Department of Orthopedic Surgery, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX; and.
Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL.
J Orthop Trauma. 2024 Sep 1;38(9):491-496. doi: 10.1097/BOT.0000000000002864.
Prophylactic cerclage cables are often placed intraoperatively about a fracture to prevent propagation. However, biomechanical data supporting optimal cable placement location are lacking. The objective of this study was to evaluate the impact of prophylactic cerclage placement location on the propagation of femoral shaft fractures.
The diaphysis of 14 fresh-frozen cadaveric femora were included. Volumetric bone mineral density in the femoral shaft was obtained from quantitative computed tomography scans. For each specimen, a 5-mm longitudinal fracture was created proximally to simulate a pre-existing fracture. After reaming of the femoral canal, a 3 degrees tapered wedge was advanced with an MTS machine at 0.2 mm/s until failure. The tests were conducted with a CoCr cable placed at varying distances (5 mm, 10 mm, 15 mm, 20 mm, and cableless) from the distal tip of the initial fracture. A compression loadcell was used to measure the cable tension during the tests. The axial force, displacement, and cable tension were monitored for comparison between groups.
In the cableless group, the mean force needed to propagate the fracture was 1017.8 ± 450.3 N. With the addition of a cable at 5 mm below the fracture, the failure force nearly doubled to 1970.4 ± 801.1 N (P < 0.001). This also led to significant increases in stiffness (P = 0.006) and total work (P = 0.001) when compared with the control group. By contrast, in the 15 and 20 mm groups, there were no significant changes in the failure force, stiffness, and total work as compared with the control group (P > 0.05).
Propagation of femoral shaft fracture was effectively resisted when a prophylactic cable was placed within 5 mm from the initial fracture, whereas cables placed more than 10 mm below the initial fracture were not effective in preventing fracture propagation.
预防性环扎线通常在手术中围绕骨折部位放置，以防止其扩展。然而，目前缺乏支持最佳电缆放置位置的生物力学数据。本研究的目的是评估预防性环扎位置对股骨干骨折扩展的影响。
本研究纳入了 14 例新鲜冷冻的尸体股骨。通过定量 CT 扫描获得股骨干的体积骨密度。对于每个标本，在近端创建 5mm 的纵向骨折以模拟预先存在的骨折。在股骨管扩孔后，使用 MTS 机器以 0.2mm/s 的速度推进一个 3 度锥形楔形物，直到发生故障。使用 CoCr 电缆在距初始骨折远端尖端不同距离（5mm、10mm、15mm、20mm 和无电缆）处进行测试。使用压缩负荷传感器测量测试过程中的电缆张力。比较各组之间的轴向力、位移和电缆张力。
在无电缆组中，需要 1017.8±450.3N 的力来扩展骨折。在骨折下方 5mm 处增加电缆时，断裂力几乎增加了一倍，达到 1970.4±801.1N（P<0.001）。与对照组相比，这也导致刚度（P=0.006）和总功（P=0.001）显著增加。相比之下，在 15mm 和 20mm 组中，与对照组相比，断裂力、刚度和总功没有显著变化（P>0.05）。
当预防性电缆放置在初始骨折 5mm 范围内时，股骨干骨折的扩展得到有效抵抗，而放置在初始骨折下方 10mm 以上的电缆在防止骨折扩展方面无效。
