VOTW: I'd Tap That

 ·   · 

Case 1: A 69 yoF with a PMHx of osteoarthritis presented to the ED with 1 day of worsening knee pain. The workup revealed a moderate-sized effusion and elevated CRP. These factors, combined with her discomfort, prompted the providers to perform an arthrocentesis.

Approach: While there are many approaches you can take to tap a knee effusion, the one I have seen most often is the suprapatellar approach (note: it is best to identify the area with the biggest pocket). Next, gather your equipment for a regular arthrocentesis plus a probe cover. Once you identify your pocket, turn your probe so it is in-plane with your needle. Advance your needle until you see it enter your fluid pocket and aspirate. Remember to put color flow over the expected trajectory of your needle to avoid vasculature.

Image 1: Knee arthrocentesis set-up

  • Video 1 shows the moderate-sized effusion in the suprapatellar region. (note: you can also see a separate, rounded, fluid-filled area, which is the pre-patellar bursae).

  • Video 2 shows the needle in-plane during active aspiration.

  • Video 3 shows the needle in the decompressed joint space.

Case 2: A 102 yoF came to the ED with difficulty ambulating due to ankle pain. On exam, she had swelling, tenderness, and pain with passive/active range of motion. Bedside US showed a joint effusion and inflammatory markers were elevated. In conjunction with the family, the decision was made to tap the ankle joint.

Image 2: normal tibiotalar joint space

Image 3: tibiotalar joint space with effusion

Video 4 shows a fluid collection at the tibiotalar joint. 

Video 5 shows Dr. Tran performing a dynamic aspiration of the ankle effusion.

Results: Results from the arthrocentesis in case 1 showed inflammatory arthritis and case 2 was gout. While neither case turned out to be septic arthritis, both patients felt much better after the tap and were able to ambulate. 

Why use ultrasound? Using ultrasound guidance to perform an arthrocentesis allows you to see the exact location of the joint effusion, improving your first-pass success rate. In addition, using color-doppler before the tap decreases the risk of neurovascular injury.

References:

https://coreultrasound.com/knee-aspiration-and-injection/

https://cdn.mdedge.com/files/s3fs-public/Document/June-2017/em049070329.PDF

https://www.tamingthesru.com/blog/mastering-minor-care/ankle-arthrocentesis

Happy scanning! 

Ariella Cohen M.D.

VOTW: Throw what you know

 ·   · 

This VOTW is brought to you by Drs. Chiu, Butt, Burns, Wong, and Sanghvi on a scan shift. 

A 42 yoM presented to the ED with a left shoulder dislocation. The ultrasound team looked at his dislocated shoulder (Image 1) and gave an Intraarticular lidocaine injection. The providers reduced his shoulder and then looked for confirmation using ultrasound (Image 2).


How can I do this?

Take your linear or curvilinear probe and place it in transverse orientation on the patient’s back next to the humerus (image 3). The glenoid should articulate directly with the humeral head (image 4). In an anterior shoulder dislocation, the humeral head will be deeper on your screen because it is further from the probe. In a posterior shoulder dislocation, the humeral head will appear more superficial because it is closer to your probe (image 5).

Why use ultrasound?

Ultrasound allows you to check in real-time whether or not the reduction was successful, rather than waiting for x-ray confirmation. I find this particularly useful for my workflow in cases where I am not 100% certain that the shoulder is back in.

References:

  • Martinoli, C. (2010). Musculoskeletal ultrasound: technical guidelines. Insights into imaging, 1(3), 99.

  • Jacobson, J. A. (2011). Shoulder US: anatomy, technique, and scanning pitfalls. Radiology, 260(1), 6-16.

  • 5 Minute Sono

  • The Pocus Atlas

Happy scanning!

Ariella Cohen, M.D.


VOTW: Biceps Tendinitis

 ·   ·  ,

Hi all,

This week’s VOTW is brought to you by Dr. Evans!

A 56 year old male presented with dull left shoulder pain for two days. He denied any trauma, swelling, erythema to the area or fevers. He did endorse repetitive lifting motions at work. The exam was unremarkable except for some pain w/ ROM of the shoulder. A POCUS showed…

In Clip 1, the long head of the biceps tendon is seen in the bicipital groove (between the greater and lesser tuberosity) in its short-axis surrounded by a rim of hypoechoic fluid. 

Clip 2 shows the biceps tendon in its long-axis, again surrounded by a small amount of hypoechoic fluid. This is consistent with biceps tendinitis. The tendon itself appears intact without tears. The patient was discharged with NSAIDs and ortho follow up.

POCUS Shoulder Exam

We have all had patients presenting with non-traumatic shoulder pain. They get their therapeutic x-ray and you tell them to try NSAIDs and follow up with ortho.

While the POCUS shoulder exam may not be life-saving, it has the potential to quickly provide the diagnosis for a range of pathologies. Finding the answer to the patient's pain may might result in a more satisfied patient 😊. The hard part is learning and remembering this multi-step exam.

Evaluting the long head of the biceps tendon is Step 1 and is the easiest part of the shoulder exam (in my opinion), so we’ll go over that today! Stay tuned for future VOTWs for the rest of the shoulder exam.

Technique

  • Have patient sitting in chair or side of the bed (see below)

  • Use a linear high-frequency probe

  • Have the patient flex elbow at 90 degrees with palm facing up and arm adducted

  • Place the probe horizontally along the bicipital groove (proximal humerus) and find the echogenic long head of biceps tendon in transverse

  • Rotate the probe 90 degrees to see the tendon in its long axis

  • Look for disruptions in the tendon, fluid around tendon, or subluxation (tendon not in bicipital groove)

Image 1. Positioning for evaluating the biceps tendon

Artifact Corner

Tendons exhibit an artifact called anisotropy. This means the appearance of tendons can be different depending on the angle of insonation (the angle of the beam onto the object). It will look hyperechoic at one angle and hypoechoic at another angle. Don’t mistake this for a tendon tear or fluid. Fluid or tendons will not change in appearance with different angles of insonation.

So next time you have a patient with shoulder pain, take a quick look at the biceps tendon, you might find the answer right away!

Happy Scanning,

Your Sono Team