Purpose: To develop and validate a sports activity scale for patients with a diagnosis of femoroacetabular impingement (FAI).
Methods: A nine level Hip Sports Activity Scale (HSAS) was constructed both in German and English languages. Fifty-nine consecutive patients undergoing surgical treatment for FAI at two centers in Switzerland and in the US completed a questionnaire set consisting of the HSAS, the University of California at Los Angeles (UCLA) activity scale and different hip joint-specific and generic outcome tools. For reliability assessment, the HSAS was completed twice about nine days apart. Evidence of reliability, validity and responsiveness was investigated by classical psychometric analyses.
Results: Reliability was excellent for both the German and the English versions with intraclass correlation coefficients of 0.94 and 0.96, respectively. Evidence of convergent validity was supported by moderate to high correlations with the UCLA activity scale and with the joint-specific measures used. Evidence of divergent validity was supported by low correlations with the SF-12 Mental Component Scale and the WOMAC stiffness subscale. The standardised response mean was 0.69.
Conclusions: The HSAS is a reliable and valid tool to determine sports levels in patients suffering from FAI. Its use in future studies investigating outcomes in young patients with hip disease can be recommended.
Level of evidence: Level III, Diagnostic Studies - An independent, masked comparison with an appropriate population of patients, but reference standard not applied to all study patients.