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18 Cards in this Set

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What is the most common ankle complaint for referrals to foot and ankle specialists.
Chronic lateral ankle pain, usually after ankle sprain due to eversion injury
Ligaments of lateral ankle
5 Ligaments that come off of the fibula


Anterior and posterior talofibular

Calcaneofibular

Anterior and posterior tibiofibular


BUT the only one you have to care about is the ANTERIOR TALOFIBULAR LIGAMENT. This is the only one you have to evaluate on every MR. Since it is the first one to tear in eversion injury, if it is normal, the others will be normal too
Order of ligament tearing
Anterior talofibular


Calcaneofibular


Posterior talofibular does not tear. The next ones to tear are the anterior and posterior talofibular ligaments. That is the "High ankle sprain" and is a more serious injury, in which 3 months rest is needed because there will be associated tear of the syndesmosis.
What is the anterior talofibular ligament, and where is it seen?
It is just a thickening of the lateral capsule of the joint, just like the glenohumeral ligaments are.


It is seen at the axial section where the medial surface of the fibula becomes concave (malleolar fossa)
What is the posterior talofibular ligament, and where is it seen
It is an extension of the peroneal tendon sheath

It is seen on axial sections at the level of the calcaneocuboid joint extending to the lateral periosteum of the calcaneus. Or you can see it on coronal sections.
How do you decide whether plain films of ankle are needed after injury
OTTAWA RULES


If the patient can take 3 steps at the time of injury or presentation to the ER, and does not have pain 5 cm above lateral malleolus, no plain film study is indicated.
Where do peroneal tendons run
Right behind fibula
Where does brevis go
Tightly applied to base of fibula, and inserts on base of 5th metatarsal. This is the structure that causes the avulsion fracture that is seen less than 1 cm from the base (greater than 1 cm is the Jones)
Where does longus go
Right behind the brevis, then courses underneath the foot to insert on the base of the 1st metatarsal
Where do they both go
Along the distal fibula, they both pass through the common peroneal synovial tendon sheath
What can longus do
During inversion ankle sprain with dorsiflexion, it sandwiches the brevis between itself and the fibula, creating a cleft resulting in a LONGITUNIDAL SPLIT TEAR of the brevis.

This is another cause of chronic lateral ankle pain like ATFL rupture, and you must look for it, like ruptured ATFL, in every ankle.

It looks like a chevron (like a lambda)
What is the third entity you must look for on all ankle MRIs, that is a common cause of lateral ankle pain
Sinus Tarsi syndrome
Normal anatomy of tarsal sinus
Fat filled structure between the talus and calcaneus

The wide part is LATERAL (lateral ankle pain), underneath the lateral malleolus.
Cause of sinus tarsi syndrom
Subtalar ligament rupture, (again due to inversion injury) -- this does not occur until the ATFL is torn, so really the first thing you ALWAYS must look for is rupture of the ATFL.
How do you make the diagnosis of sinus tarsi syndrom
Normally you should see FAT SIGNAL ONLY in the lateral (wide) part of the sinus tarsi. If you see anything that looks like scar in there instead, the diagnosis of SINUS TARSI SYNDROME is made, assuming the patient has lateral ankle pain.
What is the association between abnormal signal in sinus tarsi and other associated abnormalities?
80% have torn lateral ligaments!!!
What are the subtalar ligaments (dont need to know for boards)
There are two of them. Both connect the talus to the calcaneus.


The smaller one is anterior and lateral, and is called the cervical ligament.


The thicker and more important one is more posterior and medial, and is called the interosseous ligament.
What is the 4th cause for chronic lateral ankle pain that you should look for
Anterolateral impingement syndrome -- The patient again has inversion injury, but this time builds up scar tissue between the medial surface of lateral malleolus and lateral surface of talus/calcaneus