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Updated: May 8, 2026

Multi-Scale Modification of Metallic Implants With Pore Gradients, Polyelectrolytes and Their Indirect Monitoring In vivo
Published on: July 1, 2013
Metal ion trend may be more predictive for malfunctioning metal-on-metal implants than a single measurement
José M H Smolders1, Annemiek Hol, Job L C van Susante
1Department of Orthopaedics, Rijnstate Hospital, Arnhem - The Netherlands.
Abstract:
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.
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