Udofia I J, Yew A, Jin Z M
School of Engineering Design and Technology, University of Bradford, Bradford, UK.
Proc Inst Mech Eng H. 2004;218(5):293-305. doi: 10.1243/0954411041932854.
Finite-element method was employed to study the contact mechanics in metal-on-metal hip resurfacing prostheses, with particular reference to the effects of bone quality, the fixation condition between the acetabular cup and bone, and the clearance between the femoral head and the acetabular cup. Simple finite-element bone models were developed to simulate the contact between the articulating surfaces of the femoral head and the acetabular cup. The stresses within the bone structure were also studied. It was shown that a decrease in the clearance between the acetabular cup and femoral head had the largest effect on reducing the predicted contact-pressure distribution among all the factors considered in this study. It was found that as the clearance was reduced, the influence of the underlying materials, such as bone and cement, became increasingly important. Stress shielding was determined to occur in the bone tissue surrounding the hip resurfacing prosthesis considered in this study. However, the stress-shielding effects predicted were less than those observed in conventional total hip replacements. Both the effects of bone quality (reduction in elastic modulus) and the fixation condition between the cup and the bone were found to have a negligible effect on the predicted contact mechanics at the bearing surface. The loading was found to have a relatively small effect on the predicted maximum contact pressure at the bearing surface; this was attributed to an increase in contact area as the load was increased.
采用有限元方法研究金属对金属髋关节表面置换假体的接触力学，特别关注骨质量、髋臼杯与骨之间的固定条件以及股骨头与髋臼杯之间的间隙的影响。开发了简单的有限元骨模型来模拟股骨头和髋臼杯关节表面之间的接触。还研究了骨结构内的应力。结果表明，在本研究考虑的所有因素中，髋臼杯与股骨头之间间隙的减小对降低预测的接触压力分布影响最大。研究发现，随着间隙减小，诸如骨和骨水泥等底层材料的影响变得越来越重要。确定在本研究中考虑的髋关节表面置换假体周围的骨组织中会发生应力屏蔽。然而，预测的应力屏蔽效应小于传统全髋关节置换中观察到的效应。发现骨质量（弹性模量降低）和髋臼杯与骨之间的固定条件对轴承表面预测的接触力学影响可忽略不计。研究发现，载荷对轴承表面预测的最大接触压力影响相对较小；这归因于随着载荷增加接触面积增大。
