Premise for bioresorbable materials in joint replacement arthroplasty

Total joint replacement arthroplasty has been extremely successful since its inception in the 1960's. There have been untoward problems however that have become more apparent with the current state of the art joint replacement. These problems include thigh pain following total hip replacement arthroplasty, proximal bone resorption as a result of stress shielding, and areas of bone lysis. The progressively enlarging size of the metal implant stem with its associated increased elastic modulus has been implicated in the above noted problems. The implant stem as well as metal alloy screws utilized to fix acetabular and tibial plate components to bone have been suggested to contribute to particulate debris and the above noted problems through fretting. Bioresorbable polymers can be utilized as screws to fix the definitive implant to bone as well as utilized as a stem to allow rigid fixation of the implant until there is firm attachment, whether by mechanical or chemical bonding. When the definitive implant has been adequately attached to bone, the resorbable polymer degrades completely, thereby, obviating many of the problems seen with the presently retained screws and large, high modulus, intramedullary stems.