Anatomy

The talus has a unique surgical anatomy. The bone is divided into three parts: body, neck, and head. It articulates with four bones: the fibula, tibia, navicular, and calcaneus. It also has no tendon attachments. With more than 60% of its surface area being articular, the blood supply to the talus is significantly limited. The surgeon must have a firm understanding of the surrounding vasculature so as to limit iatrogenic injury to the talar blood supply. Vascular contributions arise from the anterior tibial, the posterior tibial, and the peroneal arteries. The tarsal canal artery (a branch of the posterior tibial artery as the deltoid artery) and the tarsal sinus artery (anterior tibial artery, peroneal artery) form an extraosseous vascular ring. The deltoid artery enters the deltoid ligament and provides contributions to the tarsal canal (extraosseous) and directly to the medial talar body.1–4 Often, this is the only remaining blood supply postinjury; therefore, care must be taken to preserve this contribution. The talar head receives the most comprehensive blood supply, with the vascularity of the medial body more tenuous and the lateral body and posterior tubercles being left relatively avascular. Despite its large articular area, there is a sizable nonarticular surface on the lateral aspect of the neck and anterior aspect of the body. Both areas are quite useful with regard to placement of fixation.

Biomechanics

The subtalar joint acts as the link between the foot distally and the leg proximally. At heel strike, the subtalar joint collapses into valgus, with the calcaneus in eversion. Distally this results in “unlocking” of the transverse tarsal joint. This unlocking gives flexibility to the longitudinal arch and aids in the passive absorption of the energy imparted to the foot at heel strike. In the movement of the foot from foot flat to toe off, the subtalar joint undergoes inversion as the calcaneus moves to a position of varus. Distally this imparts stability at the transtarsal articulation and transforms the midfoot into a rigid structure able to accept body weight.5 There is a direct correlation between varus malalignment of the talus and loss of subtalar motion. With varus position of the talus as seen in the typical varus malunion, the subtalar joint is locked in an inverted position and the arc of eversion is restricted. This results in a rigid foot that loses its shock-absorbing capabilities at heel strike.6,7

Classification

Talar neck fractures are classified by Hawkins8 into three types: type I, undisplaced; type II, displaced with subluxation of the subtalar joint; and type III, subluxation or dislocation of both the tibiotalar and the subtalar joints (Fig. 36.1). Canale and Kelly9 added a type IV, which is a type III injury with an associated talonavicular dislocation. The Hawkins classification has been related to the risk of avascular necrosis (AVN).

Nonoperative Treatment

Nonoperative treatment of talar neck fractures is often suboptimal and fraught with pitfalls. It can be considered for nondisplaced Hawkins type I fractures. Rarely, in polytrauma patients or in patients with fractures and severe soft tissue damage in whom operative intervention is not possible, closed reduction (see Percutaneous Treatment, below) of a displaced talar fracture is necessary. Because talar neck fractures often result from a dorsiflexion injury, plantarflexion is advocated for application of the cast so as not to displace the talar neck fracture.10 However, casting in plantarflexion predisposes the patient to an equinus contracture and limited motion, particularly of the subtalar joint. When closed treatment is utilized, the equinus position should be gradually eliminated by 4 weeks and the cast removed and motion started by 8 weeks. Non–weight bearing is usually recommended for 12 weeks, although limited weight bearing may be started during weeks 8 through 12 in true type I fractures.

Surgical Treatment

Operative Approach

Most talus fractures are managed through a dual-incision approach. Rarely, such as when the condition of the soft tissues prohibits incisions on the dorsum of the foot, posterior to anterior fixation is necessary through a posterior approach. All talus approaches are described in this chapter.

Dual-Incision Approach

Video 36.1 ORIF of a Talus Fracture

The medial incision is made midway between the anterior and posterior tibial tendons, beginning a few centimeters proximal to the medial malleolus and ending just slightly distal to the navicular. This incision is deepened through the subcutaneous tissue, preserving the saphenous vein. Injury to the saphenous vein can lead to significant postoperative swelling. Where necessary, the ankle joint capsule is opened with a scalpel as opposed to electrocautery, so as not to injure the articular cartilage. Exposure is then extended from the tibia to the navicular, minimizing soft tissue dissection superior and inferior on the talar neck to maintain soft tissue attachments and the blood supply that they provide. The anterolateral incision should be centered between the peroneus tertius tendon and the extensor digitorum longus tendon, starting above the ankle joint and extending distally to the midfoot region (Fig. 36.2). One should identify and protect the superficial peroneal nerve as it crosses the field. The medial border of the extensor digitorum brevis should be identified. It is common to have debris within the subtalar joint, and the exposure should continue to the inferior aspect of the talus to enable visualization and debridement of the subtalar joint. These two incisions will be used alternately to achieve an anatomic reduction and to place the appropriate fixation to stabilize the fracture.

