Histopathology of biocompatible hydroxylapatite-polyethylene composite in ossiculoplasty.

The biocompatibility of hydroxylapatite-polyethylene composite implants (HAPEX, Smith and Nephew) was investigated in this study. Eleven middle ear prostheses, removed during revision surgery, have been examined by light microscopy, transmission electron microscopy and scanning electron microscopy. The results show that the middle ear prostheses become overgrown by fibrous tissue inside a thin epithelial layer. In some cases the prosthesis is covered by fibrous tissue without an outer layer of epithelial cells. No arguments have been found for the accumulation of macrophages and foreign body giant cells associated with a foreign body reaction to the material. Therefore, hydroxylapatite-polyethylene composite implants (HAPEX, Smith and Nephew) would seem to be very suitable for reconstructive middle ear surgery.