Micromechanical bonding at a porous surface structured implant interface-the effect on implant stressing.

An experimental determination of the strains acting on femoral components of hip implants embedded in bone cement was made for the case of (a) porous surface coated and (b) conventional uncoated implants. The result indicated much lower tensile strains and stresses on the lateral surface of the porous coated implants. This was explained by micromechanical implant-cement bonding for the porous coated implant and a more effective transfer of stress from the implant to the cement for this design. The study suggests greater confidence against implant fatigue failure for the porous coated stems because of the lower strains and stresses acting on the implant.