Researchers from the Mayo Clinic have developed a new, more accurate test to detect infection in prosthetic joints. The standard method is to culture samples of tissue from around the prosthetic joint at the time it's being removed and replaced, but this method isn't very reliable. The new approach involves culturing biofilm taken from the surface of prosthetic joints. Infection involving a prosthetic joint can be difficult to diagnose because although patients may report pain, many have no other signs typically associated with infection, such as fever.
The study involved 331 patients having knee or hip prostheses removed for infection or aseptic failure. Researchers performed both diagnostic tests for each patient. The new test detected more cases of infection (78.5%) than did the standard method (60.8%).
The standard method has several shortcomings. For example, it requires multiple tissue samples because infection could be missed with just one. Also, as tissue passes by the skin during extraction, it could pick up bacteria and yield a false-positive result. The researchers found that the new test was more sensitive than the traditional one, especially in patients who'd received antimicrobial therapy within 14 days before surgery.
About 750,000 knee and hip replacements are performed each year in the United States. That number is expected to increase to 2.5 million by 2030.