A novel patient‐reported outcome measure for anterior cruciate ligament injury: evaluating the reliability, validity, and responsiveness of Japanese anterior cruciate ligament questionnaire 25

PURPOSE: Despite objectively good results, up to 70 % of individuals may not return to their pre-injury level of sports activity after anterior cruciate ligament (ACL) reconstruction surgery. Although psychological responses have been shown to affect outcomes after ACL injury, an appropriate means of measuring their effects, in addition to functional status, has not been determined. The purpose of this study was to develop a patient-reported questionnaire for measuring psychological factors associated with outcomes after ACL injury and to evaluate its reliability, validity, and responsiveness. METHODS: After item analysis based on the results of two pilot studies and a short relevance assessment, 25 questionnaire items were selected for the Japanese Anterior Cruciate Ligament Injury Questionnaire 25 (JACL-25) and assessed for validity, reliability, and responsiveness in subjects with ACL injury. RESULTS: The JACL-25 had no floor or ceiling effects and no confounding factors. A Cronbach's alpha coefficient of 0.981 and a Guttman split-half coefficient of 0.983 indicated excellent reliability. Large standardized response means (1.30-1.62) and effect sizes (0.96-1.51) from the preoperative to postoperative period indicated good responsiveness. Construct structures were created, and these items were separated into three domains. Strong correlations between the JACL-25 and the International Knee Documentation Committee Subjective Knee Form (r s = -0.86), Lysholm Score (r s = -0.73), and Tegner Activity Scale (r s = -0.65) indicated good concurrent validity of the JACL-25. CONCLUSIONS: The present study demonstrated that the JACL-25 was valid, reliable, and responsive enough to evaluate psychological factors associated with outcomes in individuals with ACL injuries. LEVEL OF EVIDENCE: Diagnostic study, Level III.