Background: Tibial plateau fractures (TPFs) are the most common among periarticular fractures. Mechanism of injuries is most from varus/valgus and flexion injury. Hyperextension type injuries are rare and easily to be overlooked. We reported 12 cases of this fracture type. Complications of early cases were reported, and treatment strategies of late cases were suggested.
Materials and methods: From 2010 to 2016, we performed a retrospective analysis of 248 cases of TPFs in our institute and 12 cases of hyperextension bicondylar TPFs were diagnosed. Diagnostic method is from both plain films and CT scans. The features of this injury included sagittal plane malalignment with loss of the normal posterior slope of the tibial plateau, tension failure of the posterior cortex, and compression of the anterior cortex. Surgical approach is predominantly via an anterolateral and/or posteromedial double incision at the first. Then anteromedial with adequate grafting to support the bone defect was modified. Postoperative radiographic analysis, physical examination findings, and complications were reported. Patient reported outcome scores from the Knee Injury and Osteoarthritis Outcome Score (KOOS) were recorded.
Results: Twelve patients were followed up for a mean period of 16.6 months (range 12-26 months). The mean time to radiographic bony union was 3.6 months (range 3-9 months, SD 8.5). About complications, the incidence of popliteal artery occlusion received PTA was 8% (1/12). And 3/12 (25%) patients had either partial or complete peroneal nerve injury. 2/12 (16%) patients developed a leg compartment syndrome. 33% (4/12) demonstrated associated injuries including posterolateral complex injuries mostly and posterior cruciate ligament avulsion fracture in one case. The average range of motion of the affected knees was 3.4-130° postoperatively. Analysis of complication about surgery included inadequate reduction and fixation in two cases, insufficient bone grafting in one case. The mean mPTA was significantly improved after fixation (preoperative 82° postoperative 3 months 86°). The mean posterior slope (PTA) was preoperative - 3° and postoperative 3 months 3°. And mean KOOS was 80.
Conclusions: Hyperextension bicondylar tibial plateau fractures show a special characteristic of changes in posterior tibial slope angle and are easy to be overlooked. Complication rate is high after injury and after ineffective fixation. Choosing correct approach with sufficient grafting and stable fixation for treatment of hyperextension bicondylar tibial plateau fractures should be used to improve patients' outcome.
Keywords: Complications; Hyperextension type injury; Tibial plateau fracture.