桡骨远端钢板联合拉力钉固定治疗Sander Ⅲ型跟骨骨折的生物力学分析

Biomechanical analysis of combining distal radius plate with transfixation screw for Sanders Ⅲ calcaneal fracture

提出并分析桡骨远端钢板(两点支撑)联合拉力钉固定治疗跟骨骨折的生物力学稳定性。在完整下肢骨骼-肌肉有限元模型的基础上,建立Sanders III型跟骨骨折模型并模拟固定,用桡骨远端钢板(两点支撑)联合拉力钉固定治疗骨折。评估该模型在静态站立和行走状态(足跟着地期、站立中期和推离期)的应力分布和位移情况。跟骨的应力集中于骨折端、跟骨与跟腱连接处,峰值为96.92 MPa。内固定的应力集中于钢板螺钉与载距突和跟骨结节接触位置,峰值为883.20 MPa。后关节面位移、Bohler角和Gissane's角均维持较好。桡骨远端钢板联合拉力钉固定治疗跟骨骨折具有良好的生物力学稳定性,体现微创原则,操作简单,术后可以早期康复训练,值得临床推广应用。

A combination of distal radius plate(two-point fixation mechanism) and transfixation screw for the treatment of Sanders Ⅲ calcaneal fractures is proposed, and its biomechanical stability is evaluated. Based on the skeleton-muscle finite element model of the lower extremity, a model of Sanders Ⅲ calcaneal fracture is established, and then fixed by distal radius plate(two-point fixation mechanism) combined with transfixation screw. The biomechanical performances of the fracture model during static standing and 3 gait phases(heel-strike, mid-stance and push-off) are analyzed in terms of stress distribution and fracture displacement. The stress of the calcaneus under load condition concentrates on the junction of fracture end, calcaneus and Achilles tendon, with a peak value of 96.92 MPa, while the stress of the internal implant concentrates on the position where plate screw is in contact with sustentaculum tail and calcaneal tubercle, with a peak value of 883.20 MPa. The posterior articular displacement,Bohler’s Angle and Gissane’s Angle all maintain at a good condition. The combination of distal radius plate and transfixation screw for the treatment of calcaneal fracture has the advantages of sufficient biomechanical stability, minimal invasion and simple operation, and it can further facilitate early postoperative rehabilitation training. The proposed approach can serve as a new recommended fixation modality for the treatment of Sanders Ⅲ calcaneal fracture, worthy of clinical application.