Ten-year risk of graft re-rupture and contralateral anterior cruciate ligament injury after primary anterior cruciate ligament reconstruction: a systematic review and meta-analysis.

Abstract

The second anterior cruciate ligament (ACL) injury after ACL reconstruction is a well-known complication. Several studies have suggested that the risk of contralateral ACL injury is comparable to that of graft re-rupture. However, this comparison is not well-established in previous reviews for studies with minimum 5-year follow-up and mean 10-year outcomes. This systematic review and meta-analysis aimed to evaluate the 10-year risk of graft re-rupture and contralateral ACL injury after primary ACL reconstruction and to assess the influence of graft type, return-to-sport, and other factors on second ACL injuries. A systematic search was conducted across the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, and Cochrane from 2000 to 2025. The literature search strategy included the following keywords: "anterior cruciate ligament reconstruction," "ACL reconstruction," "graft rupture," "graft failure," "contralateral anterior cruciate ligament injury," and "contralateral ACL injury." All studies that compare the risk of re-rupture and contralateral ACL injuries after ACL reconstruction and with a follow-up of at least five years after ACL reconstruction were included. Exclusion criteria included case reports, reviews, studies using allografts or artificial ligaments, and multi-ligament injuries. A total of 20 studies were included in this meta-analysis with 6,591 participants. The pooled rates of graft rupture and contralateral injuries were 11% and 12%, respectively with no statistically significant difference (p = 0.421). The ipsilateral graft-rupture rate was higher in patients with hamstring tendon (HT) autografts compared with bone-patellar tendon-bone (BPTB) autografts, at 13.0% and 7.74%, respectively (OR = 1.75, 95% CI 1.33-2.31; p = 0.004). Younger age (<18 years) was identified as the most substantial risk factor, with patients under 18 years showing nearly a threefold increased risk of graft rupture (OR 2.22, 95% CI 1.16-4.23, p = 0.016). Age <18 years also conferred increased risk for contralateral injury (OR 1.87, 95% CI 1.32-2.65, p = 0.001). Return to sport was achieved by 51% to 73% of patients in the included studies. However, delaying return to sports did not result in a statistically significant reduction in the risk of re-injury. Contralateral anterior cruciate ligament injuries and graft re-ruptures occurred at similar rates (12% and 11%, respectively, p = 0.421), which suggests that risk of second injury is similar between ipsilateral graft failure and contralateral anterior cruciate ligament injury. Therefore, second ACL injuries remain a crucial concern over extended follow-up periods (mean 10.3 years), driven primarily by younger age, hamstring graft use, and participation in high-demand sports. Level III.