The Patient-Specific Functional Scale - A useful tool for physiotherapists working in primary care

Abstract

Purpose: To examine content validity, reliability and responsiveness of the Patient-Specific Functional Scale (PSFS), for patients with musculoskeletal disorders receiving physiotherapy in primary care. Design: A methodological study with a cross-sectional design for the investigation of content validity and reliability and a prospective cohort design for the investigation of responsiveness. Materials: For the study of content validity and reliability 81 patients were included. For the study of responsiveness 180 patients were included. Methods: Content validity was examined by categorizing the reported activities according to ICF. In the study of reliability Intraclass Correlation Coefficient (ICC), Smallest Error of Measurement (SEM) and Smallest Detectable Change (SDC) were calculated. Responsiveness was examined through a criterion approach. Area under the curve (AUC), sensitivity, specificity and Minimal Important Change (MIC) were calculated with Receiver Operating Characteristics (ROC). Results :Patients mainly reports problems at ICF-activity level. Reliability was acceptable for first reported activity (ICC>0.7), but poorer for activity 2 and 3 (ICC<0.7). Based on SDC and MIC, 2 points change in PSFS score can be considered clinically and statistically relevant. Conclusion: PSFS is a reliable and responsive tool when used to map and evaluate activity problems in patients with musculoskeletal disorders seeking physiotherapy in primary care.

Keywords

• PSFS
• primary care
• musculoskeletal disorders
• validity
• reliability
• responsiveness