Less invasive stabilization of complex tibial plateau fractures: a biomechanical evaluation of a unilateral locked screw plate and double plating.

Objective: To compare the vertical subsidence in a bicondylar tibial plateau fracture model stabilized either by a unilateral locked screw plate (LSP) or by double plating.

Design: Biomechanical cadaver study.

Intervention: A 41-C1 fracture model was created in eight pairs of fresh-frozen human cadaver tibiae. Stabilization was performed either by open reduction and internal fixation (ORIF) using a lateral L-buttress plate and a medial four-hole, one-third tubular antiglide-plate or by a lateral LSP. Four load levels (400N, 800N, 1200N, 1600N), each with five cycles, were consecutively applied to the medial plateau.

Main Outcome Measurements: The vertical plastic deformation at the end of each cycle was the main parameter of interest. Statistical analysis was performed with the two-way ANOVA test for repeated measurements. Each individual loading level was analyzed separately using Student t test.

Results: In one pair, both fixation techniques failed at the first loading cycle of 1200N. One ORIF fixation failed at the first loading cycle of 1600N. The average plastic vertical subsidence was 0.40 mm (LSP) and 0.25 mm (ORIF) at 400N (P = 0.291), 0.83 mm (LSP) and 0.81 mm (ORIF) at 800N (P = 8.82), 1.06 mm (LSP) and 0.96 mm (ORIF) at 1200N (P = 0.98), and 1.54 mm (LSP) and 1.14 mm (ORIF) at 1600N (P = 0.53). Vertical subsidence depended on the applied load (P = 0.002), but not on the method of fixation (P = 0.236).

Conclusion: Both fixation techniques have a high resistance to vertical subsidence even with loads exceeding the average body weight. No statistically significant difference was seen between the two methods of fixation.