ROCHESTER, Minn. -- A team of Mayo Clinic researchers has discovered a new, more accurate diagnostic test to detect infection of prosthetic joints, potentially leading to better treatment options and patient outcomes.
The new method, which samples bacteria that adhere to the prosthetic surface, was tested in a study of 331 patients with prosthetic hip or knee joints who were having their prosthetic joints removed for infection or another cause. The new diagnostic test detected more of the infected cases (78.5 percent) than did the conventional approach (60.8 percent). The findings are published in the August 16 issue of the New England Journal of Medicine.
While most people who have their hips or knees replaced experience dramatic benefit, a small percentage require additional surgery, most commonly for infection or loosening of the prosthetic joint. The conventional method for detecting infection, which has been used for decades and is still commonly performed, samples tissue around the prosthetic joint at the time of surgery.
The problem with the conventional method is that you need multiple tissue specimens, because the sensitivity of a single specimen is not good -- in other words, the infection might be missed with just one sample, explains Robin Patel, M.D., Mayo Clinic Professor of Medicine, who led the multidisciplinary team of orthopedic surgeons, infectious diseases physicians and laboratory researchers. Another issue is that bacteria normally found on the skin can be picked up on the tissue specimen as it is extracted and passes through the skin, yielding a false-positive result. These same bacteria may actually cause the infection, so doctors cant always tell just by the type of bacteria detected whether the patient has an infection or not. If multiple specimens are positive for the bacteria, then this indicates that the bacteria are causing the infection.
Approximately 750,000 total hip and knee replacement sur
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