title: Metal ion levels: how can they help us?
abstract: Ion levels have been shown to reliably predict abnormal function of the bearing surface with increased wear, but ion levels should not be used alone as a trigger for when to proceed with revision surgery with metal-metal articulations. Risk stratification strategies help determine which patients should be monitored more closely with serial ion levels, cross-sectional imaging with a MARS MRI, or proceed on to revision. Based on the current data available, an ion level greater than 4.5 ppb (Cr or Co) may serve as a threshold for when abnormal wear is occurring, and is suggested as a trigger for a MARS MRI scan.
authors.affiliation: Ortho Carolina Hip & Knee Center Charlotte, North Carolina.
authors.forename: William L
authors.initials: WL
authors.lastname: Griffin
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D001672:Biocompatible Materials / Q000032:analysis; D002857:Chromium / Q000097:blood; D003035:Cobalt / Q000097:blood; D003343:Corrosion; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D007477:Ions / Q000097:blood*; D008279:Magnetic Resonance Imaging; D019216:Metals, Heavy / Q000097:blood*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation
chemical_list: D001672:Biocompatible Materials; D007477:Ions; D019216:Metals, Heavy; D002857:Chromium; D003035:Cobalt
keywords: adverse local tissue reaction; metal ion levels; metal-on-metal; total hip arthroplasty