1. Cathryn Caton, MD, MS May 23, 2013 Medical University of South Carolina Arthrocentesis

2. Objectives • Define arthrocentesis • Review reasons for procedure • Describe procedural technique • Review fluid analysis and related diagnoses

3. Definition • Procedure in which a sterile needle and syringe is used to draw fluid from a joint

4. Why do an arthrocentesis? • To diagnose and establish the cause of monoarthritis or polyarthritis • Presence of joint infection • Cause of arthritis eg. Gout • To provide therapeutic relief for joint effusions • Do not tap a prosthetic joint. Call ortho for evaluation

5. Procedural Technique • Factors taken into account • Needle size • Syringe size • Skin sterilization • Local anesthesia

6. Procedural Technique • Needle size – • 22 gauge probably adequate • Smaller for smaller joints • Larger if effusion is large knee collection eg 20 gauge • Syringe size – 5ml, larger if needed • Can be done under ultrasound guidance • Best strategy is to use one needle size and one syringe size

7. Procedural Technique • Skin preparation – three separate concentric outward spirals with an agent such as chlorhexidine prep • Local anesthesia – lidocaine, ethyl chloride spray. • Option to use no anesthesia

8. Procedural Technique • http://www.nejm.org/doi/full/10.1056/NEJMvcm051914

9. What to do once fluid is obtained? • Fluid analysis should include – • cell count with differential • Cultures • gram stain • Crystal – should be done promptly to avoid disintegration and false negative results

10. Normal Synovial Fluid • Highly viscous • Clear • Essentially acellular • Protein concentration approx. 1/3 of plasma • Glucose concentration similar to plasma

11. Categories of Joint Effusions • Noninflammatory – • Degenerative joint disease • Trauma • Osteonecrosis • Neuropathic arthropathy • Early or subsiding inflammation • Hypertrophic osteoarthropathy • Rheumatic fever • SLE • Sarcoidosis • Scleroderma

12. Categories of Joint Effusions • Inflammatory – • RA • Acute crystal-induced synovitis • Reactive arthritis • Ankylosingspondylitis • Psoriatic arthritis • Arthritis associated with inflammatory bowel disease • Rheumatic fever • SLE • Sarcoidosis

13. Categories of Joint Effusions • Septic effusions – • Bacteria • Mycobacteria • Fungus • Hemorrhagic – • Hemophilia • Anticoagulation • Scurvy • Trauma • Tumor • Neuropathic arthropathy

14. Categories of Joint Effusions Sterile processes such as reaction to intraarticular injections, flares of RA, leukemic infiltration and gout can cause synovial fluid elevations WBC>100K

15. Gout vs. Pseudogout Pseudogout Gout

16. Key Messages • Know indication for procedure • Know what analysis should be performed on fluid obtained • Know how to interpret fluid results

17. References • Krey PR, Bailen DA. Synovial fluid leukocytosis. A study of Extremes. Am J Med 1979; 67:436 • Zuber TJ. Knee Joint Aspiration and Injection. Am Fam Phys 2002; 66:1497 • Mimoz O, Karim A. Chlorhexidine compared with povidone-iodine as skin preparation before blood culture. A randomized, controlled trial. Ann Intern Med 1999; 131:834 • Shmerling RH, Delbanco TL. Synovial fluid tests. What should be ordered? JAMA 1990; 264:1009. • Guidelines for the initial evaluation of the adult with acute musculoskeletal symptoms. American College of Rheumatology Ad Hoc Committee on Clinical Guidelines. Arthritis Rheum 1996; 39:1