BSR & BHPR, BOA, RCGP and BSAC guidelines for management of the hot swollen joint in adults

The patient with a painful knee

Knee pain encompasses a wide array of differential diagnoses and can often pose a diagnostic challenge, as it can have traumatic or non-traumatic causes. A good clinical history, assessment and anatomical knowledge gives a strong foundation to narrow down the diagnosis, and understanding the correct imaging modality and findings further informs correct and timely management. This article reviews various disease processes including fractures, inflammatory, infective and neoplastic causes, and discusses the assessment and various imaging modalities to aid diagnosis in both primary and secondary care.

Diagnostic considerations in the clinical management of sudden swelling of the knee: a case report and review of the literature

BACKGROUND

Reactive arthritis and septic arthritis rarely present concomitantly in the same joint and patient. Reactive arthritis presenting after coronavirus disease 2019 is also exceedingly rare, with less than 30 cases reported thus far. Less common pathogens such as Clostridium difficile have been reported to cause reactive arthritis, especially in patients with a positive human leukocyte antigen B27, and therefore should be considered in diagnostic algorithms. The aim of this case report is to highlight the difficulties and precautions in discerning and diagnosing patients presenting with sudden swelling of the knee.

CASE PRESENTATION

We report the case of a 70-year-old Caucasian male with a recent history of coronavirus disease 2019 upper respiratory infection and diarrhea and negating trauma, who presented with a swollen and painful knee. Pain and swelling worsened and inflammatory parameters increased after an intraarticular corticosteroid injection. The patient was therefore treated with arthroscopic lavage and intravenous antibiotics for suspected septic arthritis. Synovial fluid and synovium samples were taken and sent for microbiological analysis. Synovial fluid cytology showed increased leukocytes at 10,980 × 106/L, while polymerase chain reaction and cultures came back sterile. Clostridium difficile toxin was later detected from a stool sample and the patient was treated with oral vancomycin. The patient was tested for the presence of human leukocyte antigen B27, which was positive. We present a review of the literature about the challenges of distinguishing septic from reactive arthritis, and about the mechanisms that predispose certain patients to this rheumatological disease.

CONCLUSIONS

It is still a challenge to differentiate between septic and reactive arthritis of the knee, and it is even more challenging to identify the exact cause of reactive arthritis. This case report of a human leukocyte antigen-B27-positive patient highlights the necessity of contemplating different, less common causes of a swollen knee joint as a differential diagnosis of an apparent septic infection, especially in the coronavirus disease 2019 era. Treating the patient for septic arthritis prevented any possible complications of such a condition, while treating the C. difficile infection contributed to the substantial relief of symptoms.

Management of septic arthritis and prosthetic joint infection

Management of joint infection is an evolving topic. This article reviews the literature on the management of native and prosthetic joint infection and suggests some areas of improvement in short- and long-term management which could lead to better patient outcomes. Surgical management is the mainstay of treatment for native or prosthetic knee infection and aspiration should only be used for diagnostic purposes. A multidisciplinary team approach and compliance with national guidelines, alongside referral networks and pooling of expertise, should be mandatory to improve patient outcomes.

Effect of Antibiotic Administration Before Joint Aspiration on Synovial Fluid White Blood Cell Count in Native Joint Septic Arthritis

Background

This study was performed to assess the impact of preaspiration antibiotics on synovial fluid analysis and timing of operative treatment in native-joint septic arthritis.

Methods

We performed a retrospective record review of adult patients from an urban level 1 trauma center with native joint septic arthritis in 2015-2019, identified by means of codes from the International Classification of Diseases (Ninth Revision and Tenth Revision). Univariate and multivariate analyses were performed to determine whether antibiotics were associated with lower synovial fluid white blood cell counts (WBCs), the percentage of polymorphonuclear neutrophil (PMNs), and rate of culture positivity. Secondary analysis included time elapsed from aspiration to surgery.

Results

Of the 126 patients with septic joints included, nearly two-thirds (n = 80 [63.5%]) received antibiotics before joint aspiration. The synovial fluid WBC count, percentage of PMNs, and rate of culture positivity were significantly lower in patients who received preaspiration antibiotics than in those who did not (mean WBC count, 51 379.1/μL [standard deviation, 52 576.3/μL] vs 92 162.7/μL [59 330.6/μL], respectively [P < .001]; PMN percentage, 83.6% [20.5%] vs 91.9% [6.0%; P = .01]; and culture positivity, 32.5% vs 59.1% [P = .008]). Multivariable analyses revealed that these associations remained after controlling for potential confounders (change in PMNs, -42 784.60/μL [95% confidence interval, -65 355/μL to -20 213.90/μL [P < .001]; change in PMNs, -7.8% [-13.7% to -1.8%] [P = .01]; odds ratio, 0.39 [.18-.87; P = .02). Patients with a synovial fluid WBC count ≤50 000/μL experienced significant delay in time from joint aspiration to operative intervention (mean [standard deviation], 10.5 [11.3] vs 17.9 [17.2] hours; P = .02).

Conclusions

The administration of antibiotics before joint aspiration for suspected septic arthritis appears to decrease the synovial fluid WBC count, the percentage of PMNs, and the rate of culture positivity. Efforts to limit antibiotic administration before joint aspiration are important to minimize diagnostic dilemmas and circumvent treatment delays.

Microbiological Profile and Clinical Features of Septic Arthritis of the Shoulder: A 10-Year Cohort Single-Centre Study

Introduction  Septic arthritis (SA) constitutes a pressing orthopedic emergency characterized by acute, non-traumatic joint pain. Timely diagnosis and intervention are imperative to avert complications such as chondrolysis and systemic sepsis. The etiology is predominantly hematogenous, necessitating an integrated approach involving surgical and microbiological modalities. Shoulder aspiration and microbiological analysis play pivotal roles in guiding treatment, especially when positive findings prompt more aggressive therapeutic strategies. This study aims to elucidate the nuanced clinical and epidemiological characteristics of septic arthritis in both native and prosthetic joints within a singular institutional cohort over a decade. Methods  This retrospective case series analysis spanned a 10-year period, focusing on non-prosthetic shoulder joints from January 2012 to July 2021. In this timeframe, only 183 aspirations were performed and sent to the microbiology department for analysis, including cultures, microscopy, and antibiotic sensitivity tests for positive cultures. The study delved into the microbiological profile of infections, encompassing gram stain, culture positivity rates, identification of microorganisms, and antibiotic susceptibility patterns. Additionally, the incidence of primary joint infections with resistant strains, particularly methicillin-resistant Staphylococcus aureus (MRSA), was scrutinized. Statistical analysis utilized the SPSS program version 20.0 (IBM Inc., Armonk, New York), with a significance level set at 5%. The project, registered with the trust's clinical audit department (Reg #5372), adhered to the Declaration of Helsinki and good clinical practice guidelines. Data collection involved extracting non-identifiable patient modifiers from the laboratory database bank into Excel spreadsheets. Results  The study included 183 patients, with 108 (59%) females and 75 (41%) males. The average age was 76.2±16.5 years. Among them, 138 (75.4%) reported pain, and 15 (8.2%) had a body temperature over 37.8°C. Lab results showed a mean white blood cell count of 11.6±4.5 and an average C-reactive protein level of 121.7±102.1. Leucocytosis (>11,000 WBC) was seen in 82 (44.8%) cases. Elevated C-reactive protein (CRP; >10 mg/dl) was found in 136 (74.3%) patients. Synovial fluid analysis revealed no crystals in 91.3% of cases. Microbial resistance analysis showed 19 strains resistant to co-trimoxazole and 11 to erythromycin. Among co-trimoxazole-resistant strains, 73.7% were Staphylococcus aureus, a statistically significant association (p<0.001). Conclusion The evolving sensitivity patterns of microbes in septic arthritis underscore the necessity to reassess empirical antibiotic therapy. Subsequent joint damage resulting from infection can result in substantial disability.

