Background: Although outcome measures that assess disability after isolated orthopedic injuries have been found to be valid and responsive to change, the reliability of self-reported disability has not been studied in these patients. The purpose of this study was to compare self-reported and independently observed disability in patients with isolated orthopedic injuries.
Methods: Items were selected from the Short Musculoskeletal Functional Assessment (SMFA) and Disabilities of the Arm, Shoulder, and Hand (DASH) outcome assessment instruments. Participants had either an isolated upper (n = 61) or lower extremity (n = 55) injury or were noninjured controls (n = 40). Participants completed the SMFA and DASH before being videotaped completing items selected from the outcome assessment instruments. Observers reviewed the video and rated participants' levels of disability in performing the items.
Results: Observers consistently rated the disability levels for the items lower than the participants. Overall, agreement in levels of disability between observers and participants varied greatly across the different items (quadratic weighted kappa; range, 0.00-0.82).
Conclusion: The results emphasize that patients and observers differ in their assessment of an individual's level of disability in performing items related to activities of daily living. Therefore, caution should be used when data collected by a proxy observer is used to substitute self-reported data.