ARTHROCENTESIS

Cathryn Caton, MD, MSMay 23, 2013Medical University of South Carolina

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

diagnoses

Definition Procedure in which a sterile needle and

syringe is used to draw fluid from a joint

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

Procedural Technique Factors taken into account

Needle size Syringe size Skin sterilization Local anesthesia

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

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

Procedural Technique http://www.nejm.org/doi/full/10.1056/NE

JMvcm051914

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

Normal Synovial Fluid Highly viscous Clear Essentially acellular Protein concentration approx. 1/3 of

plasma Glucose concentration similar to plasma

Categories of Joint Effusions Noninflammatory –

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

Categories of Joint Effusions Inflammatory –

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

Categories of Joint Effusions Septic effusions –

Bacteria Mycobacteria Fungus

Hemorrhagic – Hemophilia Anticoagulation Scurvy Trauma Tumor Neuropathic arthropathy

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

Gout vs. Pseudogout

Gout

Pseudogout

Key Messages Know indication for procedure

Know what analysis should be performed on fluid obtained

Know how to interpret fluid results

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