Ossification variants of the femoral condyles are not associated with osteochondritis dissecans

Purpose: To determine if ossification variants of the femoral condyles involving the subchondral bone plate are associated with osteochondritis dissecans (OCD). Materials and methods: The prevalence of ossification variants of the unaffected femoral condyle in 116 patients (aged 9-14 years) with unicondylar OCD on MRI (magnetic resonance imaging) of the knee was compared to a control group of 579 patients (aged 9-14 years) without OCD. The evolution of the ossification variants in both groups was studied by reviewing follow-up MR imaging side by side with the baseline study. Results: The prevalence of ossification variants in the unaffected condyle in patients with OCD (12.9%) and in the control group of patients without OCD (12.6%) was similar (p = 0.88). Evolution of ossification variants to OCD was not seen on follow-up MRI examinations. All variants had decreased in size or were no longer visible. Conclusion: Ossification variants of the femoral condyle that involve the subchondral bone plate are not associated with OCD. Clinical relevance statement: Ossification variants are not associated with OCD, indicating that routine MRI follow-up in affected children is not mandatory. (C) 2012 Elsevier Ireland Ltd. All rights reserved.