锁定钢板内置和外置固定Sanders Ⅱ型跟骨骨折的三维有限元分析

Finite element analysis of the calcaneal fractures of Sanders type Ⅱ fixed with locking plates in the internal and external position

目的通过三维有限元对锁定钢板内置和外置固定SandersⅡ型跟骨骨折的生物力学稳定性进行比较,为临床应用提供理论依据。方法建立SandersⅡ型跟骨骨折分别予以锁定钢板内置位固定和外置位固定的三维有限元模型,在相同条件下分别对锁定钢板两种不同固定模型加载,行线性有限元分析,分别计算两种固定模型的应力分布情况。结果在中立位载荷下两种固定模型跟骨骨折线最大位移均小于跟骨关节内骨折手术指征的骨折线分离或移位≥1 mm的标准;两种固定模型跟骨最大主应力峰值都主要位于跟骨结节周围皮质骨,均小于骨屈服强度95 Mpa;两种固定模型锁定钢板系统最大主应力峰值主要位于钢板中间部,均小于内固定失效强度225 MPa。结论锁定钢板内置与外置固定SandersⅡ型跟骨骨折,其生物力学稳定性都令人满意,而锁定钢板外置在临床上有着潜在的应用价值。

Objective To compare the biomechanical properties of the calcaneal fractures of Sanders type Ⅱ fixed with locking plates in the internal and external position using finite element（FE） analysis, and therefore to provide theoretic reference for clinic application. Methods 3D FE model of the calcaneal fractures of Sanders type Ⅱ fixed with locking plates in the internal and external position was constructed. The two fixation models were loaded under the same condition, and linear finite element analysis was carried out. The stress distribution in the two fixation models was calculated respectively. Results Under the neutral position load the maximum displacement of the fracture lines in the two fixation models were less than fracture lines displacement requirement greater than 1 mm;the peak value of the maximum principle stress of the calcaneus in the two fixation models,located mainly around the cortical bones of calcaneal tuberosity, were less than the yield strength of 95 Mpa; the peak value of the maximum principle stress of the locking plate in the two fixation models, mainly located in the middle section of the locking plate, were less than the internal fixation failure strength of 225 MPa. Conclusion The biomechanical stability is satisfactory for the treatment of the calcaneal fractures of Sanders type Ⅱ fixed with locking plates in the internal and external position.The latter have potential application in clinic compared with the former in the treatment of calcaneal fractures of Sanders type Ⅱ.