Metal ion trend may be more predictive for malfunctioning metal-on-metal implants than a single measurement.
Forty-eight unilateral hip resurfacing arthroplasty patients were evaluated for cobalt and chromium levels. The metal ion trend of 42 well-functioning patients was compared with six sub-optimal functioning patients. Median metal ion levels were significantly higher for the sub-optimal group. For the well-functioning implants, the percentage of patients with increasing cobalt/chromium levels between two consecutive time-intervals ('risers') gradually decreased from 90/86% (0-3 months) to 22/22% (24-36 months). The percentage of patients with increasing metal ion levels was higher in the sub-optimal group. The median absolute increase of this 'risers' subgroup was significantly lower for the well-functioning group at 12-24 months. Sub-optimal functioning MoM implants have a different metal ion trend than well-functioning implants, a higher chance of 'risers' and a larger absolute increase in time.
Department of Orthopaedics, Rijnstate Hospital, Arnhem - The Netherlands.
José M H
JM
Smolders
Annemiek
A
Hol
Job L C
JL
van Susante
D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D002857:Chromium / Q000097:blood*; D003035:Cobalt / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D007477:Ions / Q000097:blood; D008297:Male; D061825:Metal-on-Metal Joint Prostheses; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000097:blood* / Q000601:surgery*; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D013997:Time Factors; D016896:Treatment Outcome
D007477:Ions; D002857:Chromium; D003035:Cobalt