There is no uniform definition for periprosthetic joint infection (PJI). New diagnostic criteria were formulated in an international consensus meeting in 2013 and adopted by Centers for Disease Control (CDC) in 2016. The purpose of this study is to compare the new diagnostic criteria with the old CDC criteria from the year 1992.
Patients, who had been treated for PJI of hip or knee from 2002 to 2014, in a tertiary care hospital, were identified. Patient records were reviewed by a physician to identify PJI cases fulfilling the old or new CDC criteria and to record data concerning the diagnostic criteria. PJI frequencies were calculated for the two diagnostic criteria sets. Cross tables were formed to compare the concordance between the two sets of criteria in the whole material and in different clinical subgroups.
Overall 405 cases fulfilling either or both sets of criteria for PJI were identified. 73 (18%) of the patients fulfilled only the old criteria, whereas only one (0.2%) fulfilled only the new criteria. Of the patients who did not fulfil the new criteria, in 39 (53%) the diagnosis was based solely on the clinician’s opinion.
The number of PJIs is notably lower when using the new, more objective, diagnostic criteria. A large portion of the cases diagnosed as infection by the treating clinician, did not fulfil the new diagnostic criteria.