BACKGROUND:Klinefelter nails and external fixation were commonly used treatment methods for Bennett fracture, but study about biomechanics of two methods was little. OBJECTIVE:To establish three-dimensional finite element models of Bennett fracture by Klinefelter nails and external fixation, and analyze its biomechanics. METHODS:Three-dimensional models of Bennett fracture were established by smal external fixation and Kirschner nail treatment. The Bennett fracture models established by smal external fixation treatment were considered as model A. Bennett fracture models established by Kirschner nail treatment were considered as model B. 120 N load was applied to the first metacarpal X-axis direction. The X-direction displacement and total displacement of model A and model B, and the fracture fragments stress of model A and model B were observed. RESULTS AND CONCLUSION:(1) In the X direction, the absolute values of maximum displacement and minimum displacement of model A at proximal fragment and distal fragment were less than model B;the maximum relative displacement, minimum relative displacement and average relative displacement of model A were less than model B. The differences of the average displacement of the proximal fracture fragment and the distal fragment, and the relative mean displacement in two models were statistical y significant (P<0.05). (2) In total displacement, absolute values of the maximum displacement and minimum displacement of model A at proximal fragment were less than model B;absolute values of the maximum displacement and minimum displacement of model A at distal fragment were less than model B;the maximum relative displacement, minimum relative displacement and average relative displacement of model A were less than model B. The differences of the average displacement of the proximal fracture fragment and the distal fragment, and the relative mean displacement in two models were statistical y significant (P<0.05). (3) The maximum stress value, a minimum stress value and the average stress values of fracture fragments of model A were significantly smal er than model B. The difference of the mean stress value in two models was statistical y significant (P<0.05). (4) These findings showed that the X-direction displacement and the total displacement were smal er, and the fracture fragments stress was uniform in smal external fixation and Kirschner nail treatment for Bennett fracture, indicating that smal external fixation for Bennett fracture has more advantages compared with Klinefelter nail.%背景：克氏钉和外固定支架是修复Bennett骨折比较常用的方法，但关于两者生物力学比较的研究不多。目的：建立Bennett骨折克氏钉内固定和外固定架治疗的三维有限元模型，对其进行生物力学分析。 方法：建立Bennett骨折微型外固定支架和克氏钉内固定治疗三维模型，将Bennett骨折微型外固定支架治疗模型设为A模型，将Bennett骨折克氏钉内固定模型设为B模型。在第一掌骨沿X轴方向施加120 N的载荷。观察A模型和B模型在X轴方向的位移情况、总位移情况以及骨折断端应力值变化。 结果与结论：①在X轴方向上，A模型近端骨折块、远端骨折块的最大位移和最小位移的绝对值小于B模型， A模型最大相对位移、最小相对位移和平均相对位移小于B模型，两模型近端骨折块、远端骨折块的平均位移及相对平均位移比较差异均有显著性意义(P<0.05)；②在总位移方面，A模型近端骨折块的最大位移和最小位移的绝对值小于B模型，A模型远端骨折块的最大位移和最小位移的绝对值小于B模型，A模型最大相对位移、最小相对位移和平均相对位移均明显小于B模型，两模型近端骨折块、远端骨折块的平均位移及相对平均位移比较差异均有显著性意义(P<0.05)；③A模型骨折断端的最大应力值、最小应力值和平均应力值均明显小于B模型骨折断端，两模型平均应力值比较差异有显著性意义(P<0.05)；④结果表明，微型外固定支架治疗Bennett骨折在X轴方向上的位移及总位移小，骨折断端的应力分布均匀，提示微型外固定支架治疗Bennett骨折较克氏钉内固定更具优势。
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