In the U.S., approximately 600,000 knees and 400,000 hips are replaced every year with prosthetic (artificial) joints, according to the American Academy of Orthopaedic Surgeons.
While most surgeries lead to pain-free function, some patients experience a rare complication called periprosthetic joint infection (PJI), which involves the prosthetic joint and surrounding tissue. In this case, additional surgery may be needed.
Finding a reliable way to diagnose PJI
For a long time, orthopaedic surgeons lacked a reliable way to diagnose PJI. This made it difficult to tell whether inflammation around a prosthetic joint was due to an infection or to another cause, and therefore to recommend the best treatment plan for the patient.
Carl Deirmengian, MD, an orthopaedic surgeon at Main Line Health and a clinical assistant professor at Lankenau Institute for Medical Research (LIMR) was determined to tackle the problem.
"When surgeons tested for PJI, the results left room for interpretation, so there was a level of inconsistency among hospitals," says Dr. Deirmengian. "It was a big problem for the orthopaedic field overall."
While most previous strategies to diagnose PJI aimed at trying to detect the pathogen, with mixed results, Dr. Deirmengian instead started looking at the patient's immune response.
Experiments completed in his lab showed that alpha defensin, a protein released by white blood cells that have been activated in response to infection, was an ideal biomarker for PJI. His team then devised a test that could pinpoint alpha defensin in joint-surrounding synovial fluid.
Receiving FDA approval
Since the initial research was completed, Dr. Deirmengian's test has received FDA approval. Now known as Synovasure®, the test—which can detect PJI in 10 to 20 minutes—marks a truly exciting development in orthopaedic care.
"We were thrilled when the FDA authorized the diagnostic test after it demonstrated excellent performance in the clinical trial," says Dr. Deirmengian. "By meeting our goal to provide a more consistent, standardized approach to diagnose infection, we've also been able to improve patient care, lower risk and reduce health care costs."