Measurement properties of patient-specific instruments measuring physical function.

OBJECTIVE: To identify patient-specific self-assessment instruments, which measure physical function in patients with musculoskeletal disorders and to evaluate the descriptive properties and the psychometric qualities of these instruments. STUDY DESIGN AND SETTING: After a systematic search, included instruments were evaluated psychometrically by the checklist "quality criteria for measurement properties of health status instruments." RESULTS: Twenty-three studies were included, referring to 12 instruments. Nine different versions of the Patient-Specific Functional Scale (PSFS) were identified. The practical elaboration of the different versions of the PSFS varied widely. None of the instruments were tested on all psychometric quality criteria of the checklist. The PSFS described by Cleland et al. was most extensively investigated and obtained exclusively positive scores. Overall, construct validity, reliability, and responsiveness were evaluated most frequently. CONCLUSION: The descriptive properties and psychometric quality of patient-specific instruments measuring physical function are only partly investigated. The PSFS was the most investigated instrument: nine different versions have been evaluated psychometrically. The version of Cleland et al. was most extensively investigated, obtained exclusively positive scores following the quality criteria by Terwee et al., and could be recommended for clinical use therefore. Future research will be necessary to confirm the psychometric quality of patient-specific instruments measuring physical function in patients with musculoskeletal disorders.

Factors associated with physical activity in patients with osteoarthritis of the hip or knee: a systematic review.

OBJECTIVE: To give an overview of factors related to the level of physical activity in patients with hip or knee osteoarthritis (OA). METHODS: An extensive systematic literature search was conducted in PubMed, CINAHL and Embase. Inclusion criteria were: studies on patients with a diagnosis of OA of hip and/or knee, studies describing factors related to physical activity (objective or subjective), full length articles that were published in Dutch, German or English language. Two reviewers independently assessed the methodological quality. A best-evidence synthesis was performed for factors which were investigated in two or more studies. RESULTS: Eight studies were included, all with a cross-sectional design (five high quality and three low quality studies), resulting in, at most, limited evidence in the best-evidence synthesis. For patients with knee OA there is limited evidence that a lower level of physical function is associated with a lower level of physical activity. There is also limited evidence that depression is not associated with the level of physical activity. For patients with hip OA there is limited evidence that higher age, higher body mass index (BMI) and a low level of physical function is associated with a low level of physical activity. CONCLUSION: A high age (hip OA), a high BMI (hip OA) and a low level of physical function (both hip and knee OA) are related to a low level of physical activity. However, the level of evidence was only limited. Before new strategies and interventions to increase physical activity in patients with OA can be developed, high quality longitudinal studies are needed to get more insight in the causality between factors and low levels of physical activity.