Presentation
Knee pain.
Patient Data
Slight depression of the lateral femoral condyle articular surface. Suprapatellar joint effusion.
Lateral femoral condyle lucency with a well-defined sclerotic border.
Moderate joint effusion. No displaced meniscal tear. Cruciates and collaterals are intact. Intact extensor mechanism.
Subchondral fracture of the weight-bearing surface of the lateral femoral condyle with further bone contusion extending through the lateral femoral condyle to the metaphyseal regions. Overlying cartilage appears intact. Approximately 2.5 mm of subchondral bone plate depression. Further bone contusion of the medial tibial plateau. No cortical breach is identified.
Subcortical oval lesion with low T1, intermediate/high PD/T2 signal at the attachment of the lateral gastrocnemius head typical for distal femoral cortical irregularity (cortical desmoid).
Case Discussion
There was a history of trauma in this patient with quite impressive subchondral fracture and bone bruising without ligamentous injury.
Incidental cortical desmoid of the lateral gastrocnemius insertion - these are much more common medially.