Key points

Introduction

The optimal treatment of displaced intraarticular calcaneus fractures (DIACFs) remains a subject of debate among orthopedic surgeons. These fractures account for nearly 75% of all calcaneus fractures and are associated with unpredictable, and relatively poor, short- and long-term clinical outcomes. The social and economic impact of DIACFS is substantial on both an individual and societal level. The overwhelming majority of these fractures tend to involve young males, many of whom—an estimated 55%—earn a living by performing manual labor. Many remain incapacitated for 3 to 5 years after injury, and never return to their preinjury employment or level of activity. Analysis of Short Form (SF)-36 scores of these patients at 2 years after injury has demonstrated similar functional levels to those of patients who underwent organ transplantation or suffered from myocardial infarction.

Prospective, randomized trials concerning the management of DIACFs have shown somewhat equivocal results of operative versus nonoperative treatment. However, more recent trends in the literature (particularly recent metaanalyses and longer term follow-up studies) have suggested that anatomic reduction and stable fixation results in better outcomes in terms of early restoration of function, patient satisfaction, minimization of symptomatic posttraumatic arthritis, and better results of subtalar fusion in the setting of posttraumatic arthritis.

Unfortunately, there is no “one-size-fits-all” approach to the operative management of calcaneus fractures, nor is there a “one size fits many” approach. DIACFs pose unique and complex challenges from an operative standpoint, even for the experienced orthopedic surgeon. Careful consideration of soft tissue characteristics, fracture pattern, timing of surgery, surgical approach, and patient demographics is essential to optimizing outcomes in theses fractures. Additionally, the surgeon must be aware of and prepared to treat concurrent pathology that has a tendency to be overlooked at the time of initial injury—specifically calcaneocuboid joint (CCJ) involvement and peroneal tendon dislocation.

Introduction

The optimal treatment of displaced intraarticular calcaneus fractures (DIACFs) remains a subject of debate among orthopedic surgeons. These fractures account for nearly 75% of all calcaneus fractures and are associated with unpredictable, and relatively poor, short- and long-term clinical outcomes. The social and economic impact of DIACFS is substantial on both an individual and societal level. The overwhelming majority of these fractures tend to involve young males, many of whom—an estimated 55%—earn a living by performing manual labor. Many remain incapacitated for 3 to 5 years after injury, and never return to their preinjury employment or level of activity. Analysis of Short Form (SF)-36 scores of these patients at 2 years after injury has demonstrated similar functional levels to those of patients who underwent organ transplantation or suffered from myocardial infarction.

Prospective, randomized trials concerning the management of DIACFs have shown somewhat equivocal results of operative versus nonoperative treatment. However, more recent trends in the literature (particularly recent metaanalyses and longer term follow-up studies) have suggested that anatomic reduction and stable fixation results in better outcomes in terms of early restoration of function, patient satisfaction, minimization of symptomatic posttraumatic arthritis, and better results of subtalar fusion in the setting of posttraumatic arthritis.

Unfortunately, there is no “one-size-fits-all” approach to the operative management of calcaneus fractures, nor is there a “one size fits many” approach. DIACFs pose unique and complex challenges from an operative standpoint, even for the experienced orthopedic surgeon. Careful consideration of soft tissue characteristics, fracture pattern, timing of surgery, surgical approach, and patient demographics is essential to optimizing outcomes in theses fractures. Additionally, the surgeon must be aware of and prepared to treat concurrent pathology that has a tendency to be overlooked at the time of initial injury—specifically calcaneocuboid joint (CCJ) involvement and peroneal tendon dislocation.

Anatomic considerations

An understanding of the anatomy of the calcaneus and its surrounding structures is critical to understanding mechanisms of fracture, characteristic fracture patterns, surgical approaches, and long-term sequela of injury.

The calcaneus is the largest and the most frequently fractured tarsal bone. It has several soft tissue attachments that render it integral to weight-bearing and overall gait mechanics. The Achilles tendon attaches to the posterior inferior aspect of the calcaneal tuberosity, which allows the calcaneus to serve as the primary lever arm for the triceps surae and facilitate the transmission of force from the hindfoot to the midfoot and forefoot during gait. At the same time, the calcaneus maintains the length of the lateral column and protects the posteromedial arch contents.