Medial Malleolus Osteotomy

On occasion, particularly with Hawkins type III fractures, a medial malleolar osteotomy is necessary. A chevron osteotomy is created by making a saw cut parallel to the dome of the talus 1 cm proximal to the plafond and then utilizing a chisel to make the vertical cut, allowing the bone to fracture into the articular surface (Fig. 36.3). This creates a stable construct when repairing the osteotomy and facilitates visualization of a talar body fracture. Alternatively, the osteotomy can be done obliquely, running superomedially 45 degrees from the articular surface. With either technique, the completion of the osteotomy into the articular surface should be by way of fracture rather than by saw. This facilitates an accurate reduction of the medial malleolus at the end of the procedure. Predrilling the medial malleolus prior to the osteotomy is not necessary or significantly helpful with fixation because it is often difficult to find the pilot hole in the deltoid ligament. The osteotomy is fixed with 3.5-mm cortical screws (our preference) or 4.0-mm partially threaded screws.

Posterior Approach

This approach is not helpful for fracture reduction and is only necessary for placement of posterior to anterior fixation. For the posterior approach, an incision is made slightly posterior to the midway point between the Achilles’ tendon and the lateral malleolus. One should identify and protect the sural nerve. The approach is deepened, and the interval between the peroneal tendons and flexor hallucis longus is identified and developed. This provides access to the posterior talus.

Surgical Techniques

Percutaneous Treatment

Percutaneous treatment of talar neck fractures is rarely appropriate. It implies that a closed reduction can be accomplished, which is exceedingly difficult. Therefore, percutaneous fixation is generally limited to situations in which the soft tissues or the patient′s overall condition preclude definitive surgical stabilization for a significant period of time. The technique of closed fracture reduction should be determined based on the plain films and CT scan and tailored to the direction of displacement. Most commonly, the talar neck will be displaced dorsally and requires distraction and plantar flexion to correct the deformity. Inversion or eversion of the hindfoot may be necessary to correct a varus or valgus deformity (i.e., a medial or lateral translation). This is followed by axial loading and extension of the foot back to a neutral position. Fracture reduction should be performed in the OR because it may take more than one attempt before a satisfactory reduction is achieved. Temporary fixation may be considered when permanent fixation must be delayed.

Under fluoroscopic control, Kirschner wires (K-wires) can be placed lateral to the Achilles’ tendon from the posterior aspect of the talus, aimed anteromedially through the central portion of the talar neck and into the central part of the talar head. K-wires may be advanced through the talar head into the navicular for added stability and bone purchase if required. Posterior to anterior placement of wires allows the portal for entry of the K-wires to be away from the definitive surgical site and it allows the pins to be left outside the skin or buried just underneath the skin. Alternatively, definitive treatment with percutaneous cannulated screws can be considered if later open reduction and internal fixation (ORIF) is deemed impossible. A small incision is placed on the posterolateral aspect of the ankle, and a guide pin from a cannulated screw set is placed in the same manner. The guide pin should be placed as inferior as possible on the posterior talar body. This decreases impingement of the screw head on the posterior malleolus during plantar flexion, which can interfere with range of motion. Because the central bone in the talar body is quite dense, over-drilling is required to form a gliding hole through the body of the talus. Prior to drilling, at least one other K-wire needs to be placed so that the reduction is not lost during screw insertion. After placement of the screw, the great toe should be flexed and extended to verify that the screw is not interfering with the excursion of the flexor hallucis longus tendon.

