Early results of conversion of a failed femoral component in hip resurfacing arthroplasty.

BACKGROUND: A theoretical advantage of resurfacing arthroplasty of the hip is that a failed femoral component can be safely and successfully revised to a total hip arthroplasty. To our knowledge, this advantage has not been demonstrated to date.

METHODS: Twenty-one metal-on-metal resurfacing arthroplasties in twenty patients with an average age of 50.2 years were converted to a conventional stemmed total hip arthroplasty because of femoral component failure. In eighteen hips, the acetabular component was retained, and in three hips both components were revised. The results in the resurfacing conversion group were compared with those in a group of fifty-eight patients who had undergone sixty-four primary total hip arthroplasties that had been performed during the same time-period by the same surgeon. Clinical evaluations (the Harris hip score, the University of California at Los Angeles pain, walking, and activity scores and the Short Form-12 score) and radiographic evaluations were performed. The average duration of follow-up was forty-six months for the conversion arthroplasty group and fifty-seven months for the primary conventional total hip arthroplasty group.

RESULTS: There was no significant difference between the conversion arthroplasty group and the conventional arthroplasty group with regard to operative time, blood loss, or complication rates. At the time of the most recent follow-up, with the numbers studied, there were no significant differences between the two groups with regard to the mean Harris hip score; the University of California at Los Angeles pain, walking, and activity score; or the SF-12 score. As assessed radiographically, the quality of component fixation and the alignment of the reconstruction were equivalent between the two groups. There had been no instances of aseptic loosening of the femoral or the acetabular component in either group, and there had been no dislocations after conversion of a resurfacing arthroplasty.

CONCLUSIONS: Conversion of a hip resurfacing with a femoral-side failure to a total hip arthroplasty appears to be comparable with primary total hip arthroplasty in terms of surgical effort, safety, and early clinical outcomes.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.