Treatment of Septic Arthritis
The treatment of septic arthritis requires immediate surgical debridement combined with appropriate antibiotic therapy, with a typical duration of 3-4 weeks for uncomplicated cases. 1, 2
Diagnosis and Initial Assessment
- Septic arthritis is an orthopedic emergency requiring prompt diagnosis and treatment to prevent cartilage damage and permanent joint dysfunction 1, 2
- Joint aspiration is the definitive diagnostic procedure with synovial fluid white blood cell count ≥50,000 cells/mm³ suggestive of septic arthritis 1
- Synovial fluid culture is positive in approximately 80% of non-gonococcal septic arthritis cases 1
- Imaging with ultrasound and MRI may help detect joint effusions, soft tissue involvement, and concomitant osteomyelitis 1, 2
Surgical Management
- Immediate surgical debridement is essential for septic arthritis treatment, with arthrotomy, irrigation, and debridement being the standard surgical interventions 2
- Surgical drainage is indicated in all cases of septic arthritis 3
- For prosthetic joint infections, device removal is recommended 3
- If a prosthetic device cannot be removed, chronic suppression with fluconazole 400 mg daily (if the isolate is susceptible) is recommended 3
Antibiotic Therapy
- Empiric broad-spectrum antibiotic therapy should be initiated after obtaining cultures 2
- IV vancomycin is recommended as first-line therapy for adults with septic arthritis, particularly when MRSA is a concern 1, 2
- IV vancomycin is recommended for MRSA coverage in children, with clindamycin 10-13 mg/kg/dose IV every 6-8 hours as an alternative if clindamycin resistance is low 1
- Clindamycin is indicated for bone and joint infections including acute hematogenous osteomyelitis caused by Staphylococcus aureus and as adjunctive therapy in chronic bone and joint infections due to susceptible organisms 4
- Oral antibiotics can be given in most cases as they are not inferior to intravenous therapy 5
Pathogen-Specific Considerations
- Staphylococcus aureus is the most common pathogen isolated in septic arthritis 5
- In children <4 years, Kingella kingae should be considered as a potential causative organism 1, 2
- In patients with sickle cell disease, Salmonella species should be considered 1, 2
- For MRSA infections, adding rifampin to the regimen may be beneficial due to its excellent penetration into bone and biofilm 2
- In cases of polymicrobial infection, dual antibiotic coverage is necessary 1
Duration of Therapy
- Duration of antibiotic therapy is typically 3-4 weeks for uncomplicated septic arthritis 1, 2
- For prosthetic joint infections, longer antibiotic courses (12 weeks) show better outcomes than shorter courses (6 weeks) 1
- For Candida septic arthritis, fluconazole 400 mg daily for 6 weeks OR an echinocandin for 2 weeks followed by fluconazole 400 mg daily for at least 4 weeks is recommended 3
Special Considerations
- Concomitant osteomyelitis occurs in up to 30% of children with septic arthritis and requires longer treatment 1, 2
- For persistent or recurrent joint swelling after a course of oral antibiotics, re-treatment with another 4-week course of oral antibiotics or 2-4 weeks of IV ceftriaxone is recommended 1
- Arthroscopic synovectomy may reduce the duration of joint inflammation in cases of persistent synovitis with significant pain or functional limitation 1
- All patients with candidemia should have a dilated retinal examination within the first week of therapy to establish if endophthalmitis is present 3
Pitfalls and Caveats
- Negative joint aspirate culture does not rule out infection; consider percutaneous bone biopsy if clinical suspicion remains high 1, 2
- Poor functional outcomes, such as amputation, arthrodesis, prosthetic surgery, and severe functional deterioration, occur in approximately 24% to 33% of patients with septic arthritis 6
- 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 6
- 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 5, 7