Ankle fractures

Contents

Mechanism

pattern of fracture depends on the position of the ankle when trauma occurs
generally involves
- ipsilateral ligamentous tears or transverse bony avulsion
- contralateral shear fractures (oblique or spiral)
classification systems
- Danis-Weber: based on level of fibular fracture relative to syndesmosis (A-infra, B-trans, C-supra)
- Lauge-Hansen: describes the position of the foot & the
  motion of the talus with respect to the leg

Danis-Weber Classification

Weber	Lauge-Hansen
A	S.AD.
B	S.ER. P.AB.
C	P.ER.

Type A (infra-syndesmotic)
- pure inversion injury
- avulsion of lateral malleolus below plafond or torn calcaneofibular ligament
- ± shear fracture of medial malleolus
- Lauge-Hansen: supination adduction (SAD)

Type B (trans-syndesmotic)
- external rotation and eversion (most common)
- ± avulsion of medial malleolus or rupture of deltoid ligament
- spiral fracture of lateral malleolus starting at plafond
- Lauge-Hansen: supination external rotation (SER) or pronation abduction (PAB)
Type C (supra-syndesmotic)
- pure external rotation
- avulsion of medial malleolus or torn deltoid ligament
- ± posterior malleolus may be avulsed with posterior tibio-fibular ligament
- frequently tears syndesmosis

PEARL

when examining a patient with a suspected ankle #, always palpate the fibular head for tenderness – suprasyndesmotic proximal fibular # a.k.a. Maisonneuve #

Treatment

undisplaced: non-weightbearing below knee cast
indications for ORIF
- all fracture-dislocations
- all type C fractures
- trimalleolar (medial, posterior, lateral) fractures
- talar tilt >10 degrees
- open fracture/open joint injury
high incidence of post-traumatic arthritis

PEARL

in a mortise view of the ankle, if the distance between the medial malleolus and the medial borer of the talus is >4 mm, closed or open reduction is indicated to correct the lateral talar shift

Very common, particularly in winter

Important Question:

is it an open fracture?
is the ankle dislocated?
does it need surgery?

Note: It is essential to examine and document neurovascular status prior and following the treatment. Specifically, motor and sensory function of tibial, superficial and deep peroneal, saphenous and sural nerves should always be examined.

	Motor	Sensory
Tibial	planarflexion	posterior aspect of the heel
Superficial Peroneal	eversion	anterior lateral aspect of the shin
Deep Peroneal	dorsiflexion	big toe webspace
Saphenous	none	medial aspect of the calf
Sural	none	posterior lateral aspect of the calf

X-Rays:

Make sure the TALUS is aligned in the mortice in the mortice and lateral views.

Classification:

this is not just for exam purposes! It allows an understanding of the mechanism of injury, the best way to reduce it and whether it is likely to require surgery.

Remember:

avulsion #’s are usually transverse
shear #’s are usually oblique

TYPE AUsually due to inversion with an avulsion # of the lateral malleolus below the level of the plafond. There may be a shear # of the medial malleolus.

TYPE BDue to external rotation and eversion. The avulsion # is of the medial malleolus. The spiral or oblique # of the lateral malleolus starts at the plafond and runs superiorly.

TYPE CDue to external rotation. Avulsion # medially. Lateral # is above the plafond and may be as high as the proximal fibula (Maisonneuve #).

Note: A “trimalleolar” # includes a fragment from the posterolateral aspect of the tibia, visible on the lateral XR.

Reduction:

Undisplaced fractures require a backslab (see above) and to be non-weight bearing with crutches.

Displaced fractures should be reduced as soon as possible to avoid compromise to the skin. This is particularly true for fracture-dislocations where the talus is displaced laterally and posteriorly.

Reduction is easily carried out with sedation (fentanyl + versed) by: