Aims. The aim of this study was to determine the diagnostic accuracy of α defensin (AD) lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) tests for periprosthetic joint infection (PJI) in comparison to conventional synovial white blood cell (WBC) count and polymorphonuclear neutrophil percentage (PMN%) analysis. Methods. Patients undergoing joint aspiration for evaluation of pain after total knee arthroplasty (TKA) or total hip arthroplasty (THA) were considered for inclusion. Synovial fluids from 99 patients (25 THA and 74 TKA) were analyzed by WBC count and PMN% analysis, AD LFA, and AD ELISA. WBC and PMN% cutoffs of ≥ 1,700 cells/mm. 3. and ≥ 65% for TKA and ≥ 3,000 cells/mm. 3. and ≥ 80% for THA were used, respectively. A panel of three physicians, all with expertise in orthopaedic infections and who were blinded to the results of AD tests, independently reviewed patient data to diagnose subjects as with or without PJI. Consensus PJI classification was used as the reference standard to evaluate test performances. Results were compared using McNemar’s test and area under the receiver operating characteristic curve (AUC) analysis. Results. Expert consensus classified 18 arthroplasies as having failed due to PJI and 81 due to aseptic failure. Using these classifications, the calculated sensitivity and specificity of AD LFA was 83.3% (95% confidence interval (CI) 58.6 to 96.4) and 93.8% (95% CI 86.2 to 98.0), respectively. Sensitivity and specificity of AD ELISA was 83.3% (95% CI 58.6 to 96.4) and 96.3% (95% CI 89.6 to 99.2), respectively. There was no statistically significant difference between sensitivity (p = 1.000) or specificity (p = 0.157) of the two AD assays. AUC for AD LFA was 0.891. In comparison, AUC for synovial WBC count, PMN%, and the combination of the two values was 0.821 (sensitivity p = 1.000, specificity p < 0.001), 0.886 (sensitivity p = 0.317, specificity p = 0.011), and 0.926 (sensitivity p = 0.317, specificity p = 0.317), respectively. Conclusion. The diagnostic accuracy of synovial AD for PJI diagnosis is comparable and not statistically superior to that of synovial WBC count plus PMN% combined. Cite this article: Bone Joint J 2021;103-B(6):1119–1126

Aims. In patients with a “dry” aspiration during the investigation of prosthetic joint infection (PJI), saline lavage is commonly used to obtain a sample for analysis. The aim of this study was to investigate prospectively the impact of saline lavage on synovial fluid analysis in revision arthroplasty. Methods. Patients undergoing revision hip (THA) or knee arthroplasty (TKA) for any septic or aseptic indication were enrolled. Intraoperatively, prior to arthrotomy, the maximum amount of fluid possible was aspirated to simulate a dry tap (pre-lavage) followed by the injection with 20 ml of normal saline and re-aspiration (post-lavage). Pre- and post-lavage synovial white blood cell (WBC) count, percent polymorphonuclear cells (%PMN), and cultures were compared. Results. A total of 78 patients had data available for analysis; 17 underwent revision THA and 61 underwent revision TKA. A total of 16 patients met modified Musculoskeletal Infection Society (MSIS) criteria for PJI. Pre- and post-lavage %PMNs were similar in septic patients (87% vs 85%) and aseptic patients (35% vs 39%). Pre- and post-lavage synovial fluid WBC count were far more disparate in septic (53,553 vs 8,275 WBCs) and aseptic (1,103 vs 268 WBCs) cohorts. At a cutoff of 80% PMN, the post-lavage aspirate had a sensitivity of 75% and specificity of 95%. At a cutoff of 3,000 WBCs, the post-lavage aspirate had a sensitivity of 63% and specificity of 98%. As the post-lavage synovial WBC count increased, the difference between pre- and post-lavage %PMN decreased (mean difference of 5% PMN in WBC < 3,000 vs mean difference 2% PMN in WBC > 3,000, p = 0.013). Of ten positive pre-lavage fluid cultures, only six remained positive post-lavage. Conclusion. While saline lavage aspiration significantly lowered the synovial WBC count, the %PMN remained similar, particularly at WBC counts of > 3,000. These findings suggest that in patients with a dry-tap, the %PMN of a saline lavage aspiration has reasonable sensitivity (75%) for the detection of PJI. Cite this article: Bone Joint J 2020;102-B(6 Supple A):138–144

Aims. The aim of this study was to evaluate the diagnostic value of preoperative serum CRP, white blood cell count (WBC), percentage of neutrophils (%N), and neutrophil to lymphocyte ratio (NLR) when using the fracture-related infection (FRI) consensus definition. Methods. A cohort of 106 patients having surgery for suspected septic nonunion after failed fracture fixation were studied. Blood samples were collected preoperatively, and the concentration of serum CRP, WBC, and differential cell count were analyzed. The areas under the curve (AUCs) of diagnostic tests were compared using the z-test. Regression trees were constructed and internally cross-validated to derive a simple diagnostic decision tree. Results. Using the FRI consensus definition, 46 patients (43%) were identified as infected. Sensitivity, specificity, and AUC of CRP were 67% (95% confidence interval (CI) 52% to 80%), 61% (95% CI 47% to 74%), and 0.64 (95% CI 0.54 to 0.74); of WBC count were 17% (95% CI 9% to 31%), 95% (95% CI 86% to 99%), and 0.57 (95% CI 0.50 to 0.62); of %N 13% (95% CI 6% to 26%), 87% (95% CI 76% to 93%), and 0.50 (95% CI 0.43 to 0.56); and of NLR 28% (95% CI 17% to 43%), 80% (95% CI 68% to 88%), and 0.54 (95% CI 0.46 to 0.63), respectively. A better performance of serum CRP was shown in comparison to the leucocyte count (p = 0.006), %N (p < 0.001), and NLR (p = 0.001). A statistically lower serum CRP level was shown in patients with an infection caused by a low virulence microorganism in comparison to high virulence bacteria (p = 0.008). We found that a simple decision tree approach using only low serum neutrophils (< 3.615 × 10. 9. /l) and low CRP (< 2.45 mg/l) may allow better identification of aseptic cases. Conclusion. The evaluated serum inflammatory markers showed limited diagnostic value in the preoperative diagnosis of FRI when using the uniform FRI Consensus Definition. Therefore, they should remain as suggestive criteria in diagnosing FRI. Although CRP showed a higher performance in comparison to the other serum markers, it is insufficiently accurate to diagnose a septic nonunion, especially when caused by low virulence microorganisms. Cite this article: Bone Joint J 2020;102-B(7):904–911

Aims. It can be extremely challenging to determine whether to perform reimplantation in patients who have contradictory serum inflammatory markers and frozen section results. We investigated whether patients with a positive frozen section at reimplantation were at a higher risk of reinfection despite normal ESR and CRP. Methods. We retrospectively reviewed 163 consecutive patients with periprosthetic joint infections (PJIs) who had normal ESR and CRP results pre-reimplantation in our hospital from 2014 to 2018. Of these patients, 26 had positive frozen sections at reimplantation. The minimum follow-up time was two years unless reinfection occurred within this period. Univariable and multivariable logistic regression analyses were performed to identify the association between positive frozen sections and treatment failure. Results. Treatment failure occurred in eight (30.77%) of the 26 PJI patients with positive frozen sections at reimplantation, compared with 13 (9.49%) of 137 patients with negative results. In the multivariate analysis, positive frozen section increased the risk of failure (odds ratio 4.70; 95% confidence interval (CI) 1.64 to 13.45). The mean number of months to reinfection was lower in the positive frozen section group than in the control group (p = 0.041). While there were nine (34.62%) patients with positive frozen section and 25 (18.25%) patients with negative frozen section who had prolonged antibiotic use (p = 0.042), the mean duration of antibiotic use was comparable in two groups. Synovial white blood cell count (p = 0.137) and polymorphonuclear leucocyte percentage (p = 0.454) were not associated with treatment failure in logistic regression model. Conclusion. Positive frozen section at reimplantation was independently associated with subsequent failure and earlier reinfection, despite normal ESR and CRP levels pre-reimplantation. Surgeons should be aware of the risk of treatment failure in patients with positive frozen sections and carefully consider benefits of reimplantation. Cite this article: Bone Joint J 2021;103-B(5):916–922

