Arthrocentesis Dx

Last updated: October 31, 2014

Synonyms:  Synovial fluid aspiration, joint tap

CPT Codes:  Arthrocentesis, aspiration or injection of a small joint/bursa (20600), medium size (20605), large joint/bursa (20610); carpal tunnel injection 20526; injection of single tendon 20556

Description: Techniques for needle aspiration and injection of joints.

Indications: Indications for needle aspiration and injection of joints include (a) any undiagnosed acute or chronic monarthritis with effusion, (b) suspected infection or crystal-induced arthritis, (c) unexplained exacerbation of preexisting polyarthritis, (d) joint effusion after trauma, (e) intraarticular treatment (e.g., corticosteroids), (f) injection of contrast media for diagnostic arthrography, and (g) uncertain diagnosis. Clinical situations in which joint aspiration and injection with corticosteroids may be beneficial include painful monarticular osteoarthritis, focal pain/swelling in rheumatoid arthritis, acute gout or pseudogout, acute bursitis or tendinitis, early adhesive capsulitis, and possibly reflex sympathetic dystrophy.

Contraindications: Relative contraindications for intraarticular injection include suspected septic arthritis or bursitis (do not inject steroids!), overlying cellulitis, known bacteremia, neuropathic (Charcot disease) joint, joint pain secondary to referred pain, thrombocytopenia (platelet count <50,000/mm3), co-agulopathy, anticoagulant therapy, uncontrolled diabetes, lack of response to previous injection, prosthetic joints, and inaccessible joints (i.e., hip, sacroiliac).

Method: Access to periarticular structures (i.e., bursae), joint cavity, or synovial fluid (SF) is best achieved by percutaneous needle aspiration. Table 1 details the steps involved in arthrocentesis. Preparation of commonly used materials into an “arthrocentesis tray” facilitates the process (Table 3). Many large (i.e., knee, shoulder) and small (i.e., metacarpophalangeal, sternoclavicular) joints are easily aspirated. Difficult or inaccessible joints should not be attempted by routine needle aspiration.   Instead, the hip, sacroiliac, apophyseal, toe interphalangeal, and temporomandibular joints are best managed with the assistance of ultrasound- or fluoroscopically-guided arthrocentesis.

The operator should select an injection site after identifying anatomic landmarks and the point of maximal fluctuance or tenderness. Prepare all syringes before starting. Povidone iodine solution and alcohol swabs should be used to maintain a sterile field. (See below for methods used in arthrocentesis of selected joints.)

Table 3: Contents of Arthrocentesis Tray
Gloves (nonsterile)
Povidone iodine solution
Alcohol preparations
Ethyl chloride spray (topical anesthetic)
1.5-in. sterile needles (18, 22, 23 g)
1-in. sterile needles (21, 23, 25 g)
3 mL (to inject steroid or lidocaine)
5 mL (to instill lidocaine)
10 mL (for initial synovial fluid withdrawal
20 or 30 mL (withdraw large amount of synovial fluid)
EDTA acid/lavender (cell count)
Heparin/gree (crystals, in vitro studies)
Single-dose vials of 1% lidocaine (without epinephrine)
Single-dose vials of corticosteroid preparation
Sterile container, culture media
Glass slides/coverslips
Ballpoint pen
Cup or basin (for waste)

Precautions: Occupational Safety and Health Administration guidelines state that gloves (sterile or nonsterile) should be worn by the clinician and assistant(s) throughout the procedure and that sterile technique should be observed when handling needles, syringes, and joint fluid. Gloves and all materials contaminated by blood or SF should be disposed of in appropriate “sharps” or biohazard containers. Patients with a history of valvular heart disease should receive appropriate antibiotic prophylaxis before the procedure. Hand washing before and after arthrocentesis is advised.

Record: When applicable, the volume withdrawn, color, appearance, viscosity, cell count and differential; crystal appearance by light or polarized microscopy; Gram stain, culture, and sensitivity results; culture for acid-fast bacilli or fungi; and cytology should be recorded.

Avoid: SF protein or glucose; SF urate, lactate dehydrogenase, autoantibodies (i.e., rheumatoid factor, antinuclear antibody, lupus erythematosus cells); mucin clot test; pH; or complement testing should not be done. A low SF glucose level (50% of serum value) may be seen in rheumatoid arthritis, tuberculosis, and other forms of septic arthritis but is infrequent and not specific.

