CALCANEUS FRACTURES

EPIDEMIOLOGY

Calcaneus fractures account for approximately 1% to 2% of all fractures.

The calcaneus, or os calcis, is the most frequently fractured tarsal bone.

• Represents 60% of all tarsal fractures in adults

Annual incidence of calcaneal fractures is 11.5 per 100,000 people.

The male to female ratio is 2.4:1.

• Peak incidence is in males aged 20 to 29.

• Displaced intra-articular fractures comprise 60% to 75% of calcaneus fractures. Approximately 10% of calcaneus fractures are open injuries.

Approximately 70% of calcaneal fractures resulted from falls.

ANATOMY

The articular surface contains three facets that articulate with the talus. The posterior facet is the largest and constitutes the major weight-bearing surface. The middle facet is located anteromedially on the sustentaculum tali. The anterior facet is often confluent with the middle facet.

Between the middle and posterior facets lies the interosseous sulcus (calcaneal groove), which, with the talar sulcus, forms the sinus tarsi.

The sustentaculum tali support the neck of the talus medially; it is attached to the talus by the interosseus talocalcaneal and deltoid ligaments and contains the middle articular facet on its superior aspect. The flexor hallucis longus tendon passes beneath the sustentacular tali medially.

The peroneal tendons pass laterally between the calcaneus and the lateral malleolus.

The Achilles tendon attaches to the posterior tuberosity.

MECHANISM OF INJURY

Axial loading: Falls from a height are responsible for most intra-articular fractures; they occur as the talus is driven down into the calcaneus, which is composed of a thin cortical shell surrounding cancellous bone. In motor vehicle accidents, calcaneus fractures may occur when the accelerator or brake pedal impacts the plantar aspect of the foot.

Twisting forces may be associated with extra-articular calcaneus fractures, in particular fractures of the anterior and medial processes or the sustentaculum. In diabetic patients, there is an increased incidence of tuberosity fractures from avulsion by the Achilles tendon.

CLINICAL EVALUATION

Patients typically present with moderate to severe heel pain, associated with tenderness, swelling, heel widening, and shortening. Ecchymosis around the heel extending to the arch is highly suggestive of calcaneus fracture. Blistering may be present and results from massive swelling usually within the first 36 hours after injury. Open fractures are rare, but when present, they occur medially.

Careful evaluation of soft tissues and neurovascular status is essential. Compartment syndrome of the foot must be ruled out because it occurs in up to 10% of calcaneus fractures and may result in clawing of the lesser toes.

Associated Injuries

Up to 50% of patients with calcaneus fractures may have other associated injuries, including lumbar spine fractures (10%) or other fractures of the lower extremities (25%); intuitively, these injuries are more common in higher energy injuries.

Bilateral calcaneus fractures are present in 5% to 10% of cases.

RADIOGRAPHIC EVALUATION

The initial radiographic evaluation of the patient with a suspected calcaneus fracture should include a lateral view of the hindfoot, an anteroposterior (AP) view of the foot, a Harris axial view, and an ankle series.

Lateral radiograph

• The Böhler angle is composed of a line drawn from the highest point of the anterior process of the calcaneus to the highest point of the posterior facet and a line drawn tangential from the posterior facet to the superior edge of the tuberosity. The angle is normally between 20 and 40 degrees; a decrease in this angle indicates that the weight-bearing posterior facet of the calcaneus has collapsed, thereby shifting body weight anteriorly (Fig. 39.1).

• The Gissane (crucial) angle is formed by two strong cortical struts extending laterally, one along the lateral margin of the posterior facet and the other extending anterior to the beak of the calcaneus. These cortical struts form an obtuse angle usually between 105 and 135 degrees and are visualized directly beneath the lateral process of the talus; an increase in this angle indicates collapse of the posterior facet (Fig. 39.2).

