An update on recent progress of the epidemiology, etiology, diagnosis, and treatment of acute septic arthritis: a review

Arthroscopy or arthrotomy for native knee septic arthritis: A systematic review

Purpose

Septic arthritis of any joint is an orthopaedic emergency which requires prompt diagnosis and treatment. The knee is the commonest joint afflicted, and the primary objective of any treatment is complete source control. This commonly takes the form of antibiotic therapy and a washout of the infected joint by means of arthroscopy or arthrotomy. The primary aim of this review is to investigate if arthroscopic washout for native knee septic arthritis confers a lower risk of repeat procedure than arthrotomy.

Methods

A systematic review and meta-analysis was conducted of the MEDLINE, SCOPUS and the Cochrane Library data bases. The primary outcome of interest was requirement for repeat washout with all-cause complications, length of inpatient stay and mortality secondary outcomes.

Results

A total of 17,140 subjects were included for analysis of the primary outcome, and the overall rate of repeat procedure was 14.6%. No statistical difference was found between arthroscopy and arthrotomy for repeat washout (risk ratio 0.86 [95% confidence interval, CI: 0.72-1.02], I 2 = 36%). Eligible studies found in favour of arthroscopy for all-cause complication rate (risk ratio 0.75 [95% CI: 0.6-0.93], I 2 = 84%) and length of stay in hospital (mean difference -1.98 days [95% CI: -3.43 to -0.53], I 2 = 84%). No statistical difference was found for the mortality rate (risk ratio 1.17 [95% CI: 0.52-2.63], I 2 = 57%).

Conclusion

Our analysis found arthroscopy and open arthrotomy to be equivocal for repeat surgical washout in native knee septic arthritis. All-cause complication rate and length of inpatient stay were favourable for arthroscopy with no difference noted between mortality rates.

Level of Evidence

Level III.

Current updates in MSK infection imaging: A narrative review

This article presents a comprehensive overview of the diagnostic utility of existing imaging techniques including radiography, computed tomography, ultrasonography, magnetic resonance imaging (MRI), and radionuclide imaging in the context of the most common orthopaedic or musculoskeletal infections. It also includes illustrative images showcasing significant findings in various musculoskeletal infections including osteomyelitis, cellulitis, septic arthritis, necrotising infections and peri-prosthetic joint infections and their associated complications.

Potential value of a rapid syndromic multiplex PCR for the diagnosis of native and prosthetic joint infections: a real-world evidence study

Introduction: The BIOFIRE Joint Infection (JI) Panel is a diagnostic tool that uses multiplex-PCR testing to detect microorganisms in synovial fluid specimens from patients suspected of having septic arthritis (SA) on native joints or prosthetic joint infections (PJIs). Methods: A study was conducted across 34 clinical sites in 19 European and Middle Eastern countries from March 2021 to June 2022 to assess the effectiveness of the BIOFIRE JI Panel. Results: A total of 1527 samples were collected from patients suspected of SA or PJI, with an overall agreement of 88.4 % and 85 % respectively between the JI Panel and synovial fluid cultures (SFCs). The JI Panel detected more positive samples and microorganisms than SFC, with a notable difference on Staphylococcus aureus, Streptococcus species, Enterococcus faecalis, Kingella kingae, Neisseria gonorrhoeae, and anaerobic bacteria. The study found that the BIOFIRE JI Panel has a high utility in the real-world clinical setting for suspected SA and PJI, providing diagnostic results in approximately 1 h. The user experience was positive, implying a potential benefit of rapidity of results' turnover in optimising patient management strategies. Conclusion: The study suggests that the BIOFIRE JI Panel could potentially optimise patient management and antimicrobial therapy, thus highlighting its importance in the clinical setting.

Intracellular activity and in vivo efficacy in a mouse model of septic arthritis of the novel pseudopeptide Pep16 against Staphylococcus aureus clinical isolates

Objectives

Assessing the therapeutic potential of a novel antimicrobial pseudopeptide, Pep16, both in vitro and in vivo for the treatment of septic arthritis caused by Staphylococcus aureus.

Methods

Seven clinical isolates of S. aureus (two MRSA and five MSSA) were studied. MICs of Pep16 and comparators (vancomycin, teicoplanin, daptomycin and levofloxacin) were determined through the broth microdilution method. The intracellular activity of Pep16 and levofloxacin was assessed in two models of infection using non-professional (osteoblasts MG-63) or professional (macrophages THP-1) phagocytic cells. A mouse model of septic arthritis was used to evaluate the in vivo efficacy of Pep16 and vancomycin. A preliminary pharmacokinetic (PK) analysis was performed by measuring plasma concentrations using LC-MS/MS following a single subcutaneous injection of Pep16 (10 mg/kg).

Results

MICs of Pep16 were consistently at 8 mg/L for all clinical isolates of S. aureus (2- to 32-fold higher to those of comparators) while MBC/MIC ratios confirmed its bactericidal activity. Both Pep16 and levofloxacin (when used at 2 × MIC) significantly reduced the bacterial load of all tested isolates (two MSSA and two MRSA) within both osteoblasts and macrophages. In MSSA-infected mice, Pep16 demonstrated a significant (∼10-fold) reduction on bacterial loads in knee joints. PK analysis following a single subcutaneous administration of Pep16 revealed a gradual increase in plasma concentrations, reaching a peak of 5.6 mg/L at 12 h.

Conclusions

Pep16 is a promising option for the treatment of septic arthritis due to S. aureus, particularly owing to its robust intracellular activity.

