Article

Are Metal Ion Levels a Useful Trigger for Surgical Intervention?

OrthoCarolina Hip and Knee Center, Charlotte, North Carolina 28207, USA.
The Journal of arthroplasty (Impact Factor: 2.37). 05/2012; 27(8 Suppl):32-6. DOI: 10.1016/j.arth.2012.03.020
Source: PubMed

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.

0 Followers
 · 
248 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Erhöhter Verschleiß von Prothesen mit Metall-Metall-Gleitpaarungen führt bei betroffenen Patienten zu erhöhten systemischen und lokalen Metallkonzentrationen. Die lokalen Metallbelastungen in der Nähe des Implantats (z. B. Gelenkpunktat/Gewebe) sind dabei um ein Vielfaches höher als die systemischen Belastungen (z. B. im Blut/Serum). In Folge der erhöhten Metallbelastung kann es zu lokalen und systemischen Wirkungen, wie z. B. Osteolysen, Pseudotumoren, lokal-allergischen Reaktionen oder in seltenen Fällen zu Intoxikationen kommen. Die Bestimmung der systemischen Metallkonzentrationen hat sich mittlerweile etabliert, obwohl die genaue Definition eines Grenz- oder Schwellenwerts zur Diagnose eines klinischen Problems aufgrund der geringen Sensitivität schwierig ist. Derzeit wird ein Schwellenwert für Kobalt oder Chrom in der Größenordnung zwischen 4 und 7 µg/l diskutiert. Sehr hohe Konzentrationen (≥ 20 µg/l) oder die sukzessive Zunahme der Metallkonzentration sollten als alarmierende Zeichen gewertet werden. Nichtsdestotrotz sollte die Metallkonzentration nicht im Sinne eines isolierten diagnostischen Verfahrens, sondern im Gesamtkontext der klinischen und radiologischen Untersuchungen (Metal-artifact-reduction-sequence[MARS]-MRT, Ultraschall und CT) bewertet werden.
    Der Orthopäde 08/2013; 42(8). DOI:10.1007/s00132-012-2035-3 · 0.67 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Increased wear leads to elevated systemic and local metal ion concentrations for patients treated with metal-on-metal bearings. The local metal ion content in the close environment of the joint replacement (e.g. joint aspirate or tissue) is several times higher compared to the systemic metal content (e.g. in blood or serum). As a result of increased metal ion levels, local and systemic effects, such as osteolysis, pseudotumors, sensitization or in rare cases toxicity may occur. Although the definition of a specific threshold to define clinical problems is difficult due to a lack of sensitivity, the systemic metal concentration is frequently measured clinically. Currently a threshold for cobalt and chromium between 4 µg/l and 7 µg/l is under debate. Very high levels (≥ 20 µg/l) or a steady increase over time should be a warning sign; however, metal ion levels should not be interpreted as a single diagnostic tool but rather in the entire context of the clinical, radiological and cross-sectional imaging, metal artefact reduction sequence (MARS) magnetic resonance imaging (MRI), ultrasound and computed tomography (CT) findings.
    Der Orthopäde 07/2013; · 0.67 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Forty-eight unilateral hip resurfacing arthroplasty patients were evaluated for cobalt and chromium levels. The metal ion trend of 42 well-functioning patients was compared with six sub-optimal functioning patients. Median metal ion levels were significantly higher for the sub-optimal group. For the well-functioning implants, the percentage of patients with increasing cobalt/chromium levels between two consecutive time-intervals ('risers') gradually decreased from 90/86% (0-3 months) to 22/22% (24-36 months). The percentage of patients with increasing metal ion levels was higher in the sub-optimal group. The median absolute increase of this 'risers' subgroup was significantly lower for the well-functioning group at 12-24 months. Sub-optimal functioning MoM implants have a different metal ion trend than well-functioning implants, a higher chance of 'risers' and a larger absolute increase in time.
    Hip international: the journal of clinical and experimental research on hip pathology and therapy 08/2013; 23(5). DOI:10.5301/hipint.5000066 · 0.76 Impact Factor
Show more