The calcaneus has 4 key articulations with surrounding structures. Superiorly, the calcaneus shares 3 articulating surfaces with the talus—the anterior, middle, and posterior facets of the subtalar joint. The posterior facet is largest of the 3 articulations and forms the primary load-bearing component of the subtalar joint. Its surface is convex and runs distally and laterally at approximately 45° to the sagittal plane. The fourth articulation lies at the distal end of the anterior process of the calcaneus and forms the CCJ.

The sustentaculum tali protrudes from the medial aspect of the calcaneal body and provides a shelf of dense cortical bone to support the talar neck. The superomedial spring ligament—a key supporter of the arch and talar neck—originates here, along with the tibiocalcaneal component of the deltoid ligament—a key ankle stabilizer.

These robust soft tissue attachments, along with the interosseous talocalcaneal ligaments, are what have historically led to the sustentaculum being described as the “constant fragment,” because these attachments were thought to keep the sustentaculum tightly bound to the talus, and thus in a relatively constant position. Traditionally, open reduction and internal fixation (ORIF) through extensile lateral approach has involved reducing the remaining fragments of the calcaneus back to the nondisplaced sustentacular fragment.

However, recent literature has called into question the “constancy” of this fragment in DIACFs, particularly in more comminuted fractures with more medial extension across the posterior facet. In a 2013 study, Berberian and colleagues retrospectively reviewed the computed tomography (CT) scans of 88 patients with 100 DIACFs for evidence of sustentacular displacement and/or angulation. Gapping and intraarticular displacement of the middle facet was also examined and included in the definition of sustentacular displacement. The authors found that the sustentaculum was displaced in 42 of these fractures. Fractures involving more than 50% of the posterior facet (consistent with Sanders B and C type fractures) as well as 3 and 4 part fractures of the posterior facet were found to have significant association with sustentacular displacement. Similarly, Gitajn and colleagues found sustentacular fractures in 94 of 212 calcaneal fractures. Of these 94 sustentacular fractures, 20.3% (n = 43) demonstrated subluxation of the articulation between the sustentaculum and the talus.

Overall, as these recent studies suggest, the surgeon must pay special attention to the alignment and integrity of the “constant” fragment—particularly in those DIACFs that involve the medial aspect of the posterior facet. In cases in which the constant fragment is angulated or subluxated, it has been suggested combined medial and lateral approaches be used, although the data to support this remain scant ( Fig. 1 ). Importantly, however, no studies to date have directly assessed the utility of a combined medial and lateral approach in the reduction of a displaced sustentacular fracture in the setting of a DIACF.

Coronal computed tomography images through the anterior-most cut of the posterior facet, demonstrating a nondisplaced sustentacular fragment ( A ), and an angulated fragment ( B ). ( C , D ) Fixation of the fragment in B with a single lag screw directed from medial to lateral.

Mechanism of injury and pathoanatomy

Intraarticular calcaneal fractures occur after eccentric axial loading of the talus on the calcaneus, typically as a result of high-energy mechanism such as motor vehicle collision or fall from height. This axial loading drives the lateral border of the talus into the body of the calcaneus, creating a shear fracture through the posterior facet, resulting in medial and lateral fragments. The position of the subtalar joint during axial loading determines how medial or lateral this split occurs. As originally described by Essex-Lopresti, the classic primary fracture line runs from anterolateral to posteromedial. As the axial load continues to be applied, secondary fracture lines extend from the primary shear line. A posteriorly directed load drives the fracture line into and posterior to the posterior facet, thus separating the posterior facet and the tuberosity. The tuberosity tilts into varus and equinus as a result of the pull of the triceps surae. The posterior facet fragment is then driven into the calcaneal body, resulting in a joint depression–type fracture. As the body of the talus drives the posterior facet fragment further into the cancellous calcaneal body, it shears the attachment of the posterior facet fragment from the lateral wall, and results in lateral wall blowout.

