掌侧与背侧钢板固定关节外桡骨远端背侧粉碎性骨折的生物力学研究

Plate fixation for extra-articular dorsally comminuted distal radius fracture： a biomechanical comparison between volar plating and dorsal plating

目的探讨掌侧与背侧钢板固定桡骨远端背侧粉碎性骨折时的抗压缩、抗扭转差异性。方法将12侧新鲜成人尸体桡骨标本制成桡骨远端背侧粉碎性骨折模型，随机分为2个大组，分别进行掌侧与背侧钢板螺钉固定；再将每个大组分为2个亚组，分别进行轴向压缩试验和水平扭转试验。检测指标：轴向压缩强度、轴向压缩刚度、水平扭转强度和水平扭转刚度。结果在轴向压缩试验中，掌、背侧两组之间轴向压缩强度差异有统计学意义（P〈0．05），背侧组大于掌侧组；在生理压缩载荷下，掌、背侧两组刚度值差异有统计学意义（P〈0．05），背侧组高于掌侧组。在水平扭转试验中，两组水平扭转强度与扭转刚度差异都没有统计学意义，但数据显示，掌侧组都略强于背侧组。结论在抗压缩方面，两组的压缩强度以及压缩刚度差异均有统计学意义，背侧组要优于掌侧组；而在抗旋转方面，两组的扭转强度与扭转刚度差异均无统计学意义，但掌侧组在数据上均稍大于背侧组。

Objective To investigate the biomechanical differences in file aspects of anti-compression and anti-torsion of plate fixation applied through volar or dorsal approaches in the treatment of extra-articular distal radius fracture. Methods Dorsally comminuted distal radius fracture was created in 12 fresh cadaver radius specimens. The specimens were then randomly assigned to volar plating group and dorsal plating group, with 6 each. Plate fixation of the fracture was done via a volar approach and a dorsal approach respectively. Subsequently, each group was further divided into 2 subgroups to undergo axial compression and horizontal torsion test using MTS machine. The following parameters were measured： axial compression strength, axial compression rigidity, horizontal torsion strength, and horizontal torsion rigidity. Results The compression test showed statistically significant difference of compression strength between the volar and dorsal groups, that of the dorsal group being stronger. Similarly, there was statistically significant difference in the compression rigidity between these two groups, that of the dorsal group being stronger. In the torsion tests, however, we have noticed that although the torsion strength and rigidity of the volar group were slightly stronger than those of the dorsal group, the difference was not statistically significant. Conclusion Dorsal plating of dorsally comminuted distal radius fracture yields significantly stronger anti-compression features comparing to volar plating. The anti-torsion features between volar plating and dorsal plating are comparable although the parameters of volar plating are slightly stronger.