Abstract
Introduction
Infection after total joint arthroplasty is a challenging problem. Clinical symptoms, Erythrocyte sedimentation rate, C-reactive protein level, and cultures of synovial fluid obtained by means of percutaneous aspiration are commonly used to rule out the possibility of persistent infection before reimplantation. However, the sensitivity and specificity of the tests are low. Some authors have suggested that frozen-section analysis should always be performed during the reimplantation in order to rule out persistent infection.
Methods
Retrospective review of 126 revision hip and knee arthroplasty procedure performed from 2002 - 2007 in Derriford Hospital, Plymouth NHS truts, UK. Frozen section was performed in 86 procedures out of the 126 procedures reviewed(68.2 %). A positive frozen section with more than 10 PNLs per HPF was compared with intra operative cultures results. The preoperative CRP results were recorded as well.
Results
The sensitivity, specificity, positive predictive value, negative predictive value and accuracy for frozen section were 45.5 %, 93.1%,50%, 95%, 94% respectively. Combining the intraoperative frozen section with the CRP results, the specificity was 100%.
Discussion
A negative finding on intra operative analysis of frozen sections has a high predictive value with regard to ruling out the presence of infection; However, the sensitivity of the test for the detection of persistent infection is low. The data support the conclusion that the Frozen Section is reasonably specific but not a sensitive. Combining it with the preoperative CRP results led to increasing the specificity to 100% in our series.
