1. Trauma: Knee/Foot Flashcards
Casanova Fracture
Bilateral Calcaneal + T12-L2 compression/burst fracture
Peroneal tendons can become entrapped with lateral calcaneal fractures.
The most common Tarsal Bone Fx
Calcaneal fractures are the most common (60%) Tarsal Bone Fx
Intra-articular fractures will have a fracture line through
Bohler s Angle
The line drawn between the anterior and posterior borders o f the calcaneus on a lateral view. An angle less than 20 degrees, is concerning for a fracture.
Jones Fracture
This is a fracture at the base of the fifth metatarsal, 1.5cm distal to the tuberosity.
These are placed in a non-weight bearing cast (may require internal fixation- because o f risk of non-union.
Avulsion Fracture of the S*’’ M etatarsal
This is more common than a j ones fracture. The classic history is a dancer.
It may be secondary to tug from the lateral cord of the plantar aponeurosis or peroneus brevis (this is controversial).
Painful Os Peroneus Syndrome (POPS)
Os Peroneus (accessory ossicle) is within the Peroneus LONGUS
This ossicle is seen in about 10% of gen pop
Stress reaction and pain can progress to tendon disruption = POPS
MR Key Findings: Edema in the os peroneus just before the peroneus longus tendon enters the cuboid tunnel
most common dislocation of the foot.
Lisfranc Injury
Lisfranc Injury
The Lisfranc ligament connects the medial cuneiform to
the 2nd metatarsal base on the plantar aspect.
Fracture non-union and post traumatic arthritis are gonna occur if you miss it (plus a lawsuit).
Lisfranc Injury
Associated fractures are most common at the base of the 2nd MT
“Fleck Sign”
This is a small bony fragment in the Lisfranc Space (between 1st MT and 2nd MT) - that is associated with an avulsion of the LF ligament
Lisfranc Injury mechanism
3 Ligaments make up the complex between the medial cuneiform and 2nd MT
The plantar band is the strongest
Anatomic Trivia
Achilles Tendon
This is the largest tendon in the body.
fused tendons of the gastrocnemius and the soleus muscles.
It does NOT have a tendon sheath, so it cannot have a tenosynovitis (fluid in the sheath).
Instead inflammatory change around the tendon is referred to as a “paratendinitis.”
The Mythical
Master Knot of Henry
This is where Dick (FDL) crosses over Harry (FHL) at the medial ankle.
What is the Master Knot ofHenry? It’s a “Harry Dick”
Ligamentous Injury
highest yield fact is that the anterior talofibular ligament is the weakest ligament and the most frequently injured (usually from inversion).
Posterior Tibiai Tendon injury / Dysfunction
This results in a progressive flat foot deformity, as the PTT is the primary stabilizer of the longitudinal arch.
When chronic, the tear is most common = behind the medial malleolus (this is where the most friction is).
When acute, the tear is most common = at the insertion into the navicular bone.
You will also have a hindfoot valgus deformity (from unopposed peroneal brevis action).
Acute Flat Arch should make you think of
Posterior Tibiai Tendon Tear
I Say Acute Flat Foot,
You Say Posterior Tihial Tendon Injury
Sinus Tarsi Syndrome
Never make this diagnosis in the setting ofacute trauma
Sinus Tarsi
The space between the lateral talus and calcaneus.
It is an important source of proprioception and balance.
Fucking it up has consequences (if your goal is to make prima ballerina assoluta).
Sinus Tarsi Syndrome
The “syndrome” is caused by hemorrhage or inflammation of the synovial recess with or without tears of the associated ligaments (talocalcaneal ligaments, inferior extensor retinaculum).
There are associations with rheumatologic disorders and abnormal loading (flat foot in the setting o f a posterior tibiai tendon tear)
Sinus Tarsi Syndrome
MRI finding is obliteration of fat in the sinus tarsi space, and replacement with scar.
Plantar Fasciitis
This is an inflammation of the fascia secondary to either repetitive trauma (overuse via endless rounding on fat diabetic, smokers as a medicine intern), abnormal mechanics (pes cavus, etc), or arthritis (Reiters, etc…).
The pain is localized to the origin of the plantar fascia, and worsened by dorsiflexion of the toes. This is usually a clinical diagnosis.
The plantar fascia consists of 3 band
the central / lateral part normally thicker than the medial part the thinnest.
Coronal T1 diagram through the heel
Plantar Fasciitis
a thickened fascia (> 4mm), most often the central band
with increased T2 signal, most significant near its insertion at the heel.
CLASSIC- FLAT FOOT PROGRESSION of Plantar Fascitis
Split Peroneus Brevis
The history is usually “chronic ankle pain”.
