Calcaneal Fractures, Treatments and Problems

Calcaneal fractures are the most frequent tarsal fractures and represent 2% of all adult fractures. A high-energy trauma which causes axial loading is the most common cause of calcaneal fractures. The majority of these fractures are intra-articular. Particularly patients with displaced intra-articular calcaneal fractures must be evaluated for multiple traumatic injuries. The spine, contralateral lower extremity and the wrist fractures may accompany with calcaneal fractures. The most common symptom of calcaneal fractures is pain. Swelling is frequently encountered. Erythema and fracture blisters are other findings. Conventional radiological images should include anteroposterior, axial, lateral and oblique views. The subtalar joint, the calcaneocuboid joint and posterior facet should be assessed in radiologic images. Calcaneal fractures may involve extensive complications. Subtalar joint stiffness and arthritis, heel widening, peroneal impingement, implant-related problems and heel pad pain are the potential complications. The complex anatomy of the calcaneus should be well understood for assesing a calcaneal injury. Evaluation of the radiological findings and classification of the fracture must be performed before determining the treatment method. There is a large number and variety of classification systems that have been described for calcaneal fractures. There is a lack of consensus on treatment and operative technique in calcaneal fractures. The treatment of calcaneal fractures must be planned according to different factors such as type of trauma, classification of the fracture, skin condition and injury mechanism. No treatment, conservative treatment, open reduction and internal fixation, primary subtalar arthrodesis, delayed primary arthrodesis and calcanectomy are treatment options. Also minimally invasive techniques have developed over time. Restoring articular congruity and hindfoot morphology are the aims of calcaneal fracture treatment. Most of recent studies show that open reduction and internal fixation has better outcome in selected patients. Good evaluation, preoperative planning and appropriate treatment bring out better results.


Introduction
Calcaneal fractures are the most frequent tarsal fractures (approximately 60% of all tarsal fractures) and represent 2% of all adult fractures [1,2]. Calcaneal fractures occur mostly in motor vehicle accidents and fall from height [3]. The majority of these fractures are intra-articular [4]. Particularly patients with displaced intra-articular calcaneal fractures must be evaluated for multiple traumatic injuries which can occur with high-energy trauma. The spine, contralateral lower extremity and the wrist fractures may accompany with calcaneal fractures [5][6][7] Calcaneal fractures present a significant challenge to orthopaedic surgeons and patients [8]. These fractures are debilitating and may involve extensive complications [9]. Subtalar joint stiffness and arthritis, heel widening, peroneal impingement, implant-related problems and heel pad pain are the potential complications [4].
Satisfactory functional outcome depends on restoration of normal anatomy [10] Complex anatomy of the calcaneus should be well understood for restoration. The development of modern imaging like digital X-rays and computed tomography (CT) has facilitated the diagnosis. New developments of surgical techniques and osteosynthesis materials have improved the results of surgical procedure. Although improvement towards diagnostic and therapeutic interventions has been made, management of these fractures still remains controversial.  [8,[11][12][13].

Clinical Research on Foot & Ankle
The first skeleteal traction which applied for the reduction of a displaced calcaneal fracture was first described by Clark [13] and also minimally invasive treatment of calcaneal fractures using ligamentotaxis in 1855 was described by Clark. In 1882, Bell applied the first open reduction for an open calcaneal fracture [14]. Morestin performed the first open reduction and internal fixation of a calcaneal fracture in 1902 [15]. In 1929 Böhler described the closed reduction technique for calcaneal fractures [16,17]. In 1931 these fractures were classified according to injury mechanism and radiological view by Böhler [3]. Kocher recommended lateral approach for the calcaneus in 1948 [18]. Essex Lopresti explained the injury mechanism of calcaneal fractures and described percutanous reduction of tongue fractures of calcaneus in 1953 [15].
Most surgeons supported nonoperative treatment historically because of unpredictable surgical outcomes [19,20]. However open reduction and internal fixation has been considered the gold standard treatment method for displaced intra-articular calcaneal fractures since mid-1990s [21]. Furthermore open reduction and internal fixation is advocated in some of extra-articular fractures.

Anatomy
The complex anatomy of the calcaneus should be well understood for assesing a calcaneal injury. Calcaneus locates at the inferoposterior part of the foot. All axial loads from the body are supported by calcaneus [22]. Several joint axes of the calcaneus should be taken into account [23]. The calcaneus which is the largest tarsal bone has 6 different surfaces and 4 articular facets. The anterior, middle, and posterior facets form the subtalar joint by articulating with the talus superiorly. The most anterior facet forms the calcaneocuboid joint by articulating with the cuboid bone anteriorly [24].
The sustentaculum tali which is the site of insertion of the tibiocalcaneal component of deltoid ligament and the superomedial spring ligament is an eminence on the medial wall of the calcaneus. It supports the talar neck and the middle articular facet. At the same time it contributes the construction of the tarsal tunnel. Flexor hallucis longus (FHL) tendon passes under sustentaculum tali [22,25].
The lateral wall of the calcaneus is flat. Peroneal tendons pass from the sulcus which is on this side of the calcaneus [26].
This tarsal bone mostly consists of spongious bone which is surrounded by a thin cortex. The thalamic bone which underlies the posterior subtalar facet is a higher-density cortical bone. This part of cortical bone better supports axial loads along the angle of Gissane [27].
The calcaneal tuberosity which is the place of Achilles tendons insertion locates on the posterior and dorsal aspect of the calcaneus [28]. The calcaneus acts as the lever arm of the triceps surae through this insertion of the Achilles tendon [25].