Aims. To establish the utility of adding the laboratory-based synovial alpha-defensin immunoassay to the traditional diagnostic work-up of a prosthetic joint infection (PJI). Methods. A group of four physicians evaluated 158 consecutive patients who were worked up for PJI, of which 94 underwent revision arthroplasty. Each physician reviewed the diagnostic data and decided on the presence of PJI according to the 2014 Musculoskeletal Infection Society (MSIS) criteria (yes, no, or undetermined). Their initial randomized review of the available data before or after surgery was blinded to each alpha-defensin result and a subsequent randomized review was conducted with each result. Multilevel logistic regression analysis assessed the effect of having the alpha-defensin result on the ability to diagnose PJI. Alpha-defensin was correlated to the number of synovial white blood cells (WBCs) and percentage of polymorphonuclear cells (%PMN). Results. Intraobserver reliability and interobserver agreement did not change when the alpha-defensin result was available. Positive alpha-defensin results had greater synovial WBCs (mean 31,854 cells/μL, SD 32,594) and %PMN (mean 93.0%, SD 5.5%) than negative alpha-defensin results (mean 974 cells/μL, SD 3,988; p < 0.001 and mean 39.4% SD 28.6%; p < 0.001). Adding the alpha-defensin result did not alter the diagnosis of a PJI using preoperative (odds ratio (OR) 0.52, 95% confidence interval (CI) 0.14 to 1.88; p = 0.315) or operative (OR 0.52, CI 0.18 to 1.55; p = 0.242) data when clinicians already decided that PJI was present or absent with traditionally available testing. However, when undetermined with traditional preoperative testing, alpha-defensin helped diagnose (OR 0.44, CI 0.30 to 0.64; p < 0.001) or rule out (OR 0.41, CI 0.17 to 0.98; p = 0.044) PJI. Of the 27 undecided cases with traditional testing, 24 (89%) benefited from the addition of alpha-defensin testing. Conclusion. The laboratory-based synovial alpha-defensin immunoassay did not help diagnose or rule out a PJI when added to routine serologies and synovial fluid analyses except in cases where the diagnosis of PJI was unclear. We recommend against the routine use of alpha-defensin and suggest using it only when traditional testing is indeterminate. Cite this article: Bone Joint J 2020;102-B(5):593–599

Aims. We hypothesised that the synovial white blood cell (WBC) count in patients with a late periprosthetic joint infection (PJI) of the hip would depend on the duration of a patient’s symptoms, and that the optimal diagnostic threshold would also depend on this period of time. Patients and Methods. The synovial WBC count and percentage of polymorphonuclear cells (%PMN), and the serum CRP and ESR levels obtained > six weeks after primary THA were compared between 50 infected and 88 non-infected THAs, and in patients with symptoms for more than or less than two weeks. Diagnostic thresholds for the synovial WBC count were calculated using area under the curve calculation. Results. The synovial WBC count was significantly higher in patients with symptoms for ≤ two weeks compared with those with symptoms for > two weeks (p = 0.03). The optimal threshold for diagnosing PJI for the synovial WBC count was 5750 cells/µL (sensitivity 94; specificity 100; PPV 100%; NPV 89%; AUC 99%) and 1556 cells/µL (sensitivity 91; specificity 94; PPV 87% and NPV 97%; AUC 95%), respectively. The thresholds for the cut-offs based on duration of symptoms improved the diagnostic performance of this test. Conclusion. This study shows that the diagnostic thresholds for synovial fluid analysis in late periprosthetic infection following THA may depend on duration of symptoms. Cite this article: Bone Joint J 2016;98-B:1355–9

Aims. The aim of this study was to compare the results of 16S/28S rRNA sequencing with the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and synovial fluid analysis in the diagnosis of prosthetic joint infection (PJI). Patients and Methods. Between September 2015 and August 2016, 214 consecutive patients were enrolled. In the study population, there were 25 patients with a PJI and 189 controls. Of the PJI patients, 14 (56%) were women, and the mean age at the time of diagnosis was 65 years (38 to 83). The ESR and CRP levels were measured, and synovial fluid specimens were collected prospectively. Synovial fluid was subjected to reverse transcription polymerase chain reaction (RT-PCR)/sequence analysis targeting the 16S/28S rRNA, and to conventional culture. Laboratory personnel who were blind to the clinical information performed all tests. The diagnosis of PJI was based on the criteria of the Musculoskeletal Infection Society. Results. A total of 25 patients had a confirmed PJI. In 20 cases of monomicrobial PJI, the PCR products could be perfectly matched with the 16S/28S rRNA genes specific for different species of bacteria provided by sequence analysis. Of the five polymicrobial cases of PJI, 16S/28S rRNA PCR sequence analysis failed to identify the concordant bacteria species. In the 189 control patients, there was one false-positive RT-PCR result. The sensitivity and specificity of the molecular diagnosis method were 100% (95% confidence interval (CI) 85.7 to 100) and 99.5% (95% CI 97.1 to 99.9), respectively, whereas the positive and negative predictive values of PCR were 96.1% (95% CI 79.6 to 99.9) and 100% (95% CI 98.1 to 100), respectively. The PCR results were significantly better than serological diagnostic methods (p = 0.004 and p = 0.010 for ESR and CRP, respectively), the synovial fluid white blood cell (WBC) count (p = 0.036), and percentage of polymorphonuclear cells (PMN%) (p = 0.014). Conclusion. Stepwise RT-PCR and sequence analysis of the 16S/28S rRNA carried out under stringent laboratory conditions achieved highly sensitive and specific results for the differentiation between aseptic and septic joints undergoing arthroplasty. Sequence analysis successfully identified bacterial strains in monomicrobial infections but failed to identify molecular targets in polymicrobial infections. Further refinement of the protocols to identify the bacteria in polymicrobial infections is needed. Cite this article: Bone Joint J 2018;100-B:1345–51

Aims. This multicentre, retrospective study aimed to improve our knowledge of primary pyogenic spinal infections in children by analyzing a large consecutive case series. Patients and Methods. The medical records of children with such an infection, treated at four tertiary institutions between 2004 and 2014, were analyzed retrospectively. Epidemiological, clinical, paraclinical, radiological, and microbiological data were evaluated. There were 103 children, of whom 79 (76.7%) were aged between six months and four years. Results. We confirmed a significant male predominance in the incidence of primary pyogenic spinal infections in children (65%). The lumbar spine was the most commonly affected region, and 27 infections (26.2%) occurred at L4/5. The white blood cell count was normal in 61 children (59%), and the CRP level was normal in 43 (42%). Blood cultures were performed in 95 children, and were positive in eight (8%). A total of 20 children underwent culture of biopsy or aspiration material, which was positive in eight (40%). Methicillin-sensitive Staphylococcus aureus (MSSA) and Kingella (K.) kingae were the most frequently isolated pathogens. Conclusion. MSSA remains the most frequently isolated pathogen in children with primary pyogenic infection of the spine, but K. kingae should be considered as an important pathogen in children aged between six months and four years. Therefore, an empirical protocol for antibiotic treatment should be used, with consideration being made for the triphasic age distribution and specific bacteriological aetiology. In the near future, the results of polymerase chain reaction assay on throat swabs may allow the indirect identification of K. kingae spondylodiscitis in young children and thus aid early treatment. However, these preliminary results require validation by other prospective multicentre studies. Cite this article: Bone Joint J 2018;100-B:542–8

Inflammatory markers such as the C-reactive protein (CRP), white blood cell count and body temperature are easy to measure and are used as indicators of infection. The way in which they change in the early post-operative period after instrumented spinal surgery has not been reported in any depth. We measured these markers pre-operatively and at one, four, seven and 14 days postoperatively in 143 patients who had undergone an instrumented posterior lumbar interbody fusion. The CRP proved to be the only sensitive marker and had returned to its normal level in 48% of patients after 14 days. The CRP on day 7 was never higher than that on day 4. Age, gender, body temperature, operating time and blood loss were not related to the CRP level. A high CRP does not in itself suggest infection, but any increase after four days may presage infection

