植入物在骨科手术治疗中应用十分广泛，它们植入人体后与人体骨骼形成耦合结构，共同承担人体载荷。植入式假肢作为一种新型假肢，通过连接体内骨骼和体外假肢弥补了截肢患者残缺肢体的力学功能。然而，植入物失效会给患者生活造成严重影响，植入物-骨耦合结构中应力遮挡、骨骼二次损伤等问题亟待解决。因此，开展植入物-骨耦合结构力学研究、研发假肢植入体技术具有重要科学意义及工程应用价值。

本文利用生物力学试验及有限元模拟对常见植入物-骨耦合结构的界面及结构力学性能进行了研究，分析了骨整合效应对界面结合强度的影响以及螺钉分布对应力遮挡程度的影响。考虑到现有的界面承载或螺钉承载模式的植入式假肢对骨有较大的应力遮挡，本文研制了一种新型假肢植入体结构，并对假肢植入体-骨耦合结构的压缩、弯曲、扭转力学性能进行了研究。该结构采用骨端面承载，应力遮挡程度小；通过箍圈箍紧骨末端，提高骨末端抗劈裂能力；使用销钉使耦合结构具备抗扭能力，且体内界面生长可增强扭转稳定性。本文的主要研究内容有：

（1）螺钉-兔胫骨耦合结构界面力学性能分析。以螺钉-兔胫骨结构为例，通过压出试验测得螺钉压出力，分析了骨整合和初始松动对界面结合强度的影响。研究表明骨整合能有效提高植入物-骨界面结合强度，初始松动则会使界面结合强度明显降低。

（2）接骨板-人体股骨耦合结构应力遮挡研究。以锁定接骨板固定粉碎性骨折为例，通过有限元模拟分析了压缩工况下不同螺钉分布时接骨板-股骨耦合结构的应力遮挡程度。结果显示：螺钉分布能够明显影响结构的应力遮挡程度；Z型并联管中流量分布规律与内固定载荷分配规律有较高一致性，可以作为描述内固定应力遮挡的一种新方式。

（3）新型假肢植入体技术研制及假肢植入体-人体股骨耦合结构力学性能研究。研发了一种新型假肢植入体，使骨端面承担人体重量，箍圈提高骨末端抗劈裂能力，销钉和植入物-骨界面抗扭。通过力学试验和有限元模拟研究了假肢植入体-人体模型股骨耦合结构在压缩、弯曲和扭转工况下的力学性能，结果显示，本文研制的假肢植入体结构能够提供良好的压缩、弯曲和扭转稳定性，应力遮挡度小，且能够有效降低残骨末端劈裂风险。

（4）假肢植入体-羊胫骨耦合结构力学性能研究。通过力学试验和有限元模拟研究了压缩、弯曲和扭转工况下假肢植入体-羊胫骨耦合结构的力学性能，结果显示新型假肢植入体在羊胫骨中也能提供良好的抗压、抗弯和抗扭能力。本部分研究的样品为真实的羊尸体骨，为后期进一步进行动物体内实验做准备。

Implants are widely used in orthopedic surgery. After implanted into the body, they form a coupling structure with the human skeleton to share the human load. As a new type of prosthesis, implantable prosthesis makes up for the mechanical function of the missing limbs of amputees by connecting the internal skeleton and external prosthesis. However, implant failure has a serious impact on patients' life, and problems such as stress shielding and secondary bone damage in implant-bone coupling structure need to be solved urgently. Therefore, it is of great scientific significance and engineering application value to carry out the research of implant-bone coupling structure mechanics and develop prosthesis implant technology.

In this thesis, the interface and structure mechanical properties of common implant-bone coupling structures were studied by biomechanical tests and finite element method. The influence of osseointegration on interface strength and the influence of screw distribution on stress shielding degree were analyzed. Considering that the existing implants in the case of interface or screw bearing load have a large stress shielding on the bone, a new prosthesis implant structure was developed in this thesis. In addition, the compression, bending and torsion mechanical properties of the prosthesis implant-bone coupling structure were studied. The structure adopted bone end face to bear the weight of human body, and the stress shielding degree was small. The anti-splitting ability of the bone end was improved by tightening the bone end with a hoop. The use of pins provided the coupling structure with torsional resistance, and internal interface growth would enhance torsional stability. The research was mainly carried out from the following aspects:

(1) Study on interface mechanical properties of screw-rabbit tibia coupling structure. Taking the screw-rabbit tibia structure as an example, the push-out force of screw was measured by push-out test. The effects of osseointegration and initial loosening on the interface strength were analyzed. This study showed that osseointegration could effectively improve the implant-bone interface strength, while initial loosening could significantly reduce the interface strength.

 (2) Study on stress shielding of bone plate-human femur coupling structure. Taking the simplified model of a comminuted fracture bridged by a locking plate as an example, the stress shielding degree of the plate-femur coupling structure with different screw distribution under compression were analyzed by finite element method. The results showed that the screw distribution could significantly affect the stress shielding degree of the structure. Besides, the flow distribution regularity of the Z-type manifold could be used to characterize the regularity of load distribution in internal fixation, because there was a high similarity between them.

(3) Development of new prosthesis implant technology and study on mechanical properties of prosthesis implant-human femur coupling structure. A new prosthesis implant was developed. The end of the bone bears the weight of the body, the hoop improves the splitting resistance of the end of the bone, and the pin and implant-bone interface resist torsion in this structure. The mechanical properties of prosthesis implants-human femur coupling structure under compression, bending and torsion were studied through mechanical test and finite element method. The results showed that the prosthetic implant structure developed in this thesis could provide good compression, bending and torsional stability, low stress shielding, and effectively reduce the risk of residual bone splitting.

 (4) Study on mechanical properties of prosthetic implant-sheep tibia coupling structure. The mechanical properties of the prosthesis implant-sheep tibia coupling structure under compression, bending and torsion were studied by mechanical tests and finite element simulation. The results showed that the improved prosthesis implant could also provide good compressive, bending and torsion resistance in sheep tibia, which was prepared for further animal experiments.