Treatment of isolated posterior coronal fracture of the lateral tibial plateau through posterolateral approach for direct exposure and buttress plate fixation

To present a case series of patients with isolated posterior coronal fractures of lateral tibial plateau treated by direct exposure and buttress plate fixation through posterolateral approach. Between May 2007 and April of 2008, eight middle aged patients were identified that had isolated posterior coronal fractures of the lateral tibial plateau. All eight patients underwent direct fracture exposure, reduction under visualization, and buttress plate fixation through posterolateral approach. There were 1 case of split, two cases of pure depression and five cases of split-depression fractures. Four were associated fibular head split fractures without common peroneal nerve injuries. Five patients were injured from a simple fall on riding electrical bicycle while the knee was relaxed in 90A degrees position The articular displacement (8 cases) measured in CT scan was 10.5 mm in average (range 8-15 mm). The cortical split length (from the articular rim to the distal tip, 6 cases) was 2.8 cm in average (range 2.4-3.5 cm). The articular reduction was perfect in seven (absolutely no step-off) and imperfect in 1(< 2 mm step-off) as measured by X-ray. With a mean follow-up of 10 months (6 cases > 12 months), the average range of motion arc was 119A degrees, four patients have flexion lag 10A degrees-20A degrees. The average SMFA dysfunction score was 15.8, and average HSS score was 98. All eight patients stated they were highly satisfied. Direct posterolateral approach by dividing lateral border of soleus muscle, provides excellent fracture reduction under visualization and internal buttress plate fixation for posterior coronal fracture of the lateral tibial plateau. Good functional results and recovery can be expected.