Patient-Reported Outcome Measures Used on Patients With Anterior Cruciate Ligament Injury

Patient-reported knee-related rating scores and scales are widely used in reporting the clinical outcomes of anterior cruciate ligament (ACL) surgery. Understanding the psychometric properties of such measures is vital to recognizing the limitations that such measures may confer. The aim of this study was to review the available evidence as to the psychometric properties of patient-reported outcome measures (PROMs) used in ACL surgery. Eleven studies were identified, the majority being prospective cohort studies. Eight English, ACL-specific patient-reported outcome measures were identified and evaluated: Lysholm score, Tegner Activity Scale (TAS), Cincinnati score, ACL-Quality of Life (QOL) score, International Knee Documentation Committee (IKDC) Subjective Knee Form (SKF), Knee Injury and Osteoarthritis Outcome Score (KOOS)-ACL score, and ACL-Return to Sport Injury (RSI) scale. Only the Lysholm score, ACL-QOL, IKDC SKF, and ACL-RSI were evaluated for internal consistency, having an acceptable Cronbach's α (α>0.70). Most of the scoring systems were assessed for test-retest reliability, with four of them (Lysholm score, TAS, Cincinnati score, and IKDC SKF) having acceptable intraclass correlation coefficient (ICC) values (ICC > 0.70). Criterion validity was assessed for most measures with a good correlation with the IKDC. Effect sizes and standardized response means were large for three instruments that measured responsiveness (Lysholm score, TAS, and Cincinnati score) and moderate for one (ACL-QOL). Evidence is stronger and more robust for the Lysholm score, TAS, ACL-QOL, and IKDC SKF. However, there is variation in their psychometric properties as well as the aspect of knee-related health they are assessing. Hence, none can be universally applicable to all patients with ACL injuries. Recognizing these parameters is vital when choosing which instrument to use in reporting the outcomes of ACL injury or ACL surgery studies.