Vom Scheidt Annika, Pirrung Felix, Henyš Petr, Oppelt Birgit, Leithner Andreas, Hammer Niels, Bergovec Marko
Department of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Auenbruggerplatz 25, 8036, Graz, Austria.
Institute of New Technologies and Applied Informatics, Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Studentská 1402/2, Liberec, 461 17, Czech Republic.
J Mech Behav Biomed Mater. 2025 Jan;161:106798. doi: 10.1016/j.jmbbm.2024.106798. Epub 2024 Nov 3.
Surgical treatments of benign primary bone tumors of the femur face the challenge of limiting tissue damage and contamination while providing sufficient stabilization to avoid fracture. While no clear treatment guidelines exist, surgical treatment commonly consists of femoral fenestration and curettage with optional filling and plating of the defect. Mono- or bicortical plating of distal femoral defects aim to reduce fracture risk and have been shown to increase axial stability. However, it remains unclear whether plating increases torsional stability of the affected femur.
QUESTIONS/PURPOSES: This biomechanical study aimed to determine how much additional stability can be achieved by mono- or bicortical plating of femoral defects after fenestration. The following hypotheses were investigated: 1. Preventive plating of distal femur bone defects enhances torsional stability when compared to femoral fenestration alone. 2. A condition close to the intact (nonpathological) bone can be achieved by bone plating. 3. Defect shape influences torsional stability.
Thiel embalmed human femora (n = 24) were left intact or subjected to the following surgical treatments (A) defect creation via fenestration, (B) defect with short monocortical plating, (C) defect with long bicortical plating. All femora were torsion tested in midstance position using pre-cycling and testing until failure. Quantitative computed tomography pre and post testing allowed bone mineral density calculation and crack path analysis. Finite element analysis provided insight into defect shape variations.
Torsion experiments showed no relevant enhancement of torsional stability due to mono- or bicortical plating. There were no significant differences in maximum torque between unplated and plated femora with defect (defect: 35.38 ± 7.53 Nm, monocortical plating: 37.77 ± 9.82 Nm, bicortical plating: 50.27 ± 9.72 Nm, p > 0.05). Maximum torque for all treatment groups was significantly lower compared to intact femora (155-200 Nm, p < 0.001). Cracks originated predominantly from the proximal posterior corner of the defect and intersected with screw holes in plated femora. The influence of variations of the defect corner shapes had no significant influence on maximum torque and angle.
This biomechanical study shows that mono- or bicortical plating is not an effective preventive treatment against torsional failure of femora with distal defects as the resulting maximum torque was drastically reduced compared to intact femora. Thus, the initial hypotheses have to be rejected. As habitual loading of the femur includes a combination of axial and torsional loading, the observed lack of prevention against torsional failure might help to explain the occurrence of fractures despite plating. Future research towards ameliorating clinical outcome should address the role of defect filling with bone cement or bone grafts regarding the improvement of torsional stability after primary bone tumor treatment in the femur.
股骨原发性良性骨肿瘤的手术治疗面临着限制组织损伤和污染，同时提供足够稳定性以避免骨折的挑战。虽然目前尚无明确的治疗指南，但手术治疗通常包括股骨开窗刮除术，并可选择对缺损处进行填充和钢板固定。股骨远端缺损的单皮质或双皮质钢板固定旨在降低骨折风险，且已被证明可增加轴向稳定性。然而，钢板固定是否能增加患侧股骨的扭转稳定性仍不清楚。
问题/目的：本生物力学研究旨在确定股骨开窗术后单皮质或双皮质钢板固定能额外增加多少稳定性。研究了以下假设：1. 与单纯股骨开窗相比，预防性钢板固定股骨远端骨缺损可增强扭转稳定性。2. 通过钢板固定可实现接近完整（非病理）骨的状态。3. 缺损形状影响扭转稳定性。
选用经蒂尔氏防腐处理的人股骨（n = 24），保持完整或进行以下手术治疗：(A) 开窗造缺损；(B) 短单皮质钢板固定缺损；(C) 长双皮质钢板固定缺损。所有股骨均在站立中期位置进行预循环和测试直至失效的扭转试验。定量计算机断层扫描在测试前后进行，以计算骨密度并分析裂纹路径。有限元分析有助于了解缺损形状的变化。
扭转试验表明，单皮质或双皮质钢板固定并未显著增强扭转稳定性。有缺损的未固定和固定钢板的股骨之间的最大扭矩无显著差异（缺损：35.38 ± 7.53 N·m，单皮质钢板固定：37.77 ± 9.82 N·m，双皮质钢板固定：50.27 ± 9.72 N·m，p > 0.05）。所有治疗组的最大扭矩均显著低于完整股骨（155 - 200 N·m，p < 0.001）。裂纹主要起源于缺损的近端后角，并与固定钢板股骨上的螺钉孔相交。缺损角形状的变化对最大扭矩和角度无显著影响。
本生物力学研究表明，单皮质或双皮质钢板固定并非预防股骨远端缺损扭转失效的有效治疗方法，因为与完整股骨相比，其产生的最大扭矩大幅降低。因此，最初的假设必须被否定。由于股骨的习惯性负荷包括轴向和扭转负荷的组合，观察到的对扭转失效缺乏预防作用可能有助于解释尽管进行了钢板固定仍会发生骨折的现象。未来旨在改善临床结果的研究应探讨骨水泥或骨移植填充缺损在改善股骨原发性骨肿瘤治疗后扭转稳定性方面的作用。
