Early markers of nephrotoxicity in patients with metal-on-metal hip arthroplasty.
BACKGROUND
Metal ions released from arthroplasty devices are largely cleared in urine, leading to high exposure in renal tissues. Validated early markers of renal damage are routinely used to monitor workers in heavy metal industries, and renal risk can be quantified in these industries. It is unclear if the ion levels in patients with metal-on-metal hips are sufficient to cause renal damage.


OBJECTIVE
Does metal-on-metal (MOM) bearing use over a 10-year period lead to elevation of early renal markers compared with the levels expected in subjects with no metal exposure?


METHODS
We retrospectively reviewed 31 patients who underwent MOM hip resurfacings 10 years earlier. Whole blood specimens were collected for metal ion analysis, serum for creatinine estimation, and urine for timed metal ion output and renal markers. The renal marker levels of 30 age- and gender-matched subjects with no metal exposure and no known renal problems or diabetes mellitus were used as controls for renal markers.


RESULTS
Median serum creatinine level in the MOM group was 1.1 mg/dL (interquartile range, 1.0-1.2 mg/dL) and median creatinine clearance was 79.2 mL/min. In this cohort, the number of patients with markers of renal damage above the reference range was comparable to the controls. None of the renal markers were associated with metal levels.


CONCLUSIONS
The absence of elevation of renal markers in this cohort 10 years after MOM bearing implantation is reassuring. However, we believe surveillance through further longer-term, large-scale controlled trials are needed to monitor this arthroplasty-induced low-intensity (but long-term) trace element exposure to rule out potential nephrotoxicity.
Nephrology and Health Sciences, University of Parma, Parma, Italy.
Massimo
M
Corradi
Joseph
J
Daniel
Hena
H
Ziaee
Rossella
R
Alinovi
Antonio
A
Mutti
Derek J W
DJ
McMinn
D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D015415:Biomarkers / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008670:Metals / Q000009:adverse effects / Q000097:blood*; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000097:blood / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D051437:Renal Insufficiency / Q000097:blood / Q000139:chemically induced*; D012189:Retrospective Studies; D013997:Time Factors
D015415:Biomarkers; D008670:Metals