SENSORY NERVES IN THE INTERFACE MEMBRANE OF ASEPTIC LOOSE HIP PROSTHESES

We studied the presence of sensory nerves by immunohistochemistry in t he interface membranes of hip prostheses after aseptic loosening. Subs tance P (SP), neurokinin A (NKA) and calcitonin gene-related peptide ( CGRP) were analysed as was protein gene product (PGP) 9.5, a general m arker for nerve fibres. We identified nerve fibres in all samples but differences in their density were found. SP- and NKA-positive fibres w ere predominantly non-vascular, forming varicose nerve terminals. CGRP -immunoreactive nerve fibres with varicose terminals were seen mostly close to blood vessels, but also as free nerve endings. Sensory neurop eptides participate not only in nociception but also stimulate immune cells to release cytokines. The presence of sensory nerves in the inte rface membrane may reflect a pathophysiological response contributing to the aseptic loosening of hip prostheses.