A pilot study on the efficacy of GPT-4 in providing orthopedic treatment recommendations from MRI reports

Large language models (LLMs) have shown potential in various applications, including clinical practice. However, their accuracy and utility in providing treatment recommendations for orthopedic conditions remain to be investigated. Thus, this pilot study aims to evaluate the validity of treatment recommendations generated by GPT-4 for common knee and shoulder orthopedic conditions using anonymized clinical MRI reports. A retrospective analysis was conducted using 20 anonymized clinical MRI reports, with varying severity and complexity. Treatment recommendations were elicited from GPT-4 and evaluated by two board-certified specialty-trained senior orthopedic surgeons. Their evaluation focused on semiquantitative gradings of accuracy and clinical utility and potential limitations of the LLM-generated recommendations. GPT-4 provided treatment recommendations for 20 patients (mean age, 50 years ± 19 [standard deviation]; 12 men) with acute and chronic knee and shoulder conditions. The LLM produced largely accurate and clinically useful recommendations. However, limited awareness of a patient's overall situation, a tendency to incorrectly appreciate treatment urgency, and largely schematic and unspecific treatment recommendations were observed and may reduce its clinical usefulness. In conclusion, LLM-based treatment recommendations are largely adequate and not prone to 'hallucinations', yet inadequate in particular situations. Critical guidance by healthcare professionals is obligatory, and independent use by patients is discouraged, given the dependency on precise data input.

Failure rates in surgical treatment in adults with bacterial arthritis of a native joint: a systematic review of 8,586 native joints

INTRODUCTION

Most adult cases of bacterial-septic-arthritis of a native joint are effectively managed with a single surgical debridement, but some cases may require more than one debridement to control the infection. Consequently, this study assessed the failure rate of a single surgical debridement in adults with bacterial arthritis of a native joint. Additionally, risk factors for failure were assessed.

MATERIALS AND METHODS

The review protocol was registered on PROSPERO (CRD42021243460) before data collection and conducted in line with the 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses' (PRISMA) guidelines. Multiple libraries were systematically searched to identify articles including patients reporting on the incidence of failure (i.e. persistence of infection requiring reoperation) of the treatment of bacterial arthritis. The quality of individual evidence were assessed using the Quality in Prognosis Studies (QUIPS) tool. Failure rates were extracted from included studies and pooled. Risk factors for failure were extracted and grouped. Moreover, we evaluated which risk factors were significantly associated with failure.

RESULTS

Thirty studies (8,586 native joints) were included in the final analysis. The overall pooled failure rate was 26% (95% CI 20 to 32%). The failure rate of arthroscopy and arthrotomy was 26% (95% CI 19 to 34%) and 24% (95% CI 17 to 33%), respectively. Seventy-nine potential risk factors were extracted and grouped. Moderate evidence was found for one risk factor (synovial white blood cell count), and limited evidence was found for five risk factors (i.e. sepsis, large joint infection, the volume of irrigation, blood urea nitrogen-test, and blood urea nitrogen/creatinine ratio).

CONCLUSION

A single surgical debridement fails to control bacterial arthritis of a native joint in approximately a quarter of all adult cases. Limited to moderate evidence exists that risk factors associated with failure are: synovial white blood cell count, sepsis, large joint infection, and the volume of irrigation. These factors should urge physicians to be especially receptive to signs of an adverse clinical course.

Administering Antibiotics for Less Than Four Weeks Increases the Risk of Relapse in Culture-Positive Septic Arthritis of Native Joints

(1) Objectives: This study investigated the optimal duration of antibiotic therapy and determined the risk factors associated with relapse in patients with culture-proven septic arthritis of native joints. (2) Methods: A retrospective review was conducted on patients aged ≥18 years diagnosed with native joint septic arthritis, with bacteria isolated from joints and/or blood. The exclusion criteria were prosthetic joint infections and cases with no identified microorganisms. The outcomes were assessed in the remission and relapse groups. (3) Results: Among 479 patients with native joint septic arthritis, 137 met the inclusion criteria, with a median follow-up duration of 2.7 years. The relapse rate was 9.5%, which mainly occurred within 30 days after antibiotic treatment completion. Compared with the remission group, the relapse group showed a significantly higher proportion of cases that received antibiotic therapy for ≤ 4 weeks (4.8% vs. 46.2%, p < 0.001), synovial fluid white blood cell (WBC) counts ≥150 × 103/mm3 (25.3% vs. 60.0%, p = 0.030), acute kidney injury (19.2% vs. 50%, p = 0.024), and extended-spectrum beta-lactamases-producing Enterobacteriaceae (0.8 vs. 15.4%, p = 0.024). Independent risk factors for relapse were determined as antibiotic therapy duration of ≤ 4 weeks (odds ratio (OR), 25.47; 95% confidence interval (CI), 1.57-412.33; p = 0.023) and synovial fluid WBC counts ≥150 × 103/mm3 (OR, 17.46; 95% CI, 1.74-175.62; p = 0.015). (4) Conclusions: Patients with native joint septic arthritis require vigilant monitoring for relapse, particularly when treated with antibiotic regimens administered for less than four weeks or when synovial aspirates exhibit elevated WBC counts at diagnosis.

Managing Small Joint Septic Arthritis of the Hand

Background: Current guidance for the management of septic arthritis is limited to large joints and, therefore, unspecific to the small joints of the hand, which may present differently, require different diagnostic approaches, and have different complications. The aim of this article was to review current treatment trends for the management of small joint septic arthritis (SJSA) of the hand and offer guidelines for its management. Methods: A systematic review was carried out according to PRISMA guidelines and a survey distributed to Fellows of the British Society for Surgery of the Hand to establish expert opinion. The review and survey were combined to present a set of specific SJSA of the hand infection guidelines. Results: All 20 included studies recommended physical drainage of infected joint fluid; subsequent lavage and early antibiotic therapy, with physiotherapist-guided joint mobilisation. Statistical analysis of the 77 responses to our survey revealed that (in order of preference) the diagnosis was made by history and examination, blood tests, joint aspiration and vital signs; and for interventions: joint elevation and intravenous antibiotics; then joint washout repeated within 48 hours, if necessary. Conclusions: Small joint infection differs from large joint infection because it is difficult to obtain joint aspirate without damaging or opening the joint. We, therefore, recommend utilising exclusion blood tests, imaging and the clinical picture to establish the diagnosis and implement early treatment and rehabilitation. Level of Evidence: Level III.