Complications: Although infrequent, the  most common complications include allergic reactions (to iodine, adhesive, lidocaine), vasovagal episodes, local ecchymoses, and exacerbation of hyperglycemia in diabetics. Uncommonly, post-injection flares, corticosteroid crystal–induced synovitis, depigmentation of overlying skin, and subcutaneous atrophy are seen. Skin or joint infection, hemarthrosis, and calcification or rupture of periarticular structures are rare events with proper technique.

Therapy: Corticosteroid injection may provide significant relief as the sole therapy or as adjunctive therapy in many conditions. Steroid preparations vary in equivalent potency and diluent. (See Table 4 for a comparison of common parenteral steroid preparations.) Ideally, single-dose vials or ampules of steroids and lidocaine should be used to avoid medication sharing between patients. Whereas water-soluble steroids tend to be absorbed rapidly and have shorter durations of action, the converse is true for the insoluble steroid preparations (Table 4). The needle size and volume of steroid to be instilled depend on the relative size of the joint (Table 5). Lidocaine (1% solution) without epinephrine may be used for local anesthesia during the procedure. Depending on the size of the joint, 0.5 to 3 mL of lidocaine may be used for soft tissue anesthesia. Soft tissue anesthesia is recommended if aspiration of SF or difficulty with joint access is anticipated. Intraarticular steroid may be mixed with 0.25 to 0.5 mL (depending on size of joint/bursa) of 1% lidocaine to provide immediate pain relief, improve range of motion, and confirm the adequacy of injection. Corticosteroids should not be instilled into joints that are potentially septic, unstable, or neuropathic. Bed/home rest for 24 to 36 hours is recommended, with immobilization and local application of ice every 2 to 3 hours. An extended period of immobilization may enhance the outcome of the procedure but should be combined with nontraumatic, non–weight-bearing range-of-motion exercises.

Table 4: Comparison of Commonly Used Intraarticular Corticosteroids Preparations
Trade Name Generic Name Concentration (mg/mL) Equivalent Doses Range of Water Solubility Dosing (mg/mL)
Depo-Medrol Methylprednisolone acetate 20, 40, 80 4 Insoluble 10-80
Aristospan Triamcinolone hexacetonide 20 4 Insoluble 5-40
Kenalog, Aristocort Triamcinolone acetonide 20 4 Soluble 5-40
Celestone Betamethasone acetate 6 0.6 Insoluble 1.5-6
Hydeltra Prednisolone tebutate 20 5 Soluble 5-50


Table 5: Materials and Doses for Joint Injections
Joint Needle Length (gauge)* Volume of Intraarticular Injection (mL) Dose of Depo-Medrol (mg)
Knee 1.5 in. (22/18) 1-3 40-80
Shoulder 1.5 in. (22/18 or 19) 1-3 40-80
Wrist 1 – 1.5 in. (22/19) 0.5-2 20-40
Ankle 1.5 in. (22/19) 0.5-2 20-40
Elbow 1.5 in. (22./18) 0.5-2 20-40
MCP 5/8-1 in. (25/21) 0.25-0.5 5-10
PIP 5/8-1 in. (25/23) 0.25-0.5 5-10
MTP 5/8-1 in. (25/21) 0.25-0.5 5-10
*Sizes suggested apply to needle gauge during instillation only or aspiration/instillation, respectively. 

Comment: The maximum number of steroid injections per site is not known but should kept to a minimum. A safe recommendation is to limit intraarticular/periarticular steroid injections to three or less per year per site, not to be repeated in consecutive years. Repetitive injections may become less effective, may adversely affect cartilage, and may increase the risk of infection or tendon rupture.

Dooley P, Martin R. Corticosteroid injections and arthrocentesis. Can Fam Physician 2002;48:285–292. PMID:11889888
Pfenninger JL. Injections of joints and soft tissue: part I. General guidelines. Am Fam Physician 1991;44:1196–1202.PMID:1927834
Pfenninger JL. Injections of joints and soft tissue: part II. Guidelines for specific joints. Am Fam Physician 1991;44:1690–1702. PMID: 1950966
Lavelle W, Lavelle ED, Lavelle L. Intraarticular injections. Med Clin North Am.2007;91:241-50. PMID:17321284

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