Elbow Arthrocentesis Technique

Updated: Feb 16, 2021
  • Author: Susan C Bork, MD; Chief Editor: Erik D Schraga, MD  more...
  • Print

Aspiration of Synovial Fluid From Elbow

Explain the procedure to the patient and obtain informed consent.

With the patient positioned as described (see Positioning), identify the olecranon process, lateral epicondyle, and radial head, and find the depression (or bulge, if the effusion is large) in the soft triangle. (See the image below.) This site is used for all approaches. [10]  The landmarks may be easier to find if the arm is first extended to locate the depression and then flexed and pronated for the procedure. Do not confuse an olecranon bursitis with a joint effusion; an olecranon bursitis is located posteriorly over the olecranon.

Triangle formed between olecranon, lateral epicond Triangle formed between olecranon, lateral epicondyle, and radial head as site for needle placement.

Identify the site of entry, and mark the site with a plastic needle sheath or sterile marker. Prepare the skin with a cleansing agent, and drape with towels.

Do not pass the needle through a site with cutaneous signs of infection unless the source is strongly suspected to be from the joint. This should only be done after consultation with an orthopedist.

Anesthetize the area by injecting 1-2 mL of lidocaine 1% and forming a skin wheal. Insert an 18-gauge needle into the depression perpendicular to both the skin and radial head from the lateral side. This is the lateral approach, which is preferred.  A medial approach should not be used, because of the risk of injury to the ulnar nerve and the superior ulnar collateral artery.

As an alternative to the lateral approach, the posterolateral approach can be used. An increased risk of injury to the radial nerve and triceps tendon exists, but this approach is useful if the bulge of an effusion is palpated inferior to the lateral epicondyle. In the posterolateral approach, insert the needle perpendicular to the skin but parallel to the radial shaft. (See the image below.)

Aspiration of elbow via posterolateral approach. Aspiration of elbow via posterolateral approach.

Ultrasonography may aid detection of even a small effusion in the olecranon fossa. [11, 12, 13]

Advance the needle slowly while aspirating the syringe until synovial fluid is obtained. If the aspiration is unsuccessful, draw back, reidentify the landmarks, and correct the needle insertion position. If bone is encountered, withdraw the needle slightly and redirect it.

When synovial fluid is obtained, remove the needle. Apply a bandage and elastic wrap if a large effusion was present. Place the fluid in specimen tubes and send for analysis.



Arthrocentesis of the elbow or any joint is associated with infrequent complications, including the following:

  • Infection - In rare cases (1 per 10,000 aspirations), bacteria from the skin may be introduced into the joint
  • Iatrogenic hemarthrosis - A small amount of blood may be obtained from a small synovial blood vessel, which is a benign occurrence; obtaining larger amounts is rare, except in patients who are taking an anticoagulant or who have a history of bleeding diatheses
  • Allergic reaction - Hypersensitivity to the anesthetic agent, if present, can be identified from the history