title: The effect of component size and orientation on the concentrations of metal ions after resurfacing arthroplasty of the hip.
abstract: Increased concentrations of metal ions after metal-on-metal resurfacing arthroplasty of the hip remain a concern. Although there has been no proven link to long-term health problems or early prosthetic failure, variables associated with high metal ion concentrations should be identified and, if possible, corrected. Our study provides data on metal ion levels from a series of 76 consecutive patients (76 hips) after resurfacing arthroplasty with the Articular Surface Replacement. Chromium and cobalt ion concentrations in the whole blood of patients with smaller (<or= 51 mm) femoral components were significantly higher than in those with the larger (>or= 53 mm) components (p < 0.01). Ion concentrations in the former group were significantly related to the inclination (p = 0.01) and anteversion (p = 0.01) of the acetabular component. The same relationships were not significant in the patients with larger femoral components (p = 0.61 and p = 0.49, respectively). Accurate positioning of the acetabular component intra-operatively is essential in order to reduce the concentration of metal ions in the blood after hip resurfacing arthroplasty with the Articular Surface Replacement implant.
authors.affiliation: Joint Replacement Unit, University Hospital of North Tees, Hardwick, Stockton-on-Tees TS19 8PE, UK. djlangton22@doctors.org.uk
authors.forename: D J
authors.initials: DJ
authors.lastname: Langton
authors.forename: S S
authors.initials: SS
authors.lastname: Jameson
authors.forename: T J
authors.initials: TJ
authors.lastname: Joyce
authors.forename: J
authors.initials: J
authors.lastname: Webb
authors.forename: A V F
authors.initials: AV
authors.lastname: Nargol