Abstract
OBJECTIVES: To identify the preoperative risk factors for revision ACL surgery within the first two years after BEAR ACL repair procedure. METHODS: Data from the prospective BEAR I, II, and III trials were used to determine preoperative risk factors for ACL revision surgery. All subjects with a complete ACL tear (ages between 13-47 years, depending on the trial), who passed all other inclusion/exclusion trial criteria, and underwent a primary BEAR procedure within 30-50 days from injury (dependent on trial) were included. Demographic data (age, sex, BMI), baseline patient-reported outcomes (IKDC Subjective Score, Marx Activity score), pre-operative imaging characteristics (ACL stump length, notch size, tibial slopes), and intraoperative findings (knee hyperextension, meniscal tear status) were evaluated to determine their contribution to ipsilateral revision ACL surgery risk. RESULTS: 123 subjects, median age 17.6 years (IQR 16-23), including 67 (54%) females, met study criteria. 18 (15%) patients required revision ACL surgery in the first two years following the BEAR procedure. In bivariate analyses, younger age (p=.011), having a contact injury at the time of the initial tear (p=.048), and increased medial tibial slope (p=.029) were associated with a higher risk of ipsilateral revision surgery. Multivariable logistic regression analyses identified two independent predictors of revision: patient age and medial tibial slope. The odds of an ipsilateral revision surgery were decreased by 32% for each one-year increase in age (OR=0.684, 95% CI = 0.517 to 0.905, p=.008), and increased by 28% per each degree of increase in medial tibial slope (OR=1.280, 95% CI =1.024 to 1.601, p=.030). Sex, baseline IKDC or Marx score, knee hyperextension, or meniscus status were not significant predictors of revision. CONCLUSIONS: Younger age and higher medial tibial slope were predictors of increased odds of ipsilateral ACL revision surgery after the BEAR procedure. Younger patients with higher tibial slopes should be aware of the increased risk for revision surgery when deciding to undergo ACL restoration surgery.