POCUS - MSK Flashcards
Why should you ultrasound suspected Achilles tendon ruptures/tears?
Physical exam is unreliable in diagnosing Achilles tendon tears, but ultrasound is very sensitive.
The ____________ tendon is the strongest tendon in the body.
achilles
Achilles tendon tears usually occur in the relatively avascular region which is _____ cm above the calcaneal insertion.
2-6
What physical exam maneuver can diagnose achilles tendon tears?
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.
The achilles tendon should appear ______________.
hyperechoic with a fibrillar texture
Why do you need to scan tendons perpendicular to their axis?
If you scan a tendon at any axis other than perpendicular, then a phenomenon called anisotrophy occurs which makes the tendon appear broken.
You’re scanning a tendon and the appearance goes from hyperechoic and fibrillar to hypoechoic. The patient has pain there. What could be happening?
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.
When you see a suspected tendon tear (partial or complete), have the patient ________________.
flex and extend; this can confirm what you’re looking at
When you see a suspected complete tendon tear, be sure to _____________.
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
What injury can mimic tear of the achilles tendon?
Tear of the gastrocnemius (usually the medial head near the aponeurosis is what gets torn)
What are POCUS findings of tenosynovitis?
Enlargement of the tendon fibers and fluid around the tendon
POCUS findings of tenosynovitis (such as tendon enlargement and fluid) could be due to what causes?
Infection
Bleeding
Inflammation
Lymph nodes typically have a _______-echoic outer cortex and a ________-echoic inner medulla.
hypo; hyper
What can help you determine if a tendon appears pathologic?
Compare to the healthy side!
Importantly, tendons can either have or not have synovial __________.
sheaths
Those that have sheaths will usually collect fluid more easily than without.
Other than HCTZ, what medication can cause gout?
Cyclosporine
True or false: synovial fluid culture is the definitive test for gonococcal arthritis.
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.
Which patients are at higher risk of septic arthritis in atypical joints?
IV drug users
They can get septic arthritis in the sacroiliac joint or acromioclavicular joint.
The threshold for diagnosing septic arthritis in prosthetic joints is what?
> 1,100 WBCs
The double contour sign (a hyperechoic line in the synovium above an articular surface) is a sign of what?
Gout
The extra contour is crystal deposition on hyaline cartilage.
The best way to look for fluid in the elbow is _____________.
by placing the linear transducer in sagittal plane along the distal humerus with the elbow flexed to 90 degrees (viewing the posterior olecranon fossa)
Why do you avoid medial approaches to arthrocentesis of the elbow?
Ulnar nerve
What is the preferred method of arthrocentesis in the wrist?
Dorsal aspect of the radiocarpal junction is ulnar deviation of the wrist
To scan the hip, use what orientation?
Linear or curvilinear probe
Superficial to the axis of the femoral neck
Dot to head
Leg extended and slightly externally rotated
What defines positive hip effusion in an adult?
> 7 mm of capsular distension or > 1 mm asymmetry
What defines positive hip effusion in a child?
> 2 mm distension
True or false: the knee should be fully extended for performing US and arthrocentesis.
False
15-20 degrees flexion.
Lipohemarthrosis is a sign of what?
Fracture
