The association between metal ions from hip resurfacing and reduced T-cell counts.
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.
Royal National Orthopaedic Hospital, Stanmore, UK. alisterjhart@yahoo.com
A J
AJ
Hart
T
T
Hester
K
K
Sinclair
J J
JJ
Powell
A E
AE
Goodship
L
L
Pele
N L
NL
Fersht
J
J
Skinner
D000328:Adult; D000368:Aged; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002857:Chromium / Q000097:blood*; D003035:Cobalt / Q000097:blood*; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D020959:Polyethylene; D011474:Prosthesis Design
D002857:Chromium; D003035:Cobalt; D020959:Polyethylene