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Scientific Articles:
Thomas F. McGovern, Deborah J. Ammeen, John P. Collier, Barbara H. Currier, and Gerard A. Engh
Rapid Polyethylene Failure of Unicondylar Tibial Components Sterilized with Gamma Irradiation in Air and Implanted After a Long Shelf Life
J Bone Joint Surg Am 2002; 84: 901-906 [Abstract] [Full text] [PDF]
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[Read Letter to the Editor] Disaster strikes
David R. Graham   (17 June 2002)

Disaster strikes 17 June 2002
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David R. Graham,
Orthopaedic Surgeon
None

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Re: Disaster strikes

bonedoc2000{at}hotmail.com David R. Graham

Drs. McGovern et al are to be congratulated for their bravery in publishing this paper. Seventy-five index total knee arthroplasties were performed (in 62 patients). After a mean period of only eighteen months (range, seven to thirty months), fifty percent (thirty-seven of seventy- five) of the arthroplasties had failed due to polyethylene wear. This may rank as the worst results of any series of total knee arthroplasties reported in the orthopaedic literature - certainly in the past decade or more! I would suspect that the surgeon involved is now counting down: only 38 more revisions to go. Note that these were all arthroplasties performed by a master total knee surgeon.

I do not believe that the explanation given (oxidation secondary to gamma irradiation in air) is a sufficient explanation for these results. Using the same prosthesis, the multicenter study by Lindstrad did not find that there was early wear and rapid failure of the tibial bearing, over a follow-up interval of one to six years.

There is no question about the deleterious effects of gamma irradiation in air on polyethylene and little controversy about the cumulative effects over time. However, a polyethylene tibial bearing sitting on a shelf in a box or sitting on a shelf (the tibial plateau) in a patient continues to undergo oxidation. I am not aware that anyone has suggested that there is a protective effect of implanting gamma irradiated in air polyethylene into a patient. For many years, we all used polyethylene irradiated in air in our total hip and total knee arthroplasties. Virtually all of these components lasted longer than thirty months (some for 20 years or more).

Unfortunately, I believe someone needs to delve more deeply into why this group of patients has such a high rate of failure. Recently we have seen numerous examples (from several orthopaedic suppliers) of "glitches" in the manufacturing process of total joint implants. Whether this is the case here, I do not know. All patients that received this prosthesis using implants manufactured during the time in question (a period of several years) need to be identified and evaluated, and this responsibility now lies with the manufacturer.

Papers such as this are very important and valuable contributions. Most surgeons prefer to crow about their successes and hide their failures. The authors are to be applauded for their ethics in reporting this series of patients.

Note that I just checked the Stryker Osteonics Howmedica web site and find that the Duracon unicompartmental knee is NOT shown. I suspect therefore that the sale and use of this prosthesis has been suspended until a complete explanation has been found for the dismal results reported in this paper.