Document resource
Introduction To clear patients for return-to-sport (RTS) after anterior cruciate ligament (ACL) injury, clinicians use criteria ≥90% limb-symmetry-index (LSI) in muscle function (strength and hop performance), but only 28% achieve current clearance criteria. We aimed to evaluate the predictive capability of baseline demographical variables, 4-months follow-up psychological variables and muscle function, on recovery of ≥90% LSI muscle function and RTS 12 months after ACL injury in patients treated with rehabilitation alone (non-op).Materials and Methods Inclusion in this registry study with data from Project ACL required a pre-injury Tegner Activity Scale (Tegner) ≥6 and 4- and 12-month follow-up data from patient reported outcomes (PROs) and muscle function assessment. Univariable and stepwise multivariable logistic regression were used to evaluate demographic and clinical predictors of achieving ≥90% LSI in strength and RTS, reported as odds ratios. Predictive accuracy of PROs and LSI for 12-month recovery was assessed using ROC and AUC.Results There were 114 patients included. No baseline demographical variables could accurately predict the achievement of ≥90% LSI or RTS for patients treated with non-op 12-months after ACL injury. Knee flexion strength LSI ≥90% at 4-months reported significantly greater odds of muscle strength symmetry at the 12-month follow-up, (OR: 1.20 [95% CI 1.03; 1.40], p=0.022), with excellent differentiation capacity AUC; 0.81 [95% CI; 0.53;1.00].Conclusion Knee flexion strength recovery at 4-months follow-up was a significant predictor of achievement of symmetrical muscle strength at 12 months follow-up, which highlights the potential role of early strength recovery in patients treated with non-op.