Open Treatment

Reduction

Because the mechanism of talar neck fractures is usually an extension injury, the dorsal aspect of the talus is usually comminuted. Although anatomic reduction of the talar neck is the goal, reduction becomes more challenging as dorsal comminution increases. Because the inferior surface of the talus fails in tension, it is rarely comminuted and may be used to judge the quality of reduction (Fig. 36.4). It is critical to assess the reduction of the talar neck both on the medial side and on the lateral side utilizing both incisions. It is common for the reduction to appear ana tomic on the medial side and to be several millimeters off on the lateral side due to malrotation. The only way to predictably reduce the talus fracture is to visualize the reduction both medially and laterally. Either 0.062-inch K-wires or 2.5-mm terminally threaded Schanz pins are useful as joysticks in reducing the fragments. Because the talus is dislocated from both the ankle and subtalar joints, Hawkins type III fractures provide unique challenges. To facilitate reduction of the talus in these severe injuries, it is helpful to open the tibiocalcaneal space by some method. Use of a large lamina spreader between the tibial plafond and the posterior facet of the calcaneus is ideal because it provides distraction while allowing free flexion, extension, inversion, and eversion. Freedom of motion in these directions is often necessary to reduce the talus back into the mortise. A sponge or gauze protects the articular surfaces from the laminar spreader. Alternatively, a centrally threaded calcaneal traction pin with a traction bow, or a T-handled chuck can be used to apply traction.

Often, a medial malleolar osteotomy is required before reduction can be achieved. The posteromedial tendons and neurovascular bundle frequently block reduction and are accessible through this approach in most situations. Rarely, reduction cannot be accomplished through a medial incision with a medial malleolar osteotomy, and a direct posterior approach is required. If a posterior medial incision is necessary, it is imperative to identify and protect the neurovascular structures that are no longer in their anatomic position.

Fixation

After anatomic reduction has been accomplished, preliminary fixation can be provided with K-wires. Definitive fixation is then performed, most frequently utilizing screws alone or in combination with plates. On the medial aspect of the talus, a 2.7- or 3.5-mm cortical screw is usually used and is placed from the distal medial aspect of the talus in a retrograde fashion back into the talar body. Most often the screws are placed through the talar head and countersunk into the cartilage. To do so, abduction of the forefoot is required through the transtarsal joint. One should verify that the screw does not impinge on talonavicular motion by checking the transtarsal motion. When there is comminution of either or both the superior and medial aspects of the talus, the screw is placed as a positioning screw rather than as a lag screw (Fig. 36.5). If needed, a second parallel screw can be placed directly inferior to this. If two screws are utilized, the inferior screw should be placed first along the subchondral bone of the subtalar joint. After placement of the medial screws, lateral fixation can be placed.

When screws are placed from posterior to anterior in the talus, it is mandatory to countersink these screws below the articular surface so as not to block ankle range of motion, particularly plantar flexion. Although 4.5- and 6.5-mm screws have been advocated, it is easier to countersink smaller 3.5-mm screws. The trajectory of the screws should take into account the concavity of the subtalar joint and the convexity of the talonavicular joint. Hardware penetrating either of these joints would be disastrous (Fig. 36.6). It is also important to note that the neck and head of the talus occupy only the medial two thirds of the talar body. Therefore, any hardware placed from posterior to anterior must be directed from lateral to medial in the coronal plan, aiming for the great toe, so as not to violate the lateral wall of the talus and the sinus tarsi region. Mandatory imaging studies include an ankle mortise, lateral talus, anteroposterior (AP) foot, and oblique Canale view and will increase the odds of the screws being safely placed.

If the fracture line extends into the shoulder of the talus (the transition area between the talar neck and body), screw fixation alone is often adequate for stability. However, as the fracture line exists more distally along the neck of the talus, or as the dorsal comminution increases, a plate is quite useful for definitive stabilization. A 2.0-mm T-plate from the mini-fragment set is ideal for this purpose. A hole is either trimmed off or converted to a hook. The hook is placed on the shoulder of the talus and the T-portion is placed toward the head of the talus. Alternatively, mini–blade plates from the handsets can be used. Care should be taken when placing these screws, particularly the distalmost screws through the T-portion of the plate, to avoid penetrating the talonavicular joint on the medial side. The distal screw should angle anteriorly to stay extra-articular at the talar head. A plate can also be used on the medial aspect of the talus. This risks injuring the blood supply to the talar body from the deltoid ligament. A medial plate is placed inferior to the articular surface of the talar body proximally and should extend distally to the edge of the articular surface of the head of the talus.

Wound Closure

After the wound is irrigated, a drain is placed. Deep fascial sutures can be utilized. Subcutaneous sutures are avoided because they can injure cutaneous nerves or strangulate the cutaneous blood supply as it travels through the subcutaneous tissue to perfuse the skin edges at the incision. The wound is closed with Allgöwer-Donati stitches using 4-0 nylon. The wound is covered with Xeroform (Kendall, Mansfield, MA) alone or Adaptic (Ethicon, Johnson & Johnson, Somerville, NJ) soaked in Betadine (Purdue, Stamford, CT). The ankle is immobilized using a well-padded splint.

