The Hydroxyapatite-Tapered Stem: Any Added Value?

Abstract

Hydroxyapatite (HA) coating has been used as a biological adjuvant for noncemented femoral stem fixation. This is a long-term concise report of a previously published prospective, randomized clinical trial, comparing plasma sprayed porous noncemented stems with and without an HA coating, with focus on wear and survivorship. Between July 1991 and October 1994, 177 patients (199 hips) underwent noncemented Ranawat-Burstein (RB) Metaphyseal-Diaphyseal fit total hip replacement in a prospective randomized clinical trial. At the 5-year follow-up, the incidence of trochanter and/or thigh pain was 12% in the HA group and 24% in the non-HA group. After the mean follow-up of 17.7 ± 0.8 years, there were 3 revisions in the HA group, 1 for fracture and 2 for poly wear. There were 4 revisions in the non-HA group, 1 for infection and 3 for poly wear. There was no revision for femoral loosening in either groups. The Kaplan–Meier survivorship for failure for mechanical reasons in the HA group and non-HA group were 97.9% and 97.1%, respectively, which was not statistically significant. Noncemented femoral stems with HA coating have excellent survivorship without any substantial deleterious effect or increase in wear.