This prospective study evaluates the role of new laboratory markers in the diagnosis of deep implant infection in 78 patients (41 men and 37 women) with a revision total knee or hip replacement. The mean age at the time of operation was 64.0 years (19 to 90). Intra-operative cultures showed that 21 patients had a septic and 57 an aseptic total joint replacement. The white blood cell count, the erythrocyte sedimentation rate and levels of C-reactive protein, interleukin-6, procalcitonin and tumour necrosis factor (TNF)-α were measured in blood samples before operation. The diagnostic cut-off values were determined by Received Operating Characteristic curve analysis. C-reactive protein (> 3.2 md/dl) and interleukin-6 (> 12 pg/ml) have the highest sensitivity (0.95). Interleukin-6 is less specific than C-reactive protein (0.87 vs 0.96). Combining C-reactive protein and interleukin-6 identifies all patients with deep infection of the implant. Procalcitonin (> 0.3 ng/ml) and TNF-α (> 40 ng/ml) are very specific (0.98 vs 0.94) but have a low sensitivity (0.33 vs 0.43). The combination of C-reactive protein and interleukin-6 measurement provide excellent screening tests for infection of a deep implant. A highly specific marker such as procalcitonin and pre-operative aspiration of the joint might be useful in identifying patients with true positive C-reactive protein and/or interleukin-6 levels

Aims. Compartment syndrome results from increased intra-compartmental pressure (ICP) causing local tissue ischaemia and cell death, but the systemic effects are not well described. We hypothesised that compartment syndrome would have a profound effect not only on the affected limb, but also on remote organs. Methods. Using a rat model of compartment syndrome, its systemic effects on the viability of hepatocytes and on inflammation and circulation were directly visualised using intravital video microscopy. Results. We found that hepatocellular injury was significantly higher in the compartment syndrome group (192 PI-labelled cells/10. -1 . mm. 3. , standard error of the mean (. sem. ) 51) compared with controls (30 PI-labelled cells/10. -1 . mm. 3. , . sem . 12, p < 0.01). The number of adherent venular white blood cells was significantly higher for the compartment syndrome group (5 leukocytes/30s/10 000 μm. 2. , . sem 1. ) than controls (0.2 leukocytes/30 s/10 000 μm. 2. , . sem . 0.2, p < 0.01). Volumetric blood flow was not significantly different between the two groups, although there was an increase in the heterogeneity of perfusion. Conclusions. Compartment syndrome can be accompanied by severe systemic inflammation and end organ damage. This study provides evidence of the relationship between compartment syndrome in a limb and systemic inflammation and dysfunction in a remote organ. Cite this article: Bone Joint J 2016; 98-B:1132–7

Pyomyositis of the obturator muscles is a rare condition, characterised by pain in the hip and features of systemic infection. It may follow minor trauma to the hip, sometimes in the presence of an apparently innocuous infective source. All previously reported cases have been diagnosed conclusively on the initial CT or MR scan. We present a case of obturator pyomyositis in a 21-year-old football player in which the first MR scan was misleading. A radiolabelled, white blood cell scan was also negative and the resultant delay in diagnosis proved dangerous. The crucial importance of careful and repeated clinical examination is emphasised

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The aim of this study was to evaluate the diagnostic accuracy of the absolute synovial polymorphonuclear neutrophil cell (PMN) count for the diagnosis or exclusion of periprosthetic joint infection (PJI) after total hip (THA) or knee arthroplasty (TKA).

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Knee osteoarthritis (OA) is characterized by a chronic inflammatory process involving multiple cytokine pathways, leading to articular cartilage degeneration. Intra-articular therapies using pharmaceutical or autologous anti-inflammatory factors offer potential non-surgical treatment options. Autologous protein solution (APS) is one such product that uses the patient’s blood to produce a concentrate of cells and anti-inflammatory cytokines. This study evaluated the effect of a specific APS intra-articular injection (nSTRIDE) on patient-reported outcome measures compared to saline in moderate knee OA.

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This study aimed to compare the performance of survival prediction models for bone metastases of the extremities (BM-E) with pathological fractures in an Asian cohort, and investigate patient characteristics associated with survival.

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The diagnosis of periprosthetic joint infection (PJI) continues to present a significant clinical challenge. New biomarkers have been proposed to support clinical decision-making; among them, synovial fluid alpha-defensin has gained interest. Current research methodology suggests reference methods are needed to establish solid evidence for use of the test. This prospective study aims to evaluate the diagnostic accuracy of high-performance liquid chromatography coupled with the mass spectrometry (LC-MS) method to detect alpha-defensin in synovial fluid.

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Accurate diagnosis of chronic periprosthetic joint infection (PJI) presents a significant challenge for hip surgeons. Preoperative diagnosis is not always easy to establish, making the intraoperative decision-making process crucial in deciding between one- and two-stage revision total hip arthroplasty (THA). Calprotectin is a promising point-of-care novel biomarker that has displayed high accuracy in detecting PJI. We aimed to evaluate the utility of intraoperative calprotectin lateral flow immunoassay (LFI) in THA patients with suspected chronic PJI.

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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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This study aimed to investigate the clinical characteristics and outcomes associated with culture-negative limb osteomyelitis patients.

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Gram-negative periprosthetic joint infection (PJI) has been poorly studied despite its rapidly increasing incidence. Treatment with one-stage revision using intra-articular (IA) infusion of antibiotics may offer a reasonable alternative with a distinct advantage of providing a means of delivering the drug in high concentrations. Carbapenems are regarded as the last line of defense against severe Gram-negative or polymicrobial infection. This study presents the results of one-stage revision using intra-articular carbapenem infusion for treating Gram-negative PJI, and analyzes the characteristics of bacteria distribution and drug sensitivity.

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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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To determine whether platelet-rich plasma (PRP) injection improves outcomes two years after acute Achilles tendon rupture.

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It remains difficult to diagnose early postoperative periprosthetic joint infection (PJI) following total knee arthroplasty (TKA). We aimed to validate the optimal cutoff values of ESR, CRP, and synovial fluid analysis for detecting early postoperative PJI in a large series of primary TKAs.

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This study aimed to answer two questions: what are the best diagnostic methods for diagnosing bacterial arthritis of a native joint?; and what are the most commonly used definitions for bacterial arthritis of a native joint?

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Periprosthetic joint infections (PJIs) with prior multiple failed surgery for reinfection represent a huge challenge for surgeons because of poor vascular supply and biofilm formation. This study aims to determine the results of single-stage revision using intra-articular antibiotic infusion in treating this condition.

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Monocyte-lymphocyte ratio (MLR) or neutrophil-lymphocyte ratio (NLR) are useful for diagnosing periprosthetic joint infection (PJI), but their diagnostic values are unclear for screening fixation-related infection (FRI) in patients for whom conversion total hip arthroplasty (THA) is planned after failed internal fixation for femoral neck fracture.

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We aimed to describe the epidemiological, biological, and bacteriological characteristics of osteoarticular infections (OAIs) caused by Kingella kingae.

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As a proven and comprehensive molecular technique, metagenomic next-generation sequencing (mNGS) has shown its potential in the diagnosis of pathogens in patients with periprosthetic joint infection (PJI), using a single type of specimen. However, the optimal use of mNGS in the management of PJI has not been explored. In this study, we evaluated the diagnostic value of mNGS using three types of specimen with the aim of achieving a better choice of specimen for mNGS in these patients.

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Metagenomic next-generation sequencing (mNGS) is useful in the diagnosis of infectious disease. However, while it is highly sensitive at identifying bacteria, it does not provide information on the sensitivity of the organisms to antibiotics. The purpose of this study was to determine whether the results of mNGS can be used to guide optimization of culture methods to improve the sensitivity of culture from intraoperative samples.

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We aimed to report the mid- to long-term rates of septic and aseptic failure after two-stage revision surgery for periprosthetic joint infection (PJI) following total hip arthroplasty (THA).

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The purpose of this study was to develop a personalized outcome prediction tool, to be used with knee arthroplasty patients, that predicts outcomes (lengths of stay (LOS), 90 day readmission, and one-year patient-reported outcome measures (PROMs) on an individual basis and allows for dynamic modifiable risk factors.

