Abstract
The approach to evaluation of lower extremity impairments in the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) differs from that given in previous editions. This article uses case studies to illustrate practical applications of current approaches to ankle impairment and to foot and toe impairment. Anatomic methods for rating ankle impairments include evaluations of muscle atrophy and limb length discrepancy. The Diagnosis-related estimates section provides ratings for ligamentous laxity and displaced fractures of the ankle. The arthritis section contains ratings for radiographically determined and graded diagnosis. Methods for rating ankle impairments include assessing gait derangement, range of motion, joint ankylosis, and manual muscle testing. The methods used for rating lower extremity impairments also are applicable for the foot and toes, and examiners may deploy less commonly used rating techniques such as those employed for amputations, skin loss, causalgia and reflex sympathetic dystrophy, and vascular disorders. The examiner must understand the applicable rating methods used, estimate percentages via each, and decide which methods best describe the impairment(s) without overlooking or duplicating ratings. The examiner also should report the rating options considered, the reasons for selecting the method(s) used, the method by which the percentage was calculated, and the rationale for any variance from the AMA Guides. [A companion Quick Reference, Measuring Impairments of the Hand and Digits, appears on pp 5-6 of this issue of The Guides Newsletter.]