Overall, this mechanism tends to result in a characteristic pattern of displacement in joint depression–type DIACFs. If managed nonoperatively or malreduced, a typical constellation of findings and disabling long-term sequelae often result ( Fig. 2 ).

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  The disruption of the posterior facet and residual surface incongruity, over time, results in painful posttraumatic subtalar arthritis.

  
  
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  The expansion of the lateral wall owing to lateral wall blowout leads to heel widening, which can cause difficulty with shoe wear, subfibular impingement, peroneal stenosis, tendonitis, and possible dislocation.

  
  
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  Loss of the talar declination angle, which occurs as a result of loss of calcaneal body height (as represented by a decreased BA), results in anterior tibiotalar impingement, and decreased ankle dorsiflexion.

  
  
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  Residual varus of the calcaneal tuberosity leads to overall hindfoot varus, causing painful lateral column overload.

Lateral and axial radiographs depicting classic sequelae of calcaneal fracture malreduction including severe posttraumatic arthritis of the subtalar with loss of talar declination angle and anterior tibiotalar impingement ( A ) as well as persistent lateral wall expansion and heel varus ( B ).

Imaging and classification of injury

Initial radiographic evaluation of calcaneal fractures should include anteroposterior, oblique, and lateral images of the foot. Standard imaging of the ankle should be included as well. Specialty views—such as Harris axial view of the heel and Broden’s views of the posterior facet—may be obtained; however, many investigators have suggested that these views may be omitted as part of initial workup and preoperative planning if a CT scan is obtained.

BA and the crucial angle of Gissane are useful radiographic parameters to define the severity of initial injury. BA is measured by a line connecting the highest point of the anterior process to the highest point of the posterior facet, and a line tangential to the superior edge of the tuberosity. Normal values for BA range from 20° to 40°, and a decrease in this angle suggests collapse of the posterior facet and overall loss of calcaneal height. The crucial angle of Gissane is formed by the dense subchondral bone of the posterior and anterior and middle facets; normal values are 120° to 145°.

The BA at the time of presentation has been acknowledged widely to correlate with injury severity; however, its prognostic value in terms of predicting morbidity associated with calcaneal fractures continues to remain a subject of debate. Significant loss of calcaneal height—as measured by initial BA of less than 0° on injury radiographs—has been shown in some studies to be predictive of poor outcomes and the need for late subtalar fusion, regardless of the type of treatment. This correlation recently has been called into question, and newer literature has suggested that restoration of BA intraoperatively, regardless of the initial angle, may be a better predictor of patient outcomes over time. In a review of 274 patients with calcaneal fractures, Su and colleagues found no correlation between preoperative BA and postoperative function. Similarly, in a post hoc analysis of 2013 randomized, controlled trial comparing operative versus nonoperative treatment for DIACFs, Agren and colleagues found no association between the pretreatment BA and outcomes. Both studies, however, found a correlation between BA at the time of healing and superior functional recovery.

CT has vastly enhanced the current understanding of the pathoanatomy of calcaneal fractures, and has become an integral component in management. The coronal views allow visualization of the articular fragments of the posterior facet, the sustentaculum, the extent of widening of the calcaneal body and lateral wall blow out, angulation of the tuberosity, and position of the FHL and peroneal tendons. On sagittal imaging, the rotational and inferior displacement of the posterior facet fragments can be visualized, along with the extent of involvement of the anterior process region and superior displacement of the tuberosity relative to the posterior facet (eg, overall loss of calcaneal height.) Axial views can reveal extension of the fracture into the anterior process and calcaneocuboi joint, as well as sustentaculum and anteroinferior posterior facet. Analysis of axial cuts at the level of the distal fibula can reveal dislocation or subluxation of the peroneal tendons.

The Sanders classification, which is the most commonly used system for the classification of calcaneus fractures, is based on the number and location of the articular fragments of the posterior facet. This system uses a coronal CT image through the widest portion of the posterior facet; roman numerals I though IV are used to indicate the number of fragments; the fragments are then subclassified further by letter designation (A, B, C) to denote the location of the primary fracture line from lateral to medial. Type A represent a lateral fracture line, type B is through the middle of the facet, and type C denotes a medial fracture line through the sustentaculum.

