Open Reduction and Internal Fixation of Calcaneal Fractures

Michael P. Clare, MD

Dr. Clare or an immediate family member serves as a paid consultant to or is an employee of BESPA Global and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons and the American Orthopaedic Foot & Ankle Society.

PATIENT SELECTION

Indications

Fractures of the calcaneus generally occur in the setting of high-energy trauma, resulting in complex, three-dimensionally oriented fracture patterns. The exact pattern of fracture lines and the extent of comminution are influenced by the position of the foot at impact, the extent of force involved, and the overall bone quality of the patient. Surgical management is generally indicated for displaced intra-articular fractures involving the posterior facet. The primary goal of surgery is anatomic restoration of alignment and return of function without pain. Although a variety of surgical approaches have been described, the extensile lateral approach is currently generally preferred for displaced intra-articular fractures because it consistently allows reduction of the calcaneal body; restoration of calcaneal height, width, and overall morphology, in addition to the posterior facet articular surface where possible; and a late in situ arthrodesis as a means of salvage in the event of posttraumatic arthritis.¹

Contraindications

Nonsurgical management is best reserved for intra-articular fractures that are truly nondisplaced (Sanders type I) on CT.² Other specific indications for nonsurgical management include fractures in patients with severe peripheral vascular disease or type I diabetes mellitus, fractures in patients with medical comorbidities prohibiting surgery, and fractures in elderly patients who are minimal (household) ambulators.³ Chronologic age itself is not necessarily a contraindication to surgical treatment because many older patients are healthy and active well into their 70s.⁴ Nonsurgical management also may be necessary in certain instances in which injury severity precludes early surgical intervention, including fractures associated with severe blistering or massive prolonged edema, fractures with large open wounds, and patients with life-threatening injuries. In these instances, the injury may be managed later as a calcaneal malunion.⁵

PREOPERATIVE IMAGING

Plain Radiography

Plain radiographic evaluation includes a lateral view of the hindfoot, an AP view of the foot, a Harris axial view of the heel, and a mortise view of the ankle. These views should reveal almost any fracture, dislocation, or subluxation in the hindfoot.

Typically, a fracture of the calcaneus is most easily identified on the lateral view of the hindfoot (Figure 1). With an intra-articular fracture, loss of height in the posterior facet is seen. The articular surface is impacted within the body of the calcaneus and is usually rotated anteriorly up to 90° relative to the remaining subtalar joint. A decreased tuber angle of Böhler and an increased crucial angle of Gissane are seen in fracture patterns in which the entire posterior facet is separated from the sustentaculum and depressed; if only the lateral portion of the posterior facet is involved, the split in the articular surface manifests as a double-density sign, in which case the tuber angle of Böhler and the crucial angle of Gissane may remain normal.³ The lateral view also allows delineation as to whether the fracture is a joint depression or a tongue-type fracture.⁶

The AP view of the foot will usually reveal the extension of fracture lines into the calcaneocuboid joint and also may demonstrate anterolateral fragments and expansion of the lateral calcaneal wall. This view otherwise offers only limited information and can thus be omitted in most cases. The Harris axial view of the heel shows a loss of calcaneal height as well as increased width and (typically) varus angulation of the tuberosity fragment. The Harris view also provides visualization of the articular surface. This view is unfortunately difficult to obtain with acute fractures because of pain. A mortise view of the ankle will usually demonstrate involvement of the posterior facet.

Computed Tomography

CT is indicated if the plain radiographs reveal an intra-articular extension of the calcaneal fracture. Images are obtained at 2- to 3-mm intervals in the axial, sagittal, and 30° semicoronal planes.

FIGURE 1 Lateral hindfoot radiographs demonstrate radiographic signs used to assess for a calcaneal fracture. A, A normal tuber angle of Böhler (angle α) is seen in this uninjured foot. B, View of a foot with a calcaneal fracture demonstrates a decreased angle of Böhler. Note also the marked loss of calcaneal height with relative horizontalization of the talus. C, View of a foot with a calcaneal fracture. Impaction of the superolateral fragment manifests as double-density sign (arrows).

The axial or transverse cuts will reveal extension of fracture lines into the anterior process and the calcaneocuboid joint, as well as the sustentaculum tali and the anterior-inferior margin of the posterior facet (Figure 2, A). The sagittal reconstruction views will demonstrate displacement of the tuberosity fragment; the extent of involvement of the anterior process region, including superior displacement of the anterolateral fragment; the anterior rotational displacement of the superolateral posterior facet fragment; and delineation of the fracture as a joint depression or tongue-type pattern⁶ (Figure 2, B). The 30° semicoronal images will show displacement of articular fragments in the posterior facet, the sustentaculum tali, the extent of widening and shortening of the calcaneal body, expansion of the lateral calcaneal wall, varus angulation of the tuberosity, and the position of the flexor hallucis longus and peroneal tendons (Figure 2, C).

