STUDY DESIGN: Clinical measurement, longitudinal; multicenter prospective cohort study. OBJECTIVES: To examine the validity, reliability, and responsiveness of the Patient-Specific Functional Scale (PSFS) in patients with musculoskeletal upper extremity problems being treated in physical therapy. BACKGROUND: The clinimetric properties of the PSFS have not been established nor compared with region-specific outcome measures in patients with upper extremity problems. METHODS: Patients completed the PSFS, Upper Extremity Functional Index (UEFI), and numeric pain rating scale (NPRS) at baseline and follow-up, and were categorized as improved, stable, or worsened, using the global rating of change. Construct validity was assessed by comparing the change scores of the stable and improved groups, using independent-samples t tests. Reliability was evaluated using intraclass correlation coefficient (ICC_2,1) with 95% confidence intervals. Bland-Altman plots determined limits of agreement. Responsiveness and minimal important difference (MID) were determined with receiver operator characteristic (ROC) curves. RESULTS: One hundred eighty patients met the inclusion criteria. Construct validity was supported for the PSFS and the UEFI (P<.001). Reliability was moderate to good for the PSFS (ICC_2,1 = 0.713) and UEFI (ICC_2,1 = 0.848). Reported estimates of reliability may be lower than true values because the group of “stable” patients from this cohort had, on average, a small positive change. Bland-Altman plots indicated good agreement. The area under the ROC curve (AUC) was significantly different from the null value of 0.5 for the PSFS (0.887) and the UEFI (0.877), indicating good accuracy in distinguishing improved patients from stable patients. MID was 1.2 for the PSFS (scale, 0-10) and 8.5 for the UEFI (scale, 0-80). CONCLUSION: The PSFS is a valid, reliable, and responsive outcome measure for patients with upper extremity problems.

J Orthop Sports Phys Ther 2012;42(2):56-65. doi:10.2519/jospt.2012.3953

KEY WORDS: clinical measurement, instrument validation, outcome measure, upper limb

STUDY DESIGN: Systematic review of the literature. OBJECTIVE: To summarize peer-reviewed literature on the reliability, validity, and responsiveness of the Patient-Specific Functional Scale (PSFS), and to identify its use as an outcome measure. METHODS: Searches were performed of several electronic databases from 1995 to May 2010. Studies included were published articles containing (1) primary research investigating the psychometric and clinimetrics of the PSFS or (2) the implementation of the PSFS as an outcome measure. We assessed the methodological quality of studies included in the first category. RESULTS: Two hundred forty-two articles published from 1994 to May 2010 were identified. Of these, 66 met the inclusion criteria for this review, with 13 reporting the measurement properties of the PSFS, 55 implementing the PSFS as an outcome measure, and 2 doing both of the above. The PSFS was reported to be valid, reliable, and responsive in populations with knee dysfunction, cervical radiculopathy, acute low back pain, mechanical low back pain, and neck dysfunction. The PSFS was found to be reliable and responsive in populations with chronic low back pain. The PSFS was also reported to be valid, reliable, or responsive in individuals with a limited number of acute, subacute, and chronic conditions. This review found that the PSFS is also being used as an outcome measure in many other conditions, despite a lack of published evidence supporting its validity in these conditions. CONCLUSION: Although the use of the PSFS as an outcome measure is increasing in physiotherapypractice, there are gaps in the research literature regarding its validity, reliability, and responsiveness in many health conditions.

J Orthop Sports Phys Ther 2012;42(1):30-42, Epub 25 October 2011. doi:10.2519/jospt.2012.3727

KEY WORDS: disability evaluation, instrument validation, PSFS, questionnaires, treatment outcomes