Wu Qi, Yue Pengju, Yin Siyu, Liu Wang, Li Zhenjie, He Renjie
Orthopedic Surgery, The 82nd Hospital of People's Liberation Army, No. 100, Jiankang East Road, Qingjiangpu District, Huai'an, Jiangsu Province , 223001, China.
J Orthop Surg Res. 2025 Mar 18;20(1):294. doi: 10.1186/s13018-025-05647-w.
The long-term stability of cementless femoral prostheses is primarily affected by aseptic loosening, micromotion, and stress shielding, all of which are related to the force transfer of the prosthesis. These factors can compromise the osseointegration of the proximal prosthesis, leading to aseptic loosening within the femoral cavity. Due to the individual variability of the femur, the fit between the prosthesis and the femoral cavity during the design phase may differ from the fit achieved during the surgical procedure. Consequently, the force transfer of the prosthesis postoperatively may not align with the results obtained from finite element analysis conducted during the design phase, making it challenging to control the micromotion and stress shielding of the prosthesis. The design model of a custom femoral prosthesis is based on the CT reconstruction of the patient' femur. The fit of prosthesis within the femoral cavity during the design phase should match the fit during the surgical operation. Consequently, the results of finite element analysis conducted during the design phase can be used to control the force transfer of the prosthesis postoperatively. This approach helps to prevent improper micromotion and stress shielding of the proximal prosthesis, which can compromise the primary stability of the prosthesis within the femoral cavity, thereby facilitating the osseointegration of the proximal prosthesis.This paper proposes a novel technology that combines the design, finite element analysis, and manufacturing of custom prostheses. Specifically, a CAD/CAM/robot integration method is used to fabricate these prostheses. This innovative technology not only enhances the control of force transfer in custom prostheses but also reduces design and manufacture time while lowering costs. In conclusion, the finite element analysis of the custom prosthesis effectively manages force transfer, and the milling errors associated with the custom prosthesis are less than 1 mm.
非骨水泥型股骨假体的长期稳定性主要受无菌性松动、微动和应力遮挡的影响，所有这些都与假体的力传递有关。这些因素会损害近端假体的骨整合，导致股骨髓腔内的无菌性松动。由于股骨的个体差异，设计阶段假体与股骨髓腔之间的匹配可能与手术过程中实现的匹配不同。因此，术后假体的力传递可能与设计阶段进行的有限元分析结果不一致，使得控制假体的微动和应力遮挡具有挑战性。定制股骨假体的设计模型基于患者股骨的CT重建。设计阶段假体在股骨髓腔内的匹配应与手术操作时的匹配相匹配。因此，设计阶段进行的有限元分析结果可用于控制术后假体的力传递。这种方法有助于防止近端假体出现不当的微动和应力遮挡，而这会损害假体在股骨髓腔内的初始稳定性，从而促进近端假体的骨整合。本文提出了一种将定制假体的设计、有限元分析和制造相结合的新技术。具体而言，采用CAD/CAM/机器人集成方法来制造这些假体。这种创新技术不仅增强了对定制假体力传递的控制，还减少了设计和制造时间，同时降低了成本。总之，定制假体的有限元分析有效地管理了力传递，并且与定制假体相关的铣削误差小于1毫米。
