The assessment of work-related activities and limitations in knee disorders

Abstract

The success of knee treatment programs and surgery must be assessed, in part, by both the ability to return patients to work and the documentation of any work- related limitations. Existing occupational rating scales do not rate, in a valid manner, the effect of altered knee function on work activities. We performed a prospective randomized clinical trial in which two different occupa tional rating systems were tested on 50 patients. One system used job titles and an arbitrary numeric scale for rating occupations; the other used specific criteria for rating job functions according to the intensity, fre quency, and duration of certain tasks. The results showed that an effective and valid rating format should consist of five specific objectives: 1) evaluation of dif ferent knee functions that typically occur in the work environment; 2) evaluation of work activities separately from sports activities; 3) detection of patients who may have remained at an occupation but who have signifi cantly modified work activities because of knee symp toms ; 4) identification of patients who continue to work despite experiencing moderate to severe symptoms; and 5) identification of patients whose work activities decrease because of nonknee-related factors. Further more, the results showed that an effective rating sys tem should identify common data reduction errors that can bias the results in analyzing knee-related occupa tional limitations. The rating system developed circum vents the bias introduced by these anomalies. This system, if adopted by other researchers, would allow for the comparison of treatment results among studies.