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There is a paucity of long-term studies analyzing risk factors for failure after single-stage revision for periprosthetic joint infection (PJI) following total hip arthroplasty (THA). We report the mid- to long-term septic and non-septic failure rate of single-stage revision for PJI after THA.

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Failure of irrigation and debridement (I&D) for prosthetic joint infection (PJI) is influenced by numerous host, surgical, and pathogen-related factors. We aimed to develop and validate a practical, easy-to-use tool based on machine learning that may accurately predict outcome following I&D surgery taking into account the influence of numerous factors.

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Debridement, antibiotics, and implant retention (DAIR) remains one option for the treatment of acute periprosthetic joint infection (PJI) despite imperfect success rates. Intraosseous (IO) administration of vancomycin results in significantly increased local bone and tissue concentrations compared to systemic antibiotics alone. The purpose of this study was to evaluate if the addition of a single dose of IO regional antibiotics to our protocol at the time of DAIR would improve outcomes.

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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.

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The aim of this study was to determine the extent to which patient demographics, clinical presentation, and blood parameters vary in Kingella kingae septic arthritis when compared with those of other organisms, and whether this difference needs to be considered when assessing children in whom a diagnosis of septic arthritis is suspected.

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To clarify the effectiveness of the induced membrane technique (IMT) using beta-tricalcium phosphate (β-TCP) for reconstruction of segmental bone defects by evaluating clinical and radiological outcomes, and the effect of defect size and operated site on surgical outcomes.

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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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Use of molecular sequencing methods in periprosthetic joint infection (PJI) diagnosis and organism identification have gained popularity. Next-generation sequencing (NGS) is a potentially powerful tool that is now commercially available. The purpose of this study was to compare the diagnostic accuracy of NGS, polymerase chain reaction (PCR), conventional culture, the Musculoskeletal Infection Society (MSIS) criteria, and the recently proposed criteria by Parvizi et al in the diagnosis of PJI.

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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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The aim of this study was to evaluate the diagnostic accuracy of the synovial alpha-defensin enzyme-linked immunosorbent assay (ELISA) for the diagnosis of prosthetic joint infection (PJI) in the work-up prior to revision of total hip (THA) and knee arthroplasty (TKA).

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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.

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The aim of this study was to further evaluate the accuracy of ten promising synovial biomarkers (bactericidal/permeability-increasing protein (BPI), lactoferrin (LTF), neutrophil gelatinase-associated lipocalin (NGAL), neutrophil elastase 2 (ELA-2), α-defensin, cathelicidin LL-37 (LL-37), human β-defensin (HBD-2), human β-defensin 3 (HBD-3), D-dimer, and procalcitonin (PCT)) for the diagnosis of periprosthetic joint infection (PJI), and to investigate whether inflammatory joint disease (IJD) activity affects their concentration in synovial fluid.

Antibiotic resistance represents a threat to human health. It has been suggested that by 2050, antibiotic-resistant infections could cause ten million deaths each year. In orthopaedics, many patients undergoing surgery suffer from complications resulting from implant-associated infection. In these circumstances secondary surgery is usually required and chronic and/or relapsing disease may ensue. The development of effective treatments for antibiotic-resistant infections is needed. Recent evidence shows that bacteriophage (phages; viruses that infect bacteria) therapy may represent a viable and successful solution. In this review, a brief description of bone and joint infection and the nature of bacteriophages is presented, as well as a summary of our current knowledge on the use of bacteriophages in the treatment of bacterial infections. We present contemporary published in vitro and in vivo data as well as data from clinical trials, as they relate to bone and joint infections. We discuss the potential use of bacteriophage therapy in orthopaedic infections. This area of research is beginning to reveal successful results, but mostly in nonorthopaedic fields. We believe that bacteriophage therapy has potential therapeutic value for implant-associated infections in orthopaedics.

Cite this article: Bone Joint J 2021;103-B(2):234–244.

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As the population ages and the surgical complexity of lumbar spinal surgery increases, the preoperative stratification of risk becomes increasingly important. Understanding the risks is an important factor in decision-making and optimizing the preoperative condition of the patient. Our aim was to determine whether the modified five-item frailty index (mFI-5) and nutritional parameters could be used to predict postoperative complications in patients undergoing simple or complex lumbar spinal fusion.

There is good scientific rationale to support the use of growth factors to promote musculoskeletal tissue regeneration. However, the clinical effectiveness of platelet-rich plasma (PRP) and other blood-derived products has yet to be proven. Characterization and reporting of PRP preparation protocols utilized in clinical trials for the treatment of musculoskeletal disease is highly inconsistent, and the majority of studies do not provide sufficient information to allow the protocols to be reproduced. Furthermore, the reporting of blood-derived products in orthopaedics is limited by the multiple PRP classification systems available, which makes comparison of results between studies challenging. Several attempts have been made to characterize and classify PRP; however, no consensus has been reached, and there is lack of a comprehensive and validated classification. In this annotation, we outline existing systems used to classify preparations of PRP, highlighting their advantages and limitations. There remains a need for standardized universal nomenclature to describe biological therapies, as well as a comprehensive and reproducible classification system for autologous blood-derived products.

Cite this article: Bone Joint J 2019;101-B:891–896.

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Preoperative nasal Staphylococcus aureus screening and eradication reduces surgical site infections (SSIs) but its impact on reducing early prosthetic joint infection (PJI) remains controversial. This study aims to assess the effect of preoperative nasal S. aureus screening and eradication on the incidence of early PJI in general and S. aureus-induced early PJI.

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Of growing concern in arthroplasty is the emergence of atypical infections, particularly Cutibacterium (formerly Propionibacterium) sp. infections. Currently, the dermal colonization rate of Cutibacterium about the hip is unknown. Therefore, the aim of this study was to investigate colonization rates of Cutibacterium sp. at locations approximating anterior and posterolateral approaches to the hip joint.

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The aim of this study was to determine the diagnostic utility of histological analysis in spinal biopsies for spondylodiscitis (SD).

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In the absence of an identified organism, single-stage revision is contraindicated in prosthetic joint infection (PJI). However, no studies have examined the use of intra-articular antibiotics in combination with single-stage revision in these cases. In this study, we present the results of single-stage revision using intra-articular antibiotic infusion for treating culture-negative (CN) PJI.

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The aims of this study were to characterize the frequency of missing data in the National Surgical Quality Improvement Program (NSQIP) database and to determine how missing data can influence the results of studies dealing with elderly patients with a fracture of the hip.

Aims

Spinal tuberculosis (TB) remains an important concern. Although spinal TB often has sequelae such as myelopathy after treatment, the predictive factors affecting such unfavourable outcomes are not yet established. We investigated the clinical manifestations and predictors of unfavourable treatment outcomes in patients with spinal TB.

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The aim of this study was to evaluate the outcome of spinal instrumentation in haemodialyzed patients with native pyogenic spondylodiscitis. Spinal instrumentation in these patients can be dangerous due to rates of complications and mortality, and biofilm formation on the instrumentation.

Aims

Prosthetic joint infection (PJI) and aseptic loosening in total hip arthroplasty (THA) can present with pain and osteolysis. The Musculoskeletal Infection Society (MSIS) has provided criteria for the diagnosis of PJI. The aim of our study was to analyze the utility of F18-fluorodeoxyglucose (FDG) positron emission tomography (PET) CT scan in the preoperative diagnosis of septic loosening in THA, based on the current MSIS definition of prosthetic joint infection.

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The aim of this study was to assess the effects of transferring patients to a specialized arthroplasty centre between the first and second stages (interstage) of prosthetic joint infection (PJI) of the knee.

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The purpose of this current multicentre study is to analyse the presence of alpha-defensin proteins in synovial fluid using the Synovasure lateral flow device and to determine its diagnostic reliability and accuracy compared with the prosthetic joint infection (PJI) criteria produced by the Musculoskeletal Infection Society (MSIS).

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.

Aims

Single-stage revision is not widely pursued due to restrictive inclusion criteria. In this study, we evaluated the results of single-stage revision of chronically infected total hip arthroplasty (THA) using broad inclusion criteria and cementless implants.

