An Experimental Analysis of Micromotion of a Cementless Modular Acetabular Component in Total Hip Arthroplasty: Evaluation of the Bone

INTRODUCTION Basic daily activities, such as walking and climbing stairs produce forces on the acetabular cup that results in shear forces throughout the contacting surface producing acetabular cup micromotion. Minimizing micromotion of the acetabular component is critical to the long term survival of total hip arthroplasty. A typical cementless acetabular component is coated with a porous surface (pore size 100 400 microns) that permits osseous ingrowth. Micromotion at the cup bone interface greater than the pore size can preclude ingrowth. Micromotion at the liner cup interface can create abrasive “backside” wear which can be a source of particulate matter. This particulate matter can migrate into the bone cup interface causing osteolysis, degradation of the interface and cup loosening [1-3].