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.

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 then. RESULTS: Currently, the management of crystal and non-infectious arthropathies is 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 of a hot swollen joint.