The Utility of Metal Ion Trends in Predicting Revision in Metal-on-Metal Total Hip Arthroplasty.
There is a paucity of data examining metal ion levels over time.



We retrospectively reviewed 59 patients (69 hips) with an articular surface replacement total hip arthroplasty. We reviewed prerevision cobalt and chromium concentrations over time.



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).



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.
Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.
Bayard C
BC
Carlson
Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.
Andrew J
AJ
Bryan
Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.
Nazly T
NT
Carrillo-Villamizar
Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.
Rafael J
RJ
Sierra
D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D002857:Chromium; D003035:Cobalt; D005260:Female; D006615:Hip; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D007477:Ions; D008297:Male; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D008670:Metals; D008875:Middle Aged; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012189:Retrospective Studies
D007477:Ions; D008670:Metals; D002857:Chromium; D003035:Cobalt
ASR; adverse reaction to metal debris; metal ion levels; metal-on-metal total hip arthroplasty; pseudotumor; trunnionosis