Department of Bone and Soft Tissue Oncology, Tianjin Hospital, Tianjin, China.
Department of Hand Surgery, Second Hospital of Tangshan, Tangshan, China.
Orthop Surg. 2020 Apr;12(2):631-638. doi: 10.1111/os.12640. Epub 2020 Mar 11.
To investigate the contact stress and the contact area o tibial inserts and bushings with respect to different congruency designs in a spherical center axis and rotating bearing hinge knee prosthesis under gait cycle loading conditions using finite element analysis.
Nine prostheses with different congruency (different degrees of tibiofemoral conformity and different distances between the spherical center and the bushing) designs were developed with the same femoral and tibial components. The models were transferred to finite element software. The peak contact stresses and contact areas on tibial inserts and bushings under the gait cycle loading conditions were investigated and compared.
For tibial insert, the peak contact stress was the highest in the low conformity-long group (61.4486 MPa), and it was 1.88 times higher than that in the group with the lowest stress (moderate conformity-short group, 32.754 MPa). The contact area was the largest in the low conformity-long group (420.485 mm ), and it was 1.19 times larger than that in the group with the smallest area (moderate conformity-middle group, 352.332 mm ). For bushing, the peak contact stress was the highest in the high conformity-long group (72.8093 MPa), and it was 3.21 times higher than that in the group with the lowest stress (high conformity-short group, 22.6928 MPa). The contact area was the largest in the low conformity-short group (2.41 mm ), and it was 2.27 times larger than that in the group with the smallest area (high conformity-middle group, 1.063 mm ).
The results of our study showed that the congruency of the tibiofemoral surface and bushing surface should be considered carefully in the design of the spherical center axis and rotating bearing hinge knee prosthesis. Different levels of contact performance were observed with different congruency designs. In addition, the influence of contact stress and contact area on the polyethylene wear of rotating hinge knee prostheses should be confirmed with additional laboratory tests.
在球形中轴和旋转铰链膝关节假体的步态周期加载条件下，使用有限元分析研究不同的一致性设计对胫骨衬垫和衬套的接触压力和接触面积的影响。
用相同的股骨和胫骨组件设计了 9 种具有不同一致性（不同程度的胫股一致性和球形中心与衬套之间的不同距离）的假体。将模型转移到有限元软件中。研究并比较了步态周期加载条件下胫骨衬垫和衬套的峰值接触压力和接触面积。
对于胫骨衬垫，低一致性-长组的峰值接触压力最高（61.4486 MPa），比应力最低的组（中一致性-短组，32.754 MPa）高 1.88 倍。低一致性-长组的接触面积最大（420.485mm），比面积最小的组（中一致性-中组，352.332mm）大 1.19 倍。对于衬套，高一致性-长组的峰值接触压力最高（72.8093 MPa），比应力最低的组（高一致性-短组，22.6928 MPa）高 3.21 倍。低一致性-短组的接触面积最大（2.41mm），比面积最小的组（高一致性-中组，1.063mm）大 2.27 倍。
我们的研究结果表明，在球形中轴和旋转铰链膝关节假体的设计中，应仔细考虑胫股表面和衬套表面的一致性。不同的一致性设计观察到不同的接触性能水平。此外，还应通过额外的实验室测试来确认接触压力和接触面积对旋转铰链膝关节假体聚乙烯磨损的影响。