A Review of Current Practices and Future Trends in Body Fluid Testing

BACKGROUND

Body fluid testing in the clinical chemistry laboratory is a cornerstone in the diagnostic workup of pathological effusions. Laboratorians may not be aware of the preanalytical workflows used in the collection of body fluids though the value is evident whenever processes change or issues arise. The analytical validation requirements can vary depending on the regulations dictated by the laboratories' jurisdiction and accreditor requirements. Much of analytical validation hinges on how useful testing is to clinical care. Usefulness of testing varies with how well established and incorporated the tests and interpretation are in practice guidelines.

CONTENT

Body fluid collections are depicted and described so clinical laboratorians have a basic appreciation of what specimens are submitted to the laboratory for testing. A review of validation requirements by major laboratory accreditation entities is presented. A review of the usefulness and proposed decision limits for common body fluid chemistry analytes is presented. Body fluid tests that show promise and those that are losing (or lost long ago) value are also reviewed.

SUMMARY

The total testing process from collection to result interpretation can be complicated and easily overlooked by the clinical laboratory. This review aims to improve the understanding and awareness of collections, validation, result interpretation, and provide an update on recent trends.

Disseminated E. coli urinary tract infection resulting in septic arthritis of the glenohumeral joint

An 89-year-old male with a background of metastatic transitional cell carcinoma presented acutely with new hydronephrosis and deranged renal function secondary to high pressure chronic urinary retention. A recent urine culture was positive for Escherichia coli (E.coli). Co-incidentally, the patient's primary presenting symptom was right shoulder pain following recent low velocity trauma. X-ray demonstrated air density within the glenohumeral joint, with Magnetic Resonance Imaging (MRI) confirming features of septic arthritis. Surgical debridement was undertaken with tissue microscopy and culture identifying the presence of E. coli, confirming the diagnosis of disseminated urinary tract infection.

Performance and Hypothetical Impact on Joint Infection Management of the BioFire Joint Infection Panel: a Retrospective Analysis

Pathogen identification is key in septic arthritis. Culture-based techniques are challenging, especially when patients have been pretreated with antibiotics or when difficult-to-culture bacteria are encountered. The BioFire joint infection assay (BJA) is a multiplex PCR panel which detects 31 of the most prevalent bacterial and fungal pathogens causing septic arthritis. Here, 123 cryoconserved contemporary synovial fluid samples from 120 patients underwent BJA analysis. Results were compared to those of culture-based diagnostics (standard of care [SOC]). Clinical data were collected, and the possible impact of the molecular diagnostic application on patient management was evaluated. Fifteen of 123 synovial fluid cultures grew bacterial pathogens. All on-panel pathogens (9/15) were correctly identified by the BJA. The BJA identified four additional bacterial pathogens in four SOC-negative cases. BJA sensitivity and specificity were 100% (95% confidence interval [CI], 69.2% to 100%) and 100% (95% CI, 96.8% to 100%), respectively. Compared to the SOC, the BJA would have resulted in faster provision of species identification and molecular susceptibility data by 49 h and 99 h, respectively. Clinical data analysis indicates that in BJA-positive cases, faster species ID could have led to timelier optimization of antibiotic therapy. This retrospective study demonstrates high sensitivity and specificity of the BJA to detect on-panel organisms in bacterial arthritis. The usefulness of the BJA in prosthetic-joint infections is limited, as important pathogens (i.e., coagulase negative staphylococci and Cutibacterium acnes) are not covered. Evidence from patient data analysis suggests that the assay might prove valuable for optimizing patient management in acute arthritis related to fastidious organisms or for patients who received antibiotics prior to specimen collection.

Arthroscopic Treatment of the Septic Ankle

Ankle joint sepsis is a relatively rare but potentially devastating pathologic process of the lower extremity that requires expeditious identification and management. Establishing the diagnosis of ankle joint sepsis is often challenging as it may present with concomitant pathologies and often lacks consistency in regard to classic clinical characteristics. Once a diagnosis has been established, prompt management is imperative to minimize the potential for long-term sequelae. The purpose of this chapter is to address the diagnosis and management of the septic ankle with a focus on arthroscopic treatment.

Assessment and diagnosis of the acute hot joint: a systematic review and meta-analysis

OBJECTIVES

Prompt diagnosis of septic arthritis (SA) in acute native hot joints is essential for avoiding unnecessary antibiotics and hospital admissions. We evaluated the utility of synovial fluid (SF) and serum tests in differentiating causes of acute hot joints.

METHODS

We performed a systematic literature review of diagnostic testing for acute hot joints. Articles were included if studying ≥1 serum or SF test(s) for an acute hot joint, compared with clinical assessment and SF microscopy and culture. English-language articles only were included, without date restriction. The following were recorded for each test, threshold and diagnosis: sensitivity, specificity, positive/negative predictive values and likelihood ratios. For directly comparable tests (i.e. identical fluid, test and threshold), bivariate random-effects meta-analysis was used to pool sensitivity, specificity, and areas under the curves.

RESULTS

A total of 8443 articles were identified, and 49 were ultimately included. Information on 28 distinct markers in SF and serum, differentiating septic from non-septic joints, was extracted. Most had been tested at multiple diagnostic thresholds, yielding a total of 27 serum markers and 156 SF markers. Due to heterogeneity of study design, outcomes and thresholds, meta-analysis was possible for only eight SF tests, all differentiating septic from non-septic joints. Of these, leucocyte esterase had the highest pooled sensitivity [0.94 (0.70, 0.99)] with good pooled specificity [0.74 (0.67, 0.81)].

CONCLUSION

Our review demonstrates many single tests, individually with diagnostic utility but suboptimal accuracy for exclusion of native joint infection. A combination of several tests with or without a stratification score is required for optimizing rapid assessment of the hot joint.

Management and outcome of native joint septic arthritis: a nationwide survey in French rheumatology departments, 2016-2017

OBJECTIVES

To describe current management and outcome of native joint septic arthritis (NJSA) in French rheumatology departments.

METHODS

For this retrospective, nationwide multicentric study, 127 French rheumatology departments were contacted to report up to 12 cases of NJSA that occurred between 1 January 2016 and 31 December 2017. Characteristics, diagnosis procedures, therapeutic management and outcome were recorded.

