Development of the Skin-Implant Seal Around Intraosseous Transcutaneous Amputation Prostheses (ITAP)

Professor Gordon Blunn, PhD

Attaching artificial limbs to the body remains clinically challenging, with inadequate mechanical fixation, poor stump-socket fitting particularly to short residual limbs, friction leading to the development of pressure sores, infection of the stump soft tissues and sweating often leading to limb disuse.  Eliminating the socket, by directly attaching the artificial limb to the residual bone through osseointegration transmits forces through the bony skeleton alleviating the problems associated with the socket.  Infection is the main complication.  Based on the osseointegration concept we have developed intraosseous transcutaneous amputation prostheses (ITAP) which attempt to overcome the problems associated with infection by integrating dermal and epidermal tissues with the implant creating a soft tissue seal around the implant.

To gain an understanding of how natural transcutaneous structures are viable without the problems of epithelial layer migration and infection observed around artificial implants we analysed the skin  interfaces around deer antlers.  We found that the surface of the pedicle is highly porous, and thick Sharpey’s-like fibres were observed emanating from the pores tying down the soft tissues and preventing their relative movement.   In order to mimic the attachment of the dermal tissue seen with the deer antlers, a porous flanged structure was incorporated into transcutaneous implant inserted across the tibia in a caprine model. Compared with straight negative controls without a flange, the biomimetic implants significantly reduced the degree of downgrowth and increased dermal attachment.

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Last modified: December 22, 2010 14:56:37