Tips and Tricks

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  Because the inferior surface of the talus is usually not comminuted, use the subtalar portion of the talus as an indicator of the quality of reduction.

  
  
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  Remember to debride the subtalar joint.

  
  
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  With Hawkins III talus fractures, medial malleolus osteotomy is of great assistance. Plating should be considered more often to provide more stable fixation. The lateral aspect of the neck and shoulder of the body provide an excellent nonarticular surface area for placement of a plate.

Rehabilitation

The patient is placed into a well-padded, short leg splint immediately after surgery. If there is no concern with the skin closure the patient is allowed to begin crutch training the following day. Weight bearing on the injured leg is not allowed for at least 8 to 12 weeks. The patient is maintained in the splint until suture removal in 10 to 14 days. Then the injured foot is placed into a removable splint and an elastic stocking (Fig. 36.7), and the patient is allowed to begin working on range of motion of the ankle and subtalar joints. If the fracture pattern is stable, after 8 weeks a graduated weight-bearing program starting at 50 lb and increasing by 20 lb per week can be initiated. If there is dorsal comminution or any other concern about fixation, one should delay weight bearing for 3 months. Pool therapy can be quite valuable in the time period between 8 and 12 weeks postoperatively.

Outcomes

The midto long-term outcome after fracture of the talar neck is poorly documented. However, later studies of patients managed with better fixation and treatment methods have demonstrated improved outcomes compared with the early results reported by Hawkins.8 Vallier et al15 reported the results of surgical treatment of 102 such fractures; 60 were evaluated at an average of 3 years after surgery. Functional outcome was assessed with the Foot Function Index (FFI) and Musculoskeletal Function Assessment (MFA) surveys. With both scales, significant functional impairment was observed. According to both scales, fracture comminution was associated with a worse outcome, whereas factors such as age, Hawkins′s classification, or associated talar body fractures did not affect outcome. Based on normative scores for the MFA, patients with talar neck fractures in this series had worse outcomes than patients with hindfoot injuries and ankle or leg injuries.

Complications

Complications of talar neck fractures include osteonecrosis (such as AVN) of the talar body, delayed union, nonunion, malunion, and arthritis of the subtalar or tibiotalar joints.6,12,16–23 Of these, osteonecrosis has received the most attention. The so-called Hawkins sign is a radiolucent area immediately beneath the articular surface of the talar dome noted on the AP or mortise view typically evident at 6 to 8 weeks. It is evidence of revascularization of the talar dome and indicates a good prognosis. When the Hawkins sign is not present, one must be concerned about AVN. The overall incidence of AVN ranges between 13 and 69%,8,9,11,16,18,24–28 with the two largest series quoting 21%18 and 58%.8 Grob et al25 attributed their low incidence of AVN (13%) to rigid internal fixation. The Hawkins classification correlates with the incidence of AVN. For Hawkins type I fractures, it has been reported that up to 13% will develop AVN. For Hawkins type II, 20 to 50%, and for Hawkins type III, 69 to 100% have been reported to develop AVN. There does not seem to be a correlation between the time to surgery and the risk of AVN.15,29 When AVN occurs, there is no consensus on the amount of weight bearing that should be allowed. In the absence of evidence that weight bearing is harmful, weight bearing should be based on fracture union and not on the presence or absence of AVN. However, it is prudent to instruct the patient to avoid impact activities when AVN is present. In our experience, AVN occurring after talar neck fractures rarely involves the whole body, but rather is more localized.30 Most often, these patients are asymptomatic and can even obtain an excellent result.17,24,26,28 When talar collapse occurs or AVN is symptomatic, further treatment may be required (Fig. 36.8).

Subtalar and ankle arthritis is a common complication after talar neck fractures, with an incidence ranging from 47 to 97%.18,28 Subtalar arthritis has been reported in up to 50% of cases, and ankle arthritis in 33% of cases. Both joints may be involved in up to 25% of patients. Selective injections are helpful in evaluating hindfoot pain after talus fractures. Subtalar arthritis can often be successfully treated nonoperatively with a University of California at Berkeley Laboratory (UCBL) orthosis. Occasionally, pain due to ankle arthritis can be improved with an ankle–foot orthosis. Nonsteroidal anti-inflammatories and decreased activity level are helpful to decrease pain and preserve these two major hindfoot joints. If conservative treatment fails, an attempt to salvage at least one of the two hindfoot joints (ankle or subtalar) is quite valuable to the overall function of the patient.

