Contralateral ACL Rupture as an Indicator of Intrinsic Risk for Graft Failure After ACL Reconstruction: A Cohort Study of 7718 Patients From the SANTI Study Group.

BACKGROUND: Graft failure after anterior cruciate ligament (ACL) reconstruction (ACLR) may be influenced by both extrinsic exposure and intrinsic patient susceptibility. A contralateral ACL rupture could reflect an inherent predisposition to ligament injury.

PURPOSE: To determine whether a history of bilateral native ACL ruptures increases the risk of graft failure after primary ACLR.

METHODS: A total of 7718 consecutive patients who underwent primary ACLR by a single surgeon (2003-2022) were included. Graft failure, defined as a clinically and magnetic resonance imaging-confirmed rupture, was compared between patients with bilateral versus unilateral native ACL ruptures. Multivariable logistic regression identified independent predictors, including age, sex, Tegner score, sport type, and a history of bilateral rupture.

RESULTS: The cohort included 6327 patients with isolated native ACL rupture and 1391 patients with bilateral native ACL rupture. The overall graft failure rate was 6% (461-7718), with a mean follow-up of 135.9 months. Patients with bilateral ACL ruptures had a higher failure rate (9.3%) than those with unilateral injuries (5.2%) (P < .0001). Independent predictors included younger age (odds ratio [OR], 0.92 [95% CI, 0.90-0.93]; P < .0001), male sex (OR, 1.46 [95% CI, 1.10-1.96]; P = .0089), higher Tegner score (OR, 1.09 [95% CI, 1-1.19]; P = .043), and bilateral rupture (OR, 1.34 [95% CI, 1.03-1.73]; P = .028).

CONCLUSION: Bilateral native ACL rupture independently increases the risk of graft failure after ACLR. This finding supports its use as a marker of intrinsic vulnerability that may warrant targeted preventive or surgical strategies.

STUDY DESIGN: Cohort study; Level of evidence, 2.