RESULTS

Overall, 362 patients were included (mean age 64.0±18.6 years, median Charlson comorbidity index 3.5 (0-14)). Knee was the most frequent site (n=160 (38.9%)), and Staphylococcus sp (n=185 (51.4%)), the most frequent pathogen. All patients received antibiotics for a mean duration of 46.8 (±22.0) days, including intravenous route for a mean of 17.2 (±15.4) days. Management was heterogeneous. Surgical procedure was performed in 171 (48.3%), joint immobilisation in 128 (43.8%). During follow-up, 91 (28.3%) patients have had serious complications and 28 (9.2%) of them died. Factors associated with 1-year mortality were age (OR 1.08, 95% CI 1.04 to 1.13; p<0.001), Charlson's index (OR 1.30, 95% CI 1.06 to 1.58; p=0.012), presence of bacteraemia (OR 4.02, 95% CI 1.35 to 11.99; p=0.008), antibiotic use in the previous 3 months (OR 3.32, 95% CI 1.11 to 9.87; p=0.029) and Staphylococcus aureus NJSA compared with Streptococcus sp. NJSA (OR 7.24, 95% CI 1.26 to 41.68, p=0.027). The complete recovery with no adverse joint outcome at 1 year was observed in n=125/278 patients (55.0%).

CONCLUSION

Prognosis of NJSA remained severe with a high rate of morbimortality. Its management was very heterogeneous. This study highlights the importance of the new French recommendations, published after the completion of the study, in order to facilitate NJSA management.

PGC-1α induced mitochondrial biogenesis in stromal cells underpins mitochondrial transfer to melanoma

INTRODUCTION

Progress in the knowledge of metabolic interactions between cancer and its microenvironment is ongoing and may lead to novel therapeutic approaches. Until recently, melanoma was considered a glycolytic tumour due to mutations in mitochondrial-DNA, however, these malignant cells can regain OXPHOS capacity via the transfer of mitochondrial-DNA, a process that supports their proliferation in-vitro and in-vivo. Here we study how melanoma cells acquire mitochondria and how this process is facilitated from the tumour microenvironment.

METHODS

Primary melanoma cells, and MSCs derived from patients were obtained. Genes' expression and DNA quantification was analysed using Real-time PCR. MSC migration, melanoma proliferation and tumour volume, in a xenograft subcutaneous mouse model, were monitored through bioluminescent live animal imaging.

RESULTS

Human melanoma cells attract bone marrow-derived stromal cells (MSCs) to the primary tumour site where they stimulate mitochondrial biogenesis in the MSCs through upregulation of PGC1a. Mitochondria are transferred to the melanoma cells via direct contact with the MSCs. Moreover, inhibition of MSC-derived PGC1a was able to prevent mitochondrial transfer and improve NSG melanoma mouse tumour burden.

CONCLUSION

MSC mitochondrial biogenesis stimulated by melanoma cells is prerequisite for mitochondrial transfer and subsequent tumour growth, where targeting this pathway may provide an effective novel therapeutic approach in melanoma.

Risk factors for septic arthritis and multiple arthroscopic washouts: minimum 2-year follow-up at a major trauma centre

Background

Septic arthritis (SA) is a dangerous condition that requires emergency treatment. Managed by culture-specific antibiotics, irrigation, and debridement (I&D), some patients require repeat surgical treatment. The objectives were to determine the risk factors for SA and risk factors for repeat arthroscopic I&D in SA patients. We hypothesized that variables which directly or indirectly contributed to a larger infection burden would be associated with the development of SA and the need for repeat arthroscopic I&D.

Methods

All patients ≥ 18 years old presenting to the emergency department, orthopaedic and rheumatology clinics at our major trauma centre between January 2018 and January 2020 with a hot, swollen joint were retrospectively evaluated. Patients with previous trauma and metalwork in the affected joint, periprosthetic joint infection, previous joint arthroplasty surgery, soft tissue infection, missing data, transferred to another centre, diagnosis not concerning the joint, and < 24-month follow-up were excluded. Two hundred eleven patients were included (SA: 28; pseudogout: 32; gout: 50; others: 101). Variables of interest in the 3-month period preceding the diagnosis of SA were compared between SA and non-SA patients using univariable analysis. A multivariable logistic regression model was formed using covariates with corresponding univariable tests of p < 0.200. Similar analyses were performed to compare SA patients with multiple washouts/procedures with those with one washout/procedure.

Results

Multivariable analysis showed multiple risk factors for SA, namely rheumatoid arthritis (RA) (OR: 3.4; 95% CI: 1.2–10.0; p = 0.023); skin infection (OR: 3.3; 95% CI: 1.2–9.0; p = 0.017), liver disease (OR: 9.9; 95% CI: 2.2–43.9; p = 0.003), knee joint involvement (OR: 3.5; 95% CI: 1.3–9.4; p = 0.014), and use of immunosuppressive medication (OR: 3.5; 95% CI: 1.2–10.6; p = 0.027). Risk factors for multiple washouts included synovial WBC levels > 10.5 × 10⁹ cells/L (OR: 3.0; 95% CI: 2.3–38.8; p = 0.009) and RA (OR: 3.5; 95% CI: 1.9–66.3; p = 0.017).

Conclusions

These findings suggest that prophylactic actions against septic arthritis should be targeted at patients with liver disease, RA, or skin infection. Repeat arthroscopic I&D of septic joints may be needed, especially in patients with synovial WBC levels > 10.5 × 10⁹ cells/L and RA.

Key Points • The risk factors for septic arthritis determined in this study are rheumatoid arthritis, skin infection, liver disease, knee joint involvement, and immunosuppressant usage. • Some septic arthritis patients need multiple rounds of arthroscopic irrigation and debridement. The risk factors for this are a synovial WBC count > 10.5 × 109 cells/L and rheumatoid arthritis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10067-022-06151-w.

Management of a Hot Swollen Joint in the Acute Setting

BACKGROUND

The presentation of a hot swollen joint is common in the emergency department, general practice, rheumatology and orthopedic clinics. There is a wide set of differential diagnoses for a hot swollen joint, thus making it difficult to diagnose and manage, especially for junior doctors. Initially, it is pertinent to exclude/diagnose medical and surgical emergencies.

OBJECTIVE

This paper aims to summarize the key indications within the history, examination and investigations in order to quickly and effectively diagnose a hot swollen joint based on the original 2006 management guidelines and the papers discussing other possible indications and management strategies published since.

RESULTS

Currently, the management of crystal and non-infectious arthropathies are well recognized with little disparity. However, the treatment of infectious arthritis is not concrete and there are discrepancies in management between doctors.

CONCLUSION

We have summarized the key indications and provided a diagnostic flow chart to aid with the management.