Delayed union, nonunion, and malunion of the talus are relatively rare. Delayed union is reported in 13%,28 and nonunion is noted in 4%.18 Nonunions are usually associated with a short talar neck and an adduction deformity of the forefoot.16 Surgical reconstruction of a talar neck nonunion usually requires a tricortical bone graft to regain length and bone stock and ultimately to achieve union. Malunions are most commonly due to an undiagnosed fracture. Another cause of malunion is malreduction at the time of surgery or loss of reduction during the postoperative period. Both of the latter causes are directly under our control and should be exceedingly rare as causes of malunion.

Classification

Classification schemes for the talar body exist but are not commonly known due to the rarity of this injury. The easiest system is to separate them into three groups: group I, fractures involving the body proper regardless of the direction of the fracture line; group II, fractures of the lateral or posterior process; and group III, compression or impaction fractures. Sneppen et al31 classified these injuries based on anatomic location: type A, transchondral or osteochondral; type B, coronal shear; type C, sagittal shear; type D, posterior tubercle; type E, lateral process; and type F, crush fractures. Inokuchi et al32 made an important contribution to distinguishing between talar neck fractures and talar body fractures: if the inferior fracture line exits anterior to the lateral process, then it is considered a neck fracture, and posterior to this landmark, it becomes a talar body fracture (Fig. 36.9). This is the point where the talus transitions to the articular surface of the posterior facet of the subtalar joint; therefore, by definition, the fracture involves both the tibiotalar and the subtalar joints.

Nonoperative Treatment

These injuries are often displaced and rarely treated nonoperatively. Unfortunately, the most common reason these injuries are treated nonoperatively is failure to diagnose the injury. The most commonly missed talar body fracture is the lateral process fracture (Fig. 36.10). If the displacement is 1 mm or less, then 4 to 6 weeks of short leg casting and 8 to 12 weeks of non–weight bearing are appropriate. Once the cast is removed, range of motion should be pursued aggressively.

Surgery Treatment

Most talar body fractures are treated operatively, including any fracture with greater than 1 mm of displacement, all open fractures, and any shear injury that results in a loose body within the ankle (Fig. 36.11).

Surgical Techniques

Operative stabilization may require either the anteromedial or the anterolateral approaches already described. Medial malleolar osteotomy is frequently needed to be able to visualize and anatomically reduce talar body fractures. Often these injuries are associated with pilon fractures and one can use these fracture lines for visualization of the talar body fracture. On occasion, a fibular osteotomy is useful. Fibular osteotomy is performed as a segmental osteotomy, with the first cut being at the level of the joint and the second cut above the syndesmotic notch. The intercalary segment is then rolled posteriorly, leaving the peroneal tendon attachments intact. This provides good exposure for a very lateral talar body fracture.

Tips and Tricks

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  Osteotomy of the medial or lateral malleoli is often necessary to improve exposure of the talar body.

  
  
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  Use of titanium screws in this area may facilitate magnetic resonance imaging (MRI) evaluation of the talus and ankle at a later date.

Most talar body fractures can be fixed with screws (2.0, 2.7, and 3.5 mm), placed perpendicular to the fracture lines and countersunk into the articular surface (Fig. 36.12). Chondral flaps are often encountered. Although the majority of these chondral injuries are not salvageable and require debridement, some can be repaired with absorbable pins. If debrided, these areas heal with fibrocartilage and can provide a potential opportunity for placement of hardware without any further injury to the articular cartilage.

Complications and Outcomes

Talar body fractures are a devastating injury, and although the outcome can be improved with operative fixation, the expectations are guarded at best. The most common complication of talar body fracture is posttraumatic arthrosis. The reported incidence of ankle arthrosis ranges from 50 to 90% and that of subtalar arthrosis ranges from 48 to 90%.21,26,31,33–36 In the largest series in the literature of cases treated by ORIF, Vallier et al37 reported arthritis of the ankle joint in 65% and of the subtalar joint in 35%. Outcomes as assessed by both general (the MFA) and specific (the FFI) scales demonstrate significant impairment, with worse scores in patients with AVN and collapse or posttraumatic arthritis.

