After 40 days intra-articular injury, risk profile increases linearly with time to surgery in adolescent patients undergoing primary anterior cruciate ligament reconstruction

Purpose: Anterior cruciate ligament (ACL) injuries are becoming more common in youth athletes. Time-to-surgery has been shown to significantly affect the rates of concurrent injuries at the time of ACL reconstruction (ACLR). The purpose of this study was to evaluate if time-to-surgery in ACLR impacts observances of intra-articular injuries and to categorize injury profile in relation to time. Methods: An Institutional Review Board-approved retrospective cohort study was conducted. Included subjects were aged 21 and below and underwent primary ACLR within 6 months of injury between January 2012 and April 2020. Skeletal maturity was determined via imaging. Laterality, location and severity/pattern of meniscal and chondral injuries were recorded. Multivariate logistic regression was utilized to identify risk factors for intra-articular pathology. Cut-off analyses were added to regression models to identify trends of concurrent injuries. Results: Eight hundred and fifty patients met the inclusion criteria. Patients with observed articular cartilage injuries had a significantly longer time-to-surgery of 66 days (p = 0.01). Risk factors for chondral injury were time-to-surgery (p = 0.01) and skeletal maturity (p = 0.01), while medial meniscal tears were prognosticated by time-to-surgery (p = 0.03), skeletal maturity (p = 0.01) and body mass index (p = 0.00). Cut-off analysis showed that after 40 days the proportion of patients with observed chondral injury increased with time to surgery and that there were significantly different observances of chondral (p = 0.00) and medial meniscal (p = 0.03) injuries in the 6-week model, as compared to the continuous time model. Conclusion: Longer time-to-surgery in ACLR is associated with higher rates of concomitant intra-articular pathology, especially chondral injuries. After 40 days, the observed rates of intra-articular injury increase proportionately with time from injury. A 6-week categorical model best stratifies intra-articular injury risk profile. Risk factor analysis identified skeletally mature patients with delayed surgery of >12 weeks to be at the highest risk for both chondral and medial meniscal injuries after an ACLR. Level of Evidence: Level III.