A numerical study on the possibilities of cemented short-stem ceramic femoral resurfacing component

Short-stem resurfaced femoral implant has been found to be a promising alternative to the long-stem design, due to reduced risk of initial femoral neck fracture and more physiological load transfer. Te clinical effect of metal ion release and continued concerns regarding the use of Metal-on-Metal bearing warrants an investigation of an alternative material, like ceramics, as a low-wear bearing couple. Te objective of this study was to investigate the efect of a short-stem ceramic resurfacing implant, in comparison with the metallic design, with regard to stress-strain related failure mechanisms and bone adaptation. Te maximum principal (tensile) stress in the ceramic implant, occurring at the stem-cup junction, was found to increase from 73 MPa at the post-operative condition to 86 MPa afer bone remodelling. However, the tensile stresses generated in the cement mantle were low, around 3 MPa. Te elevated bone strains occurring at the proximal femoral neck-cup junction region were progressively reduced with bone remodelling. Bone density distribution inside the femoral head was found to be similar to those for the metallic short-stem design. Although bone resorption, 50 − 90% reduction in bone density was predominantly observed at the supero-proximal femoral head, bone apposition, 10 – 30% increase in bone density occurred in the other regions of the femoral head. Apart from better wear resistivity and chemically inert nature of ceramics, it appears from this study that alumina ceramic is a viable alternative to the metallic design.