胫骨平台后外侧髁解剖钢板的设计与生物力学研究

Biomechanical study of a self-designed anatomic plate for posterolateral tibial plateau

目的通过自制胫骨平台后外侧髁解剖钢板与传统钢板进行生物力学比较,为其治疗胫骨平台后外侧髁骨折提供科学依据。方法根据腓骨头上方区域的数据测量及三维CT分区,设计胫骨平台后外侧髁解剖钢板。选取12具新鲜冰冻下的成人尸体24侧膝关节,制作胫骨平台后外侧髁骨折模型,分3组(n=8):A组模拟腓骨头上方入路自体髂骨植骨后胫骨平台后外侧髁解剖钢板固定,B组模拟胫骨平台后侧入路自体髂骨植骨后小T型钢板固定,C组模拟腓骨头上方入路自体髂骨植骨后普通L型平台钢板固定。3组进行生物力学测试,记录500、1000、1500 N垂直压缩力载荷下劈裂骨块的垂直位移以及内固定物失效时(压缩位移达3 mm时)的最大压缩力。结果500、1000、1500 N垂直压缩力载荷下,A组、B组、C组劈裂骨块的垂直位移3组间比较差异有统计学意义(P<0.05);A组、B组分别与C组劈裂骨块的垂直位移比较差异均有统计学意义(P<0.05)。A组略优于B组,但差异无统计学意义(P>0.05)。A组、B组、C组骨块位移达3 mm时内固定物的失效载荷分别为(2576±126)、(2545±127)、(2067±146)N,3组间比较差异有统计学意义(P<0.05);A组、B组内固定物失效载荷分别与C组比较差异均有统计学意义(P<0.05),但A组与B组比较差异无统计学意义(P>0.05)。结论胫骨平台后外侧髁解剖钢板可对后外侧髁骨折块起到坚强的固定作用。

Objective To evaluate the biomechanical performance of our self-designed anatomical plate for posterolateral tibial plateau in comparison with conventional plates for treatment of posterolateral tibial plateau fractures.Methods A novel anatomic plate for posterolateral tibial plateau was designed according to the data measured in the superior fibular capitulum and 3D CT segmentation.Twenty-four knee joints were obtained from 12 freshly frozen adult cadavers to make models of posterolateral tibial plateau fracture.The models were divided into 3 groups(n=8).In group A,fixation was simulated via the supra-fibular-head approach after autogenous iliac bone-graft by our self-designed anatomic plate for posterolateral tibial plateau;in group B,fixation was simulated via the posterior tibial approach after autogenous iliac bone-graft by a small T-plate;in group C,fixation was simulated via the supra-fibular-head approach after autogenous iliac bone-graft by a normal L-plate.Biomechanical tests were carried out in the 3 groups to measure the vertical displacements of split bone fragment under the vertical compression loads of 500 N,1,000 N and 1,500 N and the maximum compression upon failure of internal fixation(compressed displacement=3 mm).Results At the vertical compression loads of 500 N,1,000 N and 1,500 N,the vertical displacements of split bone fragment showed significant differences among the 3 groups(P<0.05);there was a significant difference between group C and groups A and B,respectively(P<0.05),but an insignificant difference between group A and group B(P>0.05)though group A performed slightly better.In terms of the maximum compression upon failure of internal fixation,significant differences existed among the 3 groups(P<0.05);there was a significant difference between group C and groups A and B,respectively(P<0.05),but an insignificant difference between group A and group B(P>0.05).Conclusions Our self-designed anatomic plate for posterolateral tibial plateau can firmly fixate the fracture fragments of posterolateral condyle.