Poster 337: Graft Choice in Adolescents with Anterior Cruciate Ligament Injuries: Are All Grafts Equivalent?

Abstract

Objectives: The choice of graft for anterior cruciate ligament (ACL) reconstruction (ACLR) plays a crucial role in the outcome of the procedure. Each graft choice has its advantages and disadvantages. Surgeons must consider various factors, including patient age, activity level, and individual anatomy, to make an informed decision on the most suitable graft choice for each patient. The objective of this study was to compare the incidence of retear in patients primary ACLR based upon autograft choice. Secondary objectives of this study were to analyze multivariate trends in retears to identify significant predictors followed by a stratified subanalysis. We hypothesized that hamstring tendon autografts would be associated with an increased number of ACLR graft ruptures. Methods: An institutional review board-approved retrospective cohort study was conducted. Surgical case logs were queried by current procedural terminology code 29888 to identify potential subjects between January 2012 and April 2020. Patients 21 years old and younger underwent primary ACLR within 6 months of injury. Subjects were excluded if they were older than 21 years at the time of injury, had congenital ACL insufficiency, underwent concurrent osteotomy, sustained a multiligamentous injury, or underwent a revision ACLR. Duplicate entries were excluded. Subjects were excluded if records did not have complete data for the purposes of the study. Knee imaging review determined skeletal maturity. Demographic data included age, sex, and body mass index. Each patient’s chart was reviewed to obtain laterality, mechanism of injury, skeletal maturity, and ACLR retear. Intraoperative data such as graft choice, graft size, and concomitant intra-articular pathology was collected. Data was analyzed for incidence of retear, and logistic regression identified predictors of retear. Results: A total of 977 patients were included in final analysis with 50 retears (5.11%). Comparison of graft choice showed significantly increased retears with hamstring tendon (HT) compared to quadriceps tendon (QT) (7.3% vs 3.3% (p = .050)) and patellar tendon (PT) (7.3% vs 2.8% (p = .008)) grafts. Multivariate analysis identified male sex (p < .001), age at injury (p = .016), and smaller graft size (p = .024) as significant variables in cases of ACL rerupture. Analysis stratified by gender did not reveal any significance based upon graft choice, although, HT autograft approached significance (p = .065). During the subanalysis, skeletally immature individuals were significantly more likely to experience a retear (p = .007). Moreover, the incidence of retear based upon graft choice was significant within the skeletally mature cohort (p = .008), with a high incidence of HT retears (6.5%). HT grafts were the smallest grafts on average (8.227 mm). When comparing only QT and HT distributions, the graft size of QT was significantly larger (p < .001); however, the distribution of retears was not significantly different. Conclusions: In patients <22 years of age undergoing primary ACLR, HT autograft was associated with higher incidence of graft rupture compared to PT and QT autografts. There was no difference in retear proportion between QT and PT autografts. Multivariate regression identified male sex, older age at injury, and smaller graft size with increased risk of ACLR retear. There are many variables which portend ACLR graft failure of which sex plays a role; however, in this study, analysis via sex stratification was not significant, likely indicating some amount of variable interaction/confounding where sex as an isolated factor does not significantly influence retears rates. Given the number of variables that affect retears and the low incidence, it will likely take much larger types of meta-analysis studies to identify these traits by using multivariate models with interaction terms. Subanalysis by bone age showed that skeletal maturity does play a role in retears and should be taken into consideration by surgeons. Skeletally mature patients have a comparatively increased risk of graft rupture with HT autograft; moreover, skeletally immature patients incur graft failure not in terms of graft choice, but more so in fixation method as transphyseal and physeal-sparing methods are more technically demanding. Additionally, hamstring tendon grafts were significantly smaller than quadriceps tendon and PT autografts, which may contribute to the higher retear rates seen in this study. To our knowledge, this is the first study with large numbers showing inferiority of HT autograft as compared to both QT and PT autografts, which may be secondary to increased risk with male sex, skeletally mature patients, and smaller graft sizes. [Figure: see text][Figure: see text][Figure: see text][Figure: see text]