Findings from a study published in the February issue of the journal Clinical Orthopaedics and Related Research (CORR) suggest that the alpha-defensin assay may be a reliable diagnostic tool for the identification of periprosthetic joint infection (PJI). 

The authors conducted a prospective study of 156 patients who underwent total joint arthroplasty (65 knees, 91 hips), 29 of whom received a confirmed diagnosis of PJI. They found that the alpha-defensin immunoassay produced a sensitivity of 97 percent, specificity of 97 percent, positive predictive value of 88 percent, and negative predictive value of 99 percent. Among four false-positive patients, the authors note that two had metallosis and one had polyethylene wear, and the false-negative case presented with a draining sinus. They argue that follow-up evaluation should be conducted to estimate longer term performance of the test. Learn more...