Aims. Leucocyte esterase (LE) has been shown to be an accurate marker of prosthetic joint infection (PJI), and has been proposed as an alternative to frozen section (FS) histology for intraoperative diagnosis. In this study, the intraoperative assessment of LE was compared with FS histology for the diagnosis of prosthetic hip infection. Patients and Methods. A total of 119 patients undergoing revision total hip arthroplasty (THA) between June 2015 and December 2017 were included in the study. There were 56 men and 63 women with a mean age of 66.2 years (27 to 88). Synovial fluid was collected before arthrotomy for the assessment of LE using enzymatic colourimetric strips. Between five and six samples were stained with haematoxylin and eosin for FS histology, and considered suggestive of infection when at least five polymorphonuclear leucocytes were found in five high-power fields. Results. The sensitivity and specificity of the LE assay were 100% and 93.8%, respectively; the positive (PPV) and the negative (NPV) predictive values were 79.3% and 100%, respectively. The mean time between the collection of the sample and the result being known was 20.1 minutes (. sd. 4.4). The sensitivity and specificity of FS histology were 78.3% and 96.9%, respectively; the PPV and the NPV were 85.7% and 94.9%, respectively. The mean time between the collection of the sample and the result being known was 27.2 minutes (. sd. 6.9). Conclusion. The sensitivity of LE assay was higher, with similar specificity and diagnostic accuracy, compared with FS histology. The faster turnaround time, its ease of use, and low costs make LE assay a valuable alternative to FS histology. We now use it routinely for the intraoperative diagnosis of PJI. Cite this article: Bone Joint J 2019;101-B:372–377

No single test has demonstrated absolute accuracy in the diagnosis of periprosthetic joint infection (PJI). Leukocyte esterase (LE) is a synovial marker that has proven utility in the diagnosis of PJI. The purpose of this prospective study was to (1) identify the optimal cutoff for the use of LE in the diagnosis of PJI and (2) determine whether performance of the LE strip test varied by infecting organism. This prospective study enrolled 1,015 patients undergoing hip or knee revision arthroplasty at a single institution from 2009 to September 2021. PJI was defined using a modified version of 2018 International Consensus Meeting (ICM) criteria that excluded LE when calculating the ICM score. Receiver operating characteristic curves were used to assess the utility of the LE strip test in the diagnosis of PJI. 973 patients were included in the analyses. 246 (25.4%) were classified as ICM-positive and 727 (74.6%) were classified as ICM-negative. An LE cutoff of “1+” (AUC 0.819, sensitivity 73.2%, specificity 90.6%) had superior accuracy to an LE cutoff of “2+” (AUC 0.713, sensitivity 43.9%, specificity 98.8%) in the overall diagnosis of PJI (p<0.001). When stratifying by organism type, an LE cutoff of “1+” had the best diagnostic utility for PJI caused by methicillin resistant Staphylococcus aureus (AUC 0.888, sensitivity 87.0%, n=23) followed by Streptococcus spp. (AUC 0.882, sensitivity 85.7%, n=28), coagulase negative Staphylococci (AUC 0.836, sensitivity 76.6%, n=47), methicillin sensitive Staphylococcus aureus (AUC 0.806, sensitivity 70.6%, n=34), culture negative (AUC 0.793, sensitivity 67.9%, n=56), and gram negative rods (AUC 0.763, sensitivity 61.9%, n=21). To our knowledge, this is the largest study evaluating the utility of the LE strip test in the diagnosis of PJI. Based on our findings, it appears that a “1+” cutoff has higher diagnostic utility than a cutoff of “2+”

Leukocyte esterase (LE) has shown to be an accurate marker of prosthetic joint infections and has been proposed as an alternative to frozen section (FS) for intra-operative diagnosis. In this study, intra-operative determination of LE was compared with FS for the diagnosis of periprosthetic hip infections. One hundred and nineteen patients undergoing hip revision surgery due to prosthetic joint failure from June 2015 to December 2017 were considered. Joint fluids were collected before the arthrotomy for determination of LE which was performed by using enzymatic colorimetric strips. Four to six samples were stained with hematoxylin eosin for FS and considered suggestive for infection when at least 5 polymorphonuclear leukocytes in 5 fields at high power fields were found. Sensitivity and specificity of LE were 100% and 93.8 %, respectively. The positive predictive value was 79.3 %, while the negative predictive value was 100%. Time from collection to response was 20.1 ± 4.4 minutes. Sensitivity and specificity of FS were 83.3 % and 92.1 %, respectively. The positive and negative predictive values were 84.6 % and 97.1%. Time from sample collection response was 27.2 ± 6.9 minutes. LE showed a higher sensitivity and a slightly lower specificity and the same diagnostic accuracy of intraoperative FS. The faster turnaround time (about 20 minutes from receiving of sample by the laboratory), its ease of use and the low costs make this test a valuable alternative to frozen sections and is going to replace FS in our clinical practice

Aims

The purpose of this study was to evaluate unexpected positive cultures in total hip arthroplasty (THA) revisions for presumed aseptic loosening, to assess the prevalence of low-grade infection using two definition criteria, and to analyze its impact on implant survival after revision.

Aims

One-stage exchange for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) is gaining popularity. The outcome for a repeat one-stage revision THA after a failed one-stage exchange for infection remains unknown. The aim of this study was to report the infection-free and all-cause revision-free survival of repeat one-stage exchange, and to investigate the association between the Musculoskeletal Infection Society (MSIS) staging system and further infection-related failure.