- Email: [email protected]
Fractures of the talus: Current concepts and new developments
Accepted Manuscript Title: Fractures of the talus: Current concepts and new developments Authors: John A. Buza III MD, MS, Philipp Leucht MD, PhD PII: DOI: Reference:
S1268-7731(17)30086-3 http://dx.doi.org/doi:10.1016/j.fas.2017.04.008 FAS 1045
To appear in:
Foot and Ankle Surgery
Received date: Revised date: Accepted date:
6-1-2017 9-4-2017 14-4-2017
Please cite this article as: Buza John A, Leucht Philipp.Fractures of the talus: Current concepts and new developments.Foot and Ankle Surgery http://dx.doi.org/10.1016/j.fas.2017.04.008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Fractures of developments
the
talus:
Current
concepts
and
new
John A. Buza III, MD, MS, Philipp Leucht, MD, PhD 1
NYU Langone Medical Center, Hospital for Joint Diseases, 301 E. 17th St., New York,
NY 10003
Corresponding Author: Philipp Leucht, MD, PhD Assistant Professor, Departments of Orthopaedic Surgery and Cell Biology NYU Langone Medical Center, Hospital for Joint Diseases 301 E. 17th St, Suite 1500 New York, NY 10003 [email protected] P (646) 501-0291 F (646) 754-9825 Highlights: Fractures of the talus are challenging to manage with a high rate of complications Advanced imaging with CT scan is recommended in all talar neck fractures The Hawkin’s classification system predicts the rate of osteonecrosis Dual anteromedial and anterolateral surgical approaches may be beneficial Plate fixation often allows for precise reduction with decreased malalignment ABSTRACT Fractures of the talus are challenging to manage, with historically poor outcomes and a high rate of complications. The rare nature of this injury limits the number of studies available to guide treatment. Fortunately, a number of advancements have been made in the last decade. There is increased recognition regarding the importance of anatomic reconstruction of the osseous injury. Advanced imaging is used to assess the subtalar joint, where even slight displacement may predispose to arthritis. Increasing use of dual anteromedial and anterolateral approaches, along with plate fixation, has improved our ability to accurately restore the anatomy of the talus. Modification of the original Hawkins classification can both guide treatment and allow us to better predict which patients will develop avascular necrosis. Lastly, improved reconstructive techniques help address the most common complications after talus fracture, including arthritis, avascular necrosis, and malunion.
KEYWORDS: talus; fracture; Hawkins; osteonecrosis; post-traumatic arthritis
1. INTRODUCTION Fractures of the talus are uncommon, and typically occur after high-energy mechanisms such as a fall from a height or motor vehicle crash. While previous studies cite an incidence ranging from 0.1 – 2.5% of all fractures, the true incidence is not known.[1, 2] The infrequency of these injuries is in part responsible for the historically poor outcomes and high rate of complications, as there was little data to guide treatment. The majority of previous studies have been small case series, which has further limited our understanding of the proper treatment of these injuries. Fortunately, a number of advancements in our understanding of the treatment of talus fractures has improved outcomes and reduced complication rates. In the past decade, there have been improvements in the surgical techniques, timing, and instrumentation of talus fractures. These fractures are classified based on their primary fracture line into head, neck, body, or lateral/posterior process fractures. These fractures types have unique anatomy, presentation, and treatment, and will therefore be discussed separately. 2. RELEVANT ANATOMY The talus is unique in that over one half of its surface is covered by articular cartilage, and it has no muscular attachments. (Figure 1) The trochlea, or superior surface, articulates with the tibial plafond and is wider anteriorly such that maximal articular congruence of the ankle occurs in dorsiflexion. This superior articular surface extends both medially and laterally to articulate with the malleoli. The inferior aspect of the talus is predominantly covered with cartilage, and has posterior, middle, and anterior facets, which correspond to the articular facets of the calcaneus. The lateral process of the talus is completely covered by cartilage and articulates with the distal end of the fibula superiorly and the posterior facet of the calcaneus inferiorly. The posterior process of the talus is composed of both posteromedial and posterolateral tubercles, which form a groove that contains the flexor hallucis longus tendon. The neck of the talus is angled medially at a mean of 24 degrees (range, 10-44 degrees) and plantarly between 5 and 50 degrees.[3] Importantly, the neck is relatively devoid of articular cartilage and serves as a site of vascular inflow, particularly at the dorsal neck where capsular and ligamentous attachments originate.
