Sagittal Plane Deformity in Bicondylar Tibial Plateau Fractures

Objective: To evaluate the prevalence and magnitude of sagittal plane deformity in bicondylar tibial plateau fractures. Design: Retrospective radiographic review. Setting: Two Level I trauma centers. Main Outcome Measurement: Sagittal inclination of the medial and lateral plateau measured in relation to the longitudinal axis of the tibia using computed tomographic reconstruction images. Patients: Seventy-four patients (mean age, 49 years; range, 16-82 years; 64% male) with acute bicondylar tibial plateau fractures (Orthopaedic Trauma Association 41C, Schatzker VI) treated from October 2006 to July 2009. Results: The average sagittal plane angulation of the lateral plateau was 9.8 degrees posteriorly (range, 17 degrees anteriorly to 37 degrees posteriorly). The medial plateau was angulated 4.1 degrees posteriorly on average (range, 16 degrees anteriorly to 31 degrees posteriorly). Forty-two lateral plateaus were angulated more than 5 degrees from the "normal" anatomic slope (defined as 5 degrees of posterior tibial slope). Of these, 76% were angulated posteriorly. Forty-three (58%) of the medial plateaus were angulated greater than 5 degrees from normal, of which only 47% were inclined posteriorly (P = 0.019 compared with lateral plateaus). In 68% of patients, the difference between medial and lateral plateaus was greater than 5 degrees; the average intercondylar slope difference was 9 degrees (range, 0 degrees-31 degrees; P < 0.001). Spanning external fixation did not affect the slope of either the medial or lateral tibial plateau. Intraobserver and interobserver correlations were high for both the medial and lateral plateaus (r(2) > 0.81, P < 0.01). Conclusions: Considerable sagittal plane deformity exists in the majority of bicondylar tibial plateau fractures. The lateral plateau has a higher propensity for sagittal angulation and tends to have increased posterior slope. Most patients have a substantial difference between the lateral and medial plateau slopes. The identification of this deformity allows for accurate preoperative planning and specific reduction maneuvers to restore anatomic alignment.