WHAT IS THE OPTIMAL SURFACE FINISH OF A CEMENTED FEMORAL COMPONENT?

Abstract

Introduction: The purpose of this study was to report on the minimal 10-year followup results of a prospective randomized and a historical series of low friction cemented hip arthroplasties according to the surface finish of the femoral implant.

Patients and Methods: The prospective randomized series included 284 patients (310 hips) with a mean age of 64.1 years. Among these 310 hips, the femoral component had a highly polished surface (Ra = 0.04 micron, MKIII, Stryker) in 165 hips, and a matte surface finish (Ra = 1.7 microns, CMK3, Vector Orthopedique) in the remaining 145 hips. The historical series that was operated by the sames surgeons according to the same surgical technique included 111 patients (123 hips) with a satin finish femoral component (Ra = 0.9 micron, CMK2, Sanortho). Clinical results were rated according to the Merle d’Aubigne hip score. Radiologic analysis was performed according to the criteria of Barrack et al. for the definition of loosening. Moreover, a survival analysis according to the actuarial method was conducted.

Results: At the minimum 10-year follow-up evaluation, 43 patients (48 hips) were lost to follow-up (0.3 to 8.7 years), 80 patients (83 hips) were deceased (0.1 to 13.6 years), 26 patients had revision of either or both components (0.9 to 15.9 years), and 246 patients (276 hips) were alive and had not been revised after a mean 12.3 ± 1.9 years (10 to 16 years). Radiologic loosening of the femoral component, including revision, occured in one, four, and 15 hips for the polished, stain, and matte groups, respectively. The survival rate at 13 years of the femoral component, using loosening as the end point, was 97.3 ± 2.6% (95% CI, 92.2 to 100%), 97.1 ± 2.1% (95% CI, 93 to 100%), and 78.9 ± 5.8% (95% CI, 67.6 to 90.3%) for polished, satin, and matte stems, respectively.

Discussion: This study demonstrated that cement fixation of a femoral component was more reliable in the long term with a polished or satin surface finish. Based upon our results and the review of the literature, we recommend abondoning the use of cemented stems with a surface roughness greater than 1 micron.