ANKLE JOINT Sahil Arora PG Resident 1st Year Department of Radiology

Anteroposterior View Quantitative analysis

Tibiofibular overlap<10mm is abnormal - implies syndesmotic injuryTibiofibular clear space >5mm is abnormal - implies syndesmotic injuryTalar tilt>2mm is considered abnormalConsider a comparison with radiographs of the normal side if there are unresolved concerns of injury

Mortise View

•Foot is internally rotated and AP projection is performed •Abnormal findings:

medial joint space widening >4mmtalocural angle <8 or >15 degrees (comparison to normal side is helpful)tibia/fibula overlap <1mm

During Plantar flexionDuring Dorsiflexion

In Transverse Plane – Y axis

In SAGITTAL Plane X axis

In CORONAL plane Z axis

Pronation = ABDUCTION + EVERSION + DORSIFLEXION

THEREFORE SUPINATION = ADDUCTION + INVERSION + PLANTAR FLEXIONHENCE TRI PLANAR MOVEMENTS

Direction of FORCE

TANGENTIAL

AXIAL

• Classification systems– Lauge-Hansen– Weber

For Tangential Force

ANKLE FRACTURES

Lauge-Hansen Based on cadaveric study• First word: position of foot at time of

injury• Second word: force applied to foot

relative to tibia at time of injury

Types:Supination External RotationSupination AdductionPronation External RotationPronation Abduction

Supination Adduction: Stage 2

Lateral Injury: transverse fibular fracture at/below level of mortise

Medial injury: vertical shear type medial malleolar fractureBEWARE OF IMPACTION

Supination-External Rotation Stage 2: Stable

Lateral Injury: classic posterosuperioranteroinferior fibula fracture

Medial Injury: Stability maintained

Supination-External Rotation Stage 4: Unstable

Lateral Injury: classic posterosuperioranteroinferior fibula fracture

Medial Injury: medial malleolar fracture &*/or deltoid ligament injury

Standard: Surgical management

SER-2 vs. SER-4 How To Decide?

SER-2

Negative Stress view External rotation of

foot with ankle in neutral flexion (00)

+ Stress View

Widened Medial Clear Space

SE-4

Pronation External Rotation: Stage 4

Medial injury: deltoid ligament tear &/or transverse medial malleolar fracture

Lateral Injury: spiral proximal lateral malleolar fracture

HIGHLY UNSTABLE…SYNDESMOTIC INJURY COMMON

PER

• Must x-ray knee to ankle to assess injury

• Syndesmosis is disrupted in most cases– Eponym: Maissoneuve Fracture

Pronation-Abduction

Medial injury: tranverse to short oblique medial malleolar fracture

Lateral Injury: comminuted impaction type distal lateral malleolar fracture

Lauge-Hansen

• In each type there are several stages of injury• Imperfect system:

– Not every fracture fits exactly into one category– Even mechanismspecific pattern has been questioned– Inter and intraobserver variation not ideal– Still useful and widely used

Remember the injury starts on the tight side of the ankle! The lateral side is tight in supination, while the medial side is tight in pronation.

Weber ClassificationBased on location of fibula fracture relative to mortise and appearance Weber A fibula distal to syndesmosis Weber B fibula at level of syndesmosis Weber C fibula proximal to syndesmosisConcept - the higher the fibula the more severe the injury

Posterior Malleolus Fractures

Function:Stability- prevents posterior translation of

talus & enhances syndesmotic stability

Weight bearing- increases surface area of ankle joint

Posterior Malleolus Fracture

Type I- posterolateral oblique type Type II- medial

extension type

Type III- small shell type

67% 19%

14%

Common Names of Fracture Variants

• Maisonneuve Fracture– Fracture of proximal fibula with

syndesmotic disruption• Volkmann Fracture

– Fracture of tibial attachment of PITFL

– Posterior malleolar fracture type• Tillaux-Chaput Fracture

– Fracture of tibial attachment of AITFL

Pott fracture.

In the Pott fracture, the fibula is fractured above the intact distal tibiofibular syndesmosis, the deltoid ligament is ruptured, and the talus is subluxed laterally

Dupuytren fracture. (A) This fracture usually occurs 2 to 7 cm above the distal tibiofibular syndesmosis, with disruption of the medial collateral ligament and, typically, tear of the syndesmosis leading to ankle instability. (B) In the low variant, the fracture occurs more distally and the tibiofibular ligament remains intact.

Wagstaffe-LeFort fracture. In the Wagstaffe-LeFort fracture, seen here schematically on the anteroposterior view, the medial portion of the fibula is avulsed at the insertion of the anterior tibiofibular ligament. The ligament, however, remains intact.

Common Names of Fracture Variants

•Collicular Fractures–Avulsion fracture of distal portion of medial malleolus–Injury may continue and rupture the deep deltoid ligament

•Bosworth fracture dislocation–Fibular fracture with posterior dislocation of proximal fibular segment behind tibia

POSTERIOR COLLICULUS ANTERIOR COLLICULUS

INTERCOLLICULAR GROOVE

AXIAL FRACTURES

Tibial Pilon Fractures

The terms tibial plafond fracture, pilon fracture, and distal tibial explosion fracture all have been used to describe intraarticular fractures of the distal tibia.

These terms encompass a spectrum of skeletal injury ranging from fractures caused by low-energy rotational forces to fractures caused by high-energy axial compression forces arising from motor vehicle accidents or falls from a height.

Rotational variants typically have a more favorable prognosis, whereas high-energy fractures frequently are associated with open wounds or severe, closed, soft-tissue trauma.

Source:Rosen

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