Hip resurfacing arthroplasty with cemented highly cross-linked all polyethylene acetabular components.

BACKGROUND

Hip resurfacing arthroplasty (HRA) is needed for certain patients, such as those with in situ metal work and abnormal anatomy, and/or other needs that are not well-served by total hip replacement (THR). Over the last 20 years, almost all HRAs have been performed using Metal-on-Metal (MoM) bearings, but metal wear debris generated over time has now ended their continued use. Cemented highly cross-linked polyethylene (XLPE) acetabular bearings have shown excellent survivorship for use in THR and the aim of this study is to determine if this also applied to HRA.

METHODS

This prospective cohort study evaluated extending the use of cemented XLPE acetabular bearings to HRA. There were 122 HRA patients who received a cemented XLPE acetabular component. They were followed for a mean 15 years (range, 10-20 years). There were 65 women (53%) and 57 men (47%). The mean age at surgery was 49.2 years (range, 21-68 years) the mean body mass index (BMI) was 26 kg/m2. Clinical outcomes and survivorship were determined. Analyses of implants retrieved during revision or postmortem were performed to evaluate consequences of wear debris.

RESULTS

The 10-year survival rate for 122 hips was 93.5% [95% confidence interval (CI): 91.7-98.1%] for all-cause revision. Six acetabular bearings failed, requiring revision for: loosening [2], polyethylene wear [2], and dislocation [2]. Four additional well-functioning XLPE bearings were retrieved postmortem. Two well-functioning cemented acetabular bearings were also retrieved; one was an explant for an infection after 9 years and the other was retrieved during revision to THR because of femoral head avascular necrosis at 6 years. Analysis of the 12 retrievals found signs of limited anterior/superior wear in all bearings along with minimal wear in the dome of 10 bearings. Only two retrieved bearings had more than 50% of the anterior/superior area worn and these were after 15 and 20 years of use. Two of the retrieved implants had no signs of wear.

CONCLUSIONS

Cemented all XLPE acetabular bearings produced successful clinical outcomes initially in all patients. Six (4.9%) patients required revision for acetabular failure. Anterior/superior wear was found in the retrievals, but dome wear was limited. Cementing an XLPE acetabular component is a reasonable approach in HRA, but since it does not allow adjunct screw fixation that a metal-backed two-piece component can offer, it is not a solution for every HRA.