Musculoskeletal Problems

Patient Specific Functional Scale (PSFS)

International Knee Documentation Committee (IKDC)

Patient Specific Functional Scale (PSFS)

The Patient Specific Function Scale (PSFS) can determine the functional status of an individual patient. The Patient-Specific Functional Scale (PSFS) is a self-reported, patient-specific tool created to quantify functional progress, mainly in patients who present with musculoskeletal problems.


Validity and Reliability

Horn et al. (2012) report in their systematic review that the PSFS was found to have excellent reliability for chronic and mechanical low back pain (ICC=0.91-0.97), good reliability for acute low back pain (ICC=0.85), and moderate reliability for chronic obstructive pulmonary disease (ICC=0.55). For tracking changes over time in specific patients with a limited number of musculoskeletal problems, such as knee, low back, and neck dysfunction, the PSFS is valid, reliable, and responsive. In a limited number of musculoskeletal groups, the PSFS was found to be responsive, valid, and reliable in the majority of psychometric and clinical investigations that were assessed.


Scoring and Interpretation

Patients are asked to select up to five critical tasks they are unable to perform or are experiencing difficulties with as a result of their issue. Patients are also asked to list the activities and score the present level of difficulty for each activity on an 11-point scale (0 = impossible to perform activity, 10 = possible to perform activity). After the intervention, patients are once more asked to score the previously noted activities and are given the opportunity to suggest any other problematic activities that may have developed during that time.

Higher scores indicate better functioning.

PSFS PDF Download


PSFS Online Calculator





Stratford, Paul, et al. “Assessing disability and change on individual patients: a report of a patient specific measure.” Physiotherapy canada 47.4 (1995): 258-263.

Horn KK, Jennings S, Richardson G, Vliet DV, Hefford C, Abbott JH. The patient-specific functional scale: psychometrics, clinimetrics, and application as a clinical outcome measure. J Orthop Sports Phys Ther. 2012;42(1):30-42. 

Copyright Notice

When available, sources are cited, and the tool’s developer retains ownership of the intellectual property. We consider that the modification and creation of these tools into dynamic, interactive, online scoring calculators is fair usage. Please email us if you believe we have violated your copyright so we can take down the offending material.

Download our FREE app