A RANDOMIZED CONTROLLED TRIAL OF HYDROXYAPATITE COATED FEMORAL HIP PROSTHESES

Abstract

Sixty-two consecutive primary total hip arthroplasties were prospectively randomized to receive either hydroxyapatite coated (thirty-five hips) or nonhydroxy-apatite coated (twenty-seven hips) femoral prostheses. At a minimum eleven-year followup fifty-one hips (forty-four patients) were evaluated. Only one femoral stem had been revised (secondary to traumatic periprosthetic fracture). Radiographs were available for thirty-nine hips. None of these femoral stems were loose. Harris Hip scores were evaluated for thirty-six unrevised hips and did not differ significantly between the two groups. There appears to be no significant advantage to hydroxyapatite coating for this femoral prosthesis at an average follow-up of thirteen years.

There are a paucity of long term randomized controlled trials on results of hydroxapatite coating of femoral prostheses. The purpose of this study was to update the results of a prospective randomized study of a proximally pourous coated, tapered titanium femoral component with and without hydroxyapatite coating.

Sixty-two consecutive primary total hip arthroplasties done by one surgeon in fifty-five patients were prospectively randomized to receive either hydroxyapatite coated (thirty-five hips) or nonhydroxyapatite coated (twenty-seven hips) femoral prostheses. At a minimum eleven year followup, three hips (three patients) were lost to followup, and a further eight patients had expired (eight hips). The remaining surviving cohort of fifty-one hips (forty-four patients) were evaluated clinically, including Harris Hip Scores, and radiographically.

At an average of thirteen years followup, only one femoral stem had been revised (secondary to traumatic periprosthetic fracture), that being in the hydroxyapatite group. There were eight acetabular revisions in the hydroxyapatite group (thirty-four percent) and four acetabular revisions in the nonhydroxyapatite group (sixteen percent). Radiographs were available for thirty-nine hips. None of these femoral stems were loose. Harris Hip scores were evaluated for thirty-six unrevised hips and did not differ significantly between the two groups.

Using endpoints of femoral revision, radiographic loosening, and Harris Hip Scores there appears to be no significant advantage to hydroxyapatite coating for this femoral prosthesis at an average follow-up of thirteen years.

Funding: Biomet, Warsaw IN