上下肢体中骨整合假体固定的刚度和极限载荷。
Stiffness and ultimate load of osseointegrated prosthesis fixations in the upper and lower extremity.
机构信息
Laboratory for Biomechanics and Biomaterials, Department of Orthopaedics, Hannover Medical School, Anna-von-Borries-Str, 1-7, 30625 Hannover, Germany.
出版信息
Biomed Eng Online. 2013 Jul 11;12:70. doi: 10.1186/1475-925X-12-70.
BACKGROUND
Techniques for the skeletal attachment of amputation-prostheses have been developed over recent decades. This type of attachment has only been performed on a small number of patients. It poses various potential advantages compared to conventional treatment with a socket, but is also associated with an increased risk of bone or implant-bone interface fracture in the case of a fall. We therefore investigated the bending stiffness and ultimate bending moment of such devices implanted in human and synthetic bones.
METHODS
Eight human specimens and 16 synthetic models of the proximal femora were implanted with lower extremity prostheses and eight human specimens and six synthetic humeri were implanted with upper extremity prostheses. They were dissected according to typical amputation levels and underwent loading in a material testing machine in a four-point bending setup. Bending stiffness, ultimate bending moment and fracture modes were determined in a load to failure experiment. Additionally, axial pull-out was performed on eight synthetic specimens of the lower extremity.
RESULTS
Maximum bending moment of the synthetic femora was 160.6±27.5 Nm, the flexural rigidity of the synthetic femora was 189.0±22.6 Nm2. Maximum bending moment of the human femora was 100.4±38.5 Nm, and the flexural rigidity was 137.8±29.4 Nm2. The maximum bending moment of the six synthetic humeri was 104.9±19.0 Nm, and the flexural rigidity was 63.7±3.6 Nm2. For the human humeri the maximum bending moment was 36.7±11.0 Nm, and the flexural rigidity at was 43.7±10.5 Nm2. The maximum pull-out force for the eight synthetic femora was 3571±919 N.
CONCLUSION
Significant differences were found between human and synthetic specimens of the lower and upper extremity regarding maximum bending moment, bending displacement and flexural rigidity. The results of this study are relevant with respect to previous finding regarding the load at the interfaces of osseointegrated prosthesis fixation devices and are crucial for the development of safety devices intended to protect the bone-implant interface from damaging loadings.
背景
近年来，已经开发出了用于截肢假体骨骼附着的技术。这种类型的附着仅在少数患者中进行过。与使用插座的传统治疗相比，它具有各种潜在的优势，但在跌倒的情况下，也存在骨骼或植入物-骨骼界面骨折的风险增加。因此，我们研究了植入人体和合成骨中的此类设备的弯曲刚度和极限弯曲力矩。
方法
将 8 个人体标本和 16 个人工股骨模型植入下肢假体，将 8 个人体标本和 6 个人工肱骨植入上肢假体。根据典型的截肢水平对其进行解剖，并在四点弯曲装置中在材料试验机上进行加载。在失效试验中确定弯曲刚度、极限弯曲力矩和断裂模式。此外，还对 8 个人工下肢标本进行了轴向拔出试验。
结果
合成股骨的最大弯曲力矩为 160.6±27.5 Nm，合成股骨的弯曲刚度为 189.0±22.6 Nm2。人体股骨的最大弯曲力矩为 100.4±38.5 Nm，弯曲刚度为 137.8±29.4 Nm2。六个人工肱骨的最大弯曲力矩为 104.9±19.0 Nm，弯曲刚度为 63.7±3.6 Nm2。对于人体肱骨，最大弯曲力矩为 36.7±11.0 Nm，弯曲刚度为 43.7±10.5 Nm2。八个人工股骨的最大拔出力为 3571±919 N。
结论
在下肢和上肢的人体和合成标本中，最大弯曲力矩、弯曲位移和弯曲刚度都有显著差异。本研究的结果与先前关于骨整合假体固定装置界面处的负载的研究结果有关，对于开发旨在保护骨-植入物界面免受破坏性负载的安全装置至关重要。
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