The prognostic value of the Sanders classification of DIACFs has been heavily evaluated both in terms of short- and long-term outcomes, and the findings of these studies have become a critical component of surgical decision making and management recommendations. Sanders type III and IV fractures, which involve more significant articular comminution, are more often associated with higher energy of injury. These fractures, therefore, involve not only greater disruption of soft tissues, but also overall disruption of calcaneal shape and morphology (and are more likely to have concurrent pathology, such as calcaneocuboid disruption and peroneal dislocation). It follows that Sanders type III and IV fractures have poorer results with nonoperative management compared with lower energy Sanders type II fractures. Additionally, reflecting the significant articular damage associated with these injuries, it has been shown that operatively treated Sanders type III and IV fractures have a poorer prognosis, in terms of both function and need for late subtalar fusion, than operatively treated Sanders type II fractures. Overall, regardless of treatment, patients with Sanders type IV fractures are nearly 6 times more likely to eventually require arthrodesis than patients with a Sanders type II fracture.

Controversies in management

Operative Approaches, Techniques, and Controversies

Extensile versus “minimally invasive”

A multitude of surgical approaches have been described in operative treatment of DACFs. Careful consideration of patient factors, fracture pattern, and timing of surgery—along with surgeon experience—are all essential to achieving optimal patient outcome while minimizing risk of complications.

The traditional approach for ORIF of DIACFs involves an extensile L-shaped lateral approach to the calcaneus. This approach has been the most frequently used surgical approach for the last 3 decades with which to reliably achieve anatomic reduction and restore width, height, and alignment, with placement of appropriate plate and screw fixation. The extensile lateral approach has also been noted to provide excellent fracture exposure, both of the posterior facet and lateral wall, and thus is preferable for more complex fractures.

Although this approach offers excellent fracture visualization, it has been associated with rates of wound complication and infection as high as 20% to 37%. Devascularization of the fracture fragments, larger surgical field, increased operative time, creation of potential dead space, and disruption of the lateral calcaneal branch of the peroneal artery (the primary vascular supply to the overlying fasciocutaneous flap) have all been hypothesized to contribute to this increase rate of complications.

Recently, the sinus tarsi approach has been advocated as an alternative to the traditional lateral extensile approach. As most commonly described, this approach involves a 2- to 4-cm incision over the sinus tarsi, along a line from the tip of the fibula to the base of the fourth metatarsal. When performed appropriately, this approach allows for excellent visualization of the posterior facet, anterolateral fragment, CCJ, lateral wall, and peroneal tendons. If need be, the incision can be extended proximally to treat acute peroneal tendon dislocation. Likewise, the same incision can be used at a later date should subtalar arthrodesis or tendon debridement be indicated.

Proponents of the sinus tarsi approach cite such advantages as decreased operative time, minimization of soft tissue disruption, and fewer wound complications. In a retrospective review of 112 operatively treated calcaneus fractures (79 treated with lateral extensile approach and 33 with sinus tarsi), Kline and colleagues found a significantly lower rate of wound complications in the sinus tarsi group (6%) compared with the lateral extensile group (29%; P = .005). Patients undergoing ORIF via an extensile lateral approach were also more likely to require secondary surgery within the 3-year study period, with 20% of patients requiring return to the operating room for varying indications. Importantly, fracture severity was relatively equally distributed among the 2 groups, with 53% Sanders type II fractures and 47% Sanders type III fractures in the extensile cohort, and 61% Sanders type II fractures and 39% Sanders type III fractures in the sinus tarsi cohort. Similarly, there were no differences between the 2 groups in terms of sex, age, tobacco use, or diabetes. Both groups had 100% union rate, with no measured differences in the final postoperative Bohlers angle and angle of Gissane.

A 2014 randomized prospective trial by Xia and colleagues showed similar findings. In this study, 117 calcaneal fractures were allocated randomly to ORIF via lateral extensile approach versus sinus tarsi approach. All surgeries were performed 8 to 12 days after injury and used a titanium alloy low profile plate. The authors reported significantly decreased operative times in the sinus tarsi group compared with the extensile group (62 vs 93 minutes), as well as lower rate of wound complication (0% vs 16.3%). Although postoperative radiographic parameters of calcaneal reduction were equivalent for the 2 groups, patients in the minimally invasive group had significantly higher Maryland foot scores at the time of final follow-up.