   

   

   

   

   

AP radiograph of the foot: This may show extension of the fracture line into the calcaneocuboid joint.‌

Harris axial view

• This is taken with the foot in dorsiflexion and the beam angled at 45 degrees cephalad.

• It allows visualization of the joint surface as well as loss of height, increase in width, and angulation of the tuberosity fragment, usually in varus (Fig. 39.3).

   

   

   

Broden views have been replaced by computed tomography (CT) scanning. They are utilized intraoperatively to assess reduction. These are obtained with the patient supine and the x-ray cassette under the leg and the ankle. The foot is in neutral flexion, and the leg is internally rotated 15 to 20 degrees (Mortise). The x-ray beam is then centered over the lateral malleolus, and four radiographs are made with the tube angled 40, 30, 20, and 10 degrees toward the head of the patient.

• These radiographs show the posterior facet as it moves from posterior to anterior; the 10-degree view shows the posterior portion of the facet, and the 40-degree view shows the anterior portion.

Computed tomography

• CT images are obtained in the axial, 30-degree semicoronal, and sagittal planes.

• Two- to 3-mm slices are necessary for adequate analysis.

• The coronal views provide information about the articular surface of the posterior facet, the sustentaculum, the overall shape of the heel, and the position of the peroneal and flexor hallucis tendons (Fig. 39.4).

• The axial views reveal information about the calcaneocuboid joint, the anteroinferior aspect of the posterior facet, and the sustentaculum.

• Sagittal reconstruction views provide additional information on the posterior facet, the

  calcaneal tuberosity, and the anterior process.

   

   

   

  CLASSIFICATION

  Extra-Articular Fractures

  These do not involve the posterior facet. They make up 25% to 30% of calcaneus fractures.

Anterior process fractures: These may result from strong plantar flexion and inversion, which tighten the bifurcate and interosseous ligaments leading to avulsion fracture; alternatively, they may occur with forefoot abduction with calcaneocuboid compression. They are often confused with lateral ankle sprain and are seen on lateral or lateral oblique views.

Tuberosity fractures: These may result from avulsion by the Achilles tendon, especially in diabetic patients or osteoporotic women, or, rarely, by direct trauma; they are seen on lateral radiographs.

Medial process fractures: These vertical shear fractures are due to loading of heel in valgus; they are seen on axial radiographs.

Sustentacular fractures: These occur with heel loading accompanied by severe foot inversion. They are often confused with medial ankle sprain and are seen on axial radiographs.

Body fractures not involving the subtalar articulation: These are caused by axial loading. Significant comminution, widening, and loss of height may occur along with a reduction in the Böhler angle without posterior facet involvement.

Intra-Articular Fractures

Essex–Lopresti Classification (Fig. 39.5)

Primary Fracture Line

The posterolateral edge of the talus splits the calcaneus obliquely through the posterior facet. The

fracture line exits anterolaterally at the crucial angle or as far distally as the calcaneocuboid joint. Posteriorly, the fracture moves from plantar medial to dorsal lateral, producing two main fragments: the sustentacular (anteromedial) and tuberosity (posterolateral) fragments.

The anteromedial fragment is rarely comminuted and remains attached to the talus by the deltoid and interosseous talocalcaneal ligaments.

The posterolateral fragment usually displaces superolaterally with variable comminution, resulting in incongruity of the posterior facet as well as heel shortening and widening.

Secondary Fracture Line

With continued compressive forces, there is additional comminution, creating a free lateral piece of posterior facet separate from the tuberosity fragment.

Tongue-type fracture: A secondary fracture line appears beneath the facet and exits posteriorly through the tuberosity.

Joint depression fracture: A secondary fracture line exits just behind the posterior facet.

Continued axial force causes the sustentacular fragment to slide medially, causing heel shortening and widening. As this occurs, the tuberosity fragment will rotate into varus. The posterolateral aspect of the talus will force the free lateral piece of the posterior facet down into the tuberosity fragment, rotating it as much as 90 degrees. This causes lateral wall blowout, which may extend as far anteriorly as the calcaneocuboid joint. As the lateral edge of the talus collapses further, there will be additional comminution of the articular surface.

