Mid-term clinical results of the cementless R3 cup and Polarstem total hip arthroplasty.

ABSTRACT

BACKGROUND: There has been a shift from cemented to uncemented hip arthroplasty. One popular uncemented combination is the R3 acetabular cup with Polarstem, having the lowest revision rate in the UK National Joint Registry. However, there are no medium-term clinical outcomes on this combination in the literature. The aim of this study is to review our centre's outcomes with this combination using conventional bearings with a minimum of 7-year follow-up. METHODS: Using our centre's arthroplasty database, we identified all patients that underwent a total hip arthroplasty using these implants from August 2009 to December 2010. One hundred and forty-four procedures were performed. The primary outcome was revision rate, and the secondary outcomes were clinical and radiological evaluation. RESULTS: The mean cohort age at surgery was 68.3 years. There were three revisions, of which only one underwent a cup revision. The mean Oxford Hip Score at 7-year follow-up was 38. Radiological evaluation of both acetabular and stem component did not show any radiolucency at 7-year follow-up. Kaplan-Meier survivorship analysis showed an implant survival rate of 97.69% at 7 years using revision for all causes as endpoint. The risk of revision was 1.47% at 7 years. CONCLUSION: Our revision rates are comparable to the UK's National Joint Registry, with excellent clinical and radiological outcome. Our results correlate with the allocated rating of 7A* by the Orthopaedic Data Evaluation Panel for both R3 acetabular cup and Polarstem.