Synovial tissue examination by frozen section as an indicator of infection in hip and knee arthroplasty in community hospitals

Abstract

Twenty-five surgical synovial sections were examined in 18 consecutive patients undergoing revision hip or knee arthroplasty (9 hips and 9 knees). All cases were performed in either of two community hospitals, with frozen-section tissue examined by multiple general pathologists. By protocol, acute inflammation was defined as more than five neutrophils per 60× high-power fields on multiple areas. A positive culture was defined as organism growth from any surgical specimen. In each case, three surgical cultures and three frozen-section specimens were harvested from the synovium at corresponding periprosthetic surgical sites before antibiotics were administered. The average age of the patients was 68 years (range 40–87 years). There were 11 positive surgical cultures, 9 with positive frozen sections of synovium for acute inflammation (sensitivity, 82%; 95% confidence interval, 78–100%). There were 14 negative cultures; 13 had negative surgical frozen sections (specificity, 93%; 95% confidence interval, 83–100%). The positive predictive value of the test was 82%. There was accurate correlation between frozen section and culture in 22 of 25 cases (88%). In this community hospital setting, frozen section examination of surgical synovial tissue proved to be a reasonably sensitive and specific predictor of deep infection in revision hip and knee arthroplasty.