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Arthrocentesis Of The Elbow Joint

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Authors

Sergio Alvarez, MD
Emergency and Sports Medicine Physician
Kaiser Santa Clara Medical Center
Clinical Assistant Professor (Affiliate) of Emergency Medicine
Stanford University, School of Medicine

Summary

  • Ultrasound can evaluate elbow effusions as small at 1-3 cc
  • Posterior bulging fat pads seen on ultrasound has a sensitivity of 98-100% for occult pediatric supracondylar fractures
  • Ultrasound can be used to both evaluate for effusions and for ultrasound guided arthrocentesis of the radio-capitellar joint or the posterior joint recess
  • Do not confuse olecranon bursitis with a posterior joint recess effusion
Lateral elbow radiograph showing a joint effusion. The poisterior fat pad (blue arrow) and anterior fat pad (red arrow) are labeled.[1]Case courtesy of Dr Ian Bickle, Radiopaedia.org, rID: 59706
Patient positioning for an elbow arthrocentesis
Patient positioning for the posterior approach of the ultrasound guided elbow arthrocentesis.
This video demonstrates an ultrasound guided arthrocentesis of the elbow using the posterior approach. The first few seconds show local anesthetic in the soft tissue, then the bigger 18 gauge spinal needle can be seen in the joint. Note the effusion shrinks over the course of the video.

Introduction

  • Elbow effusions can be caused by trauma, arthritis, hemarthrosis, crystal arthropathies, and infection. Radiographs may have the characteristic findings of elevated posterior and anterior fat pads allowing for the detection of effusions measuring 5mL-10mL.
  • Ultrasound has been shown to be a reliable and sensitive modality in the evaluation of elbow effusions and may be able to detect effusions as small as 1mL-3mL.[2]Tran N, Chow K. Ultrasonography of the Elbow. Seminars in Musculoskeletal Radiology. 2007;11(2):105–116.
  • The posterior olecranon fossa with the elbow in flexion is the most sensitive location to detect elbow effusions.[3]De Maeseneer M, Jacobson JA, Jaovisidha S, et al. Elbow effusions: Distribution of joint fluid with flexion and extension and imaging implications. Invest Radiol. 1998;33(2):117-125.
  • The application of ultrasound has particular utility when evaluating the pediatric elbow in the setting of trauma when radiographs are equivocal for an occult supracondylar fracture but clinical suspicion remains high. Several studies have shown that the presence of a bulging posterior fat pad has a sensitivity for occult fracture of 98-100%.[4]Burnier M, Buisson G, Ricard A, Cunin V, Pracros JP, Chotel F. Diagnostic value of ultrasonography in elbow trauma in children: Prospective study of 34 cases. Orthop Traumatol Surg Res. … Continue reading[5]Rabiner JE, Khine H, Avner JR, Friedman LM, Tsung JW. Accuracy of point-of-care ultrasonography for diagnosis of elbow fractures in children. Ann Emerg Med. 2013;61(1):9-17.[6]Eckert K, Janssen N, Ackermann O, Schweiger B, Radeloff E, Liedgens P. Ultrasound diagnosis of supracondylar fractures in children. Eur J Trauma Emerg Surg. 2014;40(2):159-168.

Anatomy

  • The elbow joint is made up of 3 articulations: humeral-radial, humeral-ulnar, and radioulnar.
  • Elbow effusions should be evaluated in both the lateral joint recess (radioulnar articulation) and posterior joint recess (humeral-ulnar articulation aka olecranon fossa).
  • The lateral joint recess can be palpated by triangulating the lateral epicondyle, the olecranon process, and radial head
Bony anatomy of the elbow (click to enlarge).
    • This recess will have an outpouching of the radial-capitellar capsule if an effusion is present.
  • The posterior joint recess which is part of the olecranon fossa is deep to the triceps muscle-tendon unit and posterior fat pad.
    • The space between the posterior fat pad and articular cartilage of the distal humerus is where effusions can be seen on ultrasound.
Lateral recess of the elbow
Lateral recess of the elbow defined by the lateral epicondyle, radial head and olecranon process. Needle insertion site is marked (purple circle).[7]Image courtesy of epmonthly.com, “Has this laceration compromised the joint?”
Elbow anatomy posterior joint recess
Posterior recess of the elbow is noted with the posterior fat pad (red box) deep to the triceps tendon (red box). The articular cartilage (blue) sits on the olecranon posteriorly.

Ultrasound Evaluation

  • Ultrasound evaluation should be done with the elbow flexed at 90 degrees and can be performed with the patient sitting up or lying supine.
  • Evaluate the lateral joint recess and posterior joint recess in both sagittal and transverse planes (posterior joint recess is most sensitive for detecting effusions).[8]De Maeseneer M, Jacobson JA, Jaovisidha S, et al. Elbow effusions: Distribution of joint fluid with flexion and extension and imaging implications. Invest Radiol. 1998;33(2):117-125.
  • The lateral joint recess (radioulnar articulation) will show a distended capsule if an effusion is present.
  • In a normal elbow the posterior fat pad will be below the level of the humerus. A small elbow effusion may show an isolated bulging fat pad and if large enough may show the effusion itself.
Elbow US normal view of the lateral recess
Normal ultrasound of the lateral recess in long axis. Note that it is not possible to see all 3 bones that make up the lateral recess in a single view. [9]Radunovic G, Vlad V, Micu MC, et al. Ultrasound assessment of the elbow. Med Ultrason. 2012;14(2):141-146.
Elbow US normal view of the posterior recess
Normal ultrasound of the posterior recess in long axis.[10]Radunovic G, Vlad V, Micu MC, et al. Ultrasound assessment of the elbow. Med Ultrason. 2012;14(2):141-146.
Elbow US with posterior fat pad sign abnormal
Posterior elbow in long axis showing a bulging posterior fat pad with hemarthrosis.[11]Chan WW, Green-Hopkins I. PEM pearls: Ultrasound for Diagnosing Occult Supracondylar Fractures. Aliem.com. Published August 7, 2019. Accessed November 11, 2021. … Continue reading
Elbow US with posterior fat pad sign abnormal 2
A second ultrasound with a posterior elbow in long axis showing a bulging posterior fat pad with significant effusion[12]Okumura Y, Maldonado N, Lennon K, McCarty B, Underwood P, Nelson M. Point-of-care ultrasound: Sonographic posterior fat pad sign: A case report and brief literature review. J Emerg Med. … Continue reading

