SUMMARY
Calcaneal fractures are the most common fractures of the tarsal bones and typically result from high-energy axial loading mechanisms such as falls from height or motor vehicle collisions. Due to the complex anatomy of the calcaneus and its critical role in hindfoot alignment and subtalar joint function, these fractures are associated with a high rate of morbidity and long-term functional limitation.
Approximately 70–75% of calcaneal fractures are intra-articular and involve the posterior facet of the subtalar joint. Fracture displacement, degree of comminution, and the condition of the surrounding soft tissues are the primary determinants of treatment strategy and prognosis.
EPIDEMIOLOGY
Incidence
• Most common fracture of the tarsal bones
• Accounts for approximately 60% of all tarsal fractures
• Represents 1–2% of all fractures overall
• 60–75% are intra-articular fractures
• Calcaneal tuberosity fractures account for 1–3%
Associated Injuries
• Lumbar spine compression fractures (≈10%)
• Contralateral calcaneal fractures (≈10%)
• Calcaneocuboid joint involvement (≈60%)
• Peroneal tendon instability due to superior peroneal retinaculum disruption
ETIOLOGY & MECHANISM OF INJURY
Intra-Articular Fractures
• High-energy axial loading
– Fall from height
– Motor vehicle collision
• Vertical force transmitted from the talus to the calcaneus
• Leads to collapse of posterior facet and widening of the hindfoot
Calcaneal Tuberosity Fractures
• Violent concentric contraction of the triceps surae
• Forced dorsiflexion with knee in full extension
• Poor bone quality or osteoporosis
• Increased risk of posterior heel skin compromise
Stress Fractures
• Repetitive loading with increased physical activity
• Often associated with relative energy deficiency
Anterior Process Fractures
• Twisting mechanism
• Avulsion of the bifurcate ligament
PATHOANATOMY
Intra-Articular Fractures
• Primary fracture line produces two main fragments
– Superomedial fragment (constant fragment)
– Contains sustentaculum tali
– Stabilized by strong medial talocalcaneal and interosseous ligaments
– Superolateral fragment
– Contains posterior facet articular surface
• Secondary fracture lines determine fracture morphology
– Joint-depression type
– Tongue-type
Extra-Articular Fractures
• Typically avulsion injuries
• Common in osteopenic or osteoporotic bone
• Often involve Achilles tendon insertion
ANATOMY
Articular Surfaces
• Posterior facet
– Largest articular surface
– Primary weight-bearing interface with the talus
• Middle facet
– Located on sustentaculum tali
– Anteromedial position
• Anterior facet
– Often confluent with the middle facet
Key Anatomic Structures
• Sustentaculum tali
– Medial bony projection supporting the talar neck
– Forms the constant fragment
• Flexor hallucis longus tendon
– Courses inferior and medial to posterior facet
– At risk of entrapment or iatrogenic injury
• Sinus tarsi
– Formed by calcaneal and talar sulci
– Important surgical corridor
CLASSIFICATION
Essex–Lopresti Classification
• Tongue-type fracture
– Posterior facet remains attached to tuberosity
– High risk of posterior skin necrosis
• Joint-depression fracture
– Posterior facet displaced independently
Sanders Classification (CT-based)
• Type I – Nondisplaced posterior facet
• Type II – Two articular fragments
• Type III – Three articular fragments
• Type IV – Comminuted with ≥4 fragments
Increasing Sanders type correlates with worse functional outcomes and higher risk of post-traumatic arthritis.
PRESENTATION
Symptoms
• Severe heel pain
• Rapid swelling
• Inability to bear weight
Physical Examination
• Diffuse hindfoot edema and ecchymosis
• Widened and shortened heel
• Varus deformity
• Plantar ecchymosis (Mondor sign)
• Posterior heel skin tenting in tuberosity fractures
• Assess for compartment syndrome (rare but severe)
IMAGING
Radiographs
• AP, lateral, and oblique foot views
• Harris axial view
Key findings
• Decreased Böhler’s angle (normal 20–40°)
• Increased Gissane’s angle (normal 120–145°)
• Lateral wall blowout
• Varus tuberosity deformity
CT Scan
• Gold standard imaging modality
• 2–3 mm cuts recommended
Views
• Semicoronal – posterior facet involvement
• Axial – calcaneocuboid joint and width
• Sagittal – tuberosity displacement
TREATMENT
Nonoperative Treatment
• Immobilization in cast
• Strict non–weight bearing
Indications
• Sanders Type I fractures
• Small extra-articular fractures
• Calcaneal stress fractures
• High-risk surgical patients (smokers, diabetes, PVD)
Operative Treatment
• Closed reduction and percutaneous fixation
• ORIF (extensile lateral or sinus tarsi approach)
• Arthroscopic-assisted reduction
• Primary subtalar arthrodesis for Sanders Type IV
Goals of Surgery
• Restore calcaneal height and Böhler’s angle
• Restore subtalar joint congruity
• Correct hindfoot varus
• Minimize soft tissue complications
COMPLICATIONS
• Wound complications (10–25%)
• Subtalar arthritis
• Peroneal tendon impingement
• Sural nerve injury
• Malunion with loss of height and lateral impingement
PROGNOSIS
Functional outcome depends on fracture severity, quality of articular reduction, and soft tissue management.
Higher Sanders classification, smoking, bilateral fractures, and severe comminution are associated with poorer outcomes and increased likelihood of secondary subtalar arthrodesis.