Presentation
Lateral knee pain after a fall a few weeks ago.
Patient Data
Small bone bruise in the periphery of the medial femoral condyle. Marrow edema within the lateral tibial condyle with a subchondral fracture partly extending the breadth of the medullary cavity. No cortical breach is seen.
Vertical tear of the body medial meniscus with increased signal within the posterior horn is chronic, unchanged from an MRI 3 years prior. No acute meniscoligamentous injury.
Lateralization of the patella, with multifocal partial full-thickness chondral fissures of the patella, and a full-thickness chondral ulcer of the central trochlea. Partial chondral thinning of the medial compartment with near full-thickness ulceration of the medial femoral condyle weight-bearing surface along with small medial osteophytes.
Within the tibial and femoral metadiaphyses extending to but not beyond the physeal scars is heterogeneous low T1 and PD bone marrow signal with incomplete fat saturation.
Case Discussion
The subchondral fracture of the lateral tibial condyle is uncommon and not typical for an insufficiency fracture, presumably this is traumatic in nature given the history and femoral condyle bone bruise.
The background marrow signal and pattern are typical for red marrow reconversion, probably related to obesity in this patient.