[Management of joint empyema]

Joint empyema, also known as septic arthritis, is a severe disease associated with considerable morbidity and mortality. Failing to initiate immediate treatment can result in irreversible joint destruction within a short time. The knee joint is most frequently involved, followed by the shoulder and hip joints. Small joints are rarely affected. Typical risk factors include immunosuppression, renal insufficiency, diabetes mellitus and previous joint interventions. An early targeted diagnostic work-up and initiation of therapeutic steps is crucial to avoid irreversible joint destruction. Joint aspiration for diagnostic purposes is essential and should be performed immediately when a septic arthritis is suspected. An important differential diagnosis is metabolic arthritis (gout and chondrocalcinosis), which typically presents in a similar way. A differentiation from septic arthritis is important as metabolic arthritis requires a completely different treatment. After confirming the diagnosis, treatment consisting of a surgical procedure combined with antibiotics is initiated. In most cases an arthroscopic intervention is sufficient. In severe cases the arthroscopy needs to be repeated. An arthrotomy must be carried out only rarely. A pre-emptive antibiotic treatment is initially administered and is later adjusted according to the resistogram. This article gives an overview on the pathophysiology, diagnostics and general management of joint empyema.

What are the best diagnostic tests for diagnosing bacterial arthritis of a native joint? : a systematic review of 27 studies

AIMS

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?

METHODS

We performed a search of PubMed, Embase, and Cochrane libraries for relevant studies published between January 1980 and April 2020. Of 3,209 identified studies, we included 27 after full screening. Sensitivity, specificity, area under the curve, and Youden index of diagnostic tests were extracted from included studies. We grouped test characteristics per diagnostic modality. We extracted the definitions used to establish a definitive diagnosis of bacterial arthritis of a native joint per study.

RESULTS

Overall, 28 unique diagnostic tests for diagnosing bacterial arthritis of a native joint were identified. The following five tests were deemed most useful: serum ESR (sensitivity: 34% to 100%, specificity: 23% to 93%), serum CRP (sensitivity: 58% to 100%, specificity: 0% to 96%), serum procalcitonin (sensitivity: 0% to 100%, specificity: 68% to 100%), the proportion of synovial polymorphonuclear cells (sensitivity: 42% to 100%, specificity: 54% to 94%), and the gram stain of synovial fluid (sensitivity: 27% to 81%, specificity: 99% to 100%).

CONCLUSION

Diagnostic methods with relatively high sensitivities, such as serum CRP, ESR, and synovial polymorphonuclear cells, are useful for screening. Diagnostic methods with a relatively high specificity, such as serum procalcitonin and synovial fluid gram stain, are useful for establishing a diagnosis of bacterial arthritis. This review helps to interpret the value of various diagnostic tests for diagnosing bacterial arthritis of a native joint in clinical practice. Cite this article: Bone Joint J 2021;103-B(12):1745-1753.

Biosensors for Detection and Monitoring of Joint Infections

The aim of this review is to assess the use of biosensors in the diagnosis and monitoring of joint infection (JI). JI is worldwide considered a significant cause of morbidity and mortality in developed countries. Due to the progressive ageing of the global population, the request for joint replacement increases, with a significant rise in the risk of periprosthetic joint infection (PJI). Nowadays, the diagnosis of JI is based on clinical and radiological findings. Nuclear imaging studies are an option but are not cost-effective. Serum inflammatory markers and the analysis of the aspirated synovial fluid are required to confirm the diagnosis. However, a quick and accurate diagnosis of JI may remain elusive as no rapid and highly accurate diagnostic method was validated. A comprehensive search on Medline, EMBASE, Scopus, CINAH, CENTRAL, Google Scholar, and Web of Science was conducted from the inception to June 2021. The PRISMA guidelines were used to improve the reporting of the review. The MINORS was used for quality assessment. From a total of 155 studies identified, only four articles were eligible for this study. The main advantages of biosensors reported were accuracy and capability to detect bacteria also in negative culture cases. Otherwise, due to the few studies and the low level of evidence of the papers included, it was impossible to find significant results. Therefore, further high-quality studies are required.

Bacterial arthritis of native joints can be successfully managed with needle arthroscopy

PURPOSE

To assess the feasibility of needle arthroscopy for management of suspected bacterial arthritis in native joints.

METHODS

During a pilot period, patients presenting with symptoms suggestive of native joint bacterial arthritis were eligible for initial management with needle arthroscopy. Procedures were performed in the operating theatre or at the patient bedside in the emergency department or inpatient ward. As our primary outcome measure, it was assessed whether needle arthroscopic lavage resulted in a clear joint. In addition, the need for conversion to standard arthroscopy or arthrotomy, the need for conversion from local to general anaesthesia, complications and the need for additional surgical intervention at follow-up during admission were recorded.

RESULTS

Eleven joints in 10 patients (four males, age range 35 - 77) were managed with needle arthroscopy. Needle arthroscopic lavage resulted in a clear joint in all cases. Conversion to standard arthroscopy or arthrotomy was not needed. Seven procedures were performed at the patient bedside using local anaesthesia. These procedures were well tolerated and conversion to general or spinal anaesthesia was not required. There were no procedure complications. One patient received multiple needle arthroscopic lavages. No further surgical interventions beside the initial needle arthroscopic lavage were required for successful management in other cases.

CONCLUSIONS

Needle arthroscopy can be a feasible tool in the initial management of complaints suggestive for native joint bacterial arthritis, providing an effective, quick and well-tolerable intervention in the operating theatre or at the patient bedside, with the potential to relief health systems from need for scarce operating theatre time.

New Prospects in Nano Phased Co-substituted Hydroxyapatite Enrolled in Polymeric Nanofiber Mats for Bone Tissue Engineering Applications

The most common forms of tissue impairment are fracture bones and significant bone disorders caused by multiple traumas or normal aging. Surgical care sometimes necessitates the placement of a temporary or permanent prosthesis, which continues to be a challenge for orthopedic surgeons, including those with large bone defects. Electrospun scaffolds made from natural and synthetic nanofiber-based polymers are studied as natural extracellular matrix (ECM)-like scaffolds for tissue engineering. Besides, nanostructured materials have properties and functions depending on the scale of natural materials such as hydroxyapatite (HAP), ranging from 1 to 100 nm, which activity was proficient upon enrolled in nanofiber mats. The use of nanofibers in combination with nano-HAP has increased the scaffold's ability to replicate the construction of natural bone tissue that is the aim of the present text. In bone engineering, nanofiber substrates facilitate cell adhesion, proliferation, and differentiation, while HAP induces cells to secrete ECM for bone mineralization and development. This review aims to draw the reader's attention to the critical issues with synthetic and natural polymers containing HAP in bone tissue engineering; co-substituted hydroxyapatite has also been mentioned.

Leukocyte Esterase and Glucose Reagent Test Can Rule in and Rule out Septic Arthritis

BACKGROUND/AIM

Septic arthritis (SA) requires rapid diagnosis and therapy to avoid joint damage. This study evaluated the diagnostic accuracy of leukocyte esterase (LE) and glucose (GLC) strip tests for diagnosing SA.

PATIENTS AND METHODS

Synovial fluids from 455 patients with atraumatic joint effusions were assessed prospectively over a 5-year period with LE and glucose strip tests. Results were compared to modified Newman criteria for diagnosing joint infections. Synovial fluid cultures, crystal, blood and synovial cell analyses were also performed.

