Sunday, July 17, 2011

Review of the Cell biology surrounding metal on metal hips (1 of x in a series)

This review  seems to be the most recent recap describing the biology of what happens in a cell when it comes into contact with the Chromium and Cobalt.  This topic is of interest because it provides the clues as to what the long term systemic bilogical consequences of the exposures to these particles might be.
Given the techncal nature of this subject, I will break this down into a series of commentaries on the content. I don't know how many posts will be required to cover this topic so will leave the series open ended (x.)
The following  abstract  will serve as the base document for comments. 
 I have gained some understanding of the link between the change in cell biology that is caused by these metal on metal hips and the possible assocation over time with cancer  from reading this document.  Understand, there have been no direct links showing cause and effect (metal from the hip causes cancer) but my sense from reading all of these documents is that it is not because there is no link but because there has not been enough data collected from the patients who have these hips in place over time to demonstrate unequivocally that there is a link.  The early studies in this arena whereby data has been collected over a 10 year period , have certainly demonstrated that over that time frame, the changes in the cell biology (DNA) which occur are those which are seen  in Lymphoma (cancer of the immune system) and Leukemia (Leukemia is cancer of the blood cells. It starts in the bone marrow, the soft tissue inside most bones.)  That doesn't mean one causes the other necessarily.  It means that there are similarities in the processes.
In prior articles, I have demonstrated that there is certainly enough seminal research in this field to strongly support the need for a concentrated effort in this area of research.  I believe that  the company's manufacturing the metal on metal hips should, in part, underwrite these studies as a part of the hip litigation settlement. 
As usual, I want to remind the readers that I am not a medical researcher nor do I have any training in this area of study.  I can only provide my own commentary into the questions.  I have no answers.
Acta Orthop. 2008 Dec;79(6):734-47.

Metal-on-metal hip resurfacing arthroplasty: a review of periprosthetic biological reactions.


Nuffield Department of Orthopaedic Surgery, Institute of Musculoskeletal Science, Botnar Research Centre, University of Oxford, Oxford, UK.


Metal-on-metal hip resurfacing arthroplasty has undergone a recent resurgence as an alternative treatment option for young and active patients with significant osteoarthritis. The claimed advantages of metal-on-metal hip resurfacing arthroplasty include lower wear rate, preservation of bone stock for subsequent revision procedures, restoration of anatomic hip mechanics, and enhanced stability due to the larger diameter of articulation. A disadvantage, however, is that the metal-on-metal resurfacing releases large amounts of very small wear particles and metal ions. The long-term biological consequences of the exposure to these Co-Cr particles and ions remain largely unknown. The purpose of this review is to provide an overview of the current literature on the adverse periprosthetic biological reactions associated with metal-on-metal hip resurfacing arthroplasty.

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