Sanders Classification (Fig. 39.6)

This is based on CT scan.

This classification is based on the number and location of articular fragments; it is based on the coronal image, which shows the widest surface of the posterior facet of the talus.

The posterior facet of the calcaneus is divided into three fracture lines (A, B, and C, corresponding to lateral, middle, and medial fracture lines on the coronal image).

Thus, there can be a total of four potential pieces: lateral, central, medial, and sustentaculum tali.

Type I: All nondisplaced fractures regardless of the number of fracture lines

Type II: Two-part fractures of the posterior facet; subtypes IIA, IIB, IIC, based on the location of the primary fracture line

Type III: Three-part fractures with a centrally depressed fragment; subtypes IIIAB, IIIAC, IIIBC

Type IV: Four-part articular fractures; highly comminuted

Orthopaedic Trauma Association Classification of Calcaneal Fractures See Fracture and Dislocation Classification Compendium at http://www.ota.org/compendium/compendium.html.

TREATMENT

Despite adequate reduction and treatment, fractures of the os calcis may be severely disabling injuries, with variable prognoses and degrees of functional debilitation with chronic pain issues. Treatment remains controversial. Recent evidence has elucidated several factors associated with improved outcomes.

Nonoperative

Indications include:

• Nondisplaced or minimally displaced extra-articular fractures

• Nondisplaced intra-articular fractures

• Anterior process fractures with less than 25% involvement of the calcaneal–cuboid articulation

• Fractures in patients with severe peripheral vascular disease or insulin-dependent diabetes

• Fractures in patients with other medical comorbidities prohibiting surgery

• Fractures associated with blistering and massive prolonged edema, large open wounds, or life-threatening injuries

Initial treatment is placement of a bulky Jones dressing.

Nonoperative treatment consists of a supportive splint to allow dissipation of the initial fracture hematoma, followed by conversion to a prefabricated fracture boot locked in neutral flexion to prevent an equinus contracture and an elastic compression stocking to minimize dependent edema.

Early subtalar and ankle joint range-of-motion exercises are initiated, and non–weight-bearing restrictions are maintained for approximately 10 to 12 weeks, until radiographic union.

Operative

Indications

• Displaced intra-articular fractures involving the posterior facet

• Anterior process of the calcaneus fractures with >25% involvement of the calcaneal–cuboid articulation

• Displaced fractures of the calcaneal tuberosity, with or without skin compromise

• Fracture-dislocations of the calcaneus

• Open fractures of the calcaneus

Timing of surgery

• Surgery should be performed within the initial 3 weeks of injury, before early fracture consolidation.

• Surgery should not be attempted until swelling in the foot and ankle has adequately dissipated,

  as indicated by the reappearance of skin wrinkles.

Approach

• Lateral “L” incision based on the blood supply of the lateral calcaneal artery

   

  Specific Fractures

  Extra-Articular Fractures

Anterior process fractures (Fig. 39.7)

• Surgical management of anterior process fractures is performed for fractures involving >25% of the calcaneal–cuboid articulation on CT scan evaluation.

• Definitive fixation involves small or mini-fragment screws.

• The patient may ambulate in a hard-soled shoe, but regular shoes are discouraged for 10 to 12 weeks postoperatively.

   

   

   

Tuberosity (avulsion) fractures

• These result from a violent pull of the gastrocnemius–soleus complex, such as with forced dorsiflexion secondary to a low energy stumble and fall, producing an avulsed fragment of variable size.

• Indications for surgery: (1) the posterior skin is at risk from pressure from the displaced tuberosity, (2) the posterior portion of the bone is extremely prominent and will affect shoe wear, (3) the gastrocnemius–soleus complex is incompetent, or (4) the avulsion fragment involves the articular surface of the joint.

