一种新型髌骨骨折内固定装置的生物力学特点

A New Internal Fixation of Patella Fractures: a Biomechanical Investigation

目的探讨一种以双空心套筒替代传统克氏针的新型髌骨骨折内固定装置的生物力学特点。方法截取8具新鲜冰冻尸体正常膝关节标本16个,按均衡原则分两组,每组8例标本,建立同一标准的髌骨骨折创伤模型,同一标本左右髌骨骨折固定方式不同,分别以双空心套筒钢丝张力带和改良AO克氏针钢丝张力带固定,测试不同方式固定下骨折断端间压力、反复伸曲运动时骨折间位移程度及内固定损坏时内固定承受的最大负载。结果不同方式固定的两组在屈膝90°和伸直位时骨折间压力及疲劳试验中骨折前缘和关节缘的分离移位差异有统计学意义,套筒组优于克氏针组,但膝关节伸直位时骨折端前后方向位移无统计学差异。结论双空心套筒与改良AO钢丝张力带固定髌骨骨折相比较,前者更加符合滑动加压的钢丝张力带固定原理,因而具备更好的稳定性和抗疲劳性,生物力学优势明显。

Objective To compare the biomeehanical properties of tension bands made up with wires and k-wires and double hollow sleeves in internal fixation of patella fractures. Methods Sixteen cadaveric knees were divided to 2 transverse patella fracture fixation groups：tension vands of wires combined with Kirschner wires or double hollow sleeves. Biomechanical stability were tested by fracture gaps after the repetitive testing of 200th cycles knee motion from 90°flexion to full extension and interfragmentary compression as well as the biggest loads. Results Interfragmentary compression and the biggest loads of double hollow sleeves group were bigger than the Kirschner wires group. Fracture gaps of double hollow sleeves group were smaller. Conclusion In contrast to modified anterior tension wiring with Kirschner wires, tension bands of wires combined with double hollow sleeves is a better fixation device to stabilize transverse patella frac, tures securely and sustainably.