Fixation of Non-Cemented Total Hip Arthroplasty Femoral Components in a Simulated Proximal Bone Defect Model

Abstract An accelerated sequential proximal femoral bone loss model was used to measure the initial stability of three noncemented femoral stem designs: fully porous-coated, proximally porous-coated, and dual-tapered, diaphyseal press-fit (N=18). Only dual-tapered, diaphyseal press-fit stems remained stable with as much as 105mm of bone loss, with average cyclic micromotion remaining below 25μm in ML and below 10μm in AP planes. In contrast, with proximally coated and fully coated stem designs with circular or oval cross-sections, 60mm of bone loss, resulting in lower than 10cm of diaphyseal bone contact length, led to gross instability, increasing average cyclic micromotions to greater than 100μm prior to failure. Therefore, the results provide support for using a dual-tapered stem in revision cases with proximal bone loss.