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

Background: Although 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.

Methods: We 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.

Results: Mean 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).

Conclusion: Younger age and knee hyperextension were risk factors for postoperative graft laxity without re-injury in recreational athletes.