Background There is a paucity of data examining metal ion levels over time. Methods We retrospectively reviewed 59 patients (69 hips) with an articular surface replacement total hip arthroplasty. We reviewed prerevision cobalt and chromium concentrations over time. Results Seventy-one percent of patients who were revised and had multiple ion measurements (12/17) demonstrated increasing cobalt ion levels or elevated ion levels over time. There was a trend toward an elevated risk of revision for increasing cobalt and chromium levels starting at 12 and 4 ppb, respectively; this was significant for chromium levels above 7 ppb (hazard ratio 22.35, P =.001). Similarly, there was a trend toward an elevated risk of pseudotumor formation for increasing cobalt and chromium levels starting at 5 and 2.5 ppb, respectively; this was significant for cobalt levels above 7 ppb (hazard ratio 6.88, P =.027). Conclusion In this paper, cobalt and chromium levels levels above 5 and 2.5 ppb started to demonstrate an increased risk of ARMD, and should be considered as a lower cutoff for discussion with patients about the potential for future revision.
- adverse reaction to metal debris
- metal ion levels
- metal-on-metal total hip arthroplasty
ASJC Scopus subject areas
- Orthopedics and Sports Medicine