Primary and revision anterior cruciate ligament reconstruction using bone-patellar tendon-bone grafts: Higher failure rates with allograft at five-year follow-up.

Abstract

Graft selection remains a critical determinant of outcome after anterior cruciate ligament (ACL) reconstruction. While bone-patellar tendon-bone grafts are widely used, the comparative mid-term performance of autograft versus allograft tissue-particularly in primary and revision reconstruction-remains debated. The objective of this study was to compare graft survival, functional outcomes, and return to sport between bone-patellar tendon-bone autografts and allografts in both primary and revision ACL reconstruction. This retrospective cohort study included 480 ACL reconstructions with a minimum follow-up of five years, comprising 334 primary and 146 revision procedures. Mean patient age was 29.1 ± 7.9 years in the primary cohort and 33.2 ± 8.4 years in the revision cohort. Patients underwent reconstruction using either bone-patellar tendon-bone autograft or allograft. Graft failure was defined as graft rerupture confirmed by imaging or surgery, objective clinical instability, or revision reconstruction with documented failure. Outcomes included graft survival, return to sport, International Knee Documentation Committee (IKDC) score, Lysholm score, and instrumented laxity. Kaplan-Meier survival analysis and multivariable Cox regression were performed. At a mean follow-up of 5.8 ± 0.9 years, graft failure occurred in 9.3 % of autografts and 20.5 % of allografts (p < 0.001), the absolute risk difference was 11.2 % (95 % confidence interval, 5.2 %-17.2 %), corresponding to a relative risk of 2.20. Five-year graft survival was 91.2 % for autografts and 77.4 % for allografts. Allograft use independently predicted graft failure (hazard ratio: 2.42; 95 % confidence interval: 1.53-3.86). Return to preinjury sport was achieved by 82.1 % of autograft patients and 60.9 % of allograft patients. Functional outcomes favored autografts, with higher IKDC and Lysholm scores at final follow-up. At mid-term follow-up, bone-patellar tendon-bone allografts were associated with higher graft failure rates and lower return-to-sport rates compared with autografts in both primary and revision ACL reconstruction. These findings provide strong observational evidence supporting preferential use of autografts in younger, high-demand patients, while suggesting that allografts may be an acceptable option in selected lower-demand or recreational athletes. Level III-Retrospective comparative cohort study.