Aims. Calprotectin (CLP) is produced in neutrophils and monocytes and released into body fluids as a result of inflammation or infection. The aim of this study was to evaluate the utility of blood and synovial CLP in the diagnosis of chronic periprosthetic joint infection (PJI). Methods. Blood and synovial fluid samples were collected prospectively from 195 patients undergoing primary or revision hip and knee arthroplasty. Patients were divided into five groups: 1) primary total hip and knee arthroplasty performed due to idiopathic osteoarthritis (OA; n = 60); 2) revision hip and knee arthroplasty performed due to aseptic failure of the implant (AR-TJR; n = 40); 3) patients with a confirmed diagnosis of chronic PJI awaiting surgery (n = 45); 4) patients who have finished the first stage of the PJI treatment with the use of cemented spacer and were qualified for replantation procedure (SR-TJR; n = 25), and 5) patients with rheumatoid arthritis undergoing primary total hip and knee arthroplasty (RA; n = 25). CLP concentrations were measured quantitatively in the blood and synovial fluid using an immunoturbidimetric assay. Additionally, blood and synovial CRP, blood interleukin-6 (IL-6), and ESR were measured, and a leucocyte esterase (LE) strip test was performed. Results. Patients with PJI had higher CLP concentrations than those undergoing aseptic revision in blood (median PJI 2.14 mg/l (interquartile range (IQR) 1.37 to 3.56) vs AR-TJR 0.66 mg/l (IQR 0.3 to 0.83); p < 0.001) and synovial fluid samples (median PJI 20.46 mg/l (IQR 14.3 to 22.36) vs AR-TJR 0.7 mg/l (IQR 0.41 to 0.95); p < 0.001). With a cut-off value of 1.0 mg/l, blood CLP showed a sensitivity, specificity, positive predictive value, and negative predictive value of 93.3%, 87.5%, 89.4%, and 92.1%, respectively. For synovial fluid with a cut-off value of 1.5 mg/l, these were 95.6%, 95%, 95.5%, and 95%, respectively. Conclusion. This small study suggests that synovial and blood CLP are useful markers in chronic PJI diagnosis with similar or higher sensitivity and specificity than routinely used markers such as CRP, ESR, IL-6, and LE. CLP was not useful to differentiate patients with PJI from those with rheumatoid arthritis. Cite this article: Bone Joint J 2021;103-B(1):46–55

Aims. Synovial fluid white blood cell (WBC) count and percentage of polymorphonuclear cells (%PMN) are elevated at periprosthetic joint infection (PJI). Leucocytes produce different interleukins (IL), including IL-6, so we hypothesized that synovial fluid IL-6 could be a more accurate predictor of PJI than synovial fluid WBC count and %PMN. The main aim of our study was to compare the predictive performance of all three diagnostic tests in the detection of PJI. Methods. Patients undergoing total hip or knee revision surgery were included. In the perioperative assessment phase, synovial fluid WBC count, %PMN, and IL-6 concentration were measured. Patients were labeled as positive or negative according to the predefined cut-off values for IL-6 and WBC count with %PMN. Intraoperative samples for microbiological and histopathological analysis were obtained. PJI was defined as the presence of sinus tract, inflammation in histopathological samples, and growth of the same microorganism in a minimum of two or more samples out of at least four taken. Results. In total, 49 joints in 48 patients (mean age 68 years (SD 10; 26 females (54%), 25 knees (51%)) were included. Of these 11 joints (22%) were infected. The synovial fluid WBC count and %PMN predicted PJI with sensitivity, specificity, accuracy, PPV, and NPV of 82%, 97%, 94%, 90%, and 95%, respectively. Synovial fluid IL-6 predicted PJI with sensitivity, specificity, accuracy, PPV, and NPV of 73%, 95%, 90%, 80%, and 92%, respectively. A comparison of predictive performance indicated a strong agreement between tests. Conclusions. Synovial fluid IL-6 is not superior to synovial fluid WBC count and %PMN in detecting PJI. Level of Evidence: Therapeutic Level II. Cite this article: Bone Jt Open 2020;1-12:737–742

