Determining foot and ankle impairments by the AMA fifth edition guides

The fifth edition of the Guides has been criticized for its failure to provide a comprehensive, valid, reliable, unbiased, and evidenced-based system for rating impairments and the way in which workers' compensation systems use the ratings, resulting in inappropriate compensation [8]. The lower extremity chapter utilizes numerous functional and anatomic methods of assessment, as well as diagnosis-based estimates. Though this process of using multiple approaches to measure impairment increases the chances that an underlying physical impairment may be detected, it is time-consuming and may increase rating variability [9]. McCarthy et al studied the correlation between measures of impairment for patients with fractures of the lower extremity. They found that the anatomic approach of evaluation was better correlated than functional and diagnostic methods with measures of task performance based on direct observations as well as the patient's own assessment of activity limitation and disability. Also, muscle strength assessment as described in the Guides was a more sensitive measure of impairment than range of motion [9]. The most elusive part of the foot and ankle evaluation is the inability to capture the added impairment burden caused by pain. The assessment of pain is the most problematic part of any evaluation. Pain is considered and incorporated into the impairment ratings found in the foot and ankle section, as well as the other individual chapters. Chronic pain is often not adequately accounted for, however, and the examiner must evaluate permanent impairment from chronic pain separately. The examiner has the ability to increase the percentage of organ system impairment from 1% to 3% if there is pain-related impairment that increases the burden of illness slightly. If there is significant pain-related impairment, a formal pain assessment is performed. Chapter 18 provides guidance in making these determinations. Impairments for Complex Regional Pain syndrome (CRPS), type 1 (reflex sympathetic dystrophy), and CRPS, type 2 (causalgia) should incorporate the use of a formal pain assessment in addition to the standard methods of assessment. The formal pain evaluation relies mostly on self-reports from the individual and is most heavily weighted for ADL deficits. The physician must make assessments of the individual's pain behavior and credibility for this evaluation. The formal pain assessment classifies the pain-related impairment into categories of mild, moderate, moderately severe, or severe and determines whether this impairment is ratable or not. These categories do not have impairment percentages associated with them. The individual's symptoms or presentation should match known conditions or syndromes in order to be ratable. If not ratable, the examiner should report that the individual has apparent impairment that is not ratable on the basis of current medical knowledge. In the end, pain evaluations are used administratively and, depending on the situation, may be given equal weight with the standard evaluation or may be totally disregarded.