Osteonecrosis occurs in 35 to 40% of all talar body fractures. Open talar fractures and associated talar neck fractures are more likely to have this complication.38 This may be improved with early anatomic reduction and rigid stabilization.34,37

Nonoperative Treatment

Most talar head fractures require operative fixation. If the displacement is 1 mm or less as verified by CT, nonoperative treatment can be considered. Immobilization with either a short leg cast or removable Velcro boot can be used. Initiating motion as early as possible is critical with this particular joint because of the importance that it plays in overall foot mechanics during gait. Full weight bearing can be initiated 8 to 12 weeks after injury as determined by fracture healing on radiographs.

Surgical Treatment

Talar head fractures are rarely nondisplaced and therefore the majority need operative treatment. The surgical approach is determined by the location of the fracture: anterior, medial, or anterolateral. Occasionally two approaches are necessary. It has been reported that a fragment up to 50% of the head can be excised,39 but the report′s author suggests not excising more than 30%. The goal of surgery is anatomic reduction and rigid fixation. Fixation is achieved with countersunk mini-fragment screws (1.5, 2.0, 2.4 mm) placed through the articular surface (Fig. 36.13). If the articular fragment is impacted from axial loading, disimpacting the fragment is mandatory to regain the length of the medial column. Bone graft may be needed to place beneath the disimpacted fragment. If fixation with screws does not provide sufficient stability, the fragment needs to be unloaded with a medial external fixator. The fixator should be constructed in a triangular arrangement with a pin in the medial calcaneus, the medial distal tibia, and the first metatarsal. This spans the talonavicular joint and enables the appropriate distraction in all planes to unload the talar head. The patient should be placed into a posterior foot splint to maintain the foot in neutral dorsiflexion and take the tension off the distal tibia pin.

Complications and Outcomes

Avascular necrosis of the talar head occurs in fewer than 10% of cases. Other complications include midtarsal instability and talonavicular arthritis. Malunion secondary to a missed fracture or malreduction contributes to the development of talonavicular arthritis.5,39

Nonoperative Treatment

Nonoperative treatment is utilized more frequently for this type of talus injury in comparison with all other talus fractures. Displacement should be less than 2 mm or the fragment should be small to consider cast treatment. This injury is associated with a higher incidence of nonunion due to the poor vascularity of this portion of the bone. Therefore, prolonged immobilization of the foot may be appropriate. Often, weight bearing can be initiated by 6 to 8 weeks.

Surgical Treatment

Most posterior process fractures require surgical intervention, either for anatomic reduction and stabilization or for excision. The decision to fix or excise should be based on the patient′s activity level, bone stock, and overall general health and the size of the fragment. People with vascular disease should be treated with excision of the fragment because of the risk of nonunion. A preoperative CT scan helps to identify the fracture lines relative to the tendons and neurovascular structures, demonstrates any articular step-off in the subtalar joint, and helps to determine the most effective interval to develop to minimize soft tissue dissection.

The lateral process is approached through a posterolateral incision. The interval between the peroneal tendons and the flexor hallucis longus tendon is utilized. This enables direct exposure of the posterior lateral corner of the talus. Dorsiflexion of the tibial talar joint provides greater exposure of the superior articular surface of the talus and facilitates visualization of the reduction. Medial posterior process fractures are approached through a posteromedial incision, with care taken to avoid the nearby neurovascular structures. For those fractures that are repairable, fixation is performed with smalland mini-fragment screws.

Complications and Outcomes

The posterior process is poorly vascularized, in particular, the lateral process. Therefore, nonunion is the most common complication. Parsons41 reviewed the literature and found that the incidence of nonunion is 60% with conservative treatment and 5% with aggressive management (ORIF or closed reduction). Larger fragments should be fixed and smaller fragments may be excised.40,41 It should be emphasized that the lateral process fracture involves the subtalar joint; therefore, persistent malreduction could lead to subtalar stiffness and pain.41

Initial Evaluation

The initial evaluation of patients with calcaneus fractures includes a careful physical exam of the axial and appendicular skeleton with an emphasis searching for other injuries commonly associated with axial loading. Pain noted on palpation of the thoracolumbar spine, pelvis, ipsilateral or contralateral hip, knee, foot, or ankle should warrant appropriate plain radiographs. There is a 20 to 25% incidence of lumbar, pelvis, hip, or knee bony injuries in patients with concomitant calcaneus fractures.55

At the same time, the injured foot should be examined for swelling, lacerations, or blisters (either hemorrhagic or nonhemorrhagic). Most open fractures have medial wounds. Open wounds should be dressed with a sterile dressing, and appropriate parenteral antibiotics should be given. The specific management of open fractures is discussed later in this chapter. Early signs of pressure necrosis of the skin heralded by either blanching or tenting by underlying displaced bone fragments must be noted. Severe pain and pain with passive stretching of the short toe flexors should alert the surgeon to the possibility of compartment syndrome.56

Initial radiographs include a lateral view of the hindfoot and a tangential Harris view of the calcaneal tuberosity. Some surgeons add an AP view of the foot and an oblique Broden′s view of the subtalar joint. CT scans are mandatory for assessment of the posterior facet and for classification. Treatment decisions should not be made without complete imaging, including both radiographs and CT.