Aims. Prosthetic joint infection (PJI) remains a major clinical challenge. Neutrophil CD64 index, Fc-gamma receptor 1 (FcγR1), plays an important role in mediating inflammation of bacterial infections and therefore could be a valuable biomarker for PJI. The aim of this study is to compare the neutrophil CD64 index in synovial and blood diagnostic ability with the standard clinical tests for discrimination PJI and aseptic implant failure. Methods. A total of 50 patients undergoing revision hip and knee arthroplasty were enrolled into a prospective study. According to Musculoskeletal Infection Society (MSIS) criteria, 25 patients were classified as infected and 25 as not infected. In all patients, neutrophil CD64 index and percentage of polymorphonuclear neutrophils (PMN%) in synovial fluid, serum CRP, ESR, and serum CD64 index levels were measured preoperatively. Receiver operating characteristic (ROC) curves and the area under the curve (AUC) were analyzed for each biomarker. Results. Serum CD64 index showed no significant difference between the two groups (p = 0.091). Synovial fluid CD64 index and PMN% discriminated good differentiation between groups of PJI and aseptic failure with AUC of 0.946 (95% confidence interval (CI) 0.842 to 0.990) and 0.938 (95% CI 0.832 to 0.987) separately. The optimal threshold value of synovial CD64 index for the diagnosis of PJI was 0.85, with a sensitivity of 92.00%, a specificity of 96.00%, and diagnostic odds ratio (DOR) of 227.11. Conclusion. The present study demonstrates that CD64 index in synovial fluid could be a promising laboratory marker for screening PJI. The cut-off values of 0.85 for synovial CD64 index has the potential to distinguish aseptic failure from PJI. Cite this article: Bone Joint J 2020;102-B(4):463–469

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The aim of this study was to evaluate the optimal deep tissue specimen sample number for histopathological analysis in the diagnosis of periprosthetic joint infection (PJI).

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The present study aimed to investigate whether patients with inflammatory bowel disease (IBD) undergoing joint arthroplasty have a higher incidence of adverse outcomes than those without IBD.

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Histology is widely used for diagnosis of persistent infection during reimplantation in two-stage revision hip and knee arthroplasty, although data on its utility remain scarce. Therefore, this study aims to assess the predictive value of permanent sections at reimplantation in relation to reinfection risk, and to compare results of permanent and frozen sections.

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A higher failure rate has been reported in haematogenous periprosthetic joint infection (PJI) compared to non-haematogenous PJI. The reason for this difference is unknown. We investigated the outcome of haematogenous and non-haematogenous PJI to analyze the risk factors for failure in both groups of patients.

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The influence of metabolic syndrome (MetS) on the outcome after hip and knee arthroplasty is debated. We aimed to investigate the change in patient-reported outcome measure (PROM) scores after hip and knee arthroplasty, comparing patients with and without MetS.

Objectives. Hips with metal-on-metal total hip arthroplasty (MoM THA) have a high rate of adverse local tissue reactions (ALTR), often associated with hypersensitivity reactions. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measures tissue perfusion with the parameter Ktrans (volume transfer constant of contrast agent). Our purpose was 1) to evaluate the feasibility of DCE-MRI in patients with THA and 2) to compare DCE-MRI in patients with MoM bearings with metal-on-polyethylene (MoP) bearings, hypothesising that the perfusion index Ktrans in hips with MoM THA is higher than in hips with MoP THA. Methods. In this pilot study, 16 patients with primary THA were recruited (eight MoM, eight MoP). DCE-MRI of the hip was performed at 1.5 Tesla (T). For each patient, Ktrans was computed voxel-by-voxel in all tissue lateral to the bladder. The mean Ktrans for all voxels was then calculated. These values were compared with respect to implant type and gender, and further correlated with clinical parameters. Results. There was no significant difference between the two bearing types with both genders combined. However, dividing patients by THA bearing and gender, women with MoM bearings had the highest Ktrans values, exceeding those of women with MoP bearings (0.067 min. −1. versus 0.053 min. −1. ; p-value < 0.05) and men with MoM bearings (0.067 min. −1. versus 0.034 min. −1. ; p-value < 0.001). Considering only the men, patients with MoM bearings had lower Ktrans than those with MoP bearings (0.034 min. −1. versus 0.046 min. −1. ; p < 0.05). Conclusion. DCE-MRI is feasible to perform in tissues surrounding THA. Females with MoM THA show high Ktrans values in DCE-MRI, suggesting altered tissue perfusion kinematics which may reflect relatively greater inflammation. Cite this article: Dr P. E. Beaule. Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty: A pilot stud. Bone Joint Res 2016;5:73–79. DOI: 10.1302/2046-3758.53.2000572

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Debridement, antibiotics, and implant retention (DAIR) is a widely accepted form of surgical treatment for patients with an early periprosthetic joint infection (PJI) after primary arthroplasty. The outcome of DAIR after revision arthroplasty, however, has not been reported. The aim of this study was to report the success rate of DAIR after revision arthroplasty with a follow-up of two years.

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The diagnosis of periprosthetic joint infection (PJI) can be difficult. All current diagnostic tests have problems with accuracy and interpretation of results. Many new tests have been proposed, but there is no consensus on the place of many of these in the diagnostic pathway. Previous attempts to develop a definition of PJI have not been universally accepted and there remains no reference standard definition.

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Removal of infected components and culture-directed antibiotics are important for the successful treatment of chronic periprosthetic joint infection (PJI). However, as many as 27% of chronic PJI patients yield negative culture results. Although culture negativity has been thought of as a contraindication to one-stage revision, data supporting this assertion are limited. The aim of our study was to report on the clinical outcomes for one-stage and two-stage exchange arthroplasty performed in patients with chronic culture-negative PJI.

