The Patient-Specific Functional Scale: measurement properties in patients with knee dysfunction.

Background And Purpose: Assessing disability is important, and numerous interviewer-assisted and self-report questionnaires are used to accomplish this task. These questionnaires can be classified as being generic, condition or disease specific, or patient specific. The purpose of this study was to determine test-retest reliability, construct validity, and sensitivity to change of the Patient-Specific Functional Scale (PSFS) when applied to patients with knee dysfunction.