Adverse reaction to metal debris in a consecutive series of DUROM™ hip resurfacing: pseudotumour incidence and metal ion concentration

Introduction: The aim of this study was to evaluate the incidence of adverse reactions to metal debris (ARMD) in a consecutive series of DUROM (TM) Hip Resurfacing Arthroplasty (HRA) at mid-term follow-up. Methods: Between October 2003 and March 2007 a total of 134 consecutive DUROM (TM) HRA in 121 patients were performed at our institution. Follow-up could be obtained in 101 unrevised patients (83%) at a mean time of 8.51 +/- 0.97 years postoperatively and included patient-related outcome measurement, plain radiographs, MARS-MRI as well as whole blood metal ion assessment. Results: 17 (16.5%) out of 103 hips revealed pseudotumour occurrence in MRI investigation, 1 (10.6%) with a diameter of >= 2 cm. Higher incidence of pseudotumours was found patients with femoral component size < 50 mm. 38 patients had elevated cobalt levels, 36 of them (35%) in the range of 2-7 mu g/l and 2 patients (1.9%) at a rate of > 7 mu g/l. In contrast to cobalt determination, only elevated chromium values showed a positive association with pseudotumour occurrence and size. Discussion: A significant proportion of patients developed pseudotumours and metal ion elevation in a consecutive cohort of DUROM T HRA after mid-term follow-up. The incidence, however, seems not to differ from results of other well performing resurfacing brands; clinical relevance of our findings is unclear. Regarding potential local as well as systemic effects of metal particle release, close follow-up of patients is essential, even with clinically well-performing implants.