Fracture of the anteromedial tibial plateau associated with posterolateral complex injury: case study and literature review.

We report an unusual case of anteromedial tibial plateau compression fracture following hyperextension and forced varus of the knee, resulting in an anterior bone fragment large enough to require osteosynthesis. This uncommon lesion was associated with posterolateral complex injury, diagnosed with magnetic resonance imaging (MRI), while both cruciate ligaments were preserved. After proceeding with tibial plateau osteosynthesis, a peroneal tendon allograft was used for supplementation repair of the lateral collateral ligament and biceps tendon in a single surgical intervention. Tibial plateau fractures are often associated with soft-tissue involvement, mainly of the anterior cruciate ligament and external meniscus. Posterolateral complex injuries also occur with a mechanism of forced varus and hyperextension. These lesions require an accurate diagnosis to avoid future knee instability; moreover, adequate treatment in the acute phase provides a better functional outcome. Physicians should suspect associated posterolateral complex injury when an anteromedial tibial plateau fracture is diagnosed. MRI allows adequate diagnosis and permits surgical treatment in one procedure.