Abstract
Introduction:
More and more metal-on-metal hip resurfacing arthroplasty (HRA) implants have been used for active younger patients because of its higher success rate and better function outcomes for this group of patients compared to the traditional total hip arthroplasty (THA). One of the advantages of HRA is femoral neck preservation, which provides better bone structure in case a revision is necessary in the future. However, some believe that the outcomes after revision of hip resurfacing were not as good as the traditional THA. The purpose of this study was to provide our outcomes of the revisions, due to various causes, from over 3000 HRAs.
Method:
Between May 2001 and April 2013, a single surgeon performed 3180 HRA. During that same period, 88 required revision (2.8%). Among them, the primary causes of the revision were acetabular component loosening in 22 cases; femoral component loosening in 21; femoral neck fracture in 19; adverse wear in eight; deep infection in four; and other causes for the rest. 68 of these revisions were performed by the same surgeon, while the remainder were revised elsewhere. 53 among these 68 cases had reached a minimum follow-up of two years and were included in this report. In 96%(51/53) of cases, the revision bearing was a large metal type including in 6/8 cases of adverse wear failure. There were eight cases of adverse wear with ion levels elevated above 10 μg/L, metalosis and inflammatory reaction seen at the time of revision. All of these cases had acetabular inclination angles larger than 50°. 7/8 of these cases were revised to another large metal bearing with improved acetabular component position. We analyzed the clinical scores, complications and radiographic results and compared them between these groups.
Results:
The mean follow-up after the HRA revision was 5.4 ± 2.5 years (2–11 years). No patients died. No patient was lost from follow-up. The average age at the time of revision was 52 ± 11 years. The average operation time was 114 ± 42 minutes and the average hospital stay was 2 ± 1 days. All eight cases revised for adverse wear failures had extensive grey metalosis seen in surgery. There was no significant metalosis seen in the remainder. There were no failures requiring repeat revision. The average Harris hip score was 95 ± 11 at the latest follow-up. The mean UCLA score was 6 ± 2. The five year survivorship was 100%.
Four complications were identified. There were two cases of recurrent dislocation that were treated with closed reduction. There was one superficial wound breakdown at 4 months without deep infection that resolved after debridement. There was one low energy pelvic fracture that was treated nonoperatively. There were no sciatic nerve palsies, thromboembolic events or significant medical complications.
Conclusions:
Our results demonstrated that revision after hip resurfacing has a high success rate. Also, the revisions for adverse wear failure are most likely not due to the metal on metal bearing surfaces. In 7/8 cases, revisions were performed using another large metal bearing with improved acetabular component positioning, resulting in complete resolution of the problem.
