Validation of an 18‐item version of the Swedish Knee Self‐Efficacy Scale for patients after ACL injury and ACL reconstruction

Abstract

Abstract Purpose To evaluate the measurement properties of a new version of the Swedish Knee Self‐Efficacy Scale (K‐SES) in samples of individuals with an anterior cruciate ligament (ACL) injury and after ACL reconstruction. A secondary aim was to translate the new version of K‐SES into English in order to prepare for future complete cross‐cultural adaptation. Methods The reliability, structural validity, internal consistency and construct validity of the new, 18‐item version of the K‐SES (K‐SES18) were assessed according to the COnsensus‐based Standards for the selection of health Measurement INstruments (COSMIN) checklist for evaluating methodological quality. The Swedish version of the K‐SES18 was translated to English using recommended guidelines. Results The test‐retest reliability for the K‐SES18 subscale present and the K‐SES18 subscale future showed an Interclass Correlation Coefficient (ICC) = 0.92. In addition, the K‐SES18 had a Cronbach’s α ranging from 0.93 to 0.96 for the K‐SES18 subscale present and from 0.81 to 0.91 for the K‐SES18 subscale future. No floor and ceiling effects were identified for the subscale present or the subscale future of the K‐SES18. A factor analysis produced 2 factors of importance; K‐SES18present and K‐SES18future. Seven predefined hypotheses were confirmed. Conclusion The K‐SES18 has acceptable reliability and validity to assess knee self‐efficacy in patients up to 18 months after ACL injury and reconstruction. Level of evidence IV.

Keywords

• Anterior cruciate ligament
• Cross‐cultural adaptation
• Patient‐reported outcome measure
• Psychometrics
• Self‐efficacy