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To evaluate the effectiveness of an institutionally developed algorithm for evaluation and diagnosis of prosthetic joint injection and to determine the impact of this protocol on overall hospital re-admissions.p

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The present study investigated the five-year interval changes in pseudotumours and measured serum metal ions at long-term follow-up of a previous report of 28 mm diameter metal-on-metal (MoM) total hip arthroplasty (THA).

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This study aimed to assess the performance of an automated multiplex polymerase chain reaction (mPCR) technique for rapid diagnosis of native joint septic arthritis

Aims

The diagnosis of periprosthetic joint infection (PJI) remains demanding due to limitations of all the available diagnostic tests. The synovial fluid marker, α-defensin, is a promising adjunct for the assessment of potential PJI. The purpose of this study was to investigate the qualitative assessment of α-defensin, using Synovasure to detect or exclude periprosthetic infection in total joint arthroplasty.

Aims

Positive cultures are not uncommon in cases of revision total knee and hip arthroplasty (TKA and THA) for presumed aseptic causes. The purpose of this study was to assess the incidence of positive intra-operative cultures in presumed aseptic revision of TKA and THA, and to determine whether the presence of intra-operative positive cultures results in inferior survival in such cases.

Aims

To assess the diagnostic value of C-reactive protein (CRP), leucocyte count (LC), and erythrocyte sedimentation rate (ESR) in late fracture-related infection (FRI).

Aims

The results of irrigation and debridement with component retention (IDCR) in the treatment of acutely infected total knee arthroplasties (TKAs) have been variable. The aim of this study was to assess the outcome after IDCR when combined with chronic antibiotic suppression. We also evaluated survivorship free from subsequent infection, removal of the components, and death, as well as the risk factors for failure.

Aims

Limb salvage for diabetic foot infections often require multiple procedures. Some patients will eventually end up with below knee amputation (BKA) when all limb salvage attempts fail. We seek to study the patients’ ability to return to normal life, functional status, prosthesis usage and perspectives on multiple limb salvage procedures that culminated in BKA to review if they would undertake a similar path if their situation was repeated.

To assess the sustainability of our institutional bone bank, we calculated the final product cost of fresh-frozen femoral head allografts and compared these costs with the use of commercial alternatives. Between 2007 and 2010 all quantifiable costs associated with allograft donor screening, harvesting, storage, and administration of femoral head allografts retrieved from patients undergoing elective hip replacement were analysed.

From 290 femoral head allografts harvested and stored as full (complete) head specimens or as two halves, 101 had to be withdrawn. In total, 104 full and 75 half heads were implanted in 152 recipients. The calculated final product costs were €1367 per full head. Compared with the use of commercially available processed allografts, a saving of at least €43 119 was realised over four-years (€10 780 per year) resulting in a cost-effective intervention at our institution. Assuming a price of between €1672 and €2149 per commercially purchased allograft, breakeven analysis revealed that implanting between 34 and 63 allografts per year equated to the total cost of bone banking.

Cite this article: Bone Joint J 2014;96-B:1307–11

Clinical prediction algorithms are used to differentiate transient synovitis from septic arthritis. These algorithms typically include the erythrocyte sedimentation rate (ESR), although in clinical practice measurement of the C-reactive protein (CRP) has largely replaced the ESR. We evaluated the use of CRP in a predictive algorithm.

The records of 311 children with an effusion of the hip, which was confirmed on ultrasound, were reviewed (mean age 5.3 years (0.2 to 15.1)). Of these, 269 resolved without intervention and without long-term sequelae and were considered to have had transient synovitis. The remaining 42 underwent arthrotomy because of suspicion of septic arthritis. Infection was confirmed in 29 (18 had micro-organisms isolated and 11 had a high synovial fluid white cell count). In the remaining 13 no evidence of infection was found and they were also considered to have had transient synovitis. In total 29 hips were categorised as septic arthritis and 282 as transient synovitis. The temperature, weight-bearing status, peripheral white blood cell count and CRP was reviewed in each patient.

A CRP > 20 mg/l was the strongest independent risk factor for septic arthritis (odds ratio 81.9, p < 0.001). A multivariable prediction model revealed that only two determinants (weight-bearing status and CRP > 20 mg/l) were independent in differentiating septic arthritis from transient synovitis. Individuals with neither predictor had a < 1% probability of septic arthritis, but those with both had a 74% probability of septic arthritis. A two-variable algorithm can therefore quantify the risk of septic arthritis, and is an excellent negative predictor.

The purpose of this study was to evaluate whether the serum level of interleukin 6 (IL-6) could be used to identify the persistence of infection after the first stage of a two-stage revision for periprosthetic joint infection.

Between 2010 and 2011, we prospectively studied 55 patients (23 men, 32 women; mean age 69.5 years; 36 to 86) with a periprosthetic joint infection. Bacteria were identified in two intra-operative tissue samples during re-implantation in 16 patients. These cases were classified as representing persistent infection.

To calculate a precise cut-off value which could be used in everyday clinical practice, a 3 x 2 contingency table was constructed and manually defined.

We found that a serum IL-6 ≥ 13 pg/mL can be regarded as indicating infection: its positive-predictive value is 90.9%. A serum IL-6 ≤ 8 pg/mL can be regarded as indicating an absence of infection: its negative predictive value is 92.1%.

The serum IL-6 level seems to be a reasonable marker for identifying persistent infection after the first stage of a revision joint arthroplasty and before attempting re-implantation.

Cite this article: Bone Joint J 2015;97-B:71–5.

Aims

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.

We examined the usefulness of neutrophil CD64 expression in detecting local musculoskeletal infection and the impact of antibiotics on its expression. Of 141 patients suspected of musculoskeletal infection, 46 were confirmed by microbiological culture to be infected and 95 had infection excluded. The median CD64 count of patients with localised infection was 2230 molecules per cell (interquartile range (IQR) 918 to 4592) and that of the patients without infection was 937 molecules per cell (IQR 648 to 1309) (p < 0.001). The level of CD64 correlated with the CRP level in patients with infection, but not in those without infection (r = 0.59, p < 0.01). Receiver operator characteristic curve analysis revealed that CD64 was a good predictor of local infection. When the patients were subdivided into two groups based on the administration of antibiotics at the time of CD64 sampling, the sensitivity for detecting infection was better in those who had not received antibiotics.

These results suggest that measurement of CD64 expression is a useful marker for local musculoskeletal infection.

Aims

Diabetes mellitus is the most common co-morbidity associated with necrotising fasciitis. This study aims to compare the clinical presentation, investigations, Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) score, microbiology and outcome of management of this condition in diabetic and non-diabetic patients.

Aims

The aim of this consensus was to develop a definition of post-operative fibrosis of the knee.

Aims

The treatment of septic arthritis of the shoulder is challenging. The infection frequently recurs and the clinical outcome can be very poor. We aimed to review the outcomes following the use of continuous negative pressure after open debridement with a large diameter drain in patients with septic arthritis of the shoulder.

There are few reports on the treatment of pyogenic lumbar spondylodiscitis through the posterior approach using a single incision. Between October 1999 and March 2003 we operated on 18 patients with pyogenic lumbar spondylodiscitis. All underwent posterior lumbar interbody fusion using an autogenous bone graft from the iliac crest and pedicle screws via a posterior approach. The clinical outcome was assessed using the Frankel neurological classification and the criteria of Kirkaldy-Willis. Under the Frankel classification, two patients improved by two grades (C to E), 11 by one grade, and five showed no change. The Kirkaldy-Willis functional outcome was excellent in five patients, good in ten and fair in three. Bony union was confirmed six months after surgery in 17 patients, but in one patient this was not achieved until two years after operation. The mean lordotic angle before operation was 20° (−2° to 42°) and the mean lordotic angle at the final follow-up was 32.5° (17° to 44°). Two patients had a superficial wound infection and two a transient root injury. Posterior lumbar interbody fusion with an autogenous iliac crest bone graft and pedicle screw fixation via a posterior approach can provide satisfactory results in pyogenic spondylodiscitis.

An extensive review of the spinal and arthroplasty literature was undertaken to evaluate the effectiveness of local antibiotic irrigation during surgery. The efficacy of antibiotic irrigation for the prevention of acute post-operative infection after total joint arthroplasty was evaluated retrospectively in 2293 arthroplasties (1990 patients) between January 2004 and December 2013. The mean follow-up was 73 months (20 to 139). One surgeon performed all the procedures with minimal post-operative infection.