RESULTS

Forty-one patients had SA and 252 non-SA. A positive LE reading combined with negative glucose reading could detect SA with 100% specificity, 85% sensitivity, 100% positive predictive value (PPV) and 98% negative predictive value (NPV). Positive synovial LE reading alone detected SA with 82% specificity, 95% sensitivity, 47% PPV, and 99% NPV.

CONCLUSION

Combined LE and glucose strip tests represent a low-cost tool for rapidly diagnosing or ruling out SA.

Evaluation of Intra-Articular Amikacin Administration in an Equine Non-inflammatory Joint Model to Identify Effective Bactericidal Concentrations While Minimizing Cytotoxicity

Septic arthritis causes significant morbidity and mortality in veterinary and human clinical practice and is increasingly complicated by multidrug-resistant infections. Intra-articular (IA) antibiotic administration achieves high local drug concentrations but is considered off-label usage, and appropriate doses have not been defined. Using an equine joint model, we investigated the effects of amikacin injected at three different doses (500, 125, and 31.25 mg) on the immune and cartilage responses in tibiotarsal joints. Synovial fluid (SF) was sampled at multiple time points over 24 h, the cell counts determined, and amikacin concentrations measured by liquid chromatography-mass spectrometry. Cytokine concentrations and collagen degradation products in SF were measured by ELISA and multiplex immunoassays. The mean amikacin concentrations in SF were greater than or equal to the minimum inhibitory concentration (MIC) (0.004 mg/ml) for most common equine joint pathogens at all time points tested to 24 h for all three amikacin doses evaluated. The inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) increased significantly in SF in the highest amikacin dose group, despite the fact that increases in SF cell counts were not observed. Similarly, the biomarkers of cartilage type II collagen cleavage (C2C and C12C) were increased in SF following amikacin injection. Mechanistically, we further demonstrated using in vitro studies that chondrocytes and synoviocytes killed by exposure to amikacin underwent apoptotic cell death and were phagocytosed by macrophages in a non-inflammatory process resembling efferocytosis. Neutrophils and T cells were susceptible to amikacin cytotoxicity at clinically relevant doses, which may result in blunting of cellular inflammatory responses in SF and account for the lack of increase in total nucleated cell counts following amikacin injection. In summary, decisions on whether to inject cytotoxic antibiotics such as aminoglycosides intra-articularly and what doses to use should take into account the potential harm that antibiotics may cause and consider lower doses than those previously reported in equine practice.

Infection of the hip joint by Serratia marcescens

A 72-year-old male patient presented to the hospital because of sudden inability to bear weight and without a history of trauma. A fracture of the head of the femur was identified on CT scan of the pelvis. In his history, the patient had a hospital admission 3 months earlier, during which he had a urinary catheter, and a urine specimen was analysed. The same pathogen was found in the patient urine and in the head of the femur specimen. This is a report of blood-borne spread of Serratia marcescens infection from the urothelium to the hip joint, responsible for spontaneous fracture of the femoral head without history of trauma.

Comparison of bacterial culture results of preoperative synovial fluid and intraoperative specimens in patients with joint infection

OBJECTIVES

The details of relationship between bacterial culture results of preoperative and intraoperative specimens in same patients with native joint septic arthritis (NJSA) and periprosthetic joint infection (PJI) are unknown. This study aims to reveal the difference of culture results of preoperative synovial fluid and intraoperative specimens and evaluate the risk factors for detecting different species intraoperatively from preoperative synovial fluid.

METHODS

This study included 55 joints diagnosed with 16 NJSA and 39 PJI. Bacterial culture positive rates and identified bacterial species were compared between preoperative synovial fluid and intraoperative tissue/synovial fluid. We also examined the presence or absence of sinus tracts and antimicrobial agents as risk factors in patients with different bacterial species in intraoperative specimens from preoperative synovial fluid.

RESULTS

The culture positive rates were not significantly different between preoperative synovial fluid and intraoperative specimens. Different bacterium were detected in 10.9% joints by intraoperative tissue and 14.6% joints by intraoperative synovial fluid. The positive rate of sinus tract was significantly higher in patients with different bacterial species (62.5%) than without different bacterial species (12.8%, p < 0.01). Conversely, antimicrobial agent was not significantly difference.

CONCLUSION

This study demonstrated that different bacterium from preoperative culture results were detected in 10-15% joints by intraoperative specimens in NJSA and PJI. The sinus tract was a risk factor for identifying different bacterial species in the intraoperative specimens. Therefore, in cases of sinus tract, it is necessary to examine multiple specimens of both intraoperative tissue and synovial fluid for increasing the detection rate.

Synovial fluid presepsin as a novel biomarker for the rapid differential diagnosis of native joint septic arthritis from crystal arthritis

OBJECTIVE

To investigate whether presepsin can be used as a novel biomarker to differentiate between native joint septic arthritis (NJSA) and crystal arthritis (CA).

METHODS

This study included 75 patients diagnosed with either NJSA (n = 21) or CA (n = 54). Presepsin in synovial fluid and blood, C-reactive protein, and procalcitonin were measured and compared between the NJSA and CA groups. Receiver operating characteristic (ROC) curve analyses were performed to differentiate between the two groups.

RESULTS

Synovial fluid and blood presepsin were significantly higher in the NJSA group than in the CA group (p < 0.0001 and p < 0.01, respectively). The area under the ROC curve for synovial fluid presepsin in the NJSA group compared with the CA group was 0.93 (sensitivity 85.7%, specificity 85.2%, positive predictive value 69.2%, negative predictive value 93.9%, positive likelihood ratio 5.79, negative likelihood ratio 0.17). Among the tests, synovial fluid presepsin was the most accurate.

CONCLUSIONS

Measurement of synovial fluid presepsin is reliable for the early diagnosis of NJSA, and synovial fluid presepsin could be used as a novel biomarker for differentiating between NJSA and CA.

Intracellular Staphylococcus aureus in bone and joint infections: A mechanism of disease recurrence, inflammation, and bone and cartilage destruction

Bone and joint infections are devastating afflictions. Although medical interventions and advents have improved their care, bone and joint infections still portend dismal outcomes. Indeed, bone and joint infections are associated with extremely high mortality and morbidity rates and, generally, occur secondary to the aggressive pathogen Staphylococcus aureus. The consequences of bone and joint infections are further compounded by the fact that although they are aggressively treated, they frequently recur and result in massive bone and articular cartilage loss. Here, we review the literature and chronicle the fact that the fundamental cellular components of the musculoskeletal system can be internally infected with Staphylococcus aureus, which explains the ready recurrence of bone and joint infections even after extensive administration of antibiotic therapy and debridement and offer potential treatment solutions for further study. Moreover, we review the ramifications of intracellular infection and expound that the massive bone and articular cartilage loss is caused by the sustained proinflammatory state induced by infection and offer potential combination therapies for further study to protect bone and cartilage.

