Sunday, August 25, 2013
Interesting study on the rapidity of decline of Cr and Co level after metal bearings are removed.
J Arthroplasty. 2013 Aug 12. pii: S0883-5403(13)00505-6. doi: 10.1016/j.arth.2013.06.040. [Epub ahead of print]
Serum cobalt (Co) and chromium (Cr) levels are commonly used to screen for excessive wear of metal-on-metal hip replacements. However, it is unknown how rapidly these should decline after revision. 25 patients with average Co and Cr ion levels of 56.3μg/L and 20.5μg/L were followed with serial ion level testing post-revision. Over the first 6weeks post-revision, the rate of decline for Co and Cr was approximately 2% per day and this slowed to approximately 1% decline per day over the ensuing 6weeks. This translated to a decline of approximately 80% from the starting value after 6weeks and a decline of approximately 90% after 12weeks post-revision. The rate of decline for both Co and Cr was significantly faster during the first 6weeks (P<0.001). In patients with ultra-high Cr levels>20μg/L, the rate of Cr decline is less predictable and may be protracted leading to persistent elevation above 5μg/L for one year or more post-revision in some cases.
Posted by Connie at 4:33 PM