The intra-operative protocol included an irrigation solution of normal saline with vancomycin 1000 mg/l and polymyxin 250 000 units/l at the rate of 2 l per hour. No patient required re-admission for primary infection or further antibiotic treatment. Two morbidly obese patients (two total hip arthroplasties) developed subcutaneous fat necrosis requiring debridement and one was revised because the deep capsular sutures were contaminated by the draining subcutaneous haematoma. One patient who had undergone total knee arthroplasty had unrecognised damage to the lateral superior geniculate artery and developed a haematoma that became infected secondarily four months after the surgery and underwent revision.

The use of antibiotic irrigation during arthroplasty surgery has been highly effective for the prevention of infection in the author’s practice. However, it should be understood that any routine prophylactic use of antibiotics may result in resistant organisms, and the wise stewardship of the use of antibiotics is an important part of surgical practice.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):23–6.

The post-operative changes in the serum levels of CRP and serum amyloid A (SAA) were investigated prospectively in 106 patients after posterior lumbar interbody fusion. In 96 patients who did not have complications related to infection within the first year after operation, the median levels of CRP before operation and on days 3, 7 and 13 after were 0.02 (0.01 to 0.03), 9.12 (2.36 to 19.82), 1.64 (0.19 to 6.10) and 0.53 (0.05 to 2.94) mg/dl, respectively and for SAA, 2.6 (2.0 to 3.8), 1312.1 (58.0 to 3579.8), 77.3 (1.8 to 478.4), 14.1 (0.5 to 71.9) μg/ml, respectively. The levels on day 3 were the highest for both CRP and SAA and significantly decreased (p < 0.01) by day 7 and day 13.

In regard to CRP, no patient had less than the reference level (0.1 mg/dl) on day 7. In only three had the level decreased to the reference level, while in 93 it was above this on day 13. However, for SAA, the levels became normal on day 7 in 10 cases and on day 13 in 34 cases. The ratios relative to the levels on day 3 were significantly lower for SAA compared with CRP on day 7 and day 13. Of the ten patients with infection in the early stages, the level of CRP decreased slightly but an increase in SAA was observed in six.

We concluded that SAA is better than CRP as a post-operative inflammatory marker.

The crucial differentiation between septic arthritis and transient synovitis of the hip in children can be difficult. In 1999, Kocher et al introduced four clinical predictors which were highly predictive (99.6%) of septic arthritis. These included fever (temperature ≥ 38.5°C), inability to bear weight, white blood-cell count > 12.0 × 10⁹ cells/L and ESR ≥ 40 mm/hr; CRP ≥ 20 mg/L was later added as a fifth predictor. We retrospectively evaluated these predictors to differentiate septic arthritis from transient synovitis of the hip in children over a four-year period in a primary referral general hospital. When all five were positive, the predicted probability of septic arthritis in this study was only 59.9%, with fever being the best predictor. When applied to low-prevalence diseases, even highly specific tests yield a high number of false positives and the predictive value is thereby diminished.

Clinical predictors should be applied with caution when assessing a child with an irritable hip, and a high index of suspicion, and close observation of patients at risk should be maintained.

There are few reports in the literature of the diagnosis and treatment of the infected shoulder arthroplasty. Most deal with resection arthroplasty and two-stage exchange surgery. We present our results of one-stage exchange operation as treatment for the infected shoulder arthroplasty.

Our group comprised 16 patients (ten men, six women) with 16 infected arthroplasties. By the time of follow-up, two patients had died (mean 5.8 years), two could not be located and three had already undergone revision surgery. Nine patients were thus available for clinical examination and assessment.

The infections were largely caused by staphylococci, Propionibacterium species and streptococci. Two were early infections (within three months of surgery) and 14 were late infections. The mean follow-up was 5.8 years (13 months to 13.25 years) when the mean Constant-Murley score was 33.6 points and the mean University College of Los Angeles score 18.3 points.

Further revision was performed in three patients. One sustained a peri-prosthetic humeral fracture, another developed an acromial pseudarthrosis after transacromial surgery and the third suffered recurrent dislocations. No patient had a recurrence of infection.

A one-stage exchange procedure using antibiotic-loaded bone cement eradicated infection in all our patients and we suggest that such a procedure is at least as successful as either a resection arthroplasty or a two-stage exchange in the management of the infected shoulder arthroplasty.

Infection is a leading indication for revision arthroplasty. Established criteria used to diagnose prosthetic joint infection (PJI) include a range of laboratory tests. Leucocyte esterase (LE) is widely used on a colorimetric reagent strip for the diagnosis of urinary tract infections. This inexpensive test may be used for the diagnosis or exclusion of PJI. Aspirates from 30 total hip arthroplasties (THAs) and 79 knee arthroplasties (KA) were analysed for LE activity. Semi-quantitative reagent strip readings of 15, 70, 125 and 500 white blood cells (WBC) were validated against a manual synovial white cell count (WCC). A receiver operating characteristic (ROC) curve was constructed to determine the optimal cut-off point for the semi-quantitative results. Based on established criteria, six THAs and 15 KAs were classified as infected. The optimal cut-off point for the diagnosis of PJI was 97 WBC. The closest semi-quantitative reading for a positive result was 125 WBC, achieving a sensitivity of 81% and a specificity of 93%. The positive and negative predictive values of the LE test strip were 74% and 95% respectively.

The LE reagent strip had a high specificity and negative predictive value. A negative result may exclude PJI and negate the need for further diagnostic tests.

Cite this article: Bone Joint J 2015;97-B:1232–6.

In England and Wales more than 175 000 hip and knee arthroplasties were performed in 2012. There continues to be a steady increase in the demand for joint arthroplasty because of population demographics and improving survivorship. Inevitably though the absolute number of periprosthetic infections will probably increase with severe consequences on healthcare provision. The Department of Health and the Health Protection Agency in United Kingdom established a Surgical Site Infection surveillance service (SSISS) in 1997 to undertake surveillance of surgical site infections. In 2004 mandatory reporting was introduced for one quarter of each year. There has been a wide variation in reporting rates with variable engagement with the process. The aim of this article is to improve surgeon awareness of the process and emphasise the importance of engaging with SSISS to improve the quality and type of data submitted. In Exeter we have been improving our practice by engaging with SSISS. Orthopaedic surgeons need to take ownership of the data that are submitted to ensure these are accurate and comprehensive.

Cite this article: Bone Joint J 2015;97-B:1170–4.

Systemic capillary leak syndrome, or the Clarkson syndrome, is an extremely rare condition in which increased capillary permeability results in a massive shift of fluid into the extravascular space. This is followed rapidly by hypotensive shock, haemoconcentration, and, potentially, substantial oedema of the limbs resulting in an acute compartment syndrome. It is important for orthopaedic surgeons to be aware of this syndrome as our medical colleagues, who initially care for these patients, are less familiar with the diagnosis and the need for emergency management of the associated compartment syndrome should it develop. There have been fewer than 100 cases of this entity reported.

This case report is the first to describe the subsequent development of a compartment syndrome in all four limbs. Clinical vigilance and continuous monitoring of intracompartmental pressure is necessary in these patients in order to help reduce limb-threatening complications.

We have studied the relationship between metal ion levels and lymphocyte counts in patients with metal-on-metal hip resurfacings. Peripheral blood samples were analysed for lymphocyte subtypes and whole blood cobalt and chromium ion levels in 68 patients (34 with metal-on-metal hip resurfacings and 34 with standard metal-on-polyethylene total hip replacements). All hip components were radiologically well-fixed and the patients were asymptomatic. Cobalt and chromium levels were significantly elevated in the patients with metal-on-metal hip resurfacings, compared with the patients with standard metal-on-polyethylene designs (p < 0.0001). There was a statistically significant decrease in the level of CD8⁺ cells (T-cytotoxic/suppressor) (p = 0.005) in the metal-on-metal hip resurfacing group. A threshold level of blood cobalt and chromium ions was associated with reduced CD8⁺ T-cell counts. We have no evidence that our patients suffered as a result of this reduced level of CD8⁺ T-cells.

