A 14-year-old boy presents with intermittent right knee pain and locking. MRI shows a focal defect in the articular cartilage and subchondral bone of the medial femoral condyle with a T2 hyperintense rim extending through the cartilage around the fragment. What does this finding indicate?
- A Unstable lesion, at risk of detachment ✓
- B Stable lesion, suitable for conservative management
- C Septic arthritis
- D Osteosarcoma
Correct answer: A. Unstable lesion, at risk of detachment
Explanation
B T2 hyperintense rim extending through the articular cartilage around an osteochondritis dissecans fragment indicates an unstable lesion at risk of detachment. This finding suggests fluid has dissected beneath the fragment, separating it from the underlying bone. Stable lesions lack this high-signal rim. Conservative management is reserved for stable lesions without this MRI feature.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.