NSW workers compensation guidelines for the evaluation of permanent impairment

These guidelines explain permanent impairment assessment in the NSW workers compensation system. This is the fourth edition of these guidelines, reissued 1 March 2021.

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The State Insurance Regulatory Authority has reissued the 4th edition of the NSW workers compensation guidelines for the evaluation of permanent impairment (catalogue no. WC00970) (the Guidelines) for assessing the degree of permanent impairment arising from an injury or disease within the context of workers’ compensation. When a person sustains a permanent impairment, trained medical assessors must use the Guidelines to ensure an objective, fair and consistent method of evaluating the degree of permanent impairment.

The reissued Guidelines have been made to include some minor changes including changes consequent to the enactment of the Personal Injury Commission Act 2020 (PIC Act). No changes are made to the provisions in these guidelines relating to the evaluation of permanent impairment as developed in consultation with the medical Colleges under s 377(2) of the Workplace Injury Management and Workers Compensation Act 1998 and as set out in cl 13 of the Guidelines.

The Guidelines are based on a template that was developed through a national process facilitated by Safe Work Australia. They were initially developed for use in the NSW system and incorporate numerous improvements identified by the then WorkCover NSW Whole Person Impairment Coordinating Committee over 13 years of continuous use. Members of this committee and of the South Australia Permanent Impairment Committee (see list in Appendix 2) dedicated many hours to thoughtfully reviewing and improving the Guidelines. This work is acknowledged and greatly appreciated.

The methodology in the Guidelines is largely based on the American Medical Association’s Guides to the Evaluation of Permanent Impairment, 5th Edition (AMA5). The AMA guides are the most authoritative and widely used in evaluating permanent impairment around the world. Australian medical specialists representing Australian medical associations and colleges have extensively reviewed AMA5 to ensure it aligns with clinical practice in Australia.

The Guidelines consist of an introductory chapter followed by chapters dedicated to each body system.

The Introduction is divided into three parts. The first outlines the background and development of the Guidelines, including reference to the relevant legislative instrument that gives effect to the Guidelines. The second covers general assessment principles for medical practitioners applying the Guidelines in assessing permanent impairment resulting from work-related injury or disease. The third addresses administrative issues relating to the use of the Guidelines.

As the template national guideline has been progressively adapted from the NSW Guideline and is to be adopted by other jurisdictions, some aspects have been necessarily modified and generalised. Some provisions may differ between different jurisdictions. For further information, please see the Comparison of Workers’ Compensation Arrangements in Australia and New Zealand report, which is available on Safe Work Australia’s website.

Publications such as this only remain useful to the extent that they meet the needs of users and those who sustain a permanent impairment. It is, therefore, important that the protocols set out in the Guidelines are applied consistently and methodically. Any difficulties or anomalies need to be addressed through modification of the publication and not by idiosyncratic reinterpretation of any part. All queries on the Guidelines or suggestions for improvement should be addressed to SIRA at [email protected].

2. Upper extremity

AMA5 Chapter 16 (p 433) applies to the assessment of permanent impairment of the upper extremities, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

the Introduction in the Guidelines
chapters 1 and 2 of AMA5
the appropriate chapter(s) of the Guidelines for the body system they are assessing
the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

2.1 The upper extremities are discussed in AMA5 Chapter 16 (pp 433–521). This chapter provides guidelines on methods of assessing permanent impairment involving these structures. It is a complex chapter that requires an organised approach with careful documentation of findings.

2.2 Evaluation of anatomical impairment forms the basis for upper extremity impairment (UEI) assessment. The rating reflects the degree of impairment and its impact on the ability of the person to perform ADL. There can be clinical conditions where evaluation of impairment may be difficult. Such conditions are evaluated by their effect on function of the upper extremity, or, if all else fails, by analogy with other impairments that have similar effects on upper limb function.