The aim of this study was to assess the role of synovial C-reactive protein (CRP) in the diagnosis of chronic periprosthetic hip infection. We prospectively collected synovial fluid from 89 patients undergoing revision hip arthroplasty and measured synovial CRP, serum CRP, erythrocyte sedimentation rate (ESR), synovial white blood cell (WBC) count and synovial percentages of polymorphonuclear neutrophils (PMN). Patients were classified as septic or aseptic by means of clinical, microbiological, serum and synovial fluid findings. The high viscosity of the synovial fluid precluded the analyses in nine patients permitting the results in 80 patients to be studied. There was a significant difference in synovial CRP levels between the septic (n = 21) and the aseptic (n = 59) cohort. According to the receiver operating characteristic curve, a synovial CRP threshold of 2.5 mg/l had a sensitivity of 95.5% and specificity of 93.3%. The area under the curve was 0.96. Compared with serum CRP and ESR, synovial CRP showed a high diagnostic value. According to these preliminary results, synovial CRP may be a useful parameter in diagnosing chronic periprosthetic hip infection.

Cite this article: Bone Joint J 2015; 97-B:173–6.

The common recommended treatment for infected total hip replacement is two-staged exchange including removal of all components. However, removal of well-fixed femoral stems can result in structural bone damage. We recently reported on an alternative treatment of partial two-stage exchange used in selected cases, in which a well-fixed femoral stem was left and only the acetabular component removed, the joint space was debrided thoroughly, an antibiotic-laden polymethylmethacrylate spacer was moulded using a bulb-type syringe and placed in the acetabulum, intravenous antibiotics were administered during the interval, and delayed re-implantation was performed. In 19 patients treated with this technique from January 2000 to January 2011, 89% were free of infection at a mean follow-up of four years (2 to 11). Since then, disposable silicone moulds have become available to fabricate spacers in separate femoral and head units. The head spacer mould, which incorporates various neck taper adapter options, greatly facilitates the technique of partial two-stage exchange. We report our early experience using disposable silicone head spacer moulds for partial two-stage exchange in seven patients with infected primary hip replacements.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):66–9

Metaphyseal bone loss is common with revision total knee replacement (RTKR). Using the Anderson Orthopaedic Research Institute (AORI) classification, type 2-B and type 3 defects usually require large metal blocks, bulk structural allograft or highly porous metal cones. Tibial and femoral trabecular metal metaphyseal cones are a unique solution for large bone defects. These cones substitute for bone loss, improve metaphyseal fixation, help correct malalignment, restore the joint line and may permit use of a shorter stem. The technique for insertion involves sculpturing of the remaining bone with a high speed burr and rasp, followed by press-fit of the cone into the metaphysis. The fixation and osteoconductive properties of the porous cone outer surface allow ingrowth and encourage long-term biological fixation. The revision knee component is then cemented into the porous cone inner surface, which provides superior fixation compared with cementing into native but deficient metaphyseal bone. The advantages of the cone compared with allograft include: technical ease, biological fixation, no resorption, and possibly a lower risk of infection. The disadvantages include: difficult extraction and relatively short-term follow-up. Several studies using cones report promising short-term results for the reconstruction of large bone defects in RTKR.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):118–21.

Necrotising soft-tissue infections (NSTIs) of the upper limb are uncommon, but potentially life-threatening. We used a national database to investigate the risk factors for amputation of the limb and death.

We extracted data from the Japanese Diagnosis Procedure Combination database on 116 patients (79 men and 37 women) who had a NSTI of the upper extremity between 2007 and 2010.

The overall in-hospital mortality was 15.5%. Univariate analysis of in-hospital mortality showed that the significant variables were age (p = 0.015), liver dysfunction (p = 0.005), renal dysfunction (P < 0.001), altered consciousness (p = 0.049), and sepsis (p = 0.021). Logistic regression analysis showed that the factors associated with death in hospital were age over 70 years (Odds Ratio (OR) 6.6; 95% confidence interval (CI) 1.5 to 28.2; p = 0.011) and renal dysfunction (OR 15.4; 95% CI 3.8 to 62.8; p < 0.001).

Univariate analysis of limb amputation showed that the significant variables were diabetes (p = 0.017) mellitus and sepsis (p = 0.001). Multivariable logistic regression analysis showed that the factors related to limb amputation were sepsis (OR 1.8; 95% CI 1.5 to 24.0; p = 0.013) and diabetes mellitus (OR 1.6; 95% CI 1.1 to 21.1; p = 0.038).

For NSTIs of the upper extremity, advanced age and renal dysfunction are both associated with a higher rate of in-hospital mortality. Sepsis and diabetes mellitus are both associated with a higher rate of amputation.

Cite this article: Bone Joint J 2014;96-B:1530–4.

Two-stage exchange remains the gold standard for treatment of peri-prosthetic joint infection after total hip replacement (THR). In the first stage, all components and associated cement if present are removed, an aggressive debridement is undertaken including a complete synovectomy, and an antibiotic-loaded cement spacer is put in place. Patients are then treated with six weeks of parenteral antibiotics, followed by an ‘antibiotic free period’ to help ensure the infection has been eradicated. If the clinical evaluation and serum inflammatory markers suggest the infection has resolved, then the second stage can be completed, which involves removal of the cement spacer, repeat debridement, and placement of a new THR.

Cite this article: Bone Joint J 2013;95-B, Supple A:84–7.

Louis Pasteur once said that: “Fortune favours the prepared mind.” As one of the great scientists who contributed to the fight against infection, he emphasised the importance of being prepared at all times to recognise infection and deal with it. Despite the many scientific discoveries and technological advances, such as the advent of antibiotics and the use of sterile techniques, infection continues to be a problem that haunts orthopaedic surgeons and inflicts suffering on patients.

The medical community has implemented many practices with the intention of preventing infection and treating it effectively when it occurs. Although high-level evidence may support some of these practices, many are based on little to no scientific foundation. Thus, around the world, there is great variation in practices for the prevention and management of periprosthetic joint infection.

This paper summaries the instigation, conduct and findings of a recent International Consensus Meeting on Surgical Site and Periprosthetic Joint Infection.

Cite this article: Bone Joint J 2013;95-B:1450–2.

Total hip replacement (THR) is a very common procedure undertaken in up to 285 000 Americans each year. Patient satisfaction with THR is very high, with improvements in general health, quality of life, and function while at the same time very cost effective. Although the majority of patients have a high degree of satisfaction with their THR, 27% experience some discomfort, and up to 6% experience severe chronic pain. Although it can be difficult to diagnose the cause of the pain in these patients, this clinical issue should be approached systematically and thoroughly. A detailed history and clinical examination can often provide the correct diagnosis and guide the appropriate selection of investigations, which will then serve to confirm the clinical diagnosis made.

Cite this article: Bone Joint J 2013;95-B, Supple A:70–3.

Based on the first implementation of mixing antibiotics into bone cement in the 1970s, the Endo-Klinik has used one stage exchange for prosthetic joint infection (PJI) in over 85% of cases. Looking carefully at current literature and guidelines for PJI treatment, there is no clear evidence that a two stage procedure has a higher success rate than a one-stage approach. A cemented one-stage exchange potentially offers certain advantages, mainly based on the need for only one operative procedure, reduced antibiotics and hospitalisation time. In order to fulfill a one-stage approach, there are obligatory pre-, peri- and post-operative details that need to be meticulously respected, and are described in detail. Essential pre-operative diagnostic testing is based on the joint aspiration with an exact identification of any bacteria. The presence of a positive bacterial culture and respective antibiogram are essential, to specify the antibiotics to be loaded to the bone cement, which allows a high local antibiotic elution directly at the surgical side. A specific antibiotic treatment plan is generated by a microbiologist. The surgical success relies on the complete removal of all pre-existing hardware, including cement and restrictors and an aggressive and complete debridement of any infected soft tissues and bone material. Post-operative systemic antibiotic administration is usually completed after only ten to 14 days.

Cite this article: Bone Joint J 2013;95-B, Supple A:77–83.

