II. Indications
- Single most important test in Arthritis evaluation
- Septic Joint
- Crystal-Induced Arthritis (e.g. Gouty Arthritis, Pseudogout)
III. Contraindications
- Overlying infection (unable to access joint without passing through infected tissue)
IV. Preparation
- Ultrasound
- Tubes
- Heparinized Tube for crystal analysis
- Saline Tube for Cell Count
- Culture container
- Syringe (20 cc)
- Aspiration Needle
- Adequate guage (18-22 gauge) to aspirate Synovial Fluid
- Adequate Length (1.5" for superficial joints, 3.5" spinal needle for deeper joints)
-
Skin Preparation
- Lidocaine 1% with Epinephrine
- Chlorhexidine (or Betadine) skin antiseptic
- Sterile drape
V. Procedure: Arthrocentesis
VI. Labs: Synovial Fluid Volume and Appearance
- Normal Synovial Fluid
- Slightly yellow, straw colored
- Clear (Can read newsprint through the fluid)
- Viscous consistency
- No clotting
- Inflammatory fluid
- Yellow green to gray
- Cloudy to Opaque
- Decreased viscosity to Watery consistency
- Findings suggestive of acute Fracture or derangement
- Large fat droplets (sensitive for Fracture)
- Bloody fluid
VII. Labs: Synovial Fluid Gram Stain and Culture
- Bacteria (Anaerobes if arthroplasty)
- Mycobacteria, Fungal Culture on tissues