Graft Fixation and Timing of Surgery Are Predictors of Early Anterior Cruciate Ligament Revision: A Cohort Study from the Swedish and Norwegian Knee Ligament Registries Based on 18,425 Patients

The identification of surgical risk factors for early anterior cruciate ligament (ACL) revision is important when appropriate treatment for patients undergoing primary ACL reconstruction is selected. The purposes of this study were to determine the short-term ACL revision rate of patients undergoing primary ACL reconstruction and to identify surgical risk factors for ACL revision within 2 years of primary ACL reconstruction. METHODS: This study was based on data collected prospectively from the Norwegian and Swedish National Knee Ligament Registries. Patients who underwent primary ACL reconstruction from 2004 through 2014 were included. We examined revisions through 2016. The relative risks (RRs) of revision ACL reconstruction dependent on graft fixation, the time interval between injury and surgical procedure, and meniscal and cartilage injury were estimated by using generalized linear models with a binomial distribution and log-link function. The outcome was set as revision ACL reconstruction during the first 2 years. RESULTS: A total of 58,692 patients were assessed for eligibility; of these, 18,425 patients were included. The overall 2-year revision rate was 2.1%. Patients treated with a metal interference screw had an increased risk of ACL revision when compared with patients who were treated with other femoral fixations (RR, 1.78 [95% confidence interval (CI), 1.38 to 2.29]; p < 0.001). The use of the RIGIDFIX Cross Pin System (DePuy Synthes) entailed a lower risk of ACL revision compared with other femoral fixations (RR, 0.58 [95% CI, 0.42 to 0.82]; p = 0.0017). Patients undergoing ACL reconstruction within 3 months of the injury had an increased risk of ACL revision (RR, 2.07 [95% CI, 1.64 to 2.61]; p < 0.001). CONCLUSIONS: Patients undergoing ACL reconstruction within 3 months of an injury, as well as patients treated with a metal interference screw in the femur, had a significantly higher risk of ACL revision, and patients treated with the RIGIDFIX Cross Pin in the femur had a significantly lower risk of ACL revision. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.