Predicting wear and blood metal ion levels in metal-on-metal hip resurfacing

• Published in: Journal of orthopaedic research 2014-01, Vol.32 (1), p.167-174
• Main Authors: Matthies, Ashley K., Henckel, Johann, Cro, Suzie, Suarez, Alexander, Noble, Philip C., Skinner, John, Hart, Alister J.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Arthroplasty, Replacement, Hip - adverse effects; Arthroplasty, Replacement, Hip - methods; Chromium - blood; Chromium - pharmacokinetics; Cobalt - blood; Cobalt - pharmacokinetics; Equipment Failure Analysis; Female; Hip Joint - metabolism; Hip Joint - surgery; Hip Prosthesis - adverse effects; hip resurfacing; Humans; Linear Models; Male; metal ions; metal-on-metal; Middle Aged; Predictive Value of Tests; Prospective Studies; Prosthesis Design; Reoperation; retrievals; wear; Young Adult
• ISSN: 0736-0266; 1554-527X
• DOI: 10.1002/jor.22459

ABSTRACT Suboptimal component position and design are thought to lead to edge wear and raised blood metal ion levels in metal‐on‐metal hip resurfacing (MOM‐HR). These factors are thought to influence the “contact patch to rim distance” (CPRD), and calculation of this distance may improve prediction of wear and blood metal ion levels. We measured blood cobalt and chromium ion levels and the wear rates of the bearing surfaces in 165 MOM‐HR retrieval cases. We then determined the contribution and effect sizes of cup inclination and version angles, component size and design, and CPRD (calculated from case‐specific data) on blood metal ion levels and component wear rates. Acetabular orientation explained between 16.3% and 28.5% of the variation in wear rates and metal ion levels, whereas component size and design explained between 7.3% and 21.8% of the variability. In comparison, CPRD explained up to 67.7% of the variability, significantly greater than any other variable (all p