Outcomes following Birmingham hip resurfacing at a minimum of 10 years follow-up: an observational study

The role of the Birmingham Hip Resurfacing (BHR) implant in modern arthroplasty remains controversial. The purpose of this study was to evaluate the functional outcomes, radiological outcomes and revision rates following BHR in a single institution at a minimum of 10 years follow-up.

An observational study was undertaken evaluating patient demographics & surgical details. The overall revision rate was quantified, and postoperative functional status was defined using the modified Harris Hip Score (mHHS). Implant survivorship was illustrated utilising a Kaplan-Meier estimator plot. A further subgroup analysis was undertaken comparing those with a unilateral BHR (Group 1), bilateral BHRs (Group 2) and those who have underwent a unilateral BHR and contralateral non-MoM total hip arthroplasty (THA) (Group 3).

126 BHR procedures undertaken in 103 patients with a mean follow-up of 15.3 years were suitable for inclusion. This cohort consisted of 109 males (86.5%), with a mean age of 56.7 years (SD ± 8.3) at time of index BHR. 8 BHRs (6.3%) had been revised at a mean of 11.2 years (SD ± 5.4) following index BHR at time of follow-up, with an overall implant survival rate of 97% and 94% at 10 and 15 years postoperatively. In the remaining BHR cases the mean MHHS, cobalt and chromium levels at time of most recent follow-up were 85.2 (SD ± 17.6), 50 nmol/L and 42.2 nmol/L respectively. No significant difference was identified between Groups 1, 2 and 3 in regards overall revision rates, functional outcomes, radiological changes and serum metal ion levels.

BHR is associated with acceptable revision rates, functional outcomes and serum metal ion levels at a minimum of 10 years follow-up. BHR may potentially be considered as a viable alternative to THA in the carefully selected younger patient when undertaken in units with appropriate surgical expertise and follow-up.