Intraoperative Frozen Section Histology: Matched for Musculoskeletal Infection Society Criteria.

BACKGROUND: The current gold standard to diagnose periprosthetic joint infection (PJI)-the Musculoskeletal Infection Society (MSIS) criteria, requires a battery of tests, the results of which may not be available at the time of decision-making. Thus, surgeons often rely on intraoperative frozen section histology. However, the accuracy of frozen sections has not been determined when matched for the MSIS criteria. We aimed to (1) assess the value of intraoperative histology in the diagnosis of PJI and (2) evaluate discrepancy rate between frozen and permanent section analysis.

METHODS: A retrospective review of patients who underwent revision total hip or total knee arthroplasty for either PJI or mechanical failure in 2013 was conducted. Two hundred procedures where tissue samples for frozen sections had been collected were identified and included into the study. Results of frozen sections were compared to the modified MSIS criteria. Discrepancy rate between frozen and permanent sections was also calculated.

RESULTS: Frozen sections had sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 73.7% (95% confidence interval [CI], 59.7%-87.7%), 98.8% (95% CI, 97.1%-100.0%), 94.1% (95% CI, 90.6%-97.6%), 93.3.4% (95% CI, 84.4%-100.0%), 94.0% (95% CI, 90.7%-97.3%), respectively. There were 10 discrepancies between the results of frozen and permanent sections (N = 421 samples), thereby yielding 97.6% concordance.

CONCLUSION: When matched to the MSIS criteria, intraoperative frozen section histology yields a high specificity, positive predictive value, negative predictive value, accuracy, and moderate sensitivity. The discrepancy rate between frozen and permanent sections is low and both demonstrate good approximation of MSIS criteria.