Background

Augmentation of the proximal femur with bone cement (femoroplasty) has been identified as a potential preventive approach to reduce the risk of fracture. Femoroplasty, however, is associated with a risk of thermal damage as well as the leakage of bone cement or blockage of blood supply when large volumes of cement are introduced inside the bone.

Methods

Six pairs of cadaveric femora were augmented using a newly proposed planning paradigm and an in-house navigation system to control the location and volume of the injected cement. To evaluate the risk of thermal damage, we recorded the peak temperature of bone at three regions of interest as well as the exposure time for temperature rise of 8 °C, 10 °C, and 12 °C in these regions. Augmentation was followed by mechanical testing to failure resembling a sideway fall on the greater trochanter.

Findings

Results of the fracture tests correlated with those of simulations for the yield load (R² = 0.77) and showed that femoroplasty can significantly improve the yield load (42%, P < 0.001) and yield energy (139%, P = 0.062) of the specimens. Meanwhile, temperature recordings of the bone surface showed that the areas close to the greater trochanter will be exposed to more critical temperature rise than the trochanteric crest and femoral neck areas.

Interpretation

The new planning paradigm offers a more efficient injection strategy with injection volume of 9.1 ml on average. Meanwhile, temperature recordings of bone surfaces suggest that risk of thermal necrosis remains as a concern with femoroplasty using Polymethylmethacrylate.

中文翻译：

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骨质疏松髋关节增强的生物力学指导规划和执行范例：生物力学和温升的实验评估

 背景

用骨水泥增强股骨近端（股骨成形术）已被认为是降低骨折风险的潜在预防方法。然而，股骨成形术存在热损伤的风险，并且当将大量骨水泥引入骨内时，还存在骨水泥泄漏或血液供应阻塞的风险。

 方法

使用新提出的规划范例和内部导航系统来增强六对尸体股骨，以控制注入水泥的位置和体积。为了评估热损伤的风险，我们记录了三个感兴趣区域的骨骼峰值温度以及这些区域温度升高 8 °C、10 °C 和 12 °C 的暴露时间。增强后进行机械测试，直至失败，类似于大转子侧向跌倒。

 发现

断裂试验结果与屈服载荷模拟结果相关（R ² = 0.77），表明股骨成形术可以显着提高屈服载荷（42%， P < 0.001）和屈服能量（139%， P = 0.062）的标本。同时，骨表面的温度记录显示，靠近大转子的区域将比转子嵴和股骨颈区域承受更临界的温升。

 解释

新的规划范例提供了更有效的注射策略，平均注射量为 9.1 毫升。同时，骨表面的温度记录表明，热坏死的风险仍然是使用聚甲基丙烯酸甲酯股骨成形术的一个问题。