New cleaning process may stave off ACL-allograft-associated infections

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New cleaning process may stave off ACL-allograft-associated infections

Rheumawire

Aug 5, 2004

Mann

New York, NY- A new allograft cleaning process can help ensure that

tissue is pathogen- and virus-free, potentially paving the way for more

anterior-cruciate-ligament (ACL)-tear repairs among 40- and 50-year-olds

who want shorter recoveries, says a New York orthopedic surgeon.

Called the Clearant Process (Clearant, Los Angeles, CA), the new method

prepares the tissue by first controlling the pH level, then irradiating

the graft with high doses of gamma radiationwithout destroying the

quality of the tissue. Large doses of antioxidants are infused to

preserve the structural integrity of the tissue. The method, which has

already been licensed by 7 human tissue banks and distributors,

inactivates viruses (lipid enveloped and nonenveloped, DNA and RNA,

double- and single-stranded), bacteria (gram positive and negative,

aerobic and anaerobic), fungi, spores, and the causative agents for

transmissible spongiform encephalopathies (TSEs).

" The graft is put in a container to keep it sterile in case the patient

has a pathogen not picked up in allograft screening, " says Dr Fred

Cushner (Insall Institute for Orthopaedics and Sports

Medicine, New York City, NY). " Radioprotection is used because the only

way to kill pathogens is with radiation, but if you do that without

protecting tissue, you are frying it like a piece of bacon, " he tells

rheumawire.

" When you want to do a ligament reconstruction such as fixing the ACL to

help prevent arthritis, the one downside of cadaver tissue is possible

chance of infection, " Cushner tells rheumawire.

Five years ago, 15% of these repairs were done with allografts; now it

is more like 30%, he says. Allograft surgery is becoming increasingly

popular, with procedures doubling in the past decade to 850 000 a year

in the US.

" Allografts are less painful, and they ensure a faster recovery as well

as less scarring and swelling, " he says. " If you take [tissue] from your

own, you have to heal from the operation and heal from donor site, " he

says. " Today, people in their 40s and 50s are the ones undergoing these

operations, they have a job and kids and don't have as much time to get

better. "

" Patients can now be assured that the cadaver tissue has been completely

sterilized by methods like the Clearant Process, " he says.

" The only thing pending is passage of time, " he says. " Clearant has been

tested in numerous lab tests, and while I can't tell you what will

happen as far as failure rates at 10 years down the line, initially it

is very promising, " he says. " If you get hepatitis from a graft, that's

hard to cure, but failure can be fixed. " Moreover, this same process

could eventually be applied to blood products, plasma protein

derivatives, biotechnology recombinant products, and serum in other

areas such as veterinary products, food, cosmetics, and nutraceuticals.

After a highly publicized death due to an allograft infection in

Minnesota, there has been a renewed call for increased tissue-protection

safety. Public-health experts recently published their recommendations

in the June 17, 2004 issue of the New England Journal of Medicine [1].

One of the authors, Dr n A Kainer (Tennessee Department of Health,

Nashville), is familiar with the Clearant Process.

" It sounds like a good theoretical process, " Kainer tells rheumawire.

" It provides terminal sterilization, and it is something that many

tissue banks can implement because it can be added at the end, and it

doesn't require a large capital investment, " she says.

Calling the company's data " compelling, " Kainer says that the Clearant

Process " appears to be active in killing bacteria and virus. " In terms

of tissue safety, " it's really important to have new sterilization

methods that sterilize tissue but don't affect structural integrity, "

she says.

Source

Kainer MA, Linden JV, Whaley DN, et al. Clostridium

infections associated with musculoskeletal-tissue allografts. N Eng J

Med 2004; 350:2564-71.

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org