Primarily treated patients versus referred patients in the treatment of native septic arthritis of digits: a retrospective comparative study

BACKGROUND

Septic arthritis of digits needs urgent treatment. When treatments delayed or insufficient, patients may be referred to the upper-level hospital due to uncontrolled infection. We reviewed the treatment history of referred patients and compared the microorganisms and the clinical course of both primary and referred patients as relevant studies are rare.

METHODS

In this retrospective review of consecutive case series, 45 patients (primary, n = 11; referred, n = 34) were treated with multiple irrigation and debridement. Cefazolin was used as empiric antibiotics, then changed according to microbiologic study. Previously used antibiotics, treatment delay, surgical history of the referred patients were reviewed. Identified microorganisms, required surgical intervention, hospital stay, radiologic outcome, functional outcomes were compared between both groups.

RESULTS

In the referred patients, methicillin-resistant Staphylococcus aureus (MRSA) was commonly found and cefazolin was susceptible in only 15% of the cases. Longer hospital stay, prolonged antibiotic therapy, more surgical intervention including flap surgery was required to treat the referred patients. Postoperative pain was not severe in daily activities, but the final range of motion was significantly less in the referred patients compared to the primary patients.

CONCLUSIONS

This study suggests that in the treatment of uncontrolled septic arthritis of the digits, antibiotic agents covering MRSA may shorten the duration of antibiotic therapy in areas of high MRSA incidence. Besides, more number of I & D including flap surgery may be required for the referred patients compared with the primary patients. These findings can help the surgeon in setting up a treatment plan or in counseling of referred patients with uncontrolled septic arthritis of the digits.

Assessing an alpha-defensin lateral flow device for diagnosing septic arthritis: reporting on a false-negative case and a false-positive case

Alpha-defensin (αD), an antimicrobial peptide released by neutrophils in response to bacterial pathogens, was proposed as a novel diagnostic biomarker in synovial fluid. Several reports have shown that αD can serve as a reliable biomarker in the diagnosis of periprosthetic joint infection (PJI). We assessed whether αD could also serve to diagnosis of septic arthritis, a similarly difficult to diagnose PJI. To our knowledge, besides PJI, few reports exist assessing the utility of αD for septic arthritis. We have attempted to diagnose several cases of suspected septic arthritis using the Synovasure^® αD detection lateral flow device. We report a false-positive case and a false-negative case. The false-negative case we experienced was caused by Staphylococcus capitis, which is coagulase-negative, and possibly represents a low virulence micro-organism infection. The false-positive case was ultimately diagnosed as seronegative rheumatoid arthritis and possessed calcium pyrophosphate depositions. False positives have been suggested to occur in conditions where neutrophils are mobilised. As for PJI, in cases where diagnosis is difficult, αD can be an additional diagnostic indicator. However, making a definitive diagnosis using the αD lateral flow device alone was found to be difficult. The utility of αD in assessing septic arthritis is inconclusive; therefore, larger prospective clinical studies should be considered for a better assessment.

Infectious arthritis and the temporomandibular joint. A review

OBJECTIVE

Microorganisms can cause acute infectious arthritis, chronic infectious arthritis, or reactive inflammatory arthritis. The aim of this study is to perform a narrative review of the pathophysiology, etiology, and diagnostic features of infectious arthritis and TMJ infectious arthritis.

METHODS

A search of the literature was performed using Medline, Scielo, Embase, and Google Scholar databases. The terms employed for the search were "Temporomandibular Joint Disorders" and "Infectious Arthritis"; or "Septic Arthritis"; or "Bacterial, Fungal, or Viral Arthritis." Over three hundred articles were screened for eligibility.

RESULTS

The selected articles were utilized to perform a narrative review of the general aspects of infectious arthritis and infectious arthritis affecting the TMJ.

CONCLUSION

Infectious arthritis is a rare, yet very morbid, form of arthritis. Understanding general aspects of joint infections and specific features of TMJ infectious arthritis is imperative for an adequate diagnosis.

Septic Arthritis: An Evidence-Based Review of Diagnosis and Image-Guided Aspiration

OBJECTIVE. The purpose of this evidence-based review is to equip radiologists to discuss and interpret findings obtained with various imaging modalities, guide patient selection for percutaneous aspiration, and safely perform arthrocentesis to assess for infection in both native and prosthetic joints. CONCLUSION. Septic arthritis is an emergency that can lead to rapidly progressive, irreversible joint damage. Despite the urgency associated with this diagnosis, there remains a lack of consensus regarding many aspects of the management of native and periprosthetic joint infections.

2020 French recommendations on the management of septic arthritis in an adult native joint

Septic arthritis (SA) in an adult native joint is a rare condition but a diagnostic emergency due to the morbidity and mortality and the functional risk related to structural damage. Current management varies and the recommendations available are dated. The French Rheumatology Society (SFR) Bone and Joint Infection Working Group, together with the French Language Infectious Diseases Society (SPILF) and the French Orthopaedic and Trauma Surgery Society (SOFCOT) have worked according to the HAS methodology to devise clinical practice recommendations to diagnose and treat SA in an adult native joint. One new focus is on the importance of microbiological documentation (blood cultures and joint aspiration) before starting antibiotic treatment, looking for differential diagnoses (microcrystal detection), the relevance of a joint ultrasound to guide aspiration, and the indication to perform a reference X-ray. A cardiac ultrasound is indicated only in cases of SA involving Staphylococcus aureus, oral streptococci, Streptococcus gallolyticus or Enterococcus faecalis, or when infective endocarditis is clinically suspected. Regarding treatment, we stress the importance of medical and surgical collaboration. Antibiotic therapies (drugs and durations) are presented in the form of didactic tables according to the main bacteria in question (staphylococci, streptococci and gram-negative rods). Probabilistic antibiotic therapy should only be used for patients with serious symptoms. Lastly, non-drug treatments such as joint drainage and early physical therapy are the subject of specific recommendations.

A Retrospective Review of Native Septic Arthritis in Patients: Can We Diagnose Based on Laboratory Values?

Introduction The accurate diagnosis of acute septic arthritis is essential to initiating appropriate treatment and minimizing potential cartilage damage. A synovial fluid cell count of 50,000 cells/mm³ has been used as a diagnostic cutoff for acute septic arthritis, although data supporting this is lacking. The purpose of this study was to assess the efficacy of synovial cell counts to predict septic arthritis in patients with symptomatic native joints. Methods A retrospective review was performed of patients who were evaluated for septic arthritis at a single institution with the use of synovial fluid analysis and adjunctive lab tests. Exclusion criteria included history of a total joint arthroplasty of the affected joint or immunocompromised state. A true infection was considered on the basis of positive or negative synovial aspirate cultures. We evaluated the synovial cell count, synovial polymorphonuclear cell percentile (% neutrophils), serum white blood cell (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) in order to determine their association and predictive power in a true infection. Results Of the 65 patients included in the study, 40 (61.5%) had a positive culture for septic arthritis and 25 (38.5%) had negative cultures. Patients with positive cultures had a larger median % neutrophils than patients with negative cultures (median: 93 vs. median: 86, P=0.041). They also tended to have higher serum CRP levels compared to negative culture patients (median: 142.30 vs. 34.20, P=0.051). No outcomes were independently highly effective in discriminating between patient groups (area under the curve (AUC) ≤ 0.67). There was no significant difference between the synovial cell counts in patients with culture positive septic arthritis and patients with negative cultures (median: 32435 vs 35385, P = 0.94).  Conclusion Patients with culture proven septic arthritis had larger % neutrophils. However, there were no other statistically significant differences between patient groups regarding ESR, CRP, WBC, or cell count aspiration at the time of diagnosis. No synovial cell count level was highly effective in discriminating patients with a positive culture for septic arthritis from patients with negative cultures.

