Anterior cruciate ligament—return to sport after injury scale: validation of the Norwegian language version

PURPOSE: Evidence is emerging on the importance of psychological readiness to return to sport after anterior cruciate ligament (ACL) reconstruction. The ACL-Return to Sport after Injury scale (ACL-RSI) is developed to assess this. The aim of the current study was to translate ACL-RSI into Norwegian and examine the measurement properties of the Norwegian version (ACL-RSI-No). METHODS: ACL-RSI was translated according to international guidelines. A cohort of 197 ACL-reconstructed patients completed ACL-RSI-No and related questionnaires nine months post-surgery. One hundred and forty-six patients completed hop tests and 142 patients completed strength tests. Face and structural validity (confirmative factor analysis and explorative analyses), internal consistency [Cronbach’s alpha (α)], test–retest reliability [Intraclass Correlation Coefficients (ICC)], measurement error [Standard error of measurement (SEM) and smallest detectable change at individual (SDC(ind)) and group level (SDC(group))] and construct validity (hypotheses testing; independent t tests, Pearson’s r) were examined. RESULTS: ACL-RSI-No had good face validity. Factor analyses suggested that the use of a sum score is reasonable. Internal consistency and test–retest reliability were good (α 0.95, ICC 0.94 (95% CI 0.84–0.97) and measurement error low (SEM 5.7). SDC(ind) was 15.8 points and SDC(group) was 2.0. Six of seven hypotheses were confirmed. CONCLUSIONS: ACL-RSI-No displayed good measurement properties. Factor analyses suggested one underlying explanatory factor for “psychological readiness”—supporting the use of a single sum score. ACL-RSI-No can be used in the evaluation of psychological readiness to return to sport after ACL injury. LEVEL OF EVIDENCE: III.