EFFECT OF POROUS COATING AND LOADING CONDITIONS ON TOTAL HIP FEMORAL STEM STABILITY

An examination of femoral bone-prosthesis interface behavior under dif ferent load types is undertaken using finite-element analysis. Three-d imensional finite-element models are made of two designs of hip prosth eses after implantation in a femur. Femoral geometry was determined by computed tomography scans. The models were loaded in one-legged stanc e and stairclimbing configurations. The implants were modeled as both smooth surfaced and porous coated. The amount of contact and the relat ive motion between bone and implant were calculated. It is shown that torsional loads such as occur during stairclimbing contribute to large r amounts of implant micromotion than does stance loading. Contact at the bone-prosthesis interface is more dependent on load type than on i mplant geometry or surface coating type.