Biomechanical Engineering Group, Department of Biomedical Engineering, Amirkabir University of Technology, Hafez Avenue, Tehran, 15875, Iran.
Eur J Orthop Surg Traumatol. 2024 Jul;34(5):2717-2722. doi: 10.1007/s00590-024-03935-5. Epub 2024 May 18.
Lateral hinge fractures are the main complications in the high tibial osteotomy to treat varus deformities. The aim of present study is to answer the question whether the lateral hinge length (H) has an effect on the type of fracture and required force during the opening in high tibia osteotomy. It was hypothesized in this comparative research that extending the hinge length increased opening force and probability of a type II and type III fractures.
A monoplanar medial open wedge osteotomy with different intact hinge lengths varying from 9 to 32 mm was performed in 20 ostrich bones. A biomechanical experiment using unidirectional tensile testing apparatus was performed to open the wedge, and the required force was increased until a 10 mm opening was reached; then, the presence of fracture in the lateral cortex and its direction were evaluated. Lateral hinge fracture type based on direction was classified as suggested by Takeuchi et al.
Fracture that grows along the osteotomy line (type I) was observed in 4 samples with the mean hinge length (H) of 11 ± 1.54 mm. For seven bones with Takeuchi fracture type II, with downward crack propagation, the mean H was 16 ± 3.36 mm. For the mean H of 25 ± 6.53 mm, the crack propagated upward to the cutting path, displaying a Takeuchi type III fracture in seven samples. The statistical analysis showed that the fracture type significantly depends on the hinge length (P value < 0.05). Also, the mean opening force significantly increased with hinge lengthening (P value < 0.05). The peak forces at crack initiation were 41.8 ± 21.9, 115.2 ± 41.5, and 167 ± 135.3 N, respectively, for the fracture types I, II, and III samples.
The lateral cortical hinge length was significantly associated with hinge fracture type. The experimental tests indicated that the hinge lengthening increases the risk of type II and III fractures, as classified by Takeuchi.
高位胫骨截骨术治疗内翻畸形的主要并发症是外侧铰链骨折。本研究旨在回答外侧铰链长度（H）是否会影响胫骨高位截骨术中骨折类型和开口所需力的问题。本研究假设，延长铰链长度会增加开口力，并增加 II 型和 III 型骨折的发生概率。
在 20 个鸵鸟骨中进行了单平面内侧开放式楔形截骨术，不同完整铰链长度从 9 到 32mm 不等。使用单向拉伸测试装置进行生物力学实验以打开楔形，直到达到 10mm 的开口，然后评估外侧皮质骨折的存在及其方向。根据 Takeuchi 等人的建议，根据方向将外侧铰链骨折类型分类。
在铰链长度（H）平均值为 11±1.54mm 的 4 个样本中观察到沿截骨线生长的骨折（I 型）。对于 7 个具有向下裂纹扩展的 Takeuchi II 型骨折骨，H 的平均值为 16±3.36mm。对于 H 的平均值为 25±6.53mm 的 7 个样本，裂纹向上传播到切割路径，呈现 Takeuchi 型 III 骨折。统计分析表明，骨折类型与铰链长度显著相关（P 值<0.05）。此外，随着铰链长度的增加，开口力的平均值显著增加（P 值<0.05）。在裂纹起始时的峰值力分别为 I、II 和 III 型骨折样本的 41.8±21.9、115.2±41.5 和 167±135.3N。
外侧皮质铰链长度与铰链骨折类型显著相关。实验测试表明，铰链延长会增加 Takeuchi 分类的 II 型和 III 型骨折的风险。
