Effects of prosthesis surface roughness on the failure process of cemented hip implants after stem-cement debonding

Global and local finite element (FE) models with debonded stem-cement interfaces were used to study the effects of prosthesis surface roughness on the cement stresses on a global scale and microscale. Similar to earlier numerical studies, the global FE model predicted that an increased surface roughness of the stem reduced the stresses in the cement mantle. The local model provided insight in the load-transfer mechanisms on a microscale and could explain the experimental and clinical findings. From these results, it is concluded that to minimize cement abrasion, debonded stems should either have a polished microstructure to minimize the local cement stresses or have a profiled macrostructure to minimize micromotions at the stem-cement interface. [16 Refs; In English]