Flexion-valgus unicondylar tibial plateau depression fracture pattern: Classification and treatment.

PURPOSE: The authors have identified a subset of unicondylar tibial plateau depression fracture patterns caused by a flexion-valgus force. The purpose of this study was to describe this fracture pattern and suggest a modified lateral approach that may allow for improved reduction and stabilization.

METHODS: The preoperative radiographs and CT scans of 102 patients who sustained unicondylar tibial plateau fractures (OTA 41B) were reviewed. Twenty-six fracture patients had posterolateral (PL) tibial plateau depression fractures. By medical record review and telephone follow-up, the injury mechanism of the 22 unicondylar tibial plateau fractures was confirmed as a flexion-valgus force. The radiographic features of those cases were analyzed and measured. To address this specific fracture pattern, a modified approach combined with a novel intra-articular osteotomy was applied.

RESULTS: According to the morphological characteristics, this tibial plateau fracture pattern could be divided into two subtypes: type A was a confined, basin-like articular surface depression fracture located in the PL quadrant, and type B was a cancellous fracture involving the PL tibial plateau resulting in a decrease in the posterior slope. One radiographic hallmark of this fracture pattern is an anatomically or a mechanically intact posterior column wall. The novel approach was applied to both types. The postoperative radiographic measurements revealed excellent reduction quality. On axial scans, the distance between the most posterior rafting screw and the tangent line of the tibial plateau rim was 3.0 ± 2.07 mm (from -1.9 to 4.3), and the angulation between them was 8.9 ± 3.02° (from -7.3 to 15.6). These results indicated excellent PL quadrant coverage from the rafting screws.

CONCLUSION: Flexion-valgus force-induced unicondylar tibial plateau depression fracture is a unique injury pattern. We suggest a novel surgical approach to address this injury's key features, which may facilitate exposure and enhance fixation strength.