Calcaneus fractures are rare but potentially debilitating injuries. The calcaneus is one of seven tarsal bones and is part of the hind-foot which includes the calcaneus and the talus. The hindfoot articulates with the tibia and fibula creating the ankle joint. The subtalar or calcaneotalar joint accounts for at least some foot and ankle dorsal/plantar flexion. Calcaneal anatomy is demonstrated in Figure 1. Historically a burst fracture of the calcaneus was coined a "Lovers Fracture" as the injury would occur as a suitor would jump off a lovers balcony to avoid detection.
Calcaneal fractures most commonly occur during high energy events leading to axial loading of the bone but can occur with any injury to the foot and ankle. Falls from height and automobile accidents are the predominant mechanisms of injury, although jumping onto hard surfaces, blunt or penetrating trauma and twisting/shearing events may also cause injury. Most of the injuries cause the bone to flatten, widen, and shorten. Stress fractures may occur with over use or repetitive use, such as running.
The epidemiology of tarsal fractures is as follows:
Tarsal fractures account for 2% of all fractures.
Calcaneal fractures account for 50-60% of all fractured tarsal bones.
Less than 10% present as open fractures.
Traditionally, there is a male predominance of injuries due to the industrial nature of the accidents. Recent studies suggest regional variation in male/female predominance due to disparities in the types of regional accident occurrence.
Most patients with calcaneus fractures are young, with the 20-39 age group the most common.
Comorbidities such as diabetes and osteoporosis may increase the risk of all types of fractures.
Calcaneal fractures are rare in children.
Falls from height directly translates energy into the calcaneus on impact as the heel strikes a surface crushing the calcaneus against the talus. The talus acting as a wedge causes depression and widening of the calcaneal body. Similarly, a foot depressed against an accelerator, brake or floor board translates a large amount of force through the calcaneus during high-speed automobile accidents. Fracture patterns are similar in either mechanism. Gunshot wounds and other ballistic injuries cause a more diffuse nonpredictable fracture pattern but remain uncommon. Avulsion fractures require a large amount of twisting or shearing force due to the strength of the ligamentous and tendinous attachments to the calcaneus. The tibial artery and nerve run along the medial aspect of the calcaneal body and are thought to be shielded by the sustenaculum tali thus neurovascular injuries are uncommon with calcaneal fractures.
History and Physical
A traumatic event will almost invariably precede the presentation of calcaneal injury.
Patients will present with diffuse pain, edema, and ecchymosis at the affected fracture site.
The patient is not likely able to bear weight.
Plantar ecchymosis extending through the plantar arch of the foot should raise suspicion significantly.
There may be associated disability of the Achilles tendon, also raising the suspicion of a calcaneus injury.
Evaluation of a potential calcaneus fracture should include the following:
Complete neurovascular examination as well as evaluation of all lower extremity tendon function. Loss of ipsilateral dorsalis pedis or posterior tibial pulse compared to contralateral limb should raise suspicion of arterial injury and prompt further investigation with angiography or Doppler scanning.
Initial bony evaluation with AP, lateral, and oblique plain films of the foot and ankle is needed. A Harris View may be obtained which demonstrates the calcaneus in an axial orientation.
Noncontrast computed tomography remains the gold standard for traumatic calcaneal injuries. CT scan is used for preoperative planning, classification of fracture severity, and in instances where the index of suspicion for a calcaneal fracture is high despite negative initial plain radiographs.
Mondors Sign is a hematoma identified on CT that extends along the sole and is considered pathognomic for calcaneal fracture.
Stress fractures such as those seen in runners would be best evaluated with a bone scan or MRI.
Bohler's Angle may be depressed on plain radiographs. Defined as the angle between two lines drawn on plain film. The first line is between highest point on the tuberosity and the highest point of posterior facet and the second is the highest point on the anterior process and the highest point on the posterior facet. Normal angle is between 20-40 degrees.
The Critical Angle of Gissane may be increased. Defined as the angle between two lines drawn on plain film. The first along the anterior downward slope of the calcaneus and the second along the superior upward slope. A normal angle is 130-145 degrees.
Normal Bohlers and Gissane angles do not rule out a fracture.
Abnormalities of either of these findings should prompt a CT scan for further classification and evaluation of the fracture.
Calcaneal fractures can be classified into two general categories.
Extraarticular fractures account for 25 % of calcaneal fractures. These typically are avulsion injuries of either the calcaneal tuberosity from the Achilles tendon, the anterior process from the bifurcate ligament, or the sustenaculum tali.
Intraarticular Fractures account for the remaining75%. The talus acts as a hammer or wedge compressing the calcaneus at the angle of Gissane causing the fracture.
There are two main classification systems of extraarticular fractures.
Joint depression type with a single verticle fracture line through the angle of Gissane separating the anterior and posterior portions of the calcaneus.
Tongue type which has the same verticle fracture line as a depression type with another horizontal fracture line running posteriorly, creating a superior posterior fragment.
Sanders Classification: Based on reconstituted CT findings.
Type I fractures: 1 nondisplaced or minimally displaced bony fragment
Type II fractures: 2 bony fragments involving the posterior facet. Subdivided into types A, B, and C depending on the medial or lateral location of the fracture line.
Type III fractures: 3 bony fragments including an additional depressed middle fragment. Subdivided into types AB, AC, and BC, depending on the position and location of the fracture lines.
Type IV fractures: 4 comminuted bony fragments.
Treatment / Management
Emergent treatment includes:
Aggressive wound care and antibiotics as needed for contaminated wounds.
ICE and elevation.
Immobilization with splinting.
All patients who are candidates for outpatient treatment are nonweight bearing at discharge.
Open fractures require more urgent surgical treatment and wound care.
Closed fracture reduction can be delayed.
All surgical treatment is aimed at restoration of heel height and width (i.e., reconstructing the anatomy to reapproximate Bohler and Gissane angles), repair and realignment of the subtalar joint, and returning the mechanical axis of the hindfoot to functionality.
Most extraarticular fractures are treated conservatively with 10-12 weeks of casting.
Calcaneal tuberosity avulsion, displaced sustenaculum tali, and large substantial calcaneal body fractures may require operative management.
Some intraarticular injuries may be treated in a closed fashion depending upon severity. Many are treated with either open surgical reduction and internal fixation, percutaneous pinning, or sometimes arthrodesis.
Nondisplaced Sanders type I fractures may be treated in a conservative, closed fashion.
Pearls and Other Issues
Due to the severe nature and the force required to sustain calcaneal fractures concomitant injuries must be considered. Studies have shown greater than 70% of patients with calcaneus fractures have additional injuries.
A thorough evaluation of the entire spine should be performed anytime a calcaneal fracture is identified especially when a fall is a mechanism. The force from impacting the ground translates through the lower extremity and upward sometimes causing spinal compression fractures.
Compartment syndrome of the foot is a rare but severely debilitating complication of calcaneal fractures and can occur in up to 10% of the injuries. A high index of suspicion is needed in considering patients presenting with increased pain either after treatment or during the initial evaluation.
Osteomyelitis, postoperative wound infection, malunion and subtalar arthritisare all potential complications of calcaneal fractures and repair.