The Swedish version of the Anterior Cruciate Ligament Quality Of Life measure (ACL-QOL): translation and measurement properties

Abstract

Purpose: To translate the ACL-QOL from English to Swedish and evaluate measurement properties for use after surgical and non-surgical management of anterior cruciate ligament (ACL) injury. Methods: The ACL-QOL was translated from English to Swedish and data were pooled from 13 cohorts to enable a comprehensive evaluation of measurement properties in line with COSMIN guidelines. We evaluated internal consistency, test–re-test reliability, measurement error, structural validity [confirmatory factor analysis (CFA)], construct validity and responsiveness (hypothesis testing), and floor/ceiling effects. Results were stratified by time since injury (≤ 1.5 years; 2–10 years, 15–25 years; > 30 years) and ACL management strategy [surgical (n = 1163), non-surgical (n = 570)]. Results: The Swedish ACL-QOL had sufficient internal consistency (total and domain scores) for use in surgically managed (Cronbach’s alpha ≥ 0.744) and non-surgically managed (≥ 0.770) ACL-injured individuals at all time-points. Test–re-test reliability was sufficient [intraclass correlation coefficients: all domains > 0.80, total score 0.93 (95% CI 0.86–0.96)]. The standard error of measurement was 5.6 for the total score and ranged from 7.0 to 10.3 for each domain. CFA indicated sufficient SRMR values when using the total score or five domains; however, CFI and RMSEA values did not meet cut-offs for good model fit. Hypothesis testing indicated sufficient construct validity and responsiveness. Floor effects were negligible and ceiling effects were negligible or minor. Conclusion: The Swedish version of the ACL-QOL has sufficient internal consistency, test–re-test reliability, construct validity and responsiveness, for use in people with ACL injury managed with or without ACL surgery. Model fit could be improved and investigation into the source of misfit is warranted.