Although much of the recent literature supports the utilization off the sinus tarsi approach in Sanders types II and III fractures, few studies have investigated the use and complications of this approach in highly comminuted Sanders type IV fractures. Kwon and colleagues recently conducted a retrospective review of 405 operatively treated DIACFs in which they examined risk of wound complications with regard to such factors as fracture severity, operative approach, and time to fixation. Although the authors found a decreased overall risk of wound complications with minimally invasive approaches (percutaneous and sinus tarsi techniques) compared with the extensile approach, they did note an increased risk of wound complication in Sanders types III and IV fractures treated with minimally invasive approaches compared with Sanders types I and fractures II treated with similar approach (odds ratio, 3.5; 95% confidence interval, 1.3–10.3; P = .018). Other pertinent findings included an increased risk of wound complication with operative delay beyond 14 days when using minimally invasive approaches (odds ratio, 3.2; 95% confidence interval, 1.3–9.5; P = .01).

However, these results should be interpreted with some caution. The outcomes of 24 different surgeons with varying degrees of operative experience were reviewed in this study, and the operative volumes of each individual surgeon are not reported. Additionally, the authors make no distinction between “minimally invasive” percutaneous techniques and “sinus tarsi” approach in their outcomes analysis. In the absence of standardized operative technique and surgeon experience, conclusions regarding specific complications of the sinus tarsi approach are limited.

Several other minimally invasive methods of operative fixation have been described, including percutaneous as well as arthroscopically assisted techniques. A limited number of retrospective studies and case series regarding percutaneous fixation techniques have been published, all of which demonstrate mixed results in terms of wound complication, quality of articular reduction, and patient outcomes. Similarly, there is limited literature supporting routine use of arthroscopic-assisted reduction of the posterior facet in conjunction with percutaneous fixation techniques.

Restoration of articular surfaces: importance of the posterior facet and calcaneocuboid joint

The importance of restoring the anatomy of the posterior facet in DIACFs, when possible, is well-documented. In their 2002 randomized, controlled trial, Buckley and associates noted that, in patients not receiving workers’ compensation, both anatomic reduction of the posterior facet and reduction with articular stepoff of less than 2 mm were associated with better overall SF-36 scores as well as VAS scores compared with those fractures with articular comminution. However, the “comminuted” group in this analysis also included all non–workers’ compensation patients treated nonoperatively. Thus, the results are somewhat misleading and ignore confounding variables that are addressed by operative fixation. These variables include restoration of calcaneal height, realignment of tuberosity, and reduction of lateral wall.

Later studies, however, have better supported the association between posterior facet reduction and improved functional outcomes. In a post hoc analysis of a 2013 randomized, controlled trial comparing operative versus nonoperative treatment for DIACFs, Agren and colleagues noted that residual displacement of the articular surface was associated with lower AOFAS hindfoot score, VAS pain score, and Olerud-Molander score.

More recently, reduction of the calcaneocuboid surface has been suggested to be important to optimization of outcomes and restoration of lateral column function. The incidence of CCJ involvement in calcaneus fractures has been reported to be around 50%, ranging from 33% to 76%, depending on the series. Multiple analyses have shown CCJ involvement to be more common in fractures of higher severity, particularly joint depression–type fractures involving lateral wall comminution and lateral subluxation of the posterior facet ( Fig. 3 ). Despite this, a correlation between CCJ involvement and clinical outcomes has not yet been definitively established in the literature. In a comparative analysis outcomes of DIACFs involving the CCJ versus those that did not, Gallino and colleagues found no difference in VAS and SF-36 scores at a mean of 2.3 years postoperatively. Additionally, although the severity of initial CCJ injury was found to correlate with increased incidence of posttraumatic arthritic changes, there was no difference in outcome scores between those patients with CCJ arthritis and those without. This finding echoed the findings of previous work by Hutchinson and Huebner.

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