2.1 BLOOD SUPPLY The talus has a rich network of extra- and intraosseous anastomoses that is vulnerable to disruption from trauma. (Figure 2) The extraosseous blood supply of the talus comes from three arteries including the anterior tibial, posterior tibial, and perforating peroneal artery.[4] The talar head is supplied by branches of the dorsalis pedis artery and the artery of the tarsal sinus. Early anatomical studies demonstrated that the main blood supply to the talar body is through an anastomotic sling located inferior to the talar neck in the tarsal canal. This sling is composed of the artery of the tarsal canal, which is a branch of the posterior tibial artery, and the artery of the tarsal sinus, which is a branch of the perforating peroneal artery.[5] This implied that the majority of the blood supply to the talus was through retrograde flow, which explained the high rate of AVN in talar neck fractures after disruption of this sling. A recent study using gadolinium-enhanced MRI found that the greatest blood supply to the talus enters posteriorly from the posterior tibial artery, contrasting earlier studies.[6] This finding, the authors concluded, might explain the low rates of osteonecrosis following talar neck fracture in the recent literature.[6] 3. TALAR NECK FRACTURES Fractures of the neck of the talus are the most common, accounting for 50% of all talus fractures.[7] The mechanism responsible for this injury is unknown, but is often ascribed to forced dorsiflexion of the foot, which drives the weak trabecular bone of the neck of the talus against the stronger anterior tibial plafond. With increasing dorsiflexion forces, disruption of the interosseous talocalcaneal ligament and posterior tibiotalar joint capsule leads to subluxation or complete dislocation of the talus. The talus will often rotate about the intact deltoid ligament and come to rest between the posterior aspect of the medial malleolus and the Achilles tendon, where neurovascular structures may be compromised. In extreme cases, the deltoid ligament may rupture, leading to talar extrusion. Twenty percent of talus fractures are open, and the rate of associated fractures is as high as 64%, including the foot, ankle, and spine.[8] In approximately 25% of these fractures, supination of the hindfoot leads to medial neck comminution and medial malleolus fracture.[8]
3.1 CLASSIFICATION The most commonly used classification system for talar neck fractures was originally
described by Hawkins and later modified by Canale and Kelly.[8, 9] (Figure 3) There are four types which are classified based on the radiographic appearance at the time of injury. Type I fractures are nondisplaced, with congruent ankle and subtalar joints. (Figure 3A) Even minimal displacement of 1 to 2 mm of the talar neck results in subtle incongruity of the subtalar joint, and should not be classified as a Type I. These fractures are difficult to identity on routine radiographs and may require CT for diagnosis. The rate of AVN in Type I fractures is less than 10%.[8, 9] (Table 1) Hawkins type II fractures refer to a talar neck fracture with either subluxation or dislocation of the subtalar joint. (Figure 3B-C) This is the most common type of talar neck fracture. In their original series, both Hawkins and Canale noted an AVN incidence of 42 to 50% for type II fractures.[8, 9] Vallier further subdivided the type II classification into two subtypes; IIA, those with a subluxated subtalar joint (Figure 3B), and IIB, those with a dislocated subtalar joint.[10] (Figure 3C) In their series of 81 talar neck fractures, 0 of the 19 (0%) Hawkins type IIA fractures developed osteonecrosis in contrast to 4 of 16 (25%) Hawkins type IIB fractures. In subtalar dislocations (type IIB) there is an increased risk of compromise to the remaining blood supply, which may account for the increased risk of osteonecrosis. The Hawkins type III fracture is characterized by a fracture of the neck with a dislocation of the tibiotalar joint in addition to the subtalar joint. (Figure 3D) The body is typically extruded posteromedially, which places the tibial neurovascular bundle at risk. Early cohorts had a reported AVN rate approaching 100%[8, 9], with more recent reviews citing an AVN rate of 44%.[11, 12] (Table 1) Given the degree of displacement, many of these fractures are open and are irreducible by closed means. Canale and Kelly added the type IV talar neck fracture to indicate an associated subluxation or dislocation of the talonavicular joint.[9] (Figure 3E) These fractures are extremely rare, representing only 4% of talar neck fractures.[11] The reported rate of AVN among these fractures is 12-48%, but this may not be an accurate estimate given the low number of reported type IV fractures in the literature.[11, 12]
3.2 CLINICAL EVALUATION Patients with talar neck fractures typically present after a high-energy injury such as a motor vehicle crash or fall from a height, and have foot swelling, pain, or deformity. For high-energy injuries, the patient should undergo a thorough physical examination to identify associated injuries.[13] When the talus is dislocated, an urgent reduction in the emergency room is indicated to reduce the risk of osteonecrosis and skin compromise.
