Risk factors for postoperative graft laxity without re-injury after double-bundle anterior cruciate ligament reconstruction in recreational athletes

Abstract

BackgroundAlthough high activity is a risk factor for graft failure after anterior cruciate ligament (ACL) reconstruction, the risk factors for postoperative laxity after ACL reconstruction in recreational athletes are unknown. MethodsWe enrolled 91 patients (40 males, 51 females; mean age 29.2 years; mean follow-up 4.3 years) who scored ≤ 6 on the Tegner activity scale, underwent double-bundle ACL reconstruction between 2010 and 2018, and did not experience re-injury. In the stable group (75 patients, <3.0 mm side-to-side difference (SSD) in anterior translation, grade 0 or 1 pivot shift 1 year after surgery) and unstable group (16 patients, ≥3.0 mm SSD, ≥grade 2 pivot shift), multivariate logistic regression analyses adjusted for factors showing P ≤ 0.3 on univariate analysis assessed risk factors for graft laxity. Lysholm score and graft intensity on MRI (Howell grade) were compared at final follow-up. ResultsMean SSD in anterior translation was 0.7 mm (stable group) and 3.3 mm (unstable group). Pivot shift grades were 0 (88%) and 1 (12%) in the stable group, and 0 (12.5%), 1 (50%), and 2 (37.5%) in the unstable group. Multivariate regression analyses showed that younger age and knee hyperextension were significant risk factors for graft laxity (P = 0.018 and 0.0016; cutoffs 18 years old and 8°, respectively). Lysholm scores in both groups were comparable, but graft intensity on MRI demonstrated significantly worse Howell grade in the unstable group (P = 0.002). ConclusionYounger age and knee hyperextension were risk factors for postoperative graft laxity without re-injury in recreational athletes.