The effect of component size and orientation on the concentrations of metal ions after resurfacing arthroplasty of the hip
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D. J. Langton, MRCS, Orthopaedic Research Register1; S. S. Jameson, MRCS, Specialist Registrar, Trauma and Orthopaedics1; T. J. Joyce, MSc, PhD, MA, BEng, Lecturer in Bioengineering2; J. Webb, MRCS, Specialist Registrar, Trauma and Orthopaedics1; and A. V. F. Nargol, FRCS(Tr & Orth), Consultant Orthopaedic Surgeon1
1
Joint Replacement Unit, University Hospital of
North Tees, Hardwick, Stockton-on-Tees TS19 8PE,
UK.
2 Newcastle University, Claremont
Road, Newcastle upon Tyne NE1 7RU, UK.
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 (
51 mm) femoral components were significantly
higher than in those with the larger
(
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.
