The association between metal ions from hip resurfacing and reduced T-cell counts

Abstract

We have studied the relationship between metal ion levels and lymphocyte counts in patients with metal-on-metal hip resurfacings. Peripheral blood samples were analysed for lymphocyte subtypes and whole blood cobalt and chromium ion levels in 68 patients (34 with metal-on-metal hip resurfacings and 34 with standard metal-on-polyethylene total hip replacements). All hip components were radiologically well-fixed and the patients were asymptomatic. Cobalt and chromium levels were significantly elevated in the patients with metal-on-metal hip resurfacings, compared with the patients with standard metal-on-polyethylene designs (p < 0.0001). There was a statistically significant decrease in the level of CD8(+) cells (T-cytotoxic/suppressor) (p = 0.005) in the metal-on-metal hip resurfacing group. A threshold level of blood cobalt and chromium ions was associated with reduced CD8(+) T-cell counts. We have no evidence that our patients suffered as a result of this reduced level of CD8(+) T-cells.

Metal-on-metal hip resurfacing arthroplasty: A review of periprosthetic biological reactions

“…A relationship between metal ion levels and lymphocyte counts in patients with well-functioning MoM hip resurfacings has been reported (Hart et al 2006). A threshold whole blood level of Co and Cr combined of greater than 5 µg/L was found to be associated with a reduction in the circulating levels of T cytotoxic (CD8+) subsets in the MoM group.…”

Risk of Impingement and Third-body Abrasion With 28-mm Metal-on-metal Bearings

“…Both positive [2,11] and negative reports [25,34,35,37,61] have emerged with regard to using MoM bearings. There are likely many risks that could trigger a need for MoM revision.…”

Investigating the Immunologic Effects of CoCr Nanoparticles

“…Therefore, CoCr nanoparticles can inhibit Signal 1-and 2-dependent T cell proliferation and, importantly, this effect occurred at sublethal concentrations of CoCr. Hart et al [12] reported a reduction in CD8+ T cells in patients with elevated CoCr levels after M/M hip resurfacing, although how this effect is mediated has not been described [15]. Our data suggest antigen-specific stimulation is necessary for CoCr to have effects on T cell function and number, although where, when, and what antigen stimulus is necessary remains unclear.…”

“…This is evident from the perivascular infiltrate of T and B lymphocytes, including plasma cells found in association with some M/M implants, which is more pronounced in implants that have failed secondary to aseptic loosening and therefore may represent the mode of failure [5]. Furthermore, a reduction in CD8+ T lymphocyte counts associated with M/M hip resurfacing implants also has been described [12]. The presence of lymphocytes in perivascular infiltrates surrounding M/M implants suggests activation of CD4+ T helper cells.…”