FIGURE 2 Axial (A), sagittal (B), and semicoronal (C) CT images delineate typical calcaneal fracture fragments. In the semicoronal image of the injured side (left image of C), note the potential impingement of the expanded lateral wall against the peroneal tendons (arrow). AL = anterolateral; AM = anterior main; PM = posterior main; SL = superolateral; SM = superomedial

PATHOANATOMY

In a displaced intra-articular calcaneal fracture, the loss of height through the calcaneus results in a shortened and widened heel, classically with varus malalignment of the tuberosity. This loss of height is reflected in a decreased tuber angle of Böhler, such that the normal declination of the talus is diminished and the talus becomes relatively more horizontal, which leads to secondary loss of ankle dorsiflexion (Figure 1, B). As the superolateral fragment of the posterior facet is impacted plantarward, the thin lateral wall explodes laterally just posterior to the crucial angle of Gissane. This lateral wall expansion may trap the peroneal tendons against the lateral malleolus and also affect subtalar motion; in some cases, a violent contracture of the peroneal tendons may avulse the tendon sheath from the fibula, resulting in an avulsion fracture of the lateral malleolus and dislocation of the peroneal tendons.
The anterior process typically displaces superiorly, which directly limits subtalar joint motion by impinging against the lateral process of the talus.

Clarification of fragment terminology is necessary to understand the pathoanatomy of displaced intra-articular calcaneal fractures (Figure 2). The anterolateral fragment encompasses the lateral wall of the anterior process, is typically pyramidal in shape, and may include a portion of the calcaneocuboid articular surface. The anterior main fragment is the large fragment anterior to the primary fracture line, which usually includes the anterior portion of the sustentaculum and the anterior process. The superomedial fragment, also known as the sustentacular, or constant, fragment, is the fragment of variable size found posterior to the primary fracture line; this fragment almost always remains attached to the talus through the deltoid ligament complex and is therefore stable. The superolateral fragment, also referred to as the semilunar (comet) fragment, is the lateral portion of the posterior facet that is sheared from the remaining posterior facet in joint depression fractures. The tongue fragment refers to the superolateral fragment that remains attached to a portion of the posterior tuberosity, including the Achilles tendon insertion, and is found in tongue-type fractures. The posterior main fragment represents the posterior tuberosity.

FRACTURE-DISLOCATION PATTERNS

Fracture-dislocation patterns, which occur when the superolateral fragment remains contiguous with the lateral wall and the posterior tuberosity, are relatively rare.⁷ The resulting large posterolateral fragment dislocates laterally and is forcefully driven into the talofibular joint, often producing a fracture of the lateral malleolus, dislocation of the peroneal tendons, and disruption of the lateral ligamentous complex of the ankle. The hindfoot inverts through the ankle joint as the limb recoils; this is seen on plain radiographs as increased lateral talar tilt. The fracture pattern, which is confirmed on CT evaluation (Figure 3), is most commonly a simple two-part split fracture, such that as the dislocation is reduced, the articular fragments typically align anatomically. As with most dislocations, the sooner it is reduced, the easier the reduction tends to be; with delayed treatment, a formal open reduction will usually be required.⁸

PROCEDURE

Resolution of Soft-tissue Swelling

Surgery is ideally performed within the first 3 weeks after injury, before early consolidation of the fracture. Once consolidation ensues, the fragments become increasingly difficult to separate to obtain an adequate reduction, and the articular cartilage may delaminate from the underlying subchondral bone. Surgery must be delayed, however, until the associated soft-tissue swelling has adequately dissipated, which may require up to 3 weeks. Splint immobilization and limb elevation are performed initially, and the patient is later converted to a compression stocking and a fracture boot. Full resolution of soft-tissue edema is demonstrated by the wrinkle test; a positive result indicates that surgical intervention may be safely undertaken.³

FIGURE 3 Semicoronal CT image demonstrates a variant calcaneal fracture-dislocation pattern. Note the posterolateral fragment wedged within the talofibular joint (black arrow) and the varus tilt of the talus within the ankle mortise (white arrow).

Room Setup/Patient Positioning

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