Abstract
Background
Metal on metal hip resurfacing has become popular worldwide for younger patients because of perceived advantages in function and ease of revision, due to bone conservation. Joint Registry data have shown increased risk of early failure, particularly in younger females. There have been few studies comparing the outcome of resurfacing to cemented total hip arthroplasty (THA).
Methods
715 Hip Resurfacings (HR) performed between 2000 and 2010 with up to 10 years follow-up were compared with 2210 Exeter cemented Total Hip Arthroplasties (THA) performed for all diagnoses during the same period within our region. Survivorship was recorded using revision for any cause as the end point. Harris Hip Scores were collected pre-operatively and at 1,3,5 and 7 year review. Prospective independent analysis was carried out using Kaplan Meier survivorship, and non-parametric testing to investigate the effect of age (under 55 and over 55) and gender on revision rate and Harris Hip Score.
Results
Over the 10 year period survival of Exeter THA was better than HR overall. Revision rate 2% for THA and 7% for HR; P < 0.0001. There was no significant difference in risk of revision between THA and HR in males at any age. In females there was a significantly increased revision rate with HR. Under 55 Revision rates: THA 0%; HR 6.7%. 55 & over Revision rates: THA 1.3%, HR 5.9%, P < 0.0001.
Harris Hip Scores were significantly better overall in the HR group. Sub-group analysis showed that Harris Hip Scores were not significantly different for males under 55. In all other groups (males over 55 and females under and over 55) Harris Hip Scores were better after HR compared with THA.
Conclusions
In this series survivorship and functional scores for HR are at least as good as for THA in males. The increased risk of revision after HR in females should be weighed against advantages of bone conservation and better post-op hip scores.