The tendon will be C shaped or boomerang shaped with central thinning and partial envelopment of the peroneus longus. Alternatively, there may be 3 instead of 2 tendons. The tear occurs at the lateral malleolus.
There is a strong (80%) association with lateral ligament injury.
Anterolateral impingement Syndrome
Injury to the anterior talofibular ligaments and tibiofibular ligaments (usually fi-om an inversion injury) can cause lateral instability, and chronic synovial inflammation.
You can eventually produce a “mass” of hypertrophic synovial tissue in the lateral gutter
Anterolateral impingement Syndrome
The MRI finding is a “meniscoid mass” in the lateral gutter of the ankle, which is a
balled up scar (T1 and T2 dark).
Tarsal Tunnel Syndrome
Pain in the distribution of the posterior tibial nerve (first 3 toes) from compression as it passes through the tarsal tunnel (behind the medial malleolus).
Unilateral (unlike carpal tunnel which is usually bilateral),
Idiopathic
Having said that, any mass lesion (ganglion cysts, neurogenic tumors, varicosities, lipomas, severe tenosynovitis, and accessory muscles) can cause compression of the nerve in the tunnel.
Morton’s Neuroma
Soft tissue mass (tear drop shaped) shown between the and 4‘t’ metatarsal heads (third intermetatarsal space)
from compression / entrapment of the plantar digital nerve in this location by the intermetatarsal ligament. Over time this results in thickening and development of perineural fibrosis.
is a physical exam (a sonographic sign) where you squeeze the patients foot and reproduce the pain (or see the scar pop out under ultrasound).
“Mulder’s Sign ”
Morton’s Neuroma is NOT a Neuroma (a tumor).
What is it?
Its a Scar!
Morton’s Neuroma Classic look
It is a scar, so it’s gonna be dark on T1 and T2 (usually). It is tear drop shaped and projects downward.
Primary Ddx of Morton’s Neuroma
The reason is that your primary differential is intermetatarsal bursitis - which will extend above the transverse ligament, be fluid signal, and have a more cystic look.
Small bursa in this location can be normal as long as the stay smaller than 3mm.
Haglund’s Syndrome / Deformity
This is also called the “Mulholland deformity” for the purpose of fucking with you. Depending on what you read there are either 3 or 4 classic features:
- Retro-Achilles bursitis,
- Retrocalcaneal bursitis,
- Thickening of the distal Achilles tendon (insertional portion)
- Calcaneal Bony Prominence “prominent posterior superior os calcis”
The deformitv is the “bump.” The “syndrome” is the bursitis and Achilles tendon thickening. They call this thing the “pump bumps,” because wearing high- heeled shoes is supposedly a
predisposing factor
Os Trigonum Syndrome
Os Trigonum (accessory ossicle) puts the smash on the FHL (“Harry”) during extreme ankle flexion — toe pointing shit (“Pointe technique”) that ballet dancers do… or other repetitive micro trauma.
What is this “Synchondrosis ” ?
This is a joint that has essentially no movement and is lined with cartilage.
Os Trigonum Syndrome classic findings
(1) “Stenosing” tenosynovitis / collection of fluid around the FHL
(2) edema within the Os Trigonum and across the synchondrosis between the Os and the Posterior Talus.
Classic Hx of Os Trigonum Syndrome
“Ballet Dancer”
Achilles Tendon injury
Acute rupture is usually obvious with a fluid filled gap. The gap size will determine treatment (big gaps need surgery).
4 cm above teh calcaneal insertion
Achilles Tendon Injury Vs Xanthoma
Without a large gap these things can be very hard to tell apart from a Xantlioma
Plantaris Rupture
“Tennis Leg”
“Achilles tendon ruptured but can still plantar flex.”
focal fluid collection between the soleus and the medial head of the gastrocnemius. There is an association with ACL tears.
Avulsions of the Calcaneal Tuberosity
Avulsions of the Calcaneal Tuberosity
This is sort of an Aunt Minnie with the back of the bone totally ripped off via the Achilles. The classic association is diabetes. When you see this you have to think diabetes.
Plantar Fascia Rupture
-Avulsion of the Medial Plantar Process
-Fleck / Fragment near the medial process of the calcaneal tuberosity — often associated with a plantar spur.
Extensor Digitorum Brevis Avulsion
Classic look is a fragment o f bone arising at the dorsolateral aspect o f the anterior calcaneus
Calcaneocuboid Ligament Avulsion
-Classic look is a small linear bone fragment located lateral to the calcaneocuboid joint