The approach to assessment of the upper extremity and hand

2.3 Assessment of the upper extremity mainly involves clinical evaluation. Cosmetic and functional evaluations are performed in some situations. The impairment must be permanent and stable. The claimant will have a defined diagnosis that can be confirmed by examination.

2.4 The assessed impairment of a part or region can never exceed the impairment due to amputation of that part or region. For an upper limb, therefore, the maximum evaluation is 60% whole person impairment (WPI), the value for amputation through the shoulder.

2.5 Range of motion (ROM) is assessed as follows:

A goniometer or inclinometer must be used, where clinically indicated.
Passive ROM may form part of the clinical examination to ascertain clinical status of the joint, but impairment should only be calculated using active ROM measurements. Impairment values for degree measurements falling between those listed must be adjusted or interpolated.
If the assessor is not satisfied that the results of a measurement are reliable, repeated testing may be helpful in this situation.
If there is inconsistency in ROM, then it should not be used as a valid parameter of impairment evaluation. Refer to paragraph 1.36 in the Introduction.
If ROM measurements at examination cannot be used as a valid parameter of impairment evaluation, the assessor should then use discretion in considering what weight to give other available evidence to determine if an impairment is present.

2.6 To achieve an accurate and comprehensive assessment of the upper extremity, findings should be documented on a standard form. AMA5 Figures 16-1a and 16-1b (pp 436–37) are extremely useful both to document findings and to guide the assessment process.

2.7 The hand and upper extremity are divided into regions: thumb, fingers, wrist, elbow and shoulder. Close attention needs to be paid to the instructions in AMA5 Figures 16-1a and 16-1b (pp 436–37) regarding adding or combining impairments.

2.8 AMA5 Table 16-3 (p 439) is used to convert upper extremity impairment to WPI. When the Combined Values Chart is used, the assessor must ensure that all values combined are in the same category of impairment (that is WPI, upper extremity impairment percentage, hand impairment percentage and so on). Regional impairments of the same limb (eg several upper extremity impairments) should be combined before converting to percentage WPI. (Note that impairments relating to the joints of the thumb are added rather than combined – AMA5 Section 16.4d ‘Thumb ray motion impairment’, p 454.)

Specific interpretation of AMA5 - the hand and upper extremity impairment of the upper extremity due to peripheral nerve disorders

2.9 If an upper extremity impairment results solely from a peripheral nerve injury, the assessor should not also evaluate impairment(s) from AMA5 Section 16.4 ‘Abnormal motion’ (pp 450–79) for that upper extremity. AMA5 Section 16.5 should be used for evaluating such impairments.

For evaluating peripheral nerve lesions, use AMA5 Table 16-15 (p 492) together with AMA5 tables 16-10 and 16-11 (pp 482 and 484).

The assessment of carpal tunnel syndrome post-operatively is undertaken in the same way as assessment without operation.

2.10 When applying AMA5 tables 16-10 (p 482) and 16-11 (pp 482 and 484) the examiner must use clinical judgement to estimate the appropriate percentage within the range of values shown for each severity grade. The maximum value is not applied automatically.

Impairment due to other disorders of the upper extremity

2.11 AMA5 Section 16.7 ‘Impairment of the upper extremity due to other disorders’ (pp 498–507) should be used only when other criteria (as presented in AMA5 sections 16.2–16.6, pp 441–98) have not adequately encompassed the extent of the impairments. Impairments from the disorders considered in AMA5 Section 16.7 are usually estimated using other criteria. The assessor must take care to avoid duplication of impairments.

2.12 AMA5 Section 16.7 (impairment of the upper extremities due to other disorders) notes ‘the severity of impairment due to these disorders is rated separately according to Table 16-19 through 16-30 and then multiplied by the relative maximum value of the unit involved, as specified in Table 16-18’. This statement should not include tables 16-25 (carpal instability), 16-26 (shoulder instability) and 16-27 (arthroplasty), noting that the information in these tables is already expressed in terms of upper extremity impairment.

