From the Guidelines
Septic arthritis is a medical emergency that requires immediate joint aspiration and empiric antibiotic therapy, with surgical drainage often necessary to prevent permanent joint damage or systemic infection. The recommended approach involves immediate joint aspiration for synovial fluid analysis, followed by empiric antibiotic therapy while awaiting culture results, as supported by the Infectious Diseases Society of America guidelines 1. Initial treatment typically includes vancomycin 15-20 mg/kg IV every 8-12 hours (for MRSA coverage) plus ceftriaxone 2g IV daily or cefepime 2g IV every 8 hours (for gram-negative coverage), with antibiotic therapy adjusted based on culture results and continued for 2-4 weeks for uncomplicated cases, or 4-6 weeks for complex infections 1.
Key considerations in the management of septic arthritis include:
- Prompt diagnosis and treatment to prevent permanent joint damage or systemic infection
- Immediate joint aspiration for synovial fluid analysis
- Empiric antibiotic therapy while awaiting culture results
- Surgical drainage, especially for hip and shoulder infections or when there's inadequate response to antibiotics
- Immobilization of the joint initially, followed by gradual range-of-motion exercises as symptoms improve
The most recent and highest quality study, published in 2022, highlights the importance of early diagnosis and treatment of septic arthritis, and notes that US-guided hip aspiration is considered highly accurate for diagnosis 1. The study also suggests that the presence of concurrent infections, such as osteomyelitis, can be predicted by certain risk factors, including C-reactive protein levels, absolute neutrophil count, platelet level, duration of symptoms, and age 1.
Overall, the management of septic arthritis requires a prompt and aggressive approach to prevent permanent joint damage or systemic infection, and should be guided by the most recent and highest quality evidence available 1.
From the Research
Definition and Diagnosis of Septic Arthritis
- Septic arthritis is an acute onset of monoarticular inflammation of a joint due to an infectious etiology, usually bacterial but can be viral or fungal 2.
- The definitive diagnosis of septic arthritis requires the direct demonstration of bacteria in synovial fluid or on positive culture of the pathogen 3.
- Risk factors for septic arthritis include age older than 80 years, diabetes mellitus, rheumatoid arthritis, recent joint surgery, hip or knee prosthesis, skin infection, and immunosuppressive medication use 4.
- Physical examination findings and serum markers, including erythrocyte sedimentation rate and C-reactive protein, are helpful in the diagnosis but are nonspecific 4.
Treatment and Management of Septic Arthritis
- A combination of antibiotics and the prompt removal of purulent material from the affected joint constitutes the mainstay of successful treatment 3.
- Empiric antibiotic therapy should be initiated if there is clinical concern for septic arthritis, and oral antibiotics can be given in most cases because they are not inferior to intravenous therapy 4.
- Total duration of therapy ranges from two to six weeks; however, certain infections require longer courses 4.
- Medical treatment is not inferior to surgical treatment, but 30% of patients with septic arthritis ultimately require surgical treatment 2.
Complications and Prognosis of Septic Arthritis
- Septic arthritis can lead to significant morbidity and mortality, with poor functional outcomes occurring in approximately 24% to 33% of patients 2.
- The 90-day mortality rate of knee septic arthritis is 7% in patients 79 years and younger and from 22% to 69% in patients older than 79 years 2.
- Delayed management of septic arthritis can result in permanent morbidity and mortality, with mortality rates ranging from 10-15% and morbidity rates ranging from 25-50% 5.