POCUS - MSK

Question 1

Why should you ultrasound suspected Achilles tendon ruptures/tears?

Answer 1

Physical exam is unreliable in diagnosing Achilles tendon tears, but ultrasound is very sensitive.

Question 2

The ____________ tendon is the strongest tendon in the body.

Answer 2

achilles

Question 3

Achilles tendon tears usually occur in the relatively avascular region which is _____ cm above the calcaneal insertion.

Answer 3

2-6

Question 4

What physical exam maneuver can diagnose achilles tendon tears?

Answer 4

Thompson’s test

Have the patient lie prone on the exam table with their feet hanging over the edge of the table. With them relaxed, squeeze their calves. The foot should slightly plantarflex when you squeeze the calf. Failure to plantarflex is a sign of achilles tendon tears.

Question 5

The achilles tendon should appear ______________.

Answer 5

hyperechoic with a fibrillar texture

Question 6

Why do you need to scan tendons perpendicular to their axis?

Answer 6

If you scan a tendon at any axis other than perpendicular, then a phenomenon called anisotrophy occurs which makes the tendon appear broken.

Question 7

You’re scanning a tendon and the appearance goes from hyperechoic and fibrillar to hypoechoic. The patient has pain there. What could be happening?

Answer 7

Tendinosis

Degeneration of tendons can cause swelling and atrophy that makes them appear like described in the stem.

Note: you can also sometimes see areas of hyperechoic calcification in the tendonosis.

Question 8

When you see a suspected tendon tear (partial or complete), have the patient ________________.

Answer 8

flex and extend; this can confirm what you’re looking at

Question 9

When you see a suspected complete tendon tear, be sure to _____________.

Answer 9

try to identify the distance between the opposing edges and what is in between; if there’s that has slipped between then the patient is less likely to be a non-operative candidate

Question 10

What injury can mimic tear of the achilles tendon?

Answer 10

Tear of the gastrocnemius (usually the medial head near the aponeurosis is what gets torn)

Question 11

What are POCUS findings of tenosynovitis?

Answer 11

Enlargement of the tendon fibers and fluid around the tendon

Question 12

POCUS findings of tenosynovitis (such as tendon enlargement and fluid) could be due to what causes?

Answer 12

Infection
Bleeding
Inflammation

Question 13

Lymph nodes typically have a _______-echoic outer cortex and a ________-echoic inner medulla.

Answer 13

hypo; hyper

Question 14

What can help you determine if a tendon appears pathologic?

Answer 14

Compare to the healthy side!

Question 15

Importantly, tendons can either have or not have synovial __________.

Answer 15

sheaths

Those that have sheaths will usually collect fluid more easily than without.

Question 16

Other than HCTZ, what medication can cause gout?

Answer 16

Cyclosporine

Question 17

True or false: synovial fluid culture is the definitive test for gonococcal arthritis.

Answer 17

False

Synovial fluid has a relatively high false-negative rate. They are positive in only 10-50% of cases. While you should still do a synovial culture, you also need to do swabs of the GU area for gold standard detection.

Question 18

Which patients are at higher risk of septic arthritis in atypical joints?

Answer 18

IV drug users

They can get septic arthritis in the sacroiliac joint or acromioclavicular joint.

Question 19

The threshold for diagnosing septic arthritis in prosthetic joints is what?

Answer 19

> 1,100 WBCs

Question 20

The double contour sign (a hyperechoic line in the synovium above an articular surface) is a sign of what?

Answer 20

Gout

The extra contour is crystal deposition on hyaline cartilage.

Question 21

The best way to look for fluid in the elbow is _____________.

Answer 21

by placing the linear transducer in sagittal plane along the distal humerus with the elbow flexed to 90 degrees (viewing the posterior olecranon fossa)

Question 22

Why do you avoid medial approaches to arthrocentesis of the elbow?

Answer 22

Ulnar nerve

Question 23

What is the preferred method of arthrocentesis in the wrist?

Answer 23

Dorsal aspect of the radiocarpal junction is ulnar deviation of the wrist

Question 24

To scan the hip, use what orientation?

Answer 24

Linear or curvilinear probe

Superficial to the axis of the femoral neck

Dot to head

Leg extended and slightly externally rotated

Question 25

What defines positive hip effusion in an adult?

Answer 25

> 7 mm of capsular distension or > 1 mm asymmetry

Question 26

What defines positive hip effusion in a child?

Answer 26

> 2 mm distension

Question 27

True or false: the knee should be fully extended for performing US and arthrocentesis.

Answer 27

False

15-20 degrees flexion.

Question 28

Lipohemarthrosis is a sign of what?

Answer 28

Fracture