EFFECT OF SKELETAL MATURITY ON INCIDENCE OF ASSOCIATED MENISCAL AND CHONDRAL INJURIES IN ANTERIOR CRUCIATE LIGAMENT INJURED KNEES

BACKGROUND: Acute anterior cruciate ligament(ACL) rupture is associated with a significant incidence of concomitant meniscal and chondral injuries. However, to our knowledge, the incidence of these concomitant injuries in skeletally immature(SI) versus skeletally mature(SM) patients has not been directly compared. SI patients are a unique subset of ACL patients because surgical considerations are different, and subsequent re-tear rates are high. However, it is unclear if the rates and types of meniscal and chondral injuries differ. PURPOSE: The purpose of this study is to compare associated meniscal and chondral injury patterns between SI and SM patients under age 21, treated with ACL reconstruction for an acute ACL tear. We hypothesized that no significant differences would be seen. METHODS: We performed a single-center retrospective review of primary ACL reconstructions performed from January 2012 to April 2020. Patients were stratified by skeletal maturity status based on a review of records and imaging. Demographic data was recorded, including age, sex, and BMI. Associated intra-articular meniscal injury, including laterality, location, configuration, and treatment were determined. Articular cartilage injury location, grade, and treatments were determined. Revision rates, non-ACL reoperation rates, and time to surgery were also compared between the two groups. RESULTS: 785 SM and 208 SI patients met inclusion criteria. Mean BMI and mean age were significantly different between groups. Meniscal tear rates were significantly greater in SM versus SI patients in medial meniscus tears(P<.001), medial posterior horn tears(P=.001), medial longitudinal tears configuration(P=.007), lateral Radial configuration(P=.002), and lateral complex tears(P=.011). Medial repairs(P<.001) and lateral partial meniscectomies(P=.004) were more likely in the SM group. There was a significantly greater number of chondral injuries in the SM versus SI groups in the Lateral(p=.007) and medial compartments(P<.001). SM patients had a significantly increased number of outerbridge grade 1 and 2 in the Lateral(P<.001) and Medial Compartments(P=.013). ACL revisions(P=.019) and Non-ACL reoperations(P=.002) were significantly greater in the SI patients compared to SM. No other significant differences were noted. CONCLUSION: SM ACL injured patients have a significantly higher rate of medial meniscus tears and medial longitudinal configurations treated with repair, and a significantly higher rate of radial and/or complex lateral meniscus tears treated with partial meniscectomy compared to the SI group. We also found a significantly higher rate of both medial and lateral compartment chondral injuries, mainly grades 1 and 2, in SM compared to SI patients. Conversely, SI ACL reconstruction patients had higher revision and subsequent non-ACL surgery rates.