Tuberculous Septic Arthritis of the Hip Following the Incision and Drainage of a Groin Abscess: A Case Report

Tuberculosis of the hip is a relatively rare type of septic arthritis that is seldom seen in the developed world today. While pyogenic septic arthritis may present with clear features that help in early diagnosis and treatment, many of these features are absent or overlap significantly with tuberculous arthritis, making the diagnosis a clinical challenge. Here, we present a case of tuberculous septic arthritis seen in our clinic following the surgical incision and drainage of a groin abscess with minimal hip symptoms. We discuss the therapeutic approach for the patient and briefly review other reported cases of tuberculous septic arthritis in the literature.

Endogenous blocking of TLR2 along with TNF-α and IL-1β ameliorates the severity of the S. aureus arthritis via modulating STAT3/SOCS3 expressions in tissue resident macrophages

In vivo studies identifying a role of TLR2 in septic arthritis models are lacking. TNF-α played as the most important proinflammatory cytokine, and connected directly to the pathogenesis of bacterial arthritis. IL-1β is another central mediator cytokine in arthritis. It is therefore reasonable to question the role of neutralization of endogenous TNF-α and IL-1β along with TLR2 and associated downstream signaling as crucial mediators in the S. aureus -induced inflammatory arthritis. In reaction to an injury or a pathogen encounter, innate immune cells serve as the initial line of defense. TLR2 mediated entry of S. aureus into macrophage cells initiates an array of inflammatory cascades. After macrophage cell gets activated at the site inflammation, they generate elevated number of cytokines which includes TNF-α, IL-1β. This cytokines signals through STAT1/STAT3 mediated pathways. Thus, aim of this study was to discover how This bone damage could be altered by altering the STAT/STAT3/SOCS3 ratio by blocking TLR2, a particular S. aureus binding site, in conjunction with the use of IL-1 and TNF- antibodies for neutralizing endogenous IL-1β and TNF-α. Additionally, the role of local macrophages in therapy of arthritis was investigated in synovial and Splenic tissue. To comprehend the inflammatory milieu within the system, ROS and other antioxidant enzymes, along with the expression of mTOR in macrophage cells, were also taken into consideration. The detrimental impact of bacterial burden on synovial joints was reduced by simultaneously inhibiting TLR2, TNF-α, and IL-1β. Lowered IFN-γ decreases its sensitivity to STAT1 and lowered IL-6 reduces STAT3 expressions. Whereas, elevated IL-10 enhances SOSC3 expression, which thereby able to limits STAT1/STAT3 inter-conversion. As a result, NF-κB activity was downregulated.

Methicillin Resistance Increased the Risk of Treatment Failure in Native Joint Septic Arthritis Caused by Staphylococcus aureus

This study aimed to compare clinical characteristics and outcomes in patients with native joint septic arthritis (NJSA) due to methicillin-resistant Staphylococcus aureus (MRSA) in comparison to methicillin-sensitive S. aureus (MSSA) and identify treatment failure risk factors. We conducted a multi-center retrospective study on adult NJSA patients at three teaching hospitals in South Korea from 2005 to 2017. Among 101 patients diagnosed with S. aureus NJSA, 39 (38.6%) had MRSA strains. Compared to MSSA, patients with MRSA had a higher prevalence of nosocomial infections (17.9% vs. 1.6%; p = 0.005) and received inappropriate antibiotics within 48 h more frequently (74.4% vs. 0%; p < 0.001). In total, twenty patients (19.8%) experienced treatment failure, which encompassed five patients (5.0%) who passed away, nine (8.9%) requiring repeated surgical drainage after 30 days of antibiotic therapy, and seven (6.9%) with relapse. The MRSA group showed a higher rate of overall treatment failure (33.3% vs. 11.3%; p = 0.007) with a notably increased frequency of requiring repeated surgical interventions after 30 days of antibiotic therapy (17.9% vs. 3.2%, p = 0.026), in contrast to the MSSA group. Independent risk factors for treatment failure included Charlson comorbidity score, elevated CRP levels, and methicillin resistance. Methicillin resistance is an independent risk factor for treatment failure, emphasizing the need for vigilant monitoring and targeted interventions in MRSA-related NJSA cases.

Case Report and Literature Review of Parvimonas micra: Difficult-to-Treat Arthritis in Hiding

Septic arthritis is a life-threatening rheumatological syndrome that is highly related to a patient's immune status and comorbidities, and although the most common clinical presentation is rapid-onset monoarthritis, it can also appear as subacute or chronic joint swelling. In these cases, differential diagnosis is more challenging, but early diagnosis and treatment is no less urgent to ensure a good global prognosis and the best outcome of the affected joint. Anaerobic microorganisms, such as Parvimonas micra, are an uncommon cause of septic arthritis (less than 5% of cases) but may be the cause of subacute arthritis. Knowledge about Parvimonas micra is important, as it is difficult to culture in the laboratory and generates a synovial fluid with atypical characteristics for septic arthritis so that, if not suspected, its diagnosis can be easily overlooked and underdiagnosed. We present the case of a 76-year-old woman with subacute arthritis of the left knee, describe the difficult diagnosis and treatment of its unexpected cause (Parvimonas micra), and review previously described cases, identifying the possible common comorbidities that may help clinicians easily find and treat this cause of subacute septic arthritis.

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.

Septic Arthritis of the Knee in Children

Septic arthritis of the knee is the most common form of septic arthritis in children and can lead to irreversible damage to the joint. Staphylococcus aureus is the primary pathogen associated with septic arthritis, although other causative pathogens may be isolate in children with specific risk factors. The diagnosis of knee septic arthritis is based on comprehensive evaluation, including the patient's medical history, physical examination, blood tests, and arthrocentesis. Empirical treatment typically involves anti-staphylococcal penicillin or a first-generation cephalosporin, although modifications may be made based on local resistance patterns and clinical culture data. Surgical debridement, either through open surgery or arthroscopy, involving extensive debridement of the joint, is effective in eliminating the infection. In most cases, additional surgical intervention is not necessary.