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  • Metal ion levels and lymphocyte counts: ASR hip resurfacing prosthesis vs. standard THA: 2-year results from a randomized study.

Metal ion levels and lymphocyte counts: ASR hip resurfacing prosthesis vs. standard THA: 2-year results from a randomized study.

Acta orthopaedica (2013-04-20)
Jeannette Ø Penny, Jens-Erik Varmarken, Ole Ovesen, Christian Nielsen, Søren Overgaard
ABSTRACT

Wear particles from metal-on-metal arthroplasties are under suspicion for adverse effects both locally and systemically, and the DePuy ASR Hip Resurfacing System (RHA) has above-average failure rates. We compared lymphocyte counts in RHA and total hip arthroplasty (THA) and investigated whether cobalt and chromium ions affected the lymphocyte counts. In a randomized controlled trial, we followed 19 RHA patients and 19 THA patients. Lymphocyte subsets and chromium and cobalt ion concentrations were measured at baseline, at 8 weeks, at 6 months, and at 1 and 2 years. The T-lymphocyte counts for both implant types declined over the 2-year period. This decline was statistically significant for CD3(+)CD8(+) in the THA group, with a regression coefficient of -0.04 × 10(9)cells/year (95% CI: -0.08 to -0.01). Regression analysis indicated a depressive effect of cobalt ions in particular on T-cells with 2-year whole-blood cobalt regression coefficients for CD3+ of -0.10 (95% CI: -0.16 to -0.04) × 10(9) cells/parts per billion (ppb), for CD3+CD4+ of -0.06 (-0.09 to -0.03) × 10(9) cells/ppb, and for CD3(+)CD8(+) of -0.02 (-0.03 to -0.00) × 10(9) cells/ppb. Circulating T-lymphocyte levels may decline after surgery, regardless of implant type. Metal ions-particularly cobalt-may have a general depressive effect on T- and B-lymphocyte levels. Registered with ClinicalTrials.gov under # NCT01113762.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Cobalt, Carbon coated magnetic, nanopowder, <50 nm particle size (TEM), ≥99%
Sigma-Aldrich
Cobalt, foil, thickness 0.1 mm, ≥99.99%
Sigma-Aldrich
Cobalt, wire, diam. 1.0 mm, 99.995% trace metals basis
Sigma-Aldrich
Cobalt, pieces, 99.5% trace metals basis
Sigma-Aldrich
Cobalt, foil, thickness 1.0 mm, 99.95% trace metals basis
Sigma-Aldrich
Cobalt, rod, diam. 5.0 mm, 99.95% trace metals basis
Sigma-Aldrich
Cobalt, powder, <150 μm, ≥99.9% trace metals basis
Sigma-Aldrich
Chromium, chips, 99.995% trace metals basis
Sigma-Aldrich
Cobalt, granular, 99.99% trace metals basis
Sigma-Aldrich
Chromium, chips, thickness ~2 mm, 99.5%
Sigma-Aldrich
Chromium, powder, ≥99% trace metals basis, <45 μm
Sigma-Aldrich
Cobalt, foil, thickness 0.1 mm, 99.95% trace metals basis
Sigma-Aldrich
Chromium, powder, 99.5%, −100 mesh
Sigma-Aldrich
Cobalt, powder, 2 μm particle size, 99.8% trace metals basis