What is the recommended treatment for septic arthritis?

Treatment of Septic Arthritis

The cornerstone of septic arthritis treatment is immediate joint drainage combined with appropriate antibiotic therapy, with surgical drainage indicated in all cases of septic arthritis. 1

Diagnostic Approach

• Suspect septic arthritis in patients with:
  • Acute atraumatic joint pain, swelling, and fever
  • Risk factors: age >80 years, diabetes, rheumatoid arthritis, recent joint surgery, prosthetic joints, skin infection, immunosuppression 2
• Laboratory evaluation:
  • Elevated inflammatory markers (ESR, CRP)
  • Synovial fluid analysis (critical for diagnosis)
  • Synovial WBC typically >50,000/μL 3
• Imaging:
  • MRI: preferred for detecting early osteomyelitis (95% sensitivity, 90% specificity)
  • Ultrasound: useful for guided aspiration and detecting effusions 1

Treatment Algorithm

1. Joint Drainage

• Mandatory in all cases of septic arthritis 1, 4
• Options include:
  • Arthrocentesis for accessible joints without complications
  • Arthroscopic drainage
  • Open surgical drainage via arthrotomy for severe cases 3
• For prosthetic joint infections, device removal is recommended when feasible 1

2. Empiric Antibiotic Therapy

• Initiate within one hour of recognition 1
• Coverage must include Staphylococcus aureus (most common pathogen) and respiratory pathogens 5
• Initial regimens:
  • Native joints: IV vancomycin (for MRSA coverage) plus a third-generation cephalosporin
  • Prosthetic joints: Parenteral therapy plus rifampin for 2 weeks, followed by rifampin plus another oral agent for 3-6 months 1

3. Targeted Antibiotic Therapy

• Narrow therapy once culture results are available 1
• Select antibiotics with good joint penetration:
  • Fluoroquinolones, linezolid, clindamycin, rifampin, doxycycline, TMP-SMX 1
• For specific pathogens:
  • MRSA: IV vancomycin (B-II) or daptomycin 6 mg/kg/dose IV once daily (B-II) 4
  • Candida: Fluconazole 400 mg daily for 6 weeks OR an echinocandin for 2 weeks followed by fluconazole for at least 4 weeks 4
  • Lyme arthritis: Doxycycline, amoxicillin, or cefuroxime axetil for 28 days 4

4. Duration of Therapy

• Uncomplicated septic arthritis: 3-4 weeks
• With concurrent osteomyelitis: 4-6 weeks
• Prosthetic joint infections: 6-12 weeks 1, 6
• Recent evidence suggests shorter courses (10 days) may be sufficient for previously healthy children 5

5. Transition to Oral Therapy

• Can occur after:
  • Clinical improvement (decreased pain, swelling)
  • Reduction in inflammatory markers
  • 2-4 days of IV therapy in uncomplicated cases 5, 7
• Use antibiotics with good bioavailability:
  • Fluoroquinolones, linezolid, clindamycin, TMP-SMX 1

Special Considerations

Prosthetic Joint Infections

• For early-onset infections with stable implant: parenteral therapy plus rifampin for 2 weeks, followed by rifampin plus another agent for 3-6 months 1
• For late-onset infections: device removal when feasible 1
• If prosthetic device cannot be removed: chronic suppression with fluconazole (for Candida) 4

Pediatric Patients

• Children <2 years: more likely to have septic arthritis than osteomyelitis 1
• Total course of 10 days may suffice for previously healthy children 5
• Oral therapy can be safely initiated after 2-4 days of IV antibiotics 5, 7

Monitoring Response

• Daily assessment for de-escalation of antimicrobial therapy
• Regular monitoring of inflammatory markers (ESR, CRP)
• Repeat joint aspiration may be needed to ensure sterility 1

Pitfalls to Avoid

• Delaying joint drainage or antibiotic initiation
• Failing to obtain synovial fluid before starting antibiotics
• Not considering concurrent osteomyelitis (present in up to 30% of cases)
• Inadequate duration of therapy for prosthetic joint infections
• Not transitioning to targeted therapy once culture results are available