Summary

Skeletally mature patients with surgery >12 weeks from injury are at the highest risk for chondral and medial meniscal injuries in delayed ACL reconstruction.

Abstract

Introduction

Knee injuries, specifically anterior cruciate ligament (ACL) injuries, are becoming increasingly more common in the young athlete. Recent literature has highlighted the association of intra-articular pathology, specifically the menisci and articular cartilage, within ACL-deficient knees. Time-to-surgery has been shown to significantly affect the rates of concurrent injuries at the time of ACL reconstruction after 6 months; however, this has not been well studied in the transitional adolescent population with the addition of skeletal maturity as a risk factor

Purpose

To evaluate if delays in ACL reconstruction (ACLR) impact the observed incidence of concomitant meniscal and chondral injuries in an adolescent cohort and to identify and recommend a surgical timeframe after which concurrent injuries significantly worsen.

Study Design: Retrospective Cohort

Methods

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 radiographs. 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 analysis was added to regression models to identify trends of concurrent injuries.

Results

850 patients met inclusion criteria. Patients with observed articular cartilage injuries had a significantly increased average time to surgery of 66 days (p=.008), while medial meniscal injuries trended towards significance (p=.09). Survival analysis portrayed a significant degradation rate between patients with and without chondral injuries (p=.01). Multivariate regression analysis indicated that chondral injuries were predicted by time to surgery (OR 1.01, 95%CI [1.00,1.01], p=.009) and skeletally mature patients (OR 0.00, 95%CI [0.00,0.07], p=.014). Cut-off analysis showed that after 8 weeks the proportion of patients with observed chondral injury that had not undergone surgery increased with time, and that patients with surgery >12 weeks had significantly higher risk of intra-articular injury compared to acute fixation (< 6 weeks). Medial meniscal injuries were prognosticated by time-to-surgery (OR 1.52, 95% CI[1.05,2.18], p=.025), skeletally mature patients (OR 0.00, 95%CI [0.00,0.20], p=.009), Age*Skeletal Maturity (OR 1.55, 95%CI [1.16,2.13], p=.004), and Sex*Skeletal Maturity (OR 0.20, 95%CI [0.08,0.51], p<.001). Time-to-surgery was not a risk factor for lateral meniscal tears.

Conclusion

Skeletally mature patients with delays in ACL reconstruction greater than 12 weeks are at significantly increased rate of observed concurrent chondral and medial meniscal injuries. While time to surgery significantly correlated with rates of observed concurrent pathology, after approximately 8 weeks, the rates of articular chondral injury increase proportionately with time from injury in both the skeletally mature and skeletally immature populations.