We present detailed information about early morbidity after aseptic revision knee replacement from a nationwide study. All aseptic revision knee replacements undertaken between 1st October 2009 and 30th September 2011 were analysed using the Danish National Patient Registry with additional information from the Danish Knee Arthroplasty Registry. The 1218 revisions involving 1165 patients were subdivided into total revisions, large partial revisions, partial revisions and revisions of unicondylar replacements (UKR revisions). The mean age was 65.0 years (27 to 94) and the median length of hospital stay was four days (interquartile range: 3 to 5), with a 90 days re-admission rate of 9.9%, re-operation rate of 3.5% and mortality rate of 0.2%. The age ranges of 51 to 55 years (p = 0.018), 76 to 80 years (p < 0.001) and ≥ 81 years (p < 0.001) were related to an increased risk of re-admission. The age ranges of 76 to 80 years (p = 0.018) and the large partial revision subgroup (p = 0.073) were related to an increased risk of re-operation. The ages from 76 to 80 years (p < 0.001), age ≥ 81 years (p < 0.001) and surgical time > 120 min (p <  0.001) were related to increased length of hospital stay, whereas the use of a tourniquet (p = 0.008) and surgery in a low volume centre (p = 0.013) were related to shorter length of stay.

In conclusion, we found a similar incidence of early post-operative morbidity after aseptic knee revisions as has been reported after primary procedures. This suggests that a length of hospital stay ≤ four days and discharge home at that time is safe following aseptic knee revision surgery in Denmark.

Cite this article: Bone Joint J 2014;96-B:1649–56.

Technological advances and shorter rescue times have allowed early and effective resuscitation after trauma and brought attention to the host response to injury. Trauma patients are at risk of progressive organ dysfunction from what appears to be an uncontrolled immune response. The availability of improved techniques of molecular diagnosis has allowed investigation of the role of genetic variations in the inflammatory response to post-traumatic complications and particularly to sepsis.

This review examines the current evidence for the genetic predisposition to adverse outcome after trauma. While there is evidence supporting the involvement of different polymorphic variants of genes in determining the post-traumatic course and the development of complications, larger-scale studies are needed to improve the understanding of how genetic variability influences the responses to post-traumatic complications and pharmacotherapy.

The Control of Infection Committee at a specialist orthopaedic hospital prospectively collected data on all episodes of bacteriologically-proven deep infection arising after primary hip and knee replacements over a 15-year period from 1987 to 2001.

There were 10 735 patients who underwent primary hip or knee replacement. In 34 of 5947 hip replacements (0.57%) and 41 of 4788 knee replacements (0.86%) a deep infection developed. The most common infecting micro-organism was coagulase-negative staphylococcus, followed by Staphylococcus aureus, enterococci and streptococci. Of the infecting organisms, 72% were sensitive to routine prophylactic antimicrobial agents.

Of the infections, 29% (22) arose in the first three months following surgery, 35% between three months and one year (26), and 36% (27) after one year. Most cases were detected early and treated aggressively, with eradication of the infection in 96% (72). There was no significant change in the infection rate or type of infecting micro-organism over the course of this study.

These results set a benchmark, and importantly emphasise that only 64% of peri-prosthetic infections arise within one year of surgery. These results also illustrate the advantages of conducting joint replacement surgery in the isolation of a specialist hospital.

The differential diagnosis of the painful total hip arthroplasty (resurfacing or total hip) includes infection, failure of fixation (loosening), tendinitis, bursitis, synovitis, adverse local tissue reaction (ALTR) to cobalt-chromium alloys, and non-hip issues, such as spinal disorders, hernia, gynecologic, and other pelvic pain. Assuming that the hip is the source of pain, the first level question is prosthetic or non-prosthetic pain generator? The second level prosthetic question is septic or aseptic? The third level question (aseptic hips) is well-fixed or loose? ALTR is best diagnosed by cross-sectional imaging. Successful treatment is dependent on correct identification and elimination of the pain generator. Treatment recommendations for ALTR and taper corrosion are evolving.

Data on early morbidity and complications after revision total hip replacement (THR) are limited. The aim of this nationwide study was to describe and quantify early morbidity after aseptic revision THR and relate the morbidity to the extent of the revision surgical procedure. We analysed all aseptic revision THRs from 1st October 2009 to 30th September 2011 using the Danish National Patient Registry, with additional information from the Danish Hip Arthroplasty Registry. There were 1553 procedures (1490 patients) performed in 40 centres and we divided them into total revisions, acetabular component revisions, femoral stem revisions and partial revisions. The mean age of the patients was 70.4 years (25 to 98) and the median hospital stay was five days (interquartile range 3 to 7). Within 90 days of surgery, the readmission rate was 18.3%, mortality rate 1.4%, re-operation rate 6.1%, dislocation rate 7.0% and infection rate 3.0%. There were no differences in these outcomes between high- and low-volume centres. Of all readmissions, 255 (63.9%) were due to ‘surgical’ complications versus 144 (36.1%) ‘medical’ complications. Importantly, we found no differences in early morbidity across the surgical subgroups, despite major differences in the extent and complexity of operations. However, dislocations and the resulting morbidity represent the major challenge for improvement in aseptic revision THR.

Cite this article: Bone Joint J 2014; 96-B:1464–71.

There have been only a few small studies of patients with an infected shoulder replacement treated with a single-stage exchange procedure. We retrospectively reviewed 35 patients (19 men and 16 women) with a peri-prosthetic infection of the shoulder who were treated in this way. A total of 26 were available for clinical examination; three had died, two were lost to follow-up and four patients had undergone revision surgery. The mean follow-up time was 4.7 years (1.1 to 13.25), with an infection-free survival of 94%.

The organisms most commonly isolated intra-operatively were Staphylococcus epidermidis and Propionibacterium acnes; two patients developed a recurrent infection. Three different types of prosthesis were used: a hemiarthroplasty, a hemiarthroplasty with a bipolar head and reverse prosthesis. The mean Constant-Murley score at final follow-up was 43.3 (14 to 90) for patients with a hemiarthroplasty, 56 (40 to 88) for those with a hemiarthroplasty with a bipolar head and 61 (7 to 90) for those with a reverse prosthesis. The mean hospital stay was 10.6 days (5 to 29).

Single-stage exchange is a successful and practical treatment for patients with peri-prosthetic infection of the shoulder.

Cite this article: Bone Joint J 2013;95-B:391–5.

Although mechanical stabilisation has been a hallmark of orthopaedic surgical management, orthobiologics are now playing an increasing role. Platelet-rich plasma (PRP) is a volume of plasma fraction of autologous blood having platelet concentrations above baseline. The platelet α granules are rich in growth factors that play an essential role in tissue healing, such as transforming growth factor-β, vascular endothelial growth factor, and platelet-derived growth factor. PRP is used in various surgical fields to enhance bone and soft-tissue healing by placing supraphysiological concentrations of autologous platelets at the site of tissue damage. The easily obtainable PRP and its possible beneficial outcome hold promise for new regenerative treatment approaches.

The aim of this literature review was to describe the bioactivities of PRP, to elucidate the different techniques for PRP preparation, to review animal and human studies, to evaluate the evidence regarding the use of PRP in trauma and orthopaedic surgery, to clarify risks, and to provide guidance for future research.

Two major complications of hip replacement are loosening and infection. Reliable differentiation between these pathological processes is difficult since both may be accompanied by similar symptoms. Our aim was to assess the diagnostic ability of triple-phase bone scanning (TPBS) and positron-emission tomography (PET) to detect and differentiate these complications in patients with a hip arthroplasty. Both TPBS and PET were performed in 63 patients (92 prostheses). The radiotracer for PET imaging was ¹⁸F-fluorodeoxyglucose (FDG). Image interpretation was performed according to qualitative and quantitative criteria although the final diagnosis was based upon either surgical findings or clinical follow-up.

The sensitivity, specificity and accuracy of PET was 0.94, 0.95 and 0.95 respectively, compared with 0.68, 0.76 and 0.74 for TPBS. We found that an image interpretation based exclusively upon quantitative criteria was inappropriate because of its low selectivity. The histological examination indicated that increased periprosthetic uptake of FDG in patients with aseptic loosening was caused by wear-induced polyethylene particles and the subsequent growth of aggressive granulomatous tissue.