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Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_17 | Pages 67 - 67
24 Nov 2023
Gardete-Hartmann S Simon S Frank BJ Sebastian S Loew M Sommer I Hofstaetter J
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Aim. Synovial calprotectin point-of-care test (POC) has shown promising clinical value in diagnosing periprosthetic joint infections (PJIs). However, limited data are available in unclear cases. Moreover, cut-off values for calprotectin lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) need to be adapted. The aim of this study was to evaluate the performance of an upgraded and more sensitive version of a synovial calprotectin LFA along with ELISA immunoassay in patients with septic, aseptic, and unclear cases. Methods. Overall, 206 prospectively collected periprosthetic synovial fluid samples from 169 patients (106f/63m; 38 hip/131 knee) who underwent revision surgeries were retrospectively evaluated for calprotectin concentration. The following groups were analyzed: unexpected negative cultures (UNC; 32/206), unexpected positive cultures (UPC; 28/206), and unclear cases (65/206) with conflicting clinical results. In addition, we added a true aseptic (40/206), and true septic (41/206) control groups according to the international consensus meeting (ICM) 2018 PJI classification. Calprotectin concentration was determined by a rapid quantitative LFA (n=206) (Lyfstone®, Norway), and compared to calprotectin ELISA immunoassay (171/206). For the determination of a new calprotectin cut-off value, analysis of the area under the curve (AUC) followed by Youden's J statistic were performed using the calproctectin values from clear septic and aseptic cases. Sensitivity and specificity for calprotectin were calculated. All statistical analyses were performed using IBM-SPSS® version 25 (Armonk, NY, USA). Results. An absolute calprotectin value of 43 mg/ml, and 40.15 mg/ml was determined to be the optimal cut-off for PJI diagnosis using the new version of the LFA and ELISA, respectively. With this cut-off, the sensitivity and specificity of synovial calprotectin concentration for PJI were 88.1% (95% CI 77.8 to 94.7) and 76.6% (95% CI 61.9 to 87.7) for LFA, and 97.06% (95% CI 89.8 to 99.64) and 93.6% (95% CI 82.5 to 98.66) for ELISA, respectively. Of the evaluated groups, UNC 30/32 (93.8%) vs 26/27 (96.3%), UPC 6/28 (21.4%) vs 4/21 (19%), and unclear samples 45/65 (69.2%) vs 30/56 (53.6%) displayed a high likelihood of infection by using LFA, and ELISA, respectively. Conclusion. The upgraded version of the calprotectin quantitative LFA with a new suggested cut-off for infected samples showed additional clinical value in identifying cases at high risk of infection in unclear PJI revisions. Additionally, calprotectin ELISA immunoassay had a better performance than LFA. Further large sample-size validation studies are warranted


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_15 | Pages 59 - 59
1 Dec 2021
Chisari E Cho J Wouthuyzen M Friedrich AW Parvizi J
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Aim. A growing number of recent investigations on the human genome, gut microbiome, and proteomics suggests that the loss of mucosal barrier function, particularly in the gastrointestinal tract, may substantially affect antigen trafficking, ultimately influencing the close bidirectional interaction between the gut microbiome and the immune system. This cross-talk is highly influential in shaping the host immune system function and ultimately shifting genetic predisposition to clinical outcome. Therefore, we hypothesized that a similar interaction could affect the occurrence of acute and chronic periprosthetic joint infections (PJI). Method. Multiple biomarkers of gut barrier disruption were tested in parallel in plasma samples collected as part of a prospective cohort study of patients undergoing revision arthroplasty for aseptic or PJI (As defined by the 2018 ICM criteria). All blood samples were collected before any antibiotic was administered. Samples were tested for Zonulin, soluble CD14 (sCD14), and lipopolysaccharide (LPS) using commercially available enzyme-linked immunosorbent assays. Statistical analysis consisted of descriptive statistics and ANOVA. Results. A total of 96 patients were consented and included in the study. 32 were classified as PJI (23 chronic and 9 acute), and 64 as aseptic. Both Zonulin and LPS were found to be increased in the acute PJI group 8.448 ± 7.726 ng/mL and 4.106 ± 4.260 u/mL, compared to chronic PJI (p<0.001) and aseptic revisions (p=0.025). sCD14 was found to be increased in both chronic (0.463 ± 0.168 ug/mL) and acute PJI (0.463 ± 0.389 ug/mL) compared to aseptic revisions (p<0.001). Conclusions. This prospective ongoing study reveals a possible link between gut permeability and the ‘gut-immune-joint axis’ in PJI. If this association continues to be born out with larger cohort recruitment, it would have a massive implication in managing patients with PJI. In addition to the administration of antimicrobials, patients with PJI and other orthopedic infections may require gastrointestinal modulators such as pro and prebiotics


