Background: Aseptic loosening of the cemented stem is the most common cause of revision of total hip arthroplasties. The loosening is often associated with substantial lysis of the surrounding bone. The surface finish of femoral components is suspected as a contributing factor to this bone lysis. The purpose of this study was to compare the results associated with a rough surface and those associated with a polished surface in a consecutive series of cemented stems with essentially the same geometry.
Methods: The study included 244 consecutive total hip arthroplasties with a cemented femoral component performed by one surgeon. There was no difference in patient selection criteria or surgical techniques between the group treated with a polished stem and that treated with a grit-blasted stem. All arthroplasties were hybrid, with an uncemented acetabular component. Generally, patients were over the age of sixty years (mean age, 70.6 years). The stems inserted in the initial 122 hips had a grit-blasted surface with a roughness of 2.1 microm. The stem surface in the second 122 hips was polished (roughness, 0.1 microm). The results of clinical and radiographic assessments performed immediately after surgery were compared with those performed at the most recent visit. The average duration of clinical follow-up for the patients treated with the grit-blasted and polished stems was 5.98 years and 5.32 years, respectively.
Results: Four hips treated with the grit-blasted stem had aseptic loosening with substantial surrounding lysis and required revision. An additional two hips in this group had radiographic evidence of substantial lysis and were judged to have an impending need for revision. In contrast, no hip treated with the polished stem required revision, and only one had minimal lysis. This difference regarding failures and impending failures was significant (p = 0.05). The clinical results were comparable, with an Iowa hip rating of 98 points at the time of follow-up in both groups.
Conclusions: There was a significant difference between grit-blasted and polished stems with respect to the prevalence of revisions and impending revisions, all of which were identified in a relatively short follow-up period. The results in this series favor the use of a polished stem when cement is employed for fixation of the femoral component.