Impaction fracture of the medial femoral condyle.

The patient was a 20-year-old man who sustained a noncontact left knee hyperextension injury while playing soccer. In reviewing left knee radiographs that had previously been interpreted as normal, the physical therapist noted an abnormally deep depression of the medial condylopatellar sulcus, which was concerning for a possible impacted osteochondral fracture. After discussing the radiographic findings with a radiologist, the physical therapist ordered magnetic resonance imaging, which revealed a focal indentation of the anterior portion of the medial femoral condyle with adjacent bone marrow edema that was consistent with an impaction fracture of the medial femoral condyle.