should be overturned and a lower impairment rating applied based on an assessment of muscle atrophy as the next highest impairment of the left lower extremity.
The Commission was satisfied that a ground of appeal had been made out and the matter proceeded to the Appeal Panel before Arbitrator John Harris and two AMS’.
In the Statement of Reasons for Decision of the Appeal Panel in Relation to a Medical Dispute dated 7 July 2020, the Appeal Panel agreed with our submission that the AMS erred in using manual muscle strength testing as the preferred method of assessing impairment of the lower extremities where measurements varied by more than one Grade between the expert doctors and the AMS. The Appeal Panel also agreed with our submission that the assessment of the left lower extremity in this case based on manual muscle strength testing was contrary to Part 17.2e of AMA-5 and that the measurement made by the AMS was therefore invalid.
Accordingly, the Appeal Panel upheld that aspect of our appeal and agreed that the assessment of the left lower extremity was based on incorrect criteria under section 327(c) of the Workplace Injury Management and Workers Compensation Act 1998. The Appeal Panel therefore applied the findings of the AMS for muscle atrophy as the preferred method of impairment assessment in accordance with our submission, resulting in a lower level of permanent impairment of the left lower extremity.
It is worth noting that the Appeal Panel made findings that the invalid assessment only applied to the left lower extremity as the right lower extremity did not produce similar inconsistencies in the Grades of muscle function.
An interesting point for respondent insurers and solicitors to take away from this successful appeal is that examinations of impairment under the manual muscle strength testing method should be carefully reviewed to determine whether inconsistencies exist with respect to the Grades of muscle function evaluated by each respective doctor. This is particularly important noting that an alternative method of evaluation could likely result in a lower permanent impairment rating as was the result in Royal.
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