Different modes of augmentative plating for femoral shaft nonunion after intramedullary nailing: a biomechanical comparison / 中华创伤骨科杂志

ABSTRACT

Objective:To compare the anti-rotation stability between different modes of augmentative plating for femoral shaft nonunion after intramedullary nailing.Methods:Fifteen artificial synthetic femurs were used to create models of femoral shaft nonunion with rotational instability after intramedullary nailing. They were randomly divided into 3 groups ( n=5). Control group 1 was fixated with lateral locking compression plate (LCP), control group 2 with anterior LCP, and the experimental group with anterior multi-dimensional cross locking plate (MDC-LP). After fixation, all the groups were subjected to a torsional loading test, with the torsional loading starting from 0 N·m till 10 N·m and a loading speed of 6°/min. The 3 model groups were compared in terms of torsional angle and stiffness. Results:Under the torsion loading, the torsional angles for control group 1, control group 2 and the experimental group were 9.69°±0.34°, 7.15°±0.20° and 1.59°±0.02°, respectively, showing significant differences ( P=0.002); the torsional angle for the experi mental group was significantly smaller than that for control group 1 ( P<0.05). The torsion stiffness for control group 1, control group 2 and the experimental group was respectively 1.02 N·m/° ±0.04 N·m/°, 1.39 N·m/° ± 0.04 N·m/° and 6.16 N·m/° ± 0.06 N·m/°, showing significant differences ( P=14 886.140, P<0.001); there was a significant difference between any 2 groups ( P< 0.05). Conclusions:In the management of femoral shaft nonunion after intramedullary nailing, anterior augmentative plating can provide better anti-torsional stability than lateral augmentative plating, and MDC-LP can also provide better anti-torsional stability than a conventional LCP because it leads to bicortical fixation of the screws.