Objective The aim of this study was to compare the biomechanical properties of a hybrid external skeletal fixator (HESF) construct to the placement of paired interfragmentary Kirschner wires alone, and pin and tension band wire (PTBW) fixation for the stabilization of simulated tibial tuberosity fractures in dogs.

Study Design Tibias were harvested from 12 skeletally mature dog cadavers weighing 20 to 30 kg. An osteotomy was made through the base of the tibial tuberosity, which was subsequently repaired with either paired Kirschner wires, PTBW fixation or a HESF. A tensile load was applied to the tibial tuberosity until failure occurred. Mode of failure was described and biomechanical parameters obtained were compared between fixation groups.

Results The PTBW fixation and HESF construct afforded greater stiffness and load at 3 mm of axial displacement compared with fixation with Kirschner wires alone. There was no significant difference in stiffness and load at 3 mm displacement between PTBW and HESF fixation. Failure occurred by bending and pullout of the Kirschner wires for all fixation groups, preceded by untwisting of the knot in PTBW specimens.

Conclusion The HESF may provide a favourable alternative to PTBW fixation for tibial tuberosity avulsion fracture stabilization in dogs with substantial remaining growth potential.

目的 本研究的目的是比较混合外骨骼固定器 (HESF) 结构与单独放置成对断片间克氏针和针张力带线 (PTBW) 固定以稳定模拟胫骨粗隆骨折的生物力学特性在狗。

研究设计 Tibias 取自 12 具骨骼成熟的狗尸体，重 20 至 30 公斤。通过胫骨结节的基部进行截骨术，随后用成对的克氏针、PTBW 固定或 HESF 进行修复。向胫骨结节施加拉伸载荷直至发生故障。描述了失败模式，并比较了固定组之间获得的生物力学参数。

结果 与单独使用克氏针固定相比，PTBW 固定和 HESF 结构在轴向位移 3 毫米时提供了更大的刚度和负载。PTBW 和 HESF 固定之间在 3 mm 位移时的刚度和负载没有显着差异。所有固定组的克氏针弯曲和拉出导致失败，然后解开 PTBW 标本中的结。

结论 HESF 可能为 PTBW 固定提供一种有利的替代方法，用于稳定具有大量剩余生长潜力的狗的胫骨结节撕脱骨折。