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 84 - 84
1 May 2016
Niikura M Nogi S Han Y Turner A Yutani T Uetsuki K Tomita N
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INTRODUCTION. Ultra-High Molecular Weight Polyethylene (UHMWPE) wear debris is thought to be a main factor in the development of osteolysis (1). However, the method for the evaluation of the biological response to UHMWPE particles has not yet been standardized. In this study, four different types of UHMWPE particles were generated using a mechanized pulverizing method and the biological responses of macrophages to the particles were investigated using an inverted cell culturing process (2). MATERIALS & METHODS. Virgin samples were manufactured via Direct Compression Molding (DCM) technique from UHMWPE GUR1050 resin powder (Ticona, USA). For vitamin E (VE)-blended sample, the resin was mixed with VE at 0.3 wt% and the mixture was then molded using DCM. The crosslinked virgin samples were made by gamma ray irradiation to UHMWPE GUR1020 resin sheet (Meditech, USA) with doses of 95kGy ±10% and annealed. The VE-blended crosslinked samples were made by electron beam irradiation to VE-blended samples with doses of 300kGy and annealed. The material conditions were summarized in Figure 1. To pulverize the samples, the Multi-Beads Shocker (Yasui Kikai, Japan) was used. After pulverization, samples were dispersed in an ethanol solution and sequentially filtered through polycarbonate filters. Over 100 sections of the filter were selected randomly and images of the particles were analyzed using scanning electron microscope (SEM). To analyze the macrophage biological response, an inverted cell culturing process was used (2). The mouse macrophage-like cells were seeded at densities of 4×105cells per well in a 96-well culture plate and incubated for 1h. UHMWPE particles suspended in the culture medium were then added to each well in the appropriate amount. After that, fresh medium was added to fill the wells, and a sealing film was used to cover the culture plate. The culture plate was then inverted to cause the UHMWPE particles interact with the adhered macrophages. The inverted culture plate was incubated for 8h. The amount of TNF-α was measured by enzyme-linked immunosorbent assay (ELISA). RESULTS & DISCUSSION. Geometric measurements showed no significant difference in the UHMWPE particles (Figure 2). The amount of TNF-α released stimulated by the crosslinked virgin particles showed significantly higher relative to the other UHMWPE particles (Figure 3). During crosslinking irradiation, the carbon free radicals are generated in the main chain (3). In the presence of oxygen, these radicals can react to form peroxy radicals and when the peroxy free radicals react with hydrogen they form hydroperoxides, which can further degrade into other oxidation products (4). It has been reported that VE hinders this cascading in UHMWPE (5). Therefore, it is possible that oxidation of the crosslinked virgin UHMWPE was involved in the cytokine response observed in this study. However resin material, molding technique and the irradiation method were different between crosslinked virgin and VE-blended crosslinked samples. Further consideration will be needed to examine the relationship between residual radicals, hydroperoxides and biological response


The Bone & Joint Journal
Vol. 98-B, Issue 10 | Pages 1418 - 1424
1 Oct 2016
Salandy A Malhotra K Goldberg AJ Cullen N Singh D

Aims

Smoking is associated with post-operative complications but smokers often under-report the amount they smoke. Our objective was to determine whether a urine dipstick test could be used as a substitute for quantitative cotinine assays to determine smoking status in patients.

Patients and Methods

Between September 2013 and July 2014 we conducted a prospective cohort study in which 127 consecutive patients undergoing a planned foot and ankle arthrodesis or osteotomy were included. Patients self-reported their smoking status and were classified as: ‘never smoked’ (61 patients), ‘ex-smoker’ (46 patients), or ‘current smoker’ (20 patients). Urine samples were analysed with cotinine assays and cotinine dipstick tests.


The Journal of Bone & Joint Surgery British Volume
Vol. 89-B, Issue 6 | Pages 817 - 820
1 Jun 2007
Khan SA Varshney MK Hasan AS Kumar A Trikha V

A series of 14 patients suffering from tuberculosis of the sternum with a mean follow-up of 2.8 years (2 to 3.6) is presented. All were treated with antitubercular therapy: ten with primary therapy, two needed second-line therapy, and two required surgery (debridement). All showed complete healing and no evidence of recurrence at the last follow-up. MRI was useful in making the diagnosis at an early stage because atypical presentations resulting from HIV have become more common. Early adequate treatment with multidrug antitubercular therapy avoided the need for surgery in 12 of our 14 patients.