Delayed Surgical Treatment of Pediatric and Adolescent Medial Meniscus Posterior Root Tears Is Associated With Increased Odds of Medial Tibiofemoral Compartment Cartilage Injury: A Multicenter Study

Medial meniscus posterior root tears (MMPRTs) have been associated with rapidly progressive cartilage degeneration when left untreated in adults. However, their clinical presentation, tear morphology, and associated cartilage pathology remain poorly characterized in pediatric and adolescent patients. To identify risk factors for medial tibiofemoral compartment cartilage injury in pediatric and adolescent patients undergoing MMPRT repair, and secondarily to characterize MMPRT morphologies and skeletal maturity-associated injury patterns. Case series; Level of evidence, 4. Patients <19 years of age who underwent a transosseous MMPRT repair between 2015 and 2025 across 5 institutions were included. Operative records were reviewed to classify MMPRT morphology using the LaPrade classification and to document concomitant ligamentous procedures. The presence, location, and severity of arthroscopically identified medial tibiofemoral compartment cartilage injuries involving the medial femoral condyle (MFC) and/or medial tibial plateau were graded using the International Cartilage Regeneration & Joint Preservation Society (ICRS) classification. Patients with and without medial compartment cartilage injury were compared, and multivariable logistic regression was used to identify risk factors associated with its presence at the time of surgery. A total of 75 patients underwent a transosseous MMPRT repair (mean age, 15.2 &#xb1; 2.3 years), and 40% were skeletally immature. The most common MMPRT morphology was a type 5 root avulsion (55%), followed by a type 2 complete radial root tear (36%). Skeletally immature patients more frequently sustained isolated MMPRTs (60% vs 11%;< .001), whereas skeletally mature adolescents more commonly had ligament-associated MMPRTs (89% vs 40%;< .001).&#x2009;Overall, medial compartment cartilage injury was arthroscopically identified in 34 patients (45%) at the time of surgery. Most cartilage injuries involved the MFC (82%) and were classified as ICRS grade 1 (15%) or grade 2 (62%), while 24% were high-grade (ICRS grade 3 or 4). Multivariable logistic regression demonstrated that age (OR per year, 1.33; 95% CI, 1.02-1.73;= .03) and delayed surgery (&#x2265;90 days after injury) (OR, 4.96; 95% CI, 1.6-15;= .005) were significantly associated with medial compartment cartilage injury. The association between delayed surgery and medial compartment cartilage injury remained consistent in a sensitivity analysis incorporating concomitant ligament injury. Concomitant medial compartment cartilage injury was arthroscopically identified in 45% of pediatric and adolescent patients undergoing MMPRT repair. While most of these cartilage injuries involved the MFC and were classified as ICRS grade 2, nearly one-quarter were high-grade lesions (ICRS grade 3 or 4). Increasing age and delayed surgery (&#x2265;90 days after injury) were significantly associated with medial compartment cartilage injury. Overall, these findings underscore the potential importance of timely recognition and surgical treatment of MMPRTs in young patients.