More Than a 2-Fold Risk of Contralateral Anterior Cruciate Ligament Injuries Compared With Ipsilateral Graft Failure 10 Years After Primary Reconstruction.

Background: Failure of anterior cruciate ligament (ACL) reconstruction or an injury to the ACL in the contralateral knee represents a devastating event for patients, especially those young and physically active. However, controversies are still present regarding long-term failure rates and risk factors.

Purpose: To assess the long-term rate of ipsilateral graft failure and contralateral ACL injuries after ACL reconstruction performed at a single center using the same surgical technique with a hamstring autograft and to investigate the effect of sex, age, and preinjury activity level as predictors of second ACL injuries.

Study Design: Case series; Level of evidence, 4.

Methods: The study cohort consisted of 244 consecutive patients (mean age, 30.7 years) who underwent ACL reconstruction with a single bundle plus lateral plasty technique using the hamstring tendon between November 2007 and May 2009. The number of subsequent ACL injuries (ipsilateral ACL revision or contralateral ACL reconstruction) was determined at a minimum follow-up of 10 years. Survivorship of either knee and subgroup analysis included sex, age, preoperative Tegner activity level, timing of ACL reconstruction, body mass index, and smoking status.

Results: Ipsilateral ACL revision was performed in 8 (3.4%) patients and contralateral ACL reconstruction in 19 (7.8%) patients. Only 1 patient had both ipsilateral and contralateral injuries. No predictors were found for ipsilateral ACL revision, while age <18 years and preoperative Tegner level ≥7 had a higher risk of contralateral ACL reconstruction. The highest rate of a second ACL reconstruction procedure was in young (<18 years) and active (Tegner ≥7) patients, in whom the 10-year survival of either knee was 61.1%. Six years after primary ACL reconstruction, the rate of contralateral ACL reconstruction was significantly higher than that of ipsilateral ACL revision (hazard ratio, 2.4-3.6).

Conclusion: In the long term, a second injury to either the ipsilateral or the contralateral knee in young and active populations could reach 40%, with a more than double-fold risk of contralateral ACL reconstruction compared with ipsilateral ACL revision.