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° posteriorly (range, 17° anteriorly to 37° posteriorly). The medial plateau was angulated 4.1° posteriorly on average (range, 16° anteriorly to 31° posteriorly). Forty-two lateral plateaus were angulated more than 5° from the "normal" anatomic slope (defined as 5° of posterior tibial slope). Of these, 76% were angulated posteriorly. Forty-three (58%) of the medial plateaus were angulated greater than 5° 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°; the average intercondylar slope difference was 9° (range, 0°-31°; 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.