Fracture Mechanism
A high-energy trauma which causes axial loading is the most common cause of calcaneal fractures. An increased axial force drives the lateral process of the talus into the calcaneus. Thus an oblique primary fracture line occurs along the Gissane angle. Two major fragments are generally identified: an anteromedial and a posterolateral fragment. Sustentaculum tali, anterior and medial facets, and medial part of the posterior facet are in the anteromedial fragment. Calcaneal tuberosity, lateral wall, and lateral part of the posterior facet remain in the posterolateral fragment [23]. Anteromedial fragment is not significantly displaced due to its strong talocalcaneal interosseous ligament and deltoid ligament, however the posterolateral fragment is displaced laterally [26,28,29]. Greater forces can generate additional or different fracture lines [30,31]. (Figure 1)

Diagnosis Clinical assessment
Calcaneal fractures generally occur as a result of high-energy trauma [32]. When dealing with a calcaneal fracture the possibility of concomitant injuries such as ankle fractures, contralateral calcaneal fractures, vertebral fractures, wrist fractures, femoral fractures, and other tarsal bone fractures should be evaluated. [33].
The most common symptom of calcaneal fractures is pain. Swelling is frequently encountered. Erythema and fracture blisters are other findings [34,35]. Edema and widening of the heel are among the findings need to be considered [36]. Ecchymosis and inability to bear weight also may indicate a calcaneal fracture [4].

Radiologic assessment
Conventional radiological images should include anteroposterior (AP), axial, lateral and oblique views. The subtalar joint, the calcaneocuboid joint and posterior facet should be assessed in radiologic images. Conventional radiographic imaging has been the basis of various calcaneal fracture classifications. However classifications derived from radiographic findings have become obsolete because of limited visualisation of the calcaneal anatomy at conventional radiography [22].
Computed tomography (CT) provides precise diagnosis and gives more detailed information about the fracture pattern. Moreover much better images can be obtained by three-dimensional reconstruction. Therefore CT-based classifications for calcaneal fractures are more useful in guiding treatment.

Fracture classification
Evaluation of the radiological findings and classification of the fracture must be performed before determining the treatment method. There is a large number and variety of classification systems that have been described for calcaneal fractures. Sanders and Crosby-Fitzgibbons are the two most prevalent [37].
The oldest classification for calcaneal fractures which based on conventional radigraphical findings was performed by Essex-Lopresti  Crosby-Fitzgibbons is another prevalent classification. Amount of displacement of the posterior facet determines the type of fracture in this CT based classification system [39] (Figures 1 and 2).
There is still some controversy about classification systems. According to Schepers et al. [37] none of the classification systems satisfy all of the criteria required for an ideal classification system.
Although a large number of classification systems have been developed during the years calcaneal fractures can be classified basically as intra-or extra-articular [23].
Intra-articular fractures account for 70% and extra-articular fractures account for 30% of all calcaneal fractures in adults [4].

Treatment
There is a lack of consensus on treatment and operative technique in calcaneal fractures. No treatment, conservative treatment, open reduction and internal fixation, primary subtalar arthrodesis, delayed primary arthrodesis and calcanectomy are treatment options in the literature [40]. Also minimally invasive techniques have developed over the time. Restoring articular congruity and hindfoot morphology are the aims of calcaneal fracture treatment [41] (Table 1)

Non-operative treatment
Conservative treatment was preferred over surgical treatment until modern imaging methods, osteosynthesis materials, improvements of less invasive surgical techniques and the precence of effective and adequate antibiotic treatments have been developed. However current treatment protocol of calcaneal fractures has shifted in favour of ORIF [24]. Age, health, gender, status of the soft tissue, injury mechanism, comminution of the bone and Bohler angle affect the choice of treatment [42]. Open reduction and internal fixation is preferable to conservative treatment for displaced calcaneal fractures in a selected group of healthy patients [43]. In general conservative treatment is applied for non-displaced fractures and surgical treatment is applied for displaced intra-articular fractures [18].
Wound concerns, medical co-morbidities and non-compliance factors may affect the decision in favour of conservative treatment [41]. Bandaging and elevation of the foot for the treatment of calcaneal fractures have been applied for a long time [44]. Elevation, splinting and non-weight bearing for up to 12 weeks are parts of conservative treatment [25].
Controversy related to open or closed management of intraarticular calcaneal fractures still persists [4]. Jarvholm et al. [45] concluded that results of operative and non-operative treatment are almost equal and they argued that primary surgery is rarely indicated. There were no significant differences between the two groups with regard to heel pain, subtalar motion, and return to work in a matched cohort study [46]. Equal outcomes between operative and nonoperative treatment were obtained in a randomized controlled trial which involves 309 patients [43]. On the contrary Leung et al. [47] found significantly better results in operated group compared with non-operated group. Allmacher et al. [48] showed poor functional and clinical outcomes of non-operative treatment in their prospective cohort series and there were subtalar arthritis suspicious findings on CT images of patients. According to another study secondary arthrodesis is indicated after initial conservative treatment in approximately 21% to 30% of cases versus 2% to 5% of cases after operative treatment [49].

