Specific Markers of Knee Morphology and Osteochondritis Dissecans of the Medial Femoral Condyle in Pediatric and Adolescent Patients: A Matched Case-Control Study

Background: The causes of osteochondritis dissecans (OCD) of the knee remain to be further elucidated. Past literature has suggested that specific knee morphology may be associated with OCD of the medial femoral condyle (MFC); however, parameters have not been thoroughly externally validated. Hypothesis: An increased MFC width (MFCW), narrower notch width, increased normalized tibial spine height, and increased medial tibial slope (MTS) are associated with the presence of MFC OCD in pediatric and adolescent patients. Study Design: Case-control study; Level of evidence, 4. Methods: Patients aged ≤21 years and diagnosed with MFC OCD between 2016 and 2024 were matched 1:1 by age and sex to control patients, who had undergone advanced knee imaging for reasons unrelated to MFC OCD. Radiographic measurements were performed by 2 independent observers and included MFCW, tibial plateau width, femoral notch width, femoral condyle width, distance A (distance from the top of the tibial spine to the bimeniscal axis), distance B (distance from the top of the tibial spine to the proximal tibial physis), MTS, and posterior tibial slope (PTS). Medial condyle index (MCI = MFCW/tibial plateau width), notch width index (NWI = femoral notch width/femoral condyle width), and S ratio (distance A/distance B) were calculated. Measurements were compared between the 2 groups via regression modeling. Results: There were 86 patients with MFC OCD (32 female [37.2%]) matched to 86 control patients, for a total of 172. The mean age was 13.8 ± 2.8 years. The MCI (0.371 ± 0.029 vs 0.338 ± 0.023, respectively; P < .001) was significantly larger in the OCD group than in the control group, while the NWI was significantly smaller (0.232 ± 0.032 vs 0.263 ± 0.031, respectively; P < .001). No significant differences were found in distance A, distance B, S ratio, MTS, or PTS. Multivariate logistic regression identified MCI (P < .001), NWI (P = .011), and MTS (P < .001) as significant predictors of MFC OCD. Patients with an MCI >0.354, an NWI <0.240, and an MTS >18.9° had an 18.6-, 4.7-, and 9.4-fold higher likelihood of having OCD, respectively. Conclusion: A wider MFC, narrower femoral notch, and larger MTS were significantly associated with abnormal osseous morphology in pediatric and adolescent patients with MFC OCD.