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

 Define arthrocentesis  Review reasons for procedure  Describe procedural technique  Review fluid analysis and related diagnoses

 Procedure in which a sterile needle and syringe is used to draw fluid from a joint

 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

 Factors taken into account  Needle size  Syringe size  Skin sterilization  Local anesthesia

 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

 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

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 Fluid analysis should include –  cell count with differential  Cultures  gram stain  Crystal – should be done promptly to avoid disintegration and false negative results

 Highly viscous  Clear  Essentially acellular  Protein concentration approx. 1/3 of plasma  Glucose concentration similar to plasma

 Noninflammatory –  Degenerative joint disease  Trauma  Osteonecrosis  Neuropathic arthropathy  Early or subsiding inflammation  Hypertrophic osteoarthropathy  Rheumatic fever  SLE  Sarcoidosis  Scleroderma

 Inflammatory –  RA  Acute crystal-induced synovitis  Reactive arthritis  Ankylosing spondylitis  Psoriatic arthritis  Arthritis associated with inflammatory bowel disease  Rheumatic fever  SLE  Sarcoidosis

 Septic effusions –  Bacteria  Mycobacteria  Fungus  Hemorrhagic –  Hemophilia  Anticoagulation  Scurvy  Trauma  Tumor  Neuropathic arthropathy

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

Gout Pseudogout

 Know indication for procedure  Know what analysis should be performed on fluid obtained  Know how to interpret fluid results

 Krey PR, Bailen DA. Synovial fluid leukocytosis. A study of Extremes. Am J Med 1979; 67:436 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 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 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. 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 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