Tuesday, June 28, 2011

Systemic effects of metal debris (7j of 7); excerpts from the Committee on Mutagenicity

Excerpts and commentary based on the 6/4 post-Metal on Metal Bearings, The Evidence So Far http://www.mydepuyhiprecall.com/2011/06/metal-on-metal-bearings-evidence-so-far.html

Genotoxic issues surrounding systemic effects of metal debris (continued from prior posts)

The committee on mutagenicity has reported that internal exposure to orthopedic metals is associated with increased genotoxicity.

This is a series of commentary from the committee on mutangenicity evidence based on the the key journal articles examined by that committee. I think you will find the results really interesting if you are concerned about the systemic effects of the metal.

I said this would be the last in this series however, there seem to be 6 items provided in confidence and I am going to try to locate the source data (more time so I myself would like to take time to review each one daily.

6th and final  group of comments from the committee (In confidence data sumbitted by the BIRC)...[6 individual comments provided.. 6-11] 

   1 of 6

Committee members noted a preliminary study where there was evidence for a higher incidence  in chromosome aberrations in the bone marrow samples adjacent to the prosthesis (the femur) ...but agreed  that it was unclear from the paper whether the metal on metal or the metal on poly hip replacements had been studied.

[Connie added: oh for goodness sakes.  how much time does it take to go to back to the researchers to determine whether this was Metal or poly?.....amazing that no one has looked at this...  ]

Clin Orthop Relat Res. 1996 Aug;(329 Suppl):S269-79.

Preliminary observations on possible premalignant changes in bone marrow adjacent to worn total hip arthroplasty implants.

Source

Department of Histopathology, University of Bristol, United Kingdom.

Abstract

Previous epidemiologic studies have suggested that there may be a risk of malignancy, especially lymphoma and leukemia, after joint replacement, but the followup has been relatively short. This is a preliminary study to see if there is any biologic basis for such a risk. Blood and bone marrow samples from 71 patients at revision arthroplasty of a loose or worn prosthesis and 30 control patients at primary arthroplasty were analyzed with cytogenetic techniques and molecular biology. There was a higher chromosomal aberration rate in cells adjacent to the prosthesis at revision surgery compared with iliac crest marrow from the same patients or with femoral bone marrow at primary arthroplasty. Clonal expansion of lymphocytes without a serum paraprotein was seen in 2 of 21 patients at revision arthroplasty performed more than 10 years after primary arthroplasty. The results of this preliminary study suggest that future epidemiologic studies should concentrate on patients with longer postoperative intervals to see if there is any risk that would be pertinent to a young patient at primary arthroplasty.

[well, I found this study just completely fascinating.  I will track down the researchers to see what type of hips they were.  (my to do list.)

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