Mechanical Engineering, School of Engineering, The University of Edinburgh, UK.
Department of Orthopaedics, Royal Infirmary of Edinburgh, UK.
J Orthop Res. 2021 Mar;39(3):628-636. doi: 10.1002/jor.24704. Epub 2020 May 7.
At the time of medial opening wedge high tibial osteotomy (HTO) to realign the lower limb and offload medial compartment knee osteoarthritis, unwanted fractures can propagate from the osteotomy apex. The aim of this study was to use finite element (FE) analysis to determine the effect of hinge location and apical drill holes on cortical stresses and strains in HTO. A monoplanar medial opening wedge HTO was created above the tibial tuberosity in a composite tibia. Using the FE method, intact lateral hinges of different widths were considered (5, 7.5, and 10 mm). Additional apical drill holes (2, 4, and 6 mm diameters) were then incorporated into the 10 mm hinge model. The primary outcome measure was the maximum principal strain in the cortical bone surrounding the hinge axis. Secondary outcomes included the force required for osteotomy opening, minimum principal strain, and mean cortical bone stresses (maximum principal/minimum principal/von Mises). Larger intact hinges (10 mm) were associated with higher cortical bone maximum principal strain and stress, lower minimum principal strain/stress, and required greater force to open. Lateral cortex strain concentrations were present in all scenarios, but extended to the joint surface with the 10 mm hinge. Apical drill holes reduced the mean cortical bone maximum principal strain adjacent to the hinge axis: 2 mm hole 6% reduction; 4 mm 35% reduction; and 6 mm 55% reduction. Incorporating a 4-mm apical drill hole centered 10 mm from the intact lateral cortex maintains a cortical bone hinge, minimizes cortical bone strains and reduces the force required to open the HTO; thus improving control.
在进行内侧开放楔形胫骨高位截骨术（HTO）以矫正下肢和减轻内侧间室膝关节骨关节炎的负荷时，不希望的骨折可能会从截骨顶点传播。本研究的目的是使用有限元（FE）分析来确定铰链位置和顶点钻孔对 HTO 皮质骨的应力和应变的影响。在复合材料胫骨上方的胫骨结节处创建了单平面内侧开放楔形 HTO。使用 FE 方法，考虑了不同宽度的完整外侧铰链（5、7.5 和 10mm）。然后，在 10mm 铰链模型中加入了额外的顶点钻孔（2、4 和 6mm 直径）。主要结果测量指标是围绕铰链轴的皮质骨的最大主应变。次要结果包括截骨开口所需的力、最小主应变和平均皮质骨应力（最大主/最小主/冯·米塞斯）。较大的完整铰链（10mm）与较高的皮质骨最大主应变和应力、较低的最小主应变/应力以及更大的开口力相关。在所有情况下都存在外侧皮质应变集中，但在 10mm 铰链处延伸到关节表面。顶点钻孔减少了靠近铰链轴的皮质骨平均最大主应变：2mm 孔减少 6%；4mm 减少 35%；6mm 减少 55%。在距完整外侧皮质 10mm 处中心有 4mm 顶点钻孔的情况下，保留了皮质骨铰链，最小化了皮质骨应变并减少了打开 HTO 所需的力；从而改善了控制。