Management of the Soft Tissues

The soft tissue envelope of the hindfoot is so important in the management of calcaneal fractures that it warrants special consideration. The periosteocutaneous sleeve of the hindfoot should be considered an organ unto itself and demands immediate and aggressive treatment regardless of the definitive fracture treatment. Prior to any surgical procedure, soft tissue edema must be controlled and diminished. In the absence of open wounds or impending pressure-related skin necrosis, a bulky compressive Jones splint can be applied. Alternatively, cast padding and an elastic wrap can be used with cryotherapy devices, such as the Cryo/Cuff (Aircast, Summit, NJ). These rapidly decrease edema and pain. A removable, padded, posterior foot splint should be added to prevent equinus contracture. The foot is kept elevated above the level of the heart for edema control. Some authors advocate pneumatic compression devices to enhance the diminution of swelling, although many patients find them to be too uncomfortable to use.57,58

There are two aspects of the soft tissue injury that should be monitored and may demand immediate attention. First, displaced bone fragments may compromise the overlying skin. In particular, displacement of the calcaneal tuberosity in tongue-type or tuberosity avulsion fractures can compromise the skin of the posterior heel. Early signs of skin blanching on the posterior heel in tongue-type fractures mandate early reduction and fixation to relieve pressure on the skin. Loss of soft tissue of the posterior heel is disastrous, with no simple salvage options.

The second aspect of the soft tissue injury that must be monitored is the development of fracture blisters. Their formation is dependent on the magnitude of energy imparted to the hindfoot. Higher energy fractures and delays of more than 4 to 8 hours in the application of a compressive splint increase the chances of blisters. Hemorrhagic blisters indicate a deeper soft tissue injury and should be avoided when incisions are planned. Nonhemorrhagic blisters denote some viable epidermal cells attached to the dermis and represent a more superficial injury. Regardless of their appearance, fracture blisters herald injury to the soft tissue envelope of the hindfoot and should be respected (Fig. 36.15).59–61 They should be covered with nonadherent gauze dressings and allowed to decompress on their own as the swelling diminishes. Blisters generally resolve by the time the foot edema allows surgical intervention. If the blisters rupture and expose the dermis, the roof should be debrided, and an antibacterial cream such as Silvadene (Monarch Pharmaceuticals, Inc., Bristol, TN) can be used to prevent secondary bacterial colonization until the bed re-epithelializes. If extensive areas of hemorrhagic fracture blisters remain on the lateral heel in patients 3 to 4 weeks after injury, nonoperative care should be considered. Malunited fractures can be treated at a later date through a healthier soft tissue envelope utilizing a reconstructive procedure.

Soft tissue edema usually begins decreasing between the third and seventh postinjury days (Fig. 36.16). The first splint is changed at 2 to 5 days to reevaluate the skin. Gentle range of motion of the forefoot and midfoot can be started to help alleviate swelling.

These treatment algorithms apply to all calcaneus fractures regardless of whether they are to be treated operatively or nonoperatively. Acute and aggressive management of the soft tissue sleeve preserves treatment options. Some authors have advocated early operative reduction and fixation with limited incisions and percutaneous screw fixation. In their studies, they showed decreased operative time with equivalent fracture reduction.62,63 Conversely, if one does not fully evaluate, appreciate, and aggressively treat the soft tissue injuries associated with this fracture, treatment options will become limited, very quickly!

