Paper 13: Risk of Revision and Re-operation after ACL Reconstruction. Comparison of Quadriceps Tendon, BPTB, and Hamstring Autografts in a US-based Cohort Study of 19,960 Patients

OBJECTIVES: The purpose of this study was to evaluate risk for subsequent surgical outcomes, including revision and re-operation, for a cohort of primary anterior cruciate ligament reconstruction (ACLR) patients according to autograft selection. METHODS: Data from a US healthcare system’s ACLR registry was used to conduct a cohort study. Primary isolated autograft ACLR patients were identified (2012-2020); those with prior procedures in the same knee were excluded. The exposure of interest autograft type: Quadriceps tendon (QT), bone-patellar tendon-bone (BPTB), and hamstring tendons. Multivariable Cox proportional hazard regression models were used to evaluate the risk for revision and risk for re-operation within 3-years follow-up according to autograft selection. Age, body mass index, gender, race/ethnicity, American Society of Anesthesiologist’s classification, activity at the time of injury, prior contralateral ACLR, lateral meniscus injury, medial meniscus injury, femoral fixation method, femoral tunnel drilling technique, average annual surgeon volume, operative time, and operative year were considered as covariates in regression analysis; models also included a cluster term for operating surgeon to account for correlation of ACLR performed by the same surgeon. Hazard ratios (HR) and 95% confidence intervals are reported. Two-sided tests were calculated with p<0.05 the threshold for statistical significance. RESULTS: The study sample comprised 19,960 ACLR performed by 280 surgeons at 51 hospitals. QT, BPTB, and hamstring autograft were used in 733 (3.7%), 8578 (43.0%), and 10,649 (53.3%) ACLR, respectively. The Figure presents the cumulative incidence of revision (left panel) and reoperation (right panel) during follow-up by graft type; number of patients still at risk for each year of follow-up is presented along the x-axis. In adjusted models, no significant differences were observed in revision risk (HR=1.52, 95% CI=0.83-2.80, p=0.177) or re-operation risk (HR=1.00, 95% CI=0.63-1.59, p=0.742) within 3-years follow-up when comparing QT ACLR to BPTB ACLR. Additionally, no differences in 3-year revision (HR=0.89, 95% CI=0.46-1.74, p=0.742) or re-operation (HR=1.21, 95% CI=0.74-1.99, p=0.442) risks were observed when comparing QT ACLR to hamstring ACLR. BPTB were noted to have a significantly lower risk of revision (HR=0.68, 95% CI=0.52-0.89, p=0.006) compared to hamstring tendons but no difference in risk of re-operation (HR=1.24, 95% CI=0.95-1.65, p=0.113). Conclusions: The results of this large multi-center study using data from an ACLR registry found no difference in the risk of revision or re-operation when quadriceps tendon was compared to BPTB or hamstring autograft with the numbers available but did find a 1.5 times higher risk of revision when hamstring tendon autograft was compared with BPTB autograft. Surgeons may use this information when choosing the appropriate graft for ACLR in their patients.