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Commentary & Perspective | ||||||||
Commentary & Perspective on This article addresses the unresolved debate regarding the relative effects of surface finish and stem design on the duration of fixation of cemented femoral components in total hip arthroplasty. The authors studied 244 consecutive total hip arthroplasties, all performed by a single surgeon. The initial 122 femoral stems had a grit-blasted surface and the subsequent 122 stems had a polished surface. The mean duration of follow-up was 5.98 years for the patients treated with the grit-blasted stem and 5.32 years for those treated with the polished stem. The stems with a grit-blasted finish had a significantly higher rate of failure (p = 0.05). In the last twelve years, a number of studies have been published on this topic1-9. One investigation concluded that the initial event in the failure of a cemented stem is debonding at the cement-prosthesis interface2. This finding prompted the development and use of a grit-blasted stem with a polymethylmethacrylate precoating. But as experience was gained with precoated stems, it became evident that their failure rate in some series was higher than that of other stems without precoating. Of 154 patients who had undergone a total hip arthroplasty, Dowd et al. reported that twenty-three (15%) of the femoral components failed (twenty-one were revised and two were defined as loose) at an average of 3.9 years after the operation3. The authors concluded that their poor cementing technique contributed to these results. In contrast, Oishi et al.4, using the Harris Precoat design, identified only one stem failure in eighty-nine patients (average age, seventy years; average weight, 70 kg) who were followed six to eight years, although an additional five patients (6%) had radiographic evidence of endosteal cavitation. Precoated designs other than the Harris stem with a rectangular geometry have also had high rates of failure. Sporer et al.5, Callaghan et al.6, and Cannestra et al.7 reported intermediate-term results of the Iowa stem with a grit-blasted precoating. Each of these authors noted a higher rate of failure for the precoated Iowa stem in comparison with that for other non-precoated stems. Stems with surfaces that are bead-blasted (Ra = 20 to 50 µin)8 or polished (Ra = 2 to 4 µin)9 have had results superior to those reported by Collis and Mohler and by others3,5-7. We question whether a stem can be designed to be resistant to loosening at the prosthesis-cement interface for a period of ten to twenty years. Until this can be demonstrated, we believe that the use of a precoated grit-blasted femoral component should be avoided. Stems with polished and bead-blasted surfaces that are inserted with good cementing technique remain the implants of choice in total hip arthroplasty with cement. *In support of their research or preparation of this manuscript, one or more of the authors received grants or outside funding from The Journal of Bone and Joint Surgery. None of the authors received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. A commercial entity (DePuy, Smith and Nephew) paid or directed, or agreed to pay or direct, benefits to a research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated. References 1. Collis DK, Mohler CG. Loosening rates and bone lysis with rough finished and polished stems. Clin Orthop. 1998;355:113-22. | ||||||||
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