title: Are metal ion levels a useful trigger for surgical intervention?
abstract: The purpose of this study was to determine if cobalt and chromium ion levels can predict soft tissue damage at total hip revision. This study included 90 metal-on-metal total hip patients with preoperative cobalt and chromium ion levels. Tissue damage noted at revision surgery was graded on a 4-point scale. Sensitivity, specificity, and predictive values were calculated for various threshold values. Receiver operating characteristic analysis was conducted. Using 7 ppb as a threshold, cobalt and chromium ion levels had poor sensitivity and specificity (Co, 65% and 56%; Cr, 29% and 75%). Positive predictive values for cobalt and chromium were only 48% and 26% respectively. The area under the curve was 0.37 for cobalt and 0.44 for chromium. The length of time to revision significantly correlated with tissue damage (P = .001). Ion levels are unreliable predictors of periarticular soft tissue damage and should not be used in isolation as surgical intervention triggers.
authors.affiliation: OrthoCarolina Hip and Knee Center, Charlotte, North Carolina 28207, USA.
authors.forename: William L
authors.initials: WL
authors.lastname: Griffin
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Fehring
authors.forename: James C
authors.initials: JC
authors.lastname: Kudrna
authors.forename: Robert H
authors.initials: RH
authors.lastname: Schmidt
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Christie
authors.forename: Susan M
authors.initials: SM
authors.lastname: Odum
authors.forename: Anne C
authors.initials: AC
authors.lastname: Dennos
mesh_terms: D002857:Chromium / Q000097:blood*; D003035:Cobalt / Q000097:blood*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D007477:Ions; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D011183:Postoperative Complications / Q000097:blood* / Q000209:etiology / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure / Q000009:adverse effects*; D012086:Reoperation; D012189:Retrospective Studies; D018570:Risk Assessment
chemical_list: D007477:Ions; D002857:Chromium; D003035:Cobalt