Operative treatment
ORIF is routinely performed especially for displaced intra-articular calcaneal fractures currently [50]. However outcomes of previous randomised controlled trials in this subject have varied. Jiang et al [51] showed that surgery can effectively restore the anatomical structures of the calcaneus and lead to better functional recovery for displaced intra-articular calcaneal fractures in their meta-analysis. According to prospective, randomised, controlled multicenter trial outcomes of operative and non-operative treatment of displaced intra-articular calcaneal fractures are comparable at one year follow up. However the same study showed that operative treatment have some benefits at eight to twelve years [52].
There are various approaches for calcaneal fracture fixation in the literature. Surgical approach is one of the factors affecting the outcomes of surgical treatment. Medial approach which allows direct reduction of the primary fracture line is associated with poor outcomes and high complication rates [40]. Accurate reduction of lateral and medial fragments can be applied through combined lateral and medial approaches. Skin blood supply problems may develop in this approach [23].
In the short lateral approach peroneal tendons and sural nerve are at risk of injury [40].  The most commonly used approach is the extensile lateral approach which was originally described by Letournel [53]. Better visualization of the calcaneus and to allow the anatomical reduction is advantages of the approach [54]. This approach has been extended to include a fullthickness flap that protects peroneal tendons, sural nerve, and the vascularity of the flap [25]. Kirschner wires are placed in the fibula, talar neck, and cuboid bone for retraction of the subperiostal flap. A low-profile lateral neutralization plate is placed for fixation after completion of reduction. The full-thickness flap is closed over a deep drain [8].
Sinus tarsi approach is one of several open surgical techniques. Better visulization of the subtalar joint is the advantage of this technique. Surgical manipulations especially for the posterior subtalar joint may become easier through this approach.
Primary subtalar arthrodesis is one of the surgical techniques that can be applied for comminuted calcaneal fractures. This technique may be preferred especially for four or more-part fractures of the posterior facet of the subtalar joint.
Despite ORIF is the best method for achieving anatomic reduction and calcaneal restoration soft tissue problems should be taken into account [23].
Minimally invasive and percutanous methods developed for reducing the wound complication rate. Clark [13] described minimally invasive technique using ligamentotaxis for calcaneal fractures in 1855.
Percutaneous reduction of fragments by Kirschner-wires, application of external fixators, percutanous screw fixation after percutanous distraction of displaced fragments is various minimally invasive techniques [44]. Difficulty in reducing the articular surface is the main problem of percutanous techniques [54]. For this reason ORIF gained more popularity compared with minimal invasive techniques [44].
There is some debate about the treatment method of Sanders type 4 fractures. These types of fractures can be treated surgically or conservatively in deference to the surgeon's experience.
Despite these general treatment principles a case-by-case basis treatment strategy should be performed because various factors affect the development of complications in calcaneal fractures [56].

Challenges and complications
Soft tissue problems may accompany to calcaneal fractures due to high-energy trauma. Particularly severe edema may cause corruption of the soft tissue, fracture blisters and compartment syndrome [32]. These factors negatively affect or may delay the treatment.
Soft tissue complications affect the success of the surgery. Therefore timing of the surgery is important for overcoming these problems. Operation should be delayed until declining of the soft tissue edema and resolving of fracture blisters for performing a safe surgery. There is a lack of consensus in the literature about sufficiently delaying surgery after the fracture in order to allow the soft tissue swelling to subside [4]. However surgery should not be delayed more than 2 weeks, because subsequent fibrosis between fragments may complicate surgery [57].
Infection and skin necrosis may delay the treatment. Entrapment of tendons between fracture fragments may cause tendon injuries [22]. Nerve entrapment and nerve injuries may associated with calcaneal fractures. Post-traumatic arthritis of the subtalar joint, instability and subluxation of peroneal tendons, heel pad syndrome and exostoses are other complications [18].

Conclusion
Calcaneal fractures should be evaluated carefully. The treatment of calcaneal fractures must be planned according to different factors such as type of trauma, classification of the fracture, skin condition and injury mechanism. Most of recent study shows that open reduction and internal fixation has better outcome in selected patients. In conclusion; Good evaluation, preoperative planning and appropriate treatment bring out better results.