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

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 60x 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.