Cobalt, chromium, and nickel concentrations in body fluids of patients with porous‐coated knee or hip prostheses

Abstract

Co, Cr, and Ni concentrations were determined by electrothermal atomic absorption spectrophotometry in serum and urine specimens collected from a group of 28 patients at intervals of from 1 day to 2.5 years after total knee or hip arthroplasty with porous‐coated prostheses fabricated of Co‐Cr alloy (ASTM F‐75‐82). Two control groups were also tested: (a) 42 healthy adults and (b) 16 orthopaedic patients after total knee or hip arthroplasty with porous‐coated prostheses fabricated predominantly of Ti‐Al‐V alloy (ASTM F‐136‐84). All prostheses contained polyethylene components to avoid metal‐to‐metal contact. Mean Co concentrations in serum and urine were slightly increased in patients with Co‐Cr knee implants at 6–120 weeks after surgery, compared with (a) preoperative values, (b) corresponding values in patients with Co‐Cr hip implants, and (c) corresponding values in control patients with Ti‐Al‐V knee and hip prostheses. Substantially increased Co levels were observed in serum and urine of two patients at 7 weeks and 22 months postarthroplasty, associated with loosening of the prostheses; one of the patients also had elevated Cr levels in serum and urine. Although ASTM F‐75‐82 and F‐136‐84 alloys contain very little Ni (<1.0 and <0.2% Ni, respectively, by wt), mean Ni concentrations in serum and urine were greatly increased at 1–2 days after implantation of Ti‐Al‐V and Co‐Cr prostheses, diminishing by 2 weeks. The postoperative hypernickelemia and nickeluresis may reflect contamination of the operative field with Ni‐containing particles from the drills, cutting jigs, and drilling jigs, or it may represent a previously unrecognized pathophysiological response to surgery.