Suspected Septic Arthritis
Acute monoarthritis - consider infectious until proven otherwise
All Pathways
Orthopedic SurgeryEmergency
Septic Arthritis Management (SANJO Guidelines)
Septic Arthritis Management (SANJO Guidelines): Suspected Septic Arthritis → Clinical Assessment → High-Risk Features.
Pathway Overview
15 steps
Algorithm Steps
15 total
01Start 02Action Clinical Assessment
History, exam, and risk factors
- Acute onset joint pain, swelling, warmth
- Inability to bear weight (lower extremity)
- Fever (may be absent in elderly/immunocompromised)
- Limited ROM due to pain
- Risk factors: RA, DM, recent surgery, prosthesis, IV drug use
03Action High-Risk Features
Increase suspicion for septic arthritis
- Age >80 years
- Diabetes mellitus
- Rheumatoid arthritis
- Recent joint surgery or injection
- Prosthetic joint
- Immunosuppression
- IV drug use
- Skin infection
04Action Urgent Joint Aspiration
MANDATORY - Do not delay for imaging
- Sterile technique
- Send for: Cell count + differential, Gram stain, Culture
- Crystal analysis (rule out gout/pseudogout)
- Lactate, glucose (if available)
- Aspirate as much fluid as possible
05Decision Synovial Fluid Analysis
Interpret results
- WBC >50,000/µL with >90% PMNs: Highly suggestive
- WBC 25,000-50,000: Possible septic arthritis
- WBC <25,000: Less likely but does not exclude
- Gram stain positive in ~50%
- Culture positive in 70-90%
06Action Empiric IV Antibiotics
Start immediately after cultures obtained
- Cover S. aureus (most common pathogen)
- Vancomycin 15-20mg/kg IV q8-12h (if MRSA risk)
- OR Flucloxacillin 2g IV q6h / Cefazolin 2g IV q8h (if MSSA likely)
- Add Gram-negative coverage if: elderly, immunocompromised, GU source
- Ceftriaxone 2g IV daily if gonococcal suspected (young, sexually active)
07Decision Drainage Method
Joint must be adequately drained
08Action Serial Needle Aspiration
Option for accessible joints
- Repeat daily until effusion resolves
- Appropriate for knee, shoulder, ankle
- May be inadequate if loculated
- Monitor WBC count improvement
09Action Pathogen-Directed Therapy
Narrow antibiotics when culture results available
- S. aureus: Flucloxacillin or Vancomycin (MRSA)
- Streptococcus: Penicillin or Ceftriaxone
- Gonococcus: Ceftriaxone 1g IV → PO switch
- Gram-negative: Ciprofloxacin or Ceftriaxone
- Duration: 1-2 weeks IV, then 2-4 weeks oral (SANJO)
10Action Monitoring & Follow-up
Assess treatment response
- Clinical improvement within 48-72h expected
- CRP should decline
- Repeat aspiration if effusion recurs
- Physical therapy when acute phase resolves
- Total treatment: 3-6 weeks (1-2wk IV + 2-4wk PO)
11Outcome Infection Resolved
Begin rehabilitation
12Warning Complications
Joint destruction, osteomyelitis, sepsis
- Cartilage damage and arthritis
- Osteomyelitis extension
- AVN (especially hip)
- Systemic sepsis
13Action Surgical Drainage/Washout
Preferred for hip, difficult joints, or failed aspiration
- Arthroscopic washout: Less invasive
- Open arthrotomy: For complex cases
- Mandatory for hip (especially pediatric)
- If loculated fluid or debris
- If no improvement with serial aspiration
- May need repeat washout
- Path rejoins step 09Shared downstream outcome
14Warning ⚠️ Hip Septic Arthritis
Surgical emergency
- Urgent surgical drainage required
- Blood supply to femoral head at risk
- Pediatric hip: Emergency surgery within hours
- Kocher criteria guide pediatric workup
- Path rejoins step 13Shared downstream outcome
15Action Additional Studies
Blood tests and imaging
- CBC, CRP, ESR (elevated but nonspecific)
- Blood cultures (positive in 50%)
- X-ray: May be normal early, rule out osteomyelitis
- MRI: If adjacent osteomyelitis suspected
- Ultrasound: Guide aspiration, detect effusion
Guideline Source
SANJO: Guideline for Management of Septic Arthritis in Native Joints
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Does not cover prosthetic joint infections
- Pediatric septic arthritis (especially hip) may require urgent surgery
- Antibiotic regimens may vary by local resistance patterns
- Gonococcal arthritis has different management
Applicable Regions
USEU
Version 1Next review: 2027-01-11
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Related Resources
Frequently Asked Questions
What is the Septic Arthritis Management (SANJO Guidelines)?
The Septic Arthritis Management (SANJO Guidelines) is a emergency clinical algorithm for Orthopedic Surgery. It provides a structured decision tree to guide clinical decision-making, based on SANJO: Guideline for Management of Septic Arthritis in Native Joints.
What guideline is the Septic Arthritis Management (SANJO Guidelines) based on?
This algorithm is based on SANJO: Guideline for Management of Septic Arthritis in Native Joints (DOI: 10.1007/s15010-022-01963-5).
What are the limitations of the Septic Arthritis Management (SANJO Guidelines)?
Known limitations include: Does not cover prosthetic joint infections; Pediatric septic arthritis (especially hip) may require urgent surgery; Antibiotic regimens may vary by local resistance patterns; Gonococcal arthritis has different management. Individual patient factors may require deviation from these recommendations.
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