Talus Fracture Flashcards
1
Q
Anatomy
A
- Surface 60% cartilage- No muscular insertions- Blood supply in tenuous due to lack of soft tissue attachment- Component of 3 joints (STJ, TN, ANKLE)
2
Q
Blood supply
A
- Artery of tarsal canal- Artery of tarsal sinus- Dorsal neck vessels- Deltoid branchesSEE DIAGRAMS
3
Q
Artery of tarsal canal
A
- Supplies the MAJORITY of the talar body
4
Q
Fracture incidence
A
- 2 % of all fractures- 6-8% of foot fractures- High complication rates (Avascular necrosis, Post-traumatic arthritis)
5
Q
Mechanism of injury
A
- Hyper-dorsiflexion of the foot on the tibia- Neck of talus impinges against anterior distal tibia, causing neck fracture- If force continues, talar body dislocates posteromedial around deltoid ligament- Previously called “aviator’s astragalus”- Usually due to motor vehicle accident or falls from height
6
Q
Hawkins classification of talar neck fractures (1970)
A
- Of the many fracture classifications this one has value- Excellent correlation with prognosis- Predictive of AVN rate- Widely accepted- 53% Overall AVN incidence
7
Q
Hawkins I
A
- Non-displaced neck fracture- Look at the cortex for alignment - AVN 0 – 13 %
8
Q
Hawkins II
A
- Displaced neck fracture- Subtalar subluxation- AVN 20 – 50 %
9
Q
Hawkins III
A
- Subtalar and ankle joint dislocated- Talar body is tethered around deltoid ligament- AVN 83 – 100 %- This makes sense because you are tearing the blood supply to the talus
10
Q
Hawkins IV
A
- Includes talonavicular subluxation- Rare variant- Complex talar neck fractures which do not fit classification can be included
11
Q
Goals of management
A
- Immediate reduction of dislocated joints to prevent joint and soft tissue damage- Anatomic fracture reduction to restore function - Stable fixation to promote healing and facilitate union - Facilitate union- Avoid AVN- Provide a platform for early active rehabilitation (Move it or lose it)
12
Q
Avascular necrosis (AVN)
A
- Ischemia- Due to arterial interruption - Hallmarks on x-ray (increased density) = Sclerosis and Collapse****
13
Q
AVN imaging - plain radiographs
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o Sclerosis o Decreases with revascularization
14
Q
AVN imaging - MRI
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o Very sensitive to decreased vascularityo T1 = looking at fat, bone with necrosis will lose marrow (fat) so it will look darko The MRI often shows patchy areas of bone death
15
Q
AVN imaging - CAT scan
A
o Computed axial tomography o Better 3D representation o Confirms displaced vs non-displaced fractures