Fluorapatite-Coated Percutaneous Osseointegrated Prostheses Limit Epidermal Downgrowth and Promote Periprosthetic Healing in a Weight-Bearing Sheep Model-A Preliminary Study.

Percutaneous osseointegrated (OI) devices offer an advanced alternative to socket prosthetic suspension systems for amputees but can face clinical limitations due to complications at the skin-implant interface. Titanium (Ti) and its alloys, though mechanically suitable and promoting osseointegration, are unable to support epidermal cell adhesion, leading to chronic wounds, sinus tract formation, and infections. To improve epidermal tissue integration, this study explored the use of fluorapatite (FA)-a natural tooth mineral known to allow epithelial adhesion through hemidesmosomes. It was hypothesized that FA-coated Ti surfaces would enhance epidermal cell attachment, promote wound healing, and prevent epithelial downgrowth. To test this idea, FA-coated Ti devices were implanted into the transected fused 3-4 metacarpals of five sheep and evaluated at 12 weeks post-implantation. The results revealed that FA-coatings significantly improved healing outcomes and limited epithelial migration along the implant surface. These findings support FA as a promising strategy for promoting a biological seal around percutaneous implants.