Septic Arthritis Treatment Guideline
Immediate Management: Surgery Plus Antibiotics
Septic arthritis requires immediate surgical drainage combined with empiric intravenous antibiotics—this is a joint-destroying emergency where delays lead to permanent disability and death. 1, 2
Surgical Intervention (First Priority)
- Perform immediate surgical drainage in all cases of septic arthritis through arthrotomy, irrigation, and debridement—this is non-negotiable regardless of the causative organism 3, 1, 4
- Arthroscopic drainage is effective for most joints, with 91% cure rates when combined with antibiotics, though open revision is needed in 4% of cases 5
- Hip joints specifically require open surgical drainage due to anatomical constraints 3
- For prosthetic joint infections, remove the device—resection arthroplasty with two-stage reimplantation separated by 3-6 months is the standard approach 3
Empiric Antibiotic Therapy (Start Immediately After Cultures)
Initiate IV vancomycin immediately after obtaining synovial fluid cultures to cover MRSA, which is increasingly common in septic arthritis 1, 2, 4
Adult Dosing:
- Vancomycin 15 mg/kg IV every 6 hours (or 30-60 mg/kg/day in 2-4 divided doses) 4
- Alternative options if MRSA less likely: Linezolid 600 mg IV/PO every 12 hours, Daptomycin 6 mg/kg IV daily, or Teicoplanin 6-12 mg/kg IV every 12 hours for 3 doses then daily 4
Pediatric Dosing:
- Vancomycin 15 mg/kg/dose IV every 6 hours (40 mg/kg/day in 4 divided doses) 4
- Clindamycin 10-13 mg/kg/dose IV every 6-8 hours if local clindamycin resistance is <10% 1, 2
Culture-Directed Definitive Therapy
Once culture results return, narrow antibiotics based on organism and sensitivities:
For Methicillin-Susceptible Staphylococcus aureus (MSSA):
- Switch to nafcillin or oxacillin 1-2 g IV every 4 hours, OR cefazolin 1 g IV every 8 hours 4
- Clindamycin 600 mg IV every 8 hours if penicillin-allergic 4
For Methicillin-Resistant Staphylococcus aureus (MRSA):
- Continue vancomycin as primary therapy 1, 4
- Consider adding rifampin 600 mg PO daily (or 300-450 mg twice daily) for enhanced bone and biofilm penetration 1, 2, 4
For Streptococcal Infections:
- Penicillin G 20-24 million units IV daily (continuous infusion or divided doses), OR ceftriaxone 1-2 g IV every 24 hours 4
For Polymicrobial Infections:
- Dual antibiotic coverage is mandatory—for example, linezolid for MRSA plus ciprofloxacin for Pseudomonas aeruginosa 4
Transition to Oral Antibiotics
Switch to oral antibiotics after 2-4 days if the patient is clinically improving, afebrile, and can tolerate oral intake—oral therapy is not inferior to IV for most cases 2, 4, 6
Oral Options for MRSA (after initial IV therapy):
- Linezolid 600 mg PO every 12 hours 2, 4
- TMP-SMX (trimethoprim 4 mg/kg/dose) PO every 8-12 hours plus rifampin 600 mg PO daily 2, 4
- Clindamycin 600 mg PO three times daily (if susceptible) 2
Duration of Therapy
Treat for 3-4 weeks for uncomplicated bacterial septic arthritis 1, 2, 4, 6
Key duration nuances:
- Recent evidence suggests 2 weeks may be adequate after surgical drainage in select cases (predominantly small joints) 4
- Prosthetic joint infections require 12 weeks after debridement with implant retention (superior to 6 weeks) 1, 4
- Hip prostheses with one-stage or two-stage exchange: 3 months total 4
- Knee prostheses with one-stage or two-stage exchange: 6 months total 4
- Concomitant osteomyelitis (occurs in 30% of pediatric cases) requires longer treatment 1, 4
Special Pathogen Considerations
- Children <4 years: Consider Kingella kingae as causative organism 1, 4
- Sickle cell disease patients: Consider Salmonella species 1, 4
- Gonococcal arthritis: Requires specific treatment regimens (not covered in provided guidelines)
Fungal Septic Arthritis (Candida)
For confirmed Candida septic arthritis:
- Fluconazole 400 mg (6 mg/kg) daily for 6 weeks, OR 3, 1
- Echinocandin (caspofungin 50-70 mg daily, micafungin 100 mg daily, or anidulafungin 100 mg daily) for 2 weeks followed by fluconazole 400 mg daily for at least 4 weeks 3, 1
- Surgical drainage is mandatory in all Candida cases 3
- For prosthetic Candida infections that cannot be removed, chronic suppression with fluconazole 400 mg daily is required (if isolate susceptible) 3, 1
Critical Monitoring and Follow-Up
- Monitor CRP and ESR to assess treatment response 4
- Monitor vancomycin trough levels and adjust dosing to avoid toxicity 4
- All patients with candidemia require dilated retinal examination within the first week to detect endophthalmitis 3, 1
- For persistent joint swelling after oral antibiotics, re-treat with another 4-week course of oral antibiotics or 2-4 weeks of IV ceftriaxone 1, 4
Common Pitfalls to Avoid
- Never transition to oral antibiotics if the patient has ongoing bacteremia, sepsis, or is not clinically improving 2
- Never use oral antibiotics alone without prior surgical drainage 2
- Negative synovial fluid culture does not rule out infection—consider percutaneous bone biopsy if clinical suspicion remains high 1, 4
- Avoid fluoroquinolones as monotherapy due to resistance development; if used, combine with rifampin 2
- Do not perform intra-articular corticosteroid injections during active infection 4
- Arthroscopic synovectomy may reduce inflammation duration in cases of persistent synovitis with significant pain or functional limitation 1, 4