Comparison of interfragmentary compression in conventional and locked plating of proximal unicondylar tibia fractures : A biomechanical cadaver study

The extent of interfragmentary compression in intra-articular fractures treated with various fixation methods have not yet been reported. Lateral split fractures were created in six pairs of cadaver tibiae treated -using buttress plating with lag screws (group C) or locked buttress plating after clamp compression (group L). Interfragmentary compression and fracture displacement were continuously measured using pressure sensors and a stereoscopic 3-D image correlation system. Significantly larger interfragmentary compression was found initially after clamping the fragment (p < 0.05) in group C (median ± SD ; 45.1 ± 5.0 N/mm2) compared with group L (33.6 ± 3.4 N/mm2), and a statistical trend towards larger compression was also found after cyclic loading (p = 0.05) in group C (45.3 ± 8.6 N/mm2) compared with group L (28.7 ± 5.8 N/mm2). These data indicate that conventional plating with lag screws achieves higher interfragmentary compression in this model compared with external clamp compression and locked plating.