2.13 Strength evaluation, as a method of upper extremity impairment assessment, should only be used in rare cases and its use justified when loss of strength represents an impairing factor not adequately considered by more objective rating methods. If chosen as a method, the caveats detailed on AMA5 p 508 under the heading ‘16.8a Principles’ need to be observed – ie decreased strength cannot be rated in the presence of decreased motion, painful conditions, deformities and absence of parts (eg thumb amputation).

Conditions affecting the shoulder region

2.14 Most shoulder disorders with an abnormal range of movement are assessed according to AMA5 Section 16.4 ‘Evaluating abnormal motion’. (Please note that AMA5 indicates that internal and external rotation of the shoulder are to be measured with the arm abducted in the coronal plane to 90 degrees, and with the elbow flexed to 90 degrees. In those situations where abduction to 90 degrees is not possible, symmetrical measurement of rotation is to be carried out at the point of maximal abduction.)

Rare cases of rotator cuff injury, where the loss of shoulder motion does not reflect the severity of the tear, and there is no associated pain, may be assessed according to AMA5 Section 16.8c ‘Strength evaluation’. Other specific shoulder disorders where the loss of shoulder motion does not reflect the severity of the disorder, associated with pain, should be assessed by comparison with other impairments that have similar effect(s) on upper limb function.

As noted in AMA5 Section 16.7b ‘Arthroplasty’, ‘In the presence of decreased motion, motion impairments are derived separately and combined with the arthroplasty impairment’. This includes those arthroplasties in AMA5 Table 16-27 designated as (isolated).

Please note that in AMA5 Table 16-27 (p 506) the figure for resection arthroplasty of the distal clavicle (isolated) has been changed to 5% upper extremity impairment, and the figure for resection arthroplasty of the proximal clavicle (isolated) has been changed to 8% upper extremity impairment.

Please note that in AMA5 Table 16-18 (p 499) the figures for impairment suggested for the sternoclavicular joint have been changed from 5% upper extremity impairment and 3% whole person impairment, to 25% upper extremity impairment and 15% whole person impairment.

2.15 Ruptured long head of biceps shall be assessed as an upper extremity impairment (UEI) of 3%UEI or 2%WPI where it exists in isolation from other rotator cuff pathology. Impairment for ruptured long head of biceps cannot be combined with any other rotator cuff impairment or with loss of range of movement.

2.16 Diagnosis of impingement is made on the basis of positive findings on appropriate provocative testing and is only to apply where there is no loss of range of motion. Symptoms must have been present for at least 12 months. An impairment rating of 3% UEI or 2% WPI shall apply.

Fractures involving joints

2.17 Displaced fractures involving joint surfaces are generally to be rated by range of motion. If, however, this loss of range is not sufficient to give an impairment rating, and movement is accompanied by pain and there is 2mm or more displacement, allow 2% UEI (1% WPI).

Epicondylitis of the elbow

2.18 This condition is rated as 2% UEI (1% WPI). In order to assess impairment in cases of epicondylitis, symptoms must have been present for at least 18 months. Localised tenderness at the epicondyle must be present and provocative tests must also be positive. If there is an associated loss of range of movement, these figures are not combined, but the method giving the highest rating is used.

Resurfacing procedures

2.19 No additional impairment is to be awarded for resurfacing procedures used in the treatment of localised cartilage lesions and defects in major joints.

Calculating motion impairment

2.20 When calculating impairment for loss of range of movement, it is most important to always compare measurements of the relevant joint(s) in both extremities. If a contralateral ‘normal/uninjured’ joint has less than average mobility, the impairment value(s) corresponding to the uninvolved joint serves as a baseline and is subtracted from the calculated impairment for the involved joint. The rationale for this decision should be explained in the assessor’s report (see AMA5 Section 16.4c, p 543).

Complex regional pain syndrome (upper extremity)

2.21 Complex regional pain syndrome types 1 and 2 should be assessed using the method in Chapter 17 of the Guidelines.