Clinical features, risk factors, and outcomes of septic arthritis in patients on maintenance hemodialysis

The aim of this study was to investigate the clinical features, risk factors, and outcomes of septic arthritis in patients on maintenance hemodialysis (HD). We systematically reviewed medical records of 16 HD patients with septic arthritis admitted to our hospital from April 2008 to April 2018. A total of 16 HD in patients with bloodstream infection but without septic arthritis were randomly selected as controls. The incidence of septic arthritis in our patient group was 0.2% per year. Organisms isolated were Staphylococcus aureus in 11 (68.7%), Gram-negative bacilli in 3, streptococci in 1, and fungi in 1. Patients with septic arthritis were significantly older (72.7 ± 9.4 vs 63.5 ± 8.7 years, p = 0.035) and had more joint diseases (62.5% vs 12.5%, p = 0.003) and a longer duration of hospitalization (35.2 ± 5.7 vs 22.1 ± 3.5 days, p = 0.021) than the control group. In a logistic regression analysis, patients with older age and more joint diseases were more likely to have septic arthritis compared with controls (OR = 1.39, p = 0.024 and OR = 3.24, p = 0.003, respectively). These findings indicate that old age and joint diseases (osteoarthritis or inflammatory arthritis) were independent risk factors for septic arthritis in patients on HD when bloodstream infection occurred. Key Points • Patients with septic arthritis were significantly older and had more joint diseases than the control group. • Old age and joint diseases are independent risk factors for septic arthritis in patients on HD when bloodstream infection occurs.

Medical versus surgical treatment in native hip and knee septic arthritis

OBJECTIVE

Antibiotic treatment and arthroscopic or open drainage is the gold standard for septic arthritis. Full recovery takes time after surgery and hospital stay is longer than for arthrocentesis at the bedside. We aimed to evaluate the effectiveness of arthrocentesis (medical approach) versus a surgical approach.

METHOD

We retrospectively included 97 cases of native joint arthritis (hip and knee) between 2010 and 2017. The primary outcome was treatment failure of medical and surgical approaches (defined as surgical intervention within 7 days following diagnosis). Risk factors of failure were identified by univariable and multivariable logistic regression.

RESULTS

We included 72 cases of knee arthritis, of which 43 and 29 were treated medically and surgically, respectively; 25 cases of hip arthritis, of which 8 and 17 were treated medically and surgically, respectively. Failure was observed in 39.2% of cases in the medical group and in 30.4% in the surgical group (P=0.2) (37.5% vs. 52.9% and 39.5% vs. 17.2% for hip and knee, respectively). The univariate analysis identified age and male sex as risk factors for failure (P=0.048 and P=0.02, respectively), but only age was independently associated with failure (P=0.04). Hospital length of stay was 12 days shorter in the medical group (21 vs. 33 days, P=0.02), sequelae were less frequent and less important in the medical group (31.7% vs. 60%).

CONCLUSION

The medical treatment seems to be as effective as the surgical treatment for native joint septic arthritis with a shorter hospital stay and better functional outcome. Further prospective studies are warranted.

The difference between native septic arthritis and prosthetic joint infections: A review of literature

Current literature occasionally considers septic arthritis in native joints and prosthetic joint infections as equal pathologies. However, significant differences can be identified. The aim of this review of literature is to describe these differences in definitions, pathology, diagnostic workups, treatment strategies, and prognosis.

Septic Arthritis in Immunosuppressed Patients: Do Laboratory Values Help?

Previous studies have recommended synovial fluid cell count thresholds of 50,000 cells/mm^-3 to diagnose septic arthritis; however, data to support this are limited. It is also unknown if this value is valid in immunosuppressed patients.

Methods

We retrospectively reviewed 33 immunosuppressed patients treated at our institution from 2008 to 2018. We compared culture-positive patients with culture-negative patients.

Results

We found no statistically significant differences in synovial fluid cell count, percent synovial fluid neutrophils, erythrocyte sedimentation rate, or C-reactive protein between the groups (all P = 0.081). The median synovial fluid cell count in the culture-positive cohort was 29,000 cells/mm^-3, with only 31.2% having >50,000 cells/mm^-3.

Conclusion

Traditional synovial fluid cell thresholds are not a reliable method of diagnosing septic arthritis in immunosuppressed patients.

Review on calcium- and magnesium-based silicates for bone tissue engineering applications

Bone is a self-engineered structural component of the human body with multifaceted mechanical strength, which provides indomitable support to the effective functioning of the human body. It is indispensable to find a suitable biomaterial for substituting the bone as the bone substitute material requirement is very high due to the rate of bone fracture and infection lead to osteoporosis in human beings increases rapidly. It is not an easy task to design a material with good apatite deposition ability, a faster rate of dissolution, superior resorbability, high mechanical strength, and significant bactericidal activity. Since the synthetic hydroxyapatite was not able to achieve the dahlite phase of hydroxyapatite (natural bone mineral phase), silicates emerged as an alternate biomaterial to meet the need for bone graft substitutes. All silicates do not exhibit the properties required for bone graft substitutes, as their composition and methodology adopted for the synthesis are different. Calcium, magnesium, and silicon play a major role in the formation of bone mineral and their metabolism during bone formation. In this review, the relationship between composition and activity of calcium, magnesium-based silicates have been discussed along with the future scope of these materials for hard tissue engineering applications.

[Native joint infections]

Joint infections are a great challenge for the treating physicians. Infection of a native joint can result in the rapid destruction of the joint if treatment is inadequate or delayed and is associated with severe life-threatening diseases, such as sepsis. This article presents a detailed overview of the treatment of joint infections of native joints with a focus on the diagnostic approach and treatment decisions. Infections in native joints are caused either endogenously by hematogenic spreading or are caused by exogenous factors. A relevant proportion of joint infections in native joints occur in connection with iatrogenic measures, such as operations, synovial punctures and joint infiltrations. Fundamentally, acute infections represent an orthopedic surgical emergency, which is associated with the necessity for immediate operative measures. The best possible success can only be achieved by an interaction between early diagnosis, an adequate surgical approach and a tailor-made anti-infectious treatment. This is also the case with periprosthetic infections, which will be dealt with in detail in a second article.