Septic Arthritis: Orthopedic Emergency
Infectious Orthopedics: High-Yield Clinical Pearls
1. Pathogen Epidemiology
| Patient Population | Most Likely Pathogen |
|---|---|
| General Adult | Staphylococcus aureus |
| Sexually Active/Young Adult | Neisseria gonorrhoeae |
| Sickle Cell Disease | Salmonella spp. |
2. Clinical Evaluation (The Kocher Criteria)
Use these criteria for pediatric septic hip diagnosis (High probability if ≥3 criteria are met):
- Non-weight bearing on the affected extremity.
- Temperature > 38.5°C.
- ESR > 40 mm/hr.
- Serum WBC > 12,000 cells/mm³.
3. High-Yield Diagnostics & Management
- Synovial Fluid Analysis: The gold standard. Look for WBC count > 50,000/mm³ with > 90% neutrophils.
- Management: Surgical drainage (arthrotomy or arthroscopic lavage) is the definitive treatment. Do not delay for cultures; initiate empiric IV antibiotics after obtaining joint fluid samples.
- Emergency: Septic arthritis is a true orthopedic emergency because the enzymatic destruction of articular cartilage can occur within 24–48 hours.