The Value of Serial Metal Ion Levels in following up Patients with Metal-on-Metal Hip Arthroplasty
McHugh, G., Merchant, R., Kelly, G. E., Bergin, K. M., McCoy, G. F., Wozniak, A. P., & Quinlan, J. F. (2017).Hip
Background
The sensitivity of cobalt (Co) and chromium (Cr) ion-levels in detecting poorly performing metal-on-metal hip implants is low. This study proposes that serial changes in ion-levels are a more accurate marker of arthroplasties at risk.
Methods
Serial metal ion-levels and implant data of 285 patients with ASR resurfacing or replacement were studied. Patient and implant characteristics were analysed using univariate and multivariate analyses.
Results
111 (39%) had revision surgery. Time since index surgery (p≤0.001), acetabular inclination (p≤0.001), their interaction (p≤0.001) and femoral head size (p = 0.01) were significant variables. Head size (≤51 mm) had lower Co and Cr levels (p = 0.01). Cr/Co showed marginal decrease over time in the unrevised group and no decrease prerevision.
Conclusions
Repeated measurement of ion-levels were higher in the revision group suggesting that serial measurements rather than absolute values may have a role to play in predicting implant failure.
Link to article