Classification

Classification of calcaneus fractures requires a thorough understanding of the relevant osseous anatomy. The anterior process connects the distal lateral portion of the calcaneus to the cuboid. A portion of the superior surface of the anterior process serves as the base for the anterior facet, which supports the undersurface of the inferior talar head. The middle facet is upon the sustentaculum tali, which is also important in supporting the centromedial portion of the talar neck and body. The posterior facet is the largest articular surface and is juxtaposed beneath the inferior articular surface of the talar body. It transmits weight-bearing forces from the axial skeleton to the midfoot and forefoot via the calcaneocuboid and talonavicular joints as well as to the calcaneal tuberosity and therefore the ground. The lateral wall is relatively flat except for the peroneal tubercle. The neurovascular structures and extrinsic flexors course medially beneath the sustentaculum tali. The large tuberosity supports the posterior facet and serves as the attachment point for the gastrocsoleus mechanism. A thorough description of the pertinent anatomy is well represented in various texts of clinical anatomy.64

Calcaneal fractures can be described as nondisplaced or displaced and either intra-articular or extra-articular. Experimental work by Carr65 demonstrated the fracture pathoanatomy previously described clinically by others. Reproducible primary fracture lines occur that divide the calcaneus longitudinally into medial and lateral components. They can also extend into the calcaneocuboid joint further affecting the lateral column of the foot. A second fracture line originating at the angle of Gissane results from impaction of the lateral process of the talus and divides the calcaneus into anterior and posterior portions (Fig. 36.17).

Böhler′s and Gissane′s angles are universally used in the description of altered radiographic anatomy in displaced calcaneus fractures. Böhler′s angle is defined as the intersection of two lines at the posterior margin of the posterior facet on a lateral calcaneal radiograph (Fig. 36.18). One line is formed between the posterior-superior point of the tuberosity and the posterior-superior margin of the posterior facet. The second line is formed between the anteriorsuperior margin of the anterior process heading posteriorly to the same posterior-superior margin of the posterior facet. Böhler′s angle varies between 20 and 40 degrees in normal subjects. The patient′s normal value is ascertained from the uninjured, contralateral calcaneal radiograph. This angle decreases in displaced fractures because the posterior facet is impacted and rotated forward while the tuberosity is elevated. A decreased angle indicates a more displaced intra-articular fracture and possibly a worse prognosis with nonoperative care.66

The angle of Gissane is formed by the intersection of a line parallel to the superior surface of the posterior facet with a line originating at the uppermost portion of the anterior process extending downward to the most anteriorinferior portion of the posterior facet (Fig. 36.18). It parallels the outline of the lateral process of the talus. A normal value is obtained by measuring from the patient′s contralateral uninjured calcaneus. The angle lessens as the displacement increases.

The Essex-Lopresti classification differentiates two fracture types based on the relationship of the posterior facet to that of the tuberosity. The joint depression fracture is the more common intra-articular variant, in which the posterior facet is displaced varying amounts from the tuberosity fragment. It is rotated anteriorly and downward and entrapped within the impacted cancellous bone. It usually separates from the lateral wall at a point just at or superior to the attachment of the calcaneofibular ligament and parallel with the inferior margin of the angle of Gissane (Fig. 36.19). The less frequent tongue-type variant has a portion of the posterior facet still attached to the tuberosity fragment. There is a vertical fracture line extending downward through the sinus tarsi at the angle of Gissane. This intersects a more horizontal fracture line exiting posteriorly in the body of the tuberosity. The posterior facet is rotated downward and anteriorly, and the tuberosity portion is displaced upward at its posterior extent (Fig. 36.19).

Computed tomography has greatly aided our understanding of fracture patterns and enables more accurate description of the intra-articular displacement. Identifying the degree of intra-articular comminution enables prognostic information to be gathered.67,68 The Sanders classification describes the articular displacement and comminution of the posterior facet based on the coronal CT scan at the widest portion of the inferior-posterior facet of the talus.51 This anatomic landmark is divided into thirds, or columns, by two vertically oriented lines within the posterior facet. An additional line at the medial aspect of the posterior facet separates the most medial sustentacular fragment. Therefore, four potential fragments of the posterior facet can be described. Nondisplaced fractures are classified as type I regardless of the quantity of fracture lines. Type II fractures are two-part fractures of the posterior facet, with subtypes IIA, IIB, and IIC describing an increasingly more medial fracture line (Fig. 36.20). Type III fractures are threepart variants with a centrally depressed segment that is also further subtyped into IIIAB, IIIAC, or IIIBC as the depressed segment propagates medially. Type IV fractures are highly displaced and comminuted. They have at least four separate articular fragments of the posterior facet.

The Sanders classification provides prognostic information. There is a more favorable prognosis with Sanders type I and II fractures as compared with types III and IV (Fig. 36.21).51 This is intuitive because one would expect the function of the posterior facet to decrease as the comminution increases.