固定器刚度对不同类型骨折愈合的影响

目的 系统探讨固定器刚度变化（0.05~7.50 kN/mm）对AO/OTA分型下7种不同类型骨折（A1：简单螺旋、A2：简单斜形、A3：简单横形、B2：楔形螺旋形、B3：楔形碎片形、C2：复杂多段、C3：复杂不规则）愈合效果的影响。方法 以长骨骨折髓内钉固定为研究对象，基于应变调控组织分化理论，结合模糊逻辑控制算法和有限元分析技术，数值模拟骨折愈合过程。结果 中等固定器刚度（1.5~2.5 kN/mm）可以在保证骨折生物力学性能恢复的情况下缩短愈合时间。但是，每种骨折类型对应的适宜刚度不尽相同，且其愈合效果对固定器刚度变化的敏感度不一。对于A型骨折，当固定器刚度为1.5 kN/mm时，骨折断端生物力学性能恢复最佳，并且固定器刚度变化对愈合效果影响较大；对于B、C型骨折，当固定器刚度在1.5 kN/mm以上时，刚度变化对生物力学性能恢复没有显著影响。结论 骨折愈合效果受固定器刚度和骨折类型的共同影响。在临床骨折治疗中，固定器的选用应充分考虑骨折类型。

Effects of Fixator Stiffness on Healing of Fracture with Different Types

Objective To systematically explore the change of fixator stiffness (0.05-7.50 kN/mm) on healing effects of seven different types of fractures (A1: simple spiral, A2: simple oblique, A3: simple transverse; B2: wedge spiral, B3: wedge fragmented; C2: complex segment, C3: complex irregular) under the OTA/AO fracture classification. Methods Taking intramedullary nail fixation of long bone fracture as research objective, based on strain-regulated tissue differentiation theory, and combined with fuzzy logic algorithm and finite element analysis, the process of fracture healing was numerically simulated. Results Moderate fixator stiffness (1.5-2.5 kN/mm) shortened the healing time while ensuring recovery of biomechanical performance of the fractured bone. However, the appropriate fixator stiffness corresponding to each fracture type was different. The sensitivity of healing effects to change of fixator stiffness was also different. For type A fracture, when fixator stiffness was 1.5 kN/mm, optimal biomechanical recovery of the fractured site could be obtained, while the change in fixator stiffness had a large impact on healing effect. For type B and C fractures, when fixator stiffness was above 1.5 kN/mm, the change in fixator stiffness had no significant effects on recovery of biomechanical performance. Conclusions Fracture healing is affected by both fixator stiffness and fracture types. For treating fractures in clinic, the selection of fixators should carefully take fracture types into account.