Metal-on-metal resurfacing offers an alternative strategy to hip replacement in the young active patient with severe osteoarthritis of the hip. The aim of this study was to compare functional outcomes, failure rates and impending revisions in hybrid total hip arthroplasties (THAs) and Birmingham Hip Resurfacings (BHRs) in young active patients.

We compared the 5-7 year clinical and radiological results of the metal-on-metal BHR with hybrid THA in two groups of 54 hips each, matched for sex, age, body mass index and activity. Function was excellent in both groups as measured by the Oxford hip score (median 13 in the BHRs and 14 in the THAs, p=0.14), but the resurfacings had higher UCLA activity scores (median 9 v 7, p=0.001) and better EuroQol quality of life scores (0.90 v 0.78, p=0.003). The THAs had a revision or intention to revise rate of 8% and the BHRs 6%. Both groups demonstrated impending failure on surrogate end-points. 12% of THAs had polyethylene wear and osteolysis under observation, and there was femoral component migration in 8% of resurfacings. Polyethylene wear was present in 48% of hybrid hips without osteolysis. Of the femoral components in the resurfacing group which had not migrated, 66% had radiological changes of unknown significance (classification proposed).

In conclusion, the early to mid-term results of resurfacing with the BHR appear at least as good as those of hybrid THA. Only by longer term follow-up will we establish whether the change of practice recorded here represents a true advance.