Ankle Fractures

Question 1

In a suspected deltoid ligament injury, what type of radiograph is indicated?

Answer 1

External rotation stress radiograph; gravity stress

Medial clear space of >5mm with ankle dorsiflexed indicates injury

Question 2

What is a normal talocrural angle?

Answer 2

83° +/- 4°

Question 3

What are identifying features that signifies the mechanism of injury of each category of Lauge-Hansen ankle fractures?

Answer 3

SAD: vertical medial malleolar fx
SER: anteroinferior-to-posterosuperior oblique fx of fibula
PAB: high comminuted fibula fx, horizontal medial mal
PER: anterosuperior-to-posteroinferior oblique fx of fibula

Question 4

Tibfib overlap is assessed in what radiographic view?

Answer 4

Both AP and Mortise:

Question 5

What are operative indications for ankle fractures?

Answer 5

1) any talar displacement
2) displaced isolated medial malleolar fracture
3) displaced isolated lateral malleolar fracture
4) bimalleolar fracture and bimalleolar-equivalent fracture
5) posterior malleolar fracture with > 25% or > 2mm step-off
6) Bosworth fracture-dislocations
7) open fractures

Question 6

What is the effect of a 1mm talar shift?

Answer 6

42% decrease in tibiotalar contact area

Question 7

What is the most appropriate plating technique utilized for the medial malleolus fracture typically seen in a displaced supination-adduction ankle fracture?

Answer 7

Antiglide plate

Question 8

When can isolated lateral malleolus fractures be treated non-operatively?

Answer 8

If intact mortise, no talar shift, and

Question 9

What are the advantages and disadvantages of posterior plating of a fibula fracture?

Answer 9

Advantage: decreased risk of articular penetration by screw, increased stiffness
Disadvantage: increased incidence of peroneal irritation

Question 10

What are operative indications of isolated posterior malleolus fractures?

Answer 10

1) >2mm articular step-off
2) >25% articular fragment
3) syndesmotic injury

Question 11

At what level of the fibula does concern over a sysndesmotic injury come into play?

Answer 11

> 4.5cm about plafond

Question 12

In an isolated ankle syndesmotic injury, the fibula is unstable in the incisura fibularis of the tibia. In what direction is the fibula most unstable?

Answer 12

anterior to posterior

Question 13

Where is correct placement of syndesmotic screws in ankle fractures?

Answer 13

2-4cm above the joint; 1-2 screws; angled 20-30° posterior to anterior
3 or 4 cortices
3.5 mm or 4.5 mm screws
No difference if removed or allowed to break
NWB for 8-12 weeks

Question 14

What is the incidence of deep infections in ORIF of ankle fractures in diabetic pts?

Answer 14

20%; highest risk with peripheral neuropathy

Question 15

A posterolateral approach to the ankle allows access to what structures?

Answer 15

Posterior malleolus (btw FHL and peroneals) and lateral malleolus (btw peroneals and fibula)

Question 16

Where is the superficial peroneal nerve pierce through the fascia on the lateral leg?

Answer 16

10cm proximal to tip of fibula, then courses anteriorly

Short saphenous vein is also near fibula

Question 17

What is an advantage of placing a fibular plate posterolaterally?

Answer 17

1) distal screws avoid the joint
2) bicortical
3) Less prominence
4) Usually allows antiglide placement

Question 18

What additional steps are taken in ORIF of diabetic ankle fractures?

Answer 18

1) Stiffer construct
2) Multiple syndesmotic screws
3) NWB for 12 weeks

Question 19

In an isolated ankle syndesmotic injury, the fibula is unstable in the incisura fibularis of the tibia. In what direction is the fibula most unstable?

Answer 19

Anterior-to-posterior

Question 20

Following operative repair of lower extremity long bone and periarticular fractures, what is the time frame for patients to return to normal automobile braking time?

Answer 20

6 weeks after weight bearing

Or also 9 weeks from surgery

Question 21

What prevents reduction in a Bosworth fracture-dislocation?

Answer 21

Posterolateral ridge of the tibia