45 Calcaneus Fractures
History and physical examination
Moderate to severe hindfoot pain is common.
Rule out associated ankle injuries (i.e., peroneal tendon subluxation, fractures).
Head-to-toe clinical examination is necessary to diagnosis other associated injuries.
Fracture swelling is expected and greatest within the first 72 hours.
i. Acute foot compartment syndrome can occur (10%) with missed diagnosis resulting in lesser toe clawing; fasciotomies are controversial (refer to Chapter 13, Compartment Syndrome, for additional information).
Resolution of swelling can dictate timing and surgical approach.
Typically localized at the heel and into the midfoot arch.
Skin at risk:
Fracture blisters (▶ Fig. 45.1 ):
i. Occur within 24 to 72 hours; blood-filled (vs. serous) blisters indicate deeper intradermal injury.
i. Most concerning in posterior tuberosity avulsion or certain tongue-type fractures. Emergent surgical reduction with fixation is critical to prevent the difficult sequelae of full-thickness heel skin necrosis.
ii. Lateral wall blowout can result in inside-out skin pressure; may require external fixation.
Open traumatic wounds—typically on the medial side with transverse/oblique orientation.
Sural nerve paresthesias occur secondary to lateral wall blowout.
Medial more often than lateral plantar nerve paresthesias result from compartment syndrome, open medial wounds, or entrapment within the fracture.
Vascular arterial transection or injury is rare.
Complete head-to-toe physical examination is warranted with high-energy injuries.
Spine injuries are common with falls from a height (X-rays ± CT).
Ipsilateral lower extremity or other appendicular injuries do occur.
Epidemiology and fracture anatomy
The os calcis is the most commonly fractured tarsal bone.
Extra-/intra-articular patterns depend upon the mechanism of injury and energy.
Open fractures occur in up to 17% of patients, often with transverse or oblique medial wounds.
Bilateral calcaneal fractures occur in 5 to 10% of patients.
Associated injuries are common: axial spine (~10%) and lower extremities (~26%).
Mechanism of injury and fracture lines:
Axial loading injury:
i. Falls from a height often lead to displaced intra-articular calcaneal fractures (DIACFs) as the lateral talar process is driven into the calcaneus to create primary and secondary fracture lines.
Have a high clinical suspicion for associated injuries (spine and lower extremities).
Thorough patient secondary survey examination is warranted.
Primary fracture line divides the posterior facet due to oblique shear forces from anterolateral (critical angle) to posteromedial (▶ Fig. 45.2 ).
Constant fragment (anteromedial)—includes the sustentaculum tali and typically remains anatomic (“constant”) due to ligamentotaxis; may include the middle and anterior facets in less comminuted patterns.
Posterolateral fragment—includes a variable portion of the posterior facet and the posterior tuberosity, comminution includes lateral wall.
Secondary fracture lines—variable and occur with increasing energy.
Tongue-type—sagittal transverse line ± intra-articular involvement (▶ Fig. 45.3 ).
Joint depression—variable size/number of posterior facet fragments.
Lateral wall blowout—occurs with increasing posterior facet depression and creates subfibular impingement due to increased heel width.
ii. Motor vehicle accidents result from pedal or floorboard impaction into the plantar foot surface with variable fracture patterns (as described earlier).
i. Usually a variety of extra-articular fracture patterns affecting the anterior process and calcaneocuboid joint or the sustentaculum.
Posterior tuberosity avulsion injury/tongue-type variants:
i. Result of a strong eccentric contraction of the triceps surae with an avulsion fracture of the Achilles tendon insertion at the posterior tuberosity with varying size.
ii. Urgent surgical fixation is warranted to prevent full skin necrosis.
The os calcis is an asymmetrically shaped bone with four important but irregular articulations to the talus and cuboid. Fracture patterns may disrupt the normal hindfoot function (▶ Fig. 45.4 ).
The subtalar joint:
Posterior facet—largest and primary weight-bearing surface with mildly convex shape.
Anterior and middle facets may be confluent.
The calcaneocuboid joint:
Contributes to hindfoot–midfoot inversion and eversion.
Subluxation often reduces via ligamentotaxis following restoration of calcaneal height and length but may warrant open reduction and fracture-specific fixation.
Dense cortical bone contained within the medial “constant” fragment.
Flexor hallucis longus (FHL) runs directly below—at risk for injury with excessive screw length.
Deltoid and talocalcaneal ligament attachments.
Provides calcaneal height, length, and width (often disrupted in fractures).
Supports the posterior facet.
Supports anterior and middle facets, articulates with calcaneocuboid joint.
Irregularly flat’ cortical surface with peroneal tendon tubercle at risk for lateral displacement and resulting subfibular impingement pain.
Foot and ankle anteroposterior/lateral/oblique views to access adjacent joints:
i. Bohler’s angle (normal 20–40 degrees)—lateral radiographic angle between tangent line from superior aspect anterior process to crest of posterior facet and line from posterior facet to top of posterior tuberosity (▶ Fig. 45.5 ). Lower angles associated with greater intra-articular depression, increased fracture complexity, poorer functional scores, and increased risks for subtalar arthritis (▶ Fig. 45.6 ).
ii. Critical angle of gissane (normal 95–105 degrees)—lateral radiographic angle denoting dense cortical bone supporting the lateral talar process (▶ Fig. 45.5 ). Disruption associated with greater fracture comminution dividing the anterior, middle, and posterior facets.
Axial (Harris) view (▶ Fig. 45.2 ):
i. Foot maximally dorsiflexed and beam directed 45 degrees cranial.
ii. Visualizes heel axial alignment (normal 10-degree valgus).
iii. Useful to assess: varus, tuberosity shortening/widening, medial comminution, and lateral wall blowout.
Broden’s views: intraoperative adjunct (▶Fig. 45.7d ):
i. Ankle in neutral dorsiflexion with 30-degree internal rotation and X-rays taken at various degrees of cranial inclination (10–40 degrees).
ii. Allows for visualization of the posterior facet reduction and safe fixation.
Typical DIACF X-ray findings include decreased Bohler’s angle, increased angle of Gissane, calcaneal shortening (length and height), heel widening (hindfoot varus), and various degrees of comminution at the constant fragment and lateral wall.
Gold standard adjunct for fracture classification and preoperative planning.
Indicated for all DIACFs; basis for Sanders’ classification (described later).
Extra-articular fractures (25%):
Anterior process fractures visible on lateral X-ray; present like lateral ankle sprain.
Calcaneal tuberosity (Achilles avulsion) fracture—visible on lateral X-ray; urgent fixation.
Sustentacular fractures—visible on axial X-ray; present like medial ankle sprain.
Intra-articular fractures (75%):
Essex–Lopresti classification—based upon secondary fracture line on lateral X-ray:
i. Joint depression—posterior tuberosity is not attached to the posterior facet.
ii. Tongue type—posterior tuberosity is attached to the posterior facet (▶ Fig. 45.7a–e ).
Sanders’ classification—based on the number/location of posterior facet fragments seen on coronal CT image denoting the widest portion of the inferior talar facet. Three potential fracture lines (A, B, and C) with four possible fragments (lateral, middle, medial, sustentacular; ▶ Fig. 45.8 ):
i. Type I—nondisplaced fractures (rare); nonoperative.
ii. Type II—two fracture fragments; consider open reduction and internal fixation (ORIF) in appropriate patient.
iii. Type III—three fracture fragments; consider ORIF in appropriate patient.
iv. Type IV—highly comminuted; consider ORIF ± primary ST fusion in ideal patient.