The development of a procedure designed to reduce the liability to pressure sores over bony prominences is described. This employs the properties of a particular type of carbon fibre pad implanted surgically over the bony prominence. The mechanical response of the pad to loading has been examined. The host tissue response to the pad involves penetration of the interstices between the carbon fibres with organised fibrous tissue. The host-tissue--carbon fibre pad complex has been found to be highly vascular. An 'ischiobarograph' has been developed and used in order to evaluate the alteration in pressure profile produced by the presence of the implanted prosthesis (the patient being in a sitting position).