Ceramic Bearings Enlarging the Range of Indications for Bipolar Prostheses

Abstract

Bipolar hemiprostheses are widely used for the treatment of medial fractures of the femoral neck in old patients with limited life expectancy since they allow for the surgical trauma to be reduced, and involve short rehabilitation times. The typical long-term problems encountered with such type of prostheses consisted in polyethylene wear and destruction of the cartilage in the acetabulum, which as a consequence caused protrusion into the minor pelvis. In conventional dualhead prostheses, the polyethylene used in the internal joint is subject to high mechanical strain which generally exceeds the strain rated for this material. The accelerated wear resulting from this causes loss of the sliding capacity of the internal joint, and hence prepares the way for technical failure of the conventional dual-head prosthesis. For this reason, a ceramic dual-head prosthesis was designed, which allows for the friction inside the technical internal joint to be minimized, and offers maximum biological compatibility of the external ceramic joint.

With this ceramic-on-ceramic dual-head prosthesis, the range of indications can be extended to fitter patients also. So far, the implant has passed the laboratory tests and yielded good initial clinical results, hence its clinical application offers the same safety of use at such early stage as do conventional dual-head implants. Observation of the benefits offered in respect of permanent exposure must be continued.