Procedure

  • Landmark vs. Ultrasound Guided Approach
    • The aspiration of elbow effusions via ultrasound guidance has been shown to improve success rates compared to classic landmark based techniques[13]Sofka CMMD. Section Editor Ultrasound-Guided Versus Conventional Joint and Soft-tissue Fluid Aspiration in Rheumatology Practice: A Pilot Study. Ultrasound Quarterly. 2003;19(ue 2):104–105..
    • In addition to improving success rates, ultrasound can also aid in identifying surrounding anatomical structures and in evaluating alternate diagnoses such as soft-tissue infections.
  • Materials
    • 18 gauge draw needle
    • 1.0 – 1.5 inch, 25 gauge needle for aspiration and injection
    • Note: small joint but may require larger gauge for aspiration
    • 3 – 5 cc syringe
    • Local anesthetic
    • Sterile equipment (gauze, skin prep, gloves, probe cover, etc)

Palpation Guided Technique

  • General
    • Author’s positioning recommendation and technique
    • Can be performed without assistance
    • Procedure should be done with strict sterile technique
  • Position
    • The patient is seated or supine
    • Arm internally rotated, resting on a table with palm facing downward. This position allows for easy access to lateral joint recess.
    • Elbow is flexed to roughly 90 degrees. 
Demonstration of elbow arthrocentesis palpation guided
Demonstration of palpation guided technique with boundaries of the lateral recess marked. Note the patient is resting their arm in abduction with elbow flexed to maximize access to the lateral recess.[14]Bettencourt RB, Linder MM. Arthrocentesis and therapeutic joint injection: an overview for the primary care physician. Prim Care. 2010;37(4):691-702, v.
  • Technique:
    • Triangulate joint space by finding bony landmarks (lateral epicondyle, the olecranon process, and radial head) and by palpating the radial head during supination and pronation.
    • Can use roughly 1cc of lidocaine as local anesthetic for pain control prior to aspiration
    • Once joint space is located via bony landmark identification, insert and advance needle while holding suction in the syringe with the goal of entering the radioulnar joint.
  • Other
    • Because it is blind, the needle may require multiple redirections until you feel it “drop” into the joint, you aspirate fluid and/or injection becomes very easy

Ultrasound Guided Technique

  • General
    • Authors recommend posterior approach for each of access
    • Can be performed without assistance
    • Procedure should be done with strict sterile technique.
  • Patient position
    • The patient should be prone
    • Ipsilateral arm hanging off the side of the bed and with elbow bent roughly at a 90 degree angle. A pillow may be used for comfort or as a prop in the antecubital fossa. 
    • This position allows for easy access to the posterior joint recess but is not amenable to lateral joint recess approach
    • Alternatively, the patient can be seated or supine for the lateral ultrasound-guided approach
Demonstration of patient positioning for the posterior approach.
Ultrasound guided elbow arthrocentesis position for lateral approach
Demonstration of patient positioning for the lateral approach.
  • Procedure
    • This technique uses the posterior approach
    • Prior to starting the procedure, identify your landmarks including the triceps tendon, posterior fat pad, effusion and distal humero-ulnar articulation
  • Under ultrasound guidance
    • The linear transducer is placed short-axis to the triceps tendon and transverse/long-axis to the distal humerus.
    • Needle is inserted using In-Plane technique from lateral to medial as to avoid the ulnar nerve coursing medially
    • The target is deep to the posterior fat pad and above the articular cartilage of the olecranon fossa. Need Image
Elbow Ultrasound long axis pre arthrocentesis
Long axis view of the posterior approach prior to beginning the procedure. The effusion is marked (arrow).[15]Boniface KS, Ajmera K, Cohen JS, Liu YT, Shokoohi H. Ultrasound-guided arthrocentesis of the elbow: a posterior approach. J Emerg Med. 2013;45(5):698-701.
In the same patient, the probe has been rotated to short axis and the needle can be seen entering the effusion from lateral to medial.[16]Boniface KS, Ajmera K, Cohen JS, Liu YT, Shokoohi H. Ultrasound-guided arthrocentesis of the elbow: a posterior approach. J Emerg Med. 2013;45(5):698-701.
Video of ultrasound injection using the lateral approach.
Video of ultrasound injection using the posterior approach in long axis.

Pearls & Pitfalls

  • Avoid the ulnar nerve with the posterior approach by inserting needle on the lateral side
  • Arthritis may make it difficult to access the radio-capitellar joint during a lateral approach due to the proximity of both articular surfaces compared to the posterior approach
  • Do not confuse an elbow effusion with olecranon bursitis or fluid within the olecranon bursa
Elbow US olecranon bursitis
Elbow ultrasound of olecranon bursitis in long axis to the posterior elbow. Note that fluid collection is more superficial and more distal on the humerus. The fat pad can be seen at the bottom and is not displaced posteriorly.
Video demonstration of olecranon bursitis with probe in long axis.

References

References[+]