• Surgical treatment involves lag screw fixation with or without cerclage wire.

Calcaneus body fractures

• True extra-articular fractures of the calcaneus, not involving the subtalar joint, probably account for 20% of all calcaneal fractures.

• Minimally displaced fractures (<1 cm) are treated with early motion and non–weight bearing for

  10 to 12 weeks.

• Those with significant displacement resulting in varus/valgus deformity, lateral impingement, loss of heel height, or translation of the posterior tuberosity require open reduction and internal fixation.

Medial process fractures

• These are rare and usually nondisplaced.

• The fracture is best seen on the axial radiographic view or on coronal CT scans.

• Nondisplaced fractures can be treated with a short leg weightbearing cast until the fracture heals at 8 to 10 weeks.

• When fractures are displaced, closed manipulation may be considered.

  Intra-Articular Fractures

  The Canadian Orthopaedic Trauma Society trial comparing operative to nonoperative treatment of displaced intra-articular calcaneal fractures found the following:

Significantly better results occurred in patients with certain fracture groups undergoing operative treatment.

• Women

• Younger adults

• Patients with a lighter workload

• Patients not receiving Worker’s Compensation

• Patients with a higher initial Böhler angle (less severe initial injury)

• Those with an anatomic reduction on postoperative CT evaluation

Those having nonoperative treatment of their fracture were 5.5 times more likely to require a subtalar arthrodesis for posttraumatic arthritis than those undergoing operation.

Operative goals include:

1. Restoration of congruity of the subtalar articulation

2. Restoration of the Böhler angle

3. Restoration of the normal width and height of the calcaneus

4. Maintenance of the normal calcaneocuboid articulation

5. Neutralization of the varus deformity of the fracture

Open reduction and internal fixation are generally performed through a lateral L-shaped incision, with care taken not to damage the sural nerve both proximally and distally.

The posterior facet is reduced and stabilized with lag screws into the sustentaculum tali. The calcaneocuboid joint and the lateral wall are reduced. The length of the heel is regained with neutralization of varus. A thin plate is placed laterally and is used as a buttress. Bone void filling of the defect is not required but may be associated with earlier weight bearing.

Good results have been reported for tongue-type fractures using percutaneous reduction (Essex–Lopresti maneuver) and lag screw fixation (Fig. 39.8).

Primary subtalar or triple arthrodesis has had good reported results for select high-energy injuries (type 4).

Postoperative management includes:

• Early supervised subtalar range-of-motion exercises

• Non–weight bearing for 8 to 12 weeks

• Full weight bearing by 3 months

   

  COMPLICATION

Wound dehiscence: Most common at the angle of incision. Avoidance requires meticulous soft tissue technique and minimization of skin trauma during closure. It may be treated with wet to dry dressing changes, skin grafting, or muscle flap if necessary.

Calcaneal osteomyelitis: The risk may be minimized by allowing soft tissue edema to resolve preoperatively.

Posttraumatic arthritis (subtalar or calcaneocuboid): This reflects articular damage in addition to fracture displacement and comminution; thus, it may occur even in the presence of an anatomic reduction; it may be treated with injections or orthoses, or it may ultimately require subtalar or triple arthrodesis.

Increased heel width: Some degree of heel widening is expected, even with open reduction and internal fixation. It may result in lateral impingement on the peroneal tendons or the fibula. It is aggravated by increased residual lateral width and may be treated by wall resection or hardware removal.

Loss of subtalar motion: This is common with both operative and nonoperative treatment of intra-articular fractures.

Peroneal tendonitis: This is generally seen following nonoperative treatment and results from lateral impingement.

Sural nerve injury: This may occur in up to 15% of operative cases using a lateral approach.

Chronic pain: Despite nonoperative or operative treatment of calcaneal fractures, many patients have chronic heel pain that may be debilitating; many individuals are unable to return to gainful employment.

Complex regional pain syndrome: This may occur with operative or nonoperative management.