What is the recommended treatment for septic arthritis of the shoulder?

Treatment of Septic Arthritis of the Shoulder

Septic arthritis of the shoulder requires immediate surgical drainage combined with pathogen-directed antibiotic therapy for 3-4 weeks, with arthroscopic debridement being the preferred surgical approach in most cases.

Surgical Management

Drainage is Mandatory

• Drainage or debridement of the joint space must always be performed 1, 2, 1.
• Adequate drainage is critical to successful therapy and should be performed as soon as possible after diagnosis 3.

Arthroscopic vs. Open Approach

Arthroscopy is the preferred initial surgical approach for most cases of shoulder septic arthritis 4, 5:

• Arthroscopy demonstrates similar or superior outcomes compared to arthrotomy in 70% of comparative studies, with lower complication rates 4.
• Reoperation rates are comparable or favor arthroscopy in most cases 4.

However, open arthrotomy should be strongly considered in specific high-risk scenarios:

• Methicillin-resistant Staphylococcus aureus (MRSA) infection: MRSA is an independent risk factor for arthroscopic failure, with reinfection rates of 60% after arthroscopy versus 5.9% after arthrotomy 6.
• Staphylococcus aureus infections in general: One study showed significantly higher reinfection rates with arthroscopy (52.4%) versus arthrotomy (18.4%) for S. aureus 7.
• Advanced disease (Gächter stage III-IV): Higher recurrence risk warrants consideration of open surgery 8.

Technical Considerations for Arthroscopic Surgery

When arthroscopy is performed, optimize success by 5:

• Use an additional posterolateral portal and 70° arthroscope to access the posteroinferior glenohumeral joint and subacromial space.
• Irrigate with large volumes: Use >20-25 liters of saline 9, 5. The volume of irrigation is the most important modifiable factor for preventing reoperation 9.
• Place multiple suction drains (average 3-4 drains) into both the glenohumeral joint and subacromial space, removing them 8-9 days postoperatively 5.
• Debride both the glenohumeral joint and subacromial space, as both are involved in 58% of cases 5.

Antibiotic Therapy

For MRSA Septic Arthritis

Initial parenteral therapy 1, 2, 1:

• IV vancomycin 15-20 mg/kg/dose every 8-12 hours (not to exceed 2g per dose) is the primary recommendation 1.
• Alternative: Daptomycin 6 mg/kg IV once daily 1, 2, 1.
• Alternative: Linezolid 600 mg PO/IV twice daily 1, 2.

Duration: 3-4 weeks minimum 1, 2, 1.

Addition of rifampin: Some experts recommend adding rifampin 600 mg daily or 300-450 mg twice daily, particularly after clearance of any concurrent bacteremia 1, 2, 1.

For Methicillin-Susceptible Staphylococcus Aureus

Preferred agents 10:

• Nafcillin 1.5-2g IV every 4-6 hours 10.
• Cefazolin 1-2g IV every 8 hours 10.
• Ceftriaxone 1-2g IV every 24 hours 10.

Duration: 3-4 weeks 1, 2.

For Candida Septic Arthritis

Preferred regimen 3:

• Fluconazole 400 mg (6 mg/kg) daily for 6 weeks OR
• An 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.

Surgical drainage is mandatory in all cases of Candida septic arthritis 3.

For Other Organisms

• Pathogen-specific IV or highly bioavailable oral antimicrobial therapy for 4-6 weeks based on culture sensitivities 10.
• For enterococci, penicillin-susceptible strains: Penicillin G 20-24 million units IV daily or ampicillin 12g IV daily 10.
• For Pseudomonas aeruginosa: Cefepime 2g IV every 12 hours or meropenem 1g IV every 8 hours 10.

Antibiotic Administration Timing

Antimicrobials must be initiated within 1 hour of recognition in patients with sepsis or septic shock 11.

Prosthetic Joint Involvement

If a prosthetic device is present 3:

• Device removal is strongly recommended for both bacterial and fungal infections 3, 10, 3.
• If removal is not possible, chronic suppression with pathogen-specific antibiotics (e.g., fluconazole 400 mg daily for Candida if susceptible) is necessary 3.

Monitoring Response to Therapy

• ESR and CRP levels may be helpful to guide response to therapy 1, 2.
• CRP typically normalizes around 43 days post-surgery; ESR around 54 days 8.
• MRI with gadolinium is the imaging modality of choice for detecting early osteomyelitis and associated soft tissue disease 1, 2.

Common Pitfalls

• Inadequate irrigation volume during arthroscopy: This is the most important modifiable risk factor for treatment failure 9.
• Choosing arthroscopy for MRSA infections: Consider open arthrotomy given the significantly higher failure rates 6, 7.
• Premature discontinuation of antibiotics: Ensure full 3-4 week course is completed 1, 2, 1.
• Failure to drain both glenohumeral and subacromial spaces: Both compartments are frequently involved 5.