Blood nickel concentrations in patients with stainless-steel hip prostheses

Nickel concentrations were analyzed by electrothermal atomic absorption spectrophotometry in serum and whole blood specimens from patients 9 to 15 years after unilateral (N = 11) or bilateral (N = 2) hip arthroplasty. The hip prostheses were of the "Charnley" or "TR-28" (metal-to-plastic) types, fabricated of stainless-steel (14 to 16 percent Ni) with polyethylene acetabular cups. In 12 of the 13 patients, nickel concentrations (+/- SD) averaged 0.30 +/- 0.25 microgram per L (range 0.05 to 0.85) in serum and 0.36 +/- 0.20 microgram per L (range 0.11 to 0.67) in whole blood; these values did not differ significantly from the corresponding nickel concentrations in specimens from 30 healthy controls (0.28 +/- 0.24 microgram per L, range less than 0.05 to 1.08, in serum; 0.34 +/- 0.28 microgram per L, range less than 0.05 to 1.05, in whole blood). The remaining patient, a 78-year-old man with bilateral hip arthroplasty, had nickel concentrations of 3.1 micrograms per L in serum and 2.3 micrograms per L in whole blood; renal insufficiency apparently contributed to hypernickelemia in this patient. The arthroplasty patients were asymptomatic with respect to their joint replacements; X-rays at the last follow-up examinations did not reveal bone resorption around the implants. This study shows that patients with stainless-steel hip prostheses of the metal-to-plastic types do not develop hypernickelemia in the apparent absence of corrosion, local complications, or systemic conditions, such as renal insufficiency.