Background

 

Anatomy

 

Facets	Tuberosities	Process
Posterior facet / subtalar joint	Posterior - tendoacilles	Anterior - calcaneocuboid joint
Middle facet (sustenaculum tali)	Medial - adductor hallucis, plantar fascia
Anterior facet	Lateral  - abductor digiti minimi

 

Etiology

 

Usually fall from height - calcaneum driven up against talus

 

Epidemiology

 

10% bilateral

10% associated with lumbar spine fracture

 

Fracture patterns

 

Primary fracture line

- lateral process of talus driven into crucial angle

- starts at lateral wall near tarsal sinus

- passes obliquely across posterior facet

- exits at medial wall posterior to sustentaculum tali

 

Secondary fracture lines 

- passes immediately behind the posterior facet of the subtalar joint              

- exits posterior to posterior facet & anterior to tendoachilles insertion

- creates thalamic portion containing posterior facet

 

Common fracture fragments

Sustanacular	Superolateral	Lateral wall	Posterior tuberosity
Superomedial	Lateral fragment of posterior facet		Tongue fracture
Attached to talus by deltoid ligament	Thalamic fragement		Secondary fracture line exits below tendoacilles

 

 

X-ray Views

 

Lateral	Oblique view
Bohler's angle Crucial angle of Guisane	Calcaneocuboid joint

 

Harris axial view	Broden's view
45o axial of heel - normally hindfoot 10o of valgus - assess varus malalignment & heel width	Internally rotate foot 45 degrees - ankle neutral initially - plantar flex the foot 10° increments from 10° to 40   Useful intra-op to assess congruency of subtalar joint

 

Xray Angles

 

Bohler's angle  (20-40°)

 

Lateral xray

 

Highest point anterior process - highest point on posterior facet - highest point on tuberosity

- represents the height of the calcaneus

- normal 20-40°

 

Angle of </=0° is associated with a poor outcome

 

Normal Bohler's angle

 

Calcaneal fracture with Bohler's angle < 0

 

Crucial Angle Gissane (120-140°)

 

Lateral xray

 

Posterior facet of calcaneum - anterior process of calcaneum

 

Normal angle of Gissane

 

Reduced angle of Gissane after fracture

 

CT scan

 

Coronal	Sagittal	Axial
Posterior facet / number of fragments Sustenaculum tali Heel widening	Bohlers angle Posterior facet depression / angulation	Calcaneocuboid joint Sustenaculum tali

 

Sanders Coronal CT Classification

 

Posterior facet on coronal CT

- number of longitudinal fracture lines (Type II - IV)

- location of fractures (A: lateral, B: central, C: medial)

 

Type I	Type II	Type III	Type IV
Undisplaced	Two parts Displaced > 2 mm	Three parts Displaced > 2 mm	Highly comminuted
Non operative	ORIF	ORIF / fusion	Primary fusion