Tissue response to titanium plates: a transmitted electron microscopic study.

Abstract

This study investigated the tissue response associated with titanium plates. Titanium miniplates were used to stabilize fractured bones and a bone graft in 14 patients. At the time of plate removal, the osteosynthesis sites were carefully examined macroscopically. After the removal of the plates, biopsies of the 14 soft tissues and two bony sites surrounding the plates were performed for light microscopic and transmitted electron microscopic examination. Macroscopically, visible pigmentation was found in the soft tissue in 14% of the patients, but none in the bone. With light microscopy, pigmentation was found in the soft tissue of 10 of 14 sites and in one of two bony sites. Transmitted electron microscopy showed suspected titanium particles in the connective tissue of all specimens. The small particles were located between the collagen fibers. In some specimens, small particles were noted within the fibroblasts and macrophages. There were degenerative changes around the minute particles in the bone matrix. Local macroscopic or microscopic tissue destruction was observed in hard and soft tissue near the titanium miniplates. If the plates remain for a long time, there is a possibility that they may cause further tissue damage. These findings suggest that the titanium miniplates should be removed routinely after bone healing.