Transplant tissue cited in knee surgery infections

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Transplant tissue cited in knee surgery infections

By Emma Hitt, PhD

ATLANTA, Dec 06 (Reuters Health) - Four patients undergoing knee surgery

developed an infection from transplant tissue used for the surgery,

highlighting the need for improved sterilization methods, according to

the US Centers for Disease Control and Prevention (CDC).

Approximately 50,000 procedures to repair the knee's anterior cruciate

ligament (ACL) are conducted each year in the US. Rarely, infection

during the surgery causes inflammation in the joint called septic

arthritis, CDC researchers note in the December 7th issue of agency's

Morbidity and Mortality Weekly Report.

" The number of persons who develop septic arthritis caused by

bacterially contaminated (donor tissue) is unknown, " the researchers

write, but they point out that in 1999, US tissue banks distributed

approximately 750,000 tissue samples for transplantation.

According to the report, four people developed bacterial infections

after their surgeries: three in Florida--a 16-year-old girl, a

40-year-old man and a 55-year-old woman--and a 29-year-old woman in

Louisiana.

Each patient sought medical care a few days after surgery because of

infection in the recovering knee. All four were placed on antibiotics

for several weeks.

The transplant tissue used in each of the four surgeries came from two

different tissue banks, one in Texas and the other in Florida. Two

donors had provided tissue for the four surgeries, one donor at each

tissue bank.

According to the CDC, the tissue from the Texas bank was infected

despite " no apparent lapses in tissue processing. " But the tissue from

the Florida bank was released " inadvertently " before sterilization

procedures were conducted.

Although the American Association of Tissue Banks provides guidelines

for transplant tissue processing, the guidelines are unclear about when

a tissue sample should be further disinfected or discarded, the CDC

researchers note. And about 44% of tissue banks are not accredited by

the association.

Furthermore, one of the methods used to sterilize tissue, called gamma

irradiation, may impair the functioning of this type of tissue in a

transplant patient. And the other method, called ethylene oxide

sterilization, is not particularly effective, the CDC authors add.

" Effective sterilization methods that do not functionally alter

musculoskeletal tissue are needed, " the CDC's Dr. n Kainer told

Reuters Health. " There are several tissue banks that are involved in

research and development of such methods. "

The CDC also points out that reporting of infections from contaminated

transplant tissue is not required, although the transplants must be

screened for HIV, hepatitis and other blood-borne pathogens.

This report underscores the need for standardized screening procedures,

improved oversight of tissue banks, a system for reporting infections

transmitted through human tissue and the development of better

sterilization methods, the CDC team indicates.

" CDC is collaborating with other health agencies to identify other cases

of transplant-related infections, " Kainer said. " This will better

determine the risk and identify ways to further reduce the chance of

infection. "

Another report in the same issue updates the CDC investigation involving

three Minnesota patients who died unexpectedly following elective knee

surgery last month. According to the CDC, the investigation is now

focused on the possible contamination of transplant tissue received by

one of the patients.

SOURCE: Morbidity and Mortality Weekly Report 2001;50:1080, 1081-1084.