桡骨头骨折两种内固定方式的生物力学研究

A biomechanical study on two types of internal fixation for radial head fracture

[目的]探讨桡骨头骨折两种内固定的生物力学特性。寻找最佳内固定方法,为临床运用提供基础理论依据。[方法]20具人工桡骨制作桡骨头颈骨折模型,10具采用普通微型钢板固定(普通板组),另外10具采用解剖型钢板固定(解剖板组),分别进行轴向压缩应力强度和刚度、弯曲强度和挠度及扭转力学性能的生物力测试。比较两种内固定方式的优劣性。[结果]普通板组的轴向压缩强度显著低于解剖板组,差异有统计学意义(P<0.05)。普通板组的刚度显著低于解剖板组,两者刚度相差17%,差异有统计学意义(P<0.05)。普通板组与解剖板组的三点弯曲强度相差17%,差异有统计意义(P<0.05)。在相同载荷下,普通板组的挠度明显高于解剖板组,两者相差15%,差异有统计学意义(P<0.05)。普通板和解剖板两种不同型式钢板固定后,桡骨头的扭转强度和刚度恢复达90%以上。两组相比较,解剖板组的扭转强度高于普通板组,达18%,扭转刚度达13%,差异有统计学意义(P<0.05)。[结论]桡骨头骨折采用解剖型钢板固定较采用普通钢板具有生物力学优势,是一种比较理想的内固定方式。

[Objective] To investigate the biomechanical characteristics of two types of internal fixation for radial head fracture, and to find out the better fixation procedure. [Method] Twenty artificial radius were divided into the two groups with 10 in each group. After making radial neck fracture models, 10 samples were fixed with the conventional plate （the conventional group）, while the remaining 10 samples fixed with the anatomic plate （the anatomic group） . The biomechanical characters, including axial compression strength and stiffness, bending strength and deflection, as well as torsion strength, were assessed and compared between the two groups. [Results] The conventional group had statistically inferior axial compression strength to the anatomic group （P〈0.05） , additionally, the former proved 17% less stiffness than the latter, which was statistically significant （P〈0.05） . Regarding to three point bending test, the conventional group had 17% less bending strength whereas 15% more deflection than the anatomic group with significant differences （P〈0.05）. After fixation with both the conventional plate and anatomic plate, the torsion strength recovered to more than 90% of normal control, however, the conventional group was proved 18% less torsion strength and 13% less torsion stiffness than the anatomic group with significant differences （P〈0.05）. [Conclusion] For fixation of radial head fracture, this anatomic plate has significant advantage in biomechanical properties over the conventional plate.