Monday, January 30, 2012

Evidence that there is no differentitation long term re effectives of one bearing surface over another in hip replacements! what?

Yet another surprising conclusion from a great school.  I can't believe this conclusion.  If this conclusion is so, why did so many surgeons jump into the metal abyss?  There is so much literature in existence to direct surgeons to be selective about whether they use ceramic, poly, metal etc on certain patient types.  This study conclusion sort of turns all of this on its head doesn't it?

I was also surprised that the ceramic on ceramic hip didn't turn out to have less revisions than the others. 

I wonder if I am misinterpreting this?

Good Lord!

BMJ. 2011 Nov 29;343:d7434. doi: 10.1136/bmj.d7434.

Comparative assessment of implantable hip devices with different bearing surfaces: systematic appraisal of evidence.


Weill Cornell Medical College, New York, NY 10065, USA.



To determine comparative safety and effectiveness of combinations of bearing surfaces of hip implants.


Systematic review of clinical trials, observational studies, and registries.


Medline, Embase, Cochrane Controlled Trials Register, reference lists of articles, annual reports of major registries, summaries of safety and effectiveness for pre-market application and mandated post-market studies at the United States Food and Drug Administration.


Criteria for inclusion were comparative studies in adults reporting information for various combinations of bearings (such as metal on metal and ceramic on ceramic). Data search, abstraction, and analyses were independently performed and confirmed by at least two authors. Qualitative data syntheses were performed.


There were 3139 patients and 3404 hips enrolled in 18 comparative studies and over 830 000 operations in national registries. The mean age range in the trials was 42-71, and 26-88% were women. Disease specific functional outcomes and general quality of life scores were no different or they favoured patients receiving metal on polyethylene rather than metal on metal in the trials. While one clinical study reported fewer dislocations associated with metal on metal implants, in the three largest national registries there was evidence of higher rates of implant revision associated with metal on metal implants compared with metal on polyethylene. One trial reported fewer revisions with ceramic on ceramic compared with metal on polyethylene implants, but data from national registries did not support this finding.


There is limited evidence regarding comparative effectiveness of various hip implant bearings. Results do not indicate any advantage for metal on metal or ceramic on ceramic implants compared with traditional metal on polyethylene or ceramic on polyethylene bearings.

1 comment:

  1. It looks like the study was done last Nov. so it isn't relative to decisions to use MOM in prior years. I have seen numerous studies prior to 2010 suggesting major issues with metal ion poisoning as far back as the 50's. There has never been any data that supports the MOM design being superior to PE ceramic or any other combo. The facts are that surgeon's were inticed by the MOM manuf. to use the product. We as the end user were made to believe the MOM design was better by our surgeons based on nicely pointed ads of a woman running on the beach and a nice golf swing.
    Just my take on it