Abstract
Introduction
Metal on metal hip resurfacing (MMHR) has been advocated for the younger patient for several reasons including for the preservation of bone stock and ease of revision to total hip replacement (THR), thus ‘buying an additional operation’ for the patient. This rationale however assumes a good functional outcome after the revision to a THR and that the results of the ‘revision primary’ will not be compromised by the resurfacing which preceded it. We present our data on a consecutive series of 68 revised MMHRs.
Methods
Between September 1997 and September 2009, 927 consecutive patients underwent a hip resurfacing procedure performed by one of three senior surgeons at our institution. The Cormet resurfacing system was used for all patients. Sixty-eight of these patients had their resurfacing revised. Oxford hip score (OHS) obtained at a minimum of 12 months follow-up was used as the primary outcome measure.
Results
Average age at time of index procedure was 51.9 (24 to 68) years. The MMHRs were revised an average of 49 (1 to 121) months after index procedure. At time of writing OHS post revision was 21.4 (range 12 to 48) at an average of 42 months post revision (range 16 to 111 months). Patients with a primary diagnosis of dysplasia were at an increased risk of revision RR 3.7 (1.9–7.1, p < 0.05).). No other primary diagnosis significantly increased risk of revision. Five patients underwent a second revision procedure.
Discussion
We present the fuctional outcome scores of a large series of revised MMHRs. Despite MMHRs offering the advantage of preservation of bone stock we have found revision of MMHRs to THRs technically difficult. Our functional outcome scores in patients post revision were disappointing. We cannot support the concept that MMHR “buys patients another operation”.
