THE LOOSENING OF INTRAMEDULLARY ANCHORED COMPONENTS OF HIP PROSTHESIS IS A SIGNIFICANT PROBLEM ASSOCIATED WITH AN OTHERWISE VERY SUCCESSFUL SURGICAL PROCEDURE.

THE LOOSENING OF INTRAMEDULLARY ANCHORED COMPONENTS OF HIP PROSTHESIS IS A SIGNIFICANT PROBLEM ASSOCIATED WITH AN OTHERWISE VERY SUCCESSFUL SURGICAL PROCEDURE. IDENTIFICATION OF LOOSENING AT EARLY STAGES MAY PROVIDE THE BASIS TO PROLONG THE SERVICE OF THE IMPLANT BY ALLOWING PRESCRIPTION OF LIMITED WEIGHT BEARING AND DECREASED ACTIVITY. A TESTING TECHNIQUE IS PROPOSED WHICH IS NOT SOLELY DIRECTED TOWARD THESE IMPLANTS BUT IN GENERAL MAY FIND USEFULNESS IN EVALUATION OF THE INTERFACE BETWEEN ANY NONCONDUCTIVE MATERIAL AND AN ELECTRICALLY CONDUCTIVE MATERIAL BOTH IN BIOMEDICINE AND GENERAL ENGINEERING. THE METHOD INVOLVES IMPARTING A STRESS WAVE IN THE CONDUCTIVE MATERIAL BY ELECTROMAGNETIC MEANS. SUBSEQUENTLY, THE WAVE WHICH IS PARTIALLY REFLECTED FROM BOUNDARY TO BOUNDARY OF THE CONDUCTIVE MATERIAL (USUALLY A MATERIAL OF HIGH ACOUSTICIMPEDANCE) WILL DIMINISH IN ENERGY AS ENERGY IS TRANSMITTED ACROSS THE INTERFACE SURFACE. IT IS THEORETICALLY POSSIBLE WITH SIMPLE GEOMETRIES TO DETERMINE THE AREA OF CONTACT OF THE TWO SURFACES IF THE ACOUSTIC IMPEDANCES ARE KNOWN AND THE RATE AT WHICH THE ENERGY IS LOST IS MEASURED. IN THIS PROPOSAL, BOTH THE ELECTROMAGNETIC EXCITATION SYSTEM AND THEENERGY LOSS MEASUREMENT TECHNIQUE WILL BE INVESTIGATED WITH RESPECT TO APPLICABILITY TO DETERMINATION OF HIP PROSTHESIS LOOSENING.