Presentation
Twisted knee.
Patient Data
No joint effusion or soft tissue swelling. No fracture or malalignment.
There is a long gap of missing cartilage on the posterior surface of the lateral femoral condyle with the delaminated fragment observed free within the joint effusion anteriorly (shearing injury). Also a tiny focal cartilage injury is observed in the posterior aspect of the lateral tibial plateau.
The anterior cruciate ligament has normal morphology and mildly increased signal inferring partial tear. Posterior cruciate ligament is intact. The medial and lateral collateral ligaments are intact.
Menisci are likely preserved, with no tears identified.
Small focus of partial cartilage disruption within the medial patellar articular surface. Quadriceps tendon and patellar ligament are normal in appearance.
The biceps femoris and pes anserinus tendons are unremarkable.
Large joint effusion, especially noted within the suprapatellar recess.
Subcutaneous edema in the anterior aspect of the knee.
Conclusion: Cartilage shearing injury involving the posterior aspect of the lateral femoral condyle. Small foci of cartilage injury within the patella and posterior tibial plateau. Signs of anterior cruciate ligament partial tear. Large joint effusion.
Delamination injury of the lateral femoral condyle with separation and anterior migration of articular cartilage from the subchondral bone.
Case Discussion
This case demonstrates multiple foci of cartilage injuries in the knee, in special the delamination injury of the lateral femoral condyle with separation and anterior migration of articular cartilage from the subchondral bone.