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Arthrofibrosis is a relatively common complication after joint injuries and surgery, particularly in the knee. The present study used a previously described and validated rabbit model to assess the biomechanical, histopathological, and molecular effects of the mast cell stabilizer ketotifen on surgically induced knee joint contractures in female rabbits.

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The aim of this study was to determine the prevalence and characteristics of C-reactive protein (CRP)-negative prosthetic joint infection (PJI) and evaluate the influence of the type of infecting organism on the CRP level.

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This study aimed to develop a virtual clinic for the purpose of reducing face-to-face orthopaedic consultations.

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Surgical site infection (SSI) is a common complication of surgery with an incidence of about 1% in the United Kingdom. Sutures can lead to the development of a SSI, as micro-organisms can colonize the suture as it is implanted. Triclosan-coated sutures, being antimicrobical, were developed to reduce the rate of SSI. Our aim was to assess whether triclosan-coated sutures cause a reduction in SSIs following arthroplasty of the hip and knee.

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Recently, several synovial biomarkers have been introduced into the algorithm for the diagnosis of a prosthetic joint infection (PJI). Alpha defensin is a promising biomarker, with a high sensitivity and specificity, but it is expensive. Calprotectin is a protein that is present in the cytoplasm of neutrophils, is released upon neutrophil activation and exhibits anti-microbial activity. Our aim, in this study, was to determine the diagnostic potential of synovial calprotectin in the diagnosis of a PJI.

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The aims of this study were to increase the diagnostic accuracy of the analysis of synovial fluid in the differentiation of prosthetic joint infection (PJI) by the addition of inexpensive biomarkers such as the levels of C-reactive protein (CRP), adenosine deaminase (ADA), alpha-2-macrogloblulin (α2M) and procalcitonin.

Objectives

Effective analgesia after total knee arthroplasty (TKA) improves patient satisfaction, mobility and expedites discharge. This study assessed whether continuous femoral nerve infusion (CFNI) was superior to a single-shot femoral nerve block in primary TKA surgery completed under subarachnoid blockade including morphine.

The purpose of this study was to compare the diagnostic accuracy for the detection of infection between the culture of fluid obtained by sonication (SFC) and the culture of peri-implant tissues (PITC) in patients with early and delayed implant failure, and those with unsuspected and suspected septic failure. It was hypothesised that SFC increases the diagnostic accuracy for infection in delayed, but not early, implant failure, and in unsuspected septic failure. The diagnostic accuracy for infection of all consecutive implants (hardware or prostheses) that were removed for failure was compared between SFC and PITC. This prospective study included 317 patients with a mean age of 62.7 years (9 to 97). The sensitivity for detection of infection using SFC was higher than using PITC in an overall comparison (89.9% versus 67%, respectively; p < 0.001), in unsuspected septic failure (100% versus 48.5%, respectively; p < 0.001), and in delayed implant failure (88% versus 58%, respectively; p < 0.001). PITC sensitivity dropped significantly in unsuspected compared with suspected septic failure (p = 0.007), and in delayed compared with early failure (p = 0.013). There were no differences in specificity.

Sonication is mainly recommended when there is implant failure with no clear signs of infection and in patients with delayed implant failure. In early failure, SFC is not superior to PITC for the diagnosis of infection and, therefore, is not recommended as a routine diagnostic test in these patients.

Cite this article: Bone Joint J 2013;95-B:244–9.

We wished to estimate the incidence of surgical-site infection (SSI) after total hip replacement (THR) and hemiarthroplasty and its strength of association with major risk factors. The SSI surveillance service prospectively gathered clinical, operative and infection data on inpatients from 102 hospitals in England during a four-year period.

The overall incidence of SSI was 2.23% for 16 291 THRs, 4.97% for 5769 hemiarthroplasty procedures, 3.68% for 2550 revision THRs and 7.6% for 198 revision hemiarthroplasties. Staphylococcus aureus was identified in 50% of SSIs; 59% of these isolates were methicillin-resistant (MRSA). In the single variable analysis of THRs, age, female gender, American Society of Anesthesiologists (ASA) score, body mass index, trauma, duration of operation and pre-operative stay were significantly associated with the risk of SSI (p < 0.05). For hemiarthroplasty, the ASA score and age were significant factors. In revision THRs male gender, ASA score, trauma, wound class, duration of operation and pre-operative stay were significant risk factors. The median time to detection of SSI was eight days for superficial incisional, 11 days for deep incisional and 11 days for joint/bone infections. For each procedure the mean length of stay doubled for patients with SSI. The multivariate analysis identified age group, trauma, duration of operation and ASA score as significant, independent risk factors for SSI. There was significant interhospital variation in the rates of SSI. MRSA was the most common pathogen to cause SSI in hip arthroplasty, especially in patients undergoing hemiarthroplasty, but coagulase-negative Staph. aureus may be more important in deep infections involving the joint.