Skeletal Maturity is Associated with Increased Meniscal and Chondral Pathology in Patients Under 21 Years of Age Undergoing Primary Anterior Cruciate Ligament Reconstruction Within 6 Months of Injury.

PURPOSE: To compare injury profiles of meniscal and/or chondral injury in skeletally mature (SM) versus immature (SI) patients undergoing primary anterior cruciate ligament reconstruction (ACLR).

METHODS: CPT code 29888 was queried from January 2012 to April 2020. Subjects aged under 22 who underwent primary ACLR within 6 months of injury were included. Exclusion criteria included age greater than 22, treatment after 6 months, revision ACLR, concurrent osteotomy, or multi-ligamentous injury. All subjects required a minimum of one year follow-up. Demographics and intra-operative pathology was recorded. Data was analyzed for factors affecting intra-articular injury and stratified by sport.

RESULTS: Of 927 patients (739 SM,188 SI), the average age was 16.63 and 14.00 for the SM and SI cohorts, respectively(p<.001). There were more SM males (51.4%) compared to SI males (81.9%)(p<.001); however in univariate analysis gender did not significantly affect the rates of meniscal(p=.519) or chondral injury(p=.961). 887 meniscal injuries were recorded (344 medial, 543 lateral) in 659 patients. SM sustained greater rates of medial meniscal tear (MMT) (p<.001), and underwent higher rates of partial meniscectomy(p=.022). Male sex conferred meniscal injury (95%CI[0.43,0.81],p=.001). BMI prognosticated medial meniscal (95%CI[1.01,1.06],p=.002) and medial chondral injuries (95%CI[1.02,1.09],p<.001). Skeletal maturity was a superior predictor of intra-articular pathology than age for all outcomes: MMT (95%CI[0.00,0.06],p=.002), LMT (95%CI[0.00,0.75],p=.034), and chondral injury (95%CI[0.00,0.49],p=.049). In sport sub-analysis, soccer ACL injuries were most common (32.6%). Soccer and basketball athletes were more likely SM (p=.016,p=.003 respectively) with increased medial compartment pathology. Football ACL injuries occurred significantly in SI athletes(p=.001) via contact mechanisms(p=.025).

CONCLUSION: Skeletal maturity affects the meniscal and chondral injury profile in ACL-injured patients. SM patients have greater risk of sustaining concomitant meniscal injury, while chondral injury profile depends more on the mechanism of injury. Mechanism of injury and skeletal maturity status impact risk of sports related ACL rupture and ACL-concurrent pathology in young patients. Patient-specific variables influence injury profiles within each sport. Skeletal maturity rather than age predicts concomitant intra-articular injury risk.

LEVEL OF EVIDENCE: III - Retrospective Cohort Study.