Closed reduction is attempted with knee flexion along with plantar flexion and inversion or eversion. Repeated forceful reduction attempts should be avoided. Irreducible injuries should be considered an indication of surgical urgency. Open fractures require urgent irrigation and debridement in the operating room.[14-16] In severe cases of complete or partial talar extrusion, the extruded bone fragments should be cleaned and saved to preserve all future surgical reconstruction options.[17]
3.4 RADIOGRAPHIC EVALUATION Initial radiographic views should include anteroposterior, lateral, and mortise views of the foot and ankle. While these views will allow assessment of the talar body, talar neck, and associated processes, they are often inadequate to assess the alignment and degree of comminution of the talar neck. Canale and Kelly described a view of the talar neck which is obtained by maximal plantarflexion at the ankle, 15o of eversion, and angling the beam 75o degrees from the horizontal.[9, 18] CT scans are invaluable to assess for comminution, intra-articular fragments, and congruent reduction of the tibiotalar, subtalar, and talonavicular joints.
3.5 TREATMENT The goals of treatment for talar neck fractures are anatomic reduction, restoration of articular and axial alignment, preservation of motion, and minimization of complications including AVN, post-traumatic arthritis, malunion, nonunion, and infection.
3.5.1 Non-operative Non-operative treatment is reserved for truly nondisplaced Hawkins Type I fractures. Biomechanical studies have demonstrated that as little as 2mm of displacement significantly alters subtalar contact forces, which may predispose to arthritis.[19] Thus, a CT scan should be used to assess displacement prior to selecting non-operative treatment. Treatment consists of non-weight bearing in a cast for 6 weeks or until radiographic union, which may take up to 12 weeks.
3.5.2 Operative The current standard of care for all displaced talar neck fractures is operative reduction and internal fixation. Closed reduction may be difficult, and when possible it is preferable to proceed directly to operative fixation to avoid multiple unsuccessful reduction attempts.
3.5.3 Surgical Approaches There are various surgical approaches to the talar neck. Regardless of approach, it is imperative that full-thickness flaps are created with no undermining to avoid soft tissue necrosis. The anteromedial approach to the talus involves making an incision medial to the anterior tibial tendon.[16] This incision may be extended proximally if a malleolar osteotomy is required, or in the presence of a medial malleolar fracture that requires operative fixation. The major disadvantage of this approach is the inability to visualize the lateral aspect of the talar neck, which is necessary to judge the quality of reduction. The anterolateral approach is performed with an incision between the tibia and fibula and in line with the fourth ray, just lateral to the extensor digitorum longus. (Figure 4) This incision is the distal extension of the Bohler incision, which is the extensile anterolateral approach to the foot and ankle.[16] When this incision is used in conjunction with the anteromedial approach, it is important to maintain an adequate skin bridge to avoid skin necrosis. This approach allows for anatomic reduction of the lateral talar neck. If needed, an anterolateral fibular osteotomy can be performed for gaining access to the proximal lateral talus. Often, there is a cortical fragment at the anterolateral corner of the talar neck near the margin with the lateral process, from which one can base an anatomic reduction. Dissection of the inferior neck, deltoid ligament, and sinus tarsi should all be avoided to maintain the vascular supply of the talar neck. The posterolateral approach involves making an incision just lateral to the Achilles tendon, and developing the interval between the flexor hallucis longus and peroneal muscles. This approach can be used to facilitate lag screw fixation, as the screw trajectory if perpendicular to the fracture line. Care should be taken to avoid injury to the peroneal artery and saphenous nerve.
3.5.4 Timing of Surgery Talar neck fractures were long thought to be orthopaedic emergencies, in which immediate reduction of the talar neck would minimize the incidence of osteonecrosis.[9] Recent studies have shown that this is not true, and that osteonecrosis may be more strongly correlated to other factors such as open fracture or comminution of the talar neck.[14, 20] Increased time between surgery and operative treatment did not increase the risk of complications or future surgery.[15] Timing of definitive surgery should be based on injury to the surrounding soft tissues, as the rate of soft tissue complications ranges between 2% and 10%.[10] Definitive surgery should be deferred until there is adequate
resolution of swelling, which may take up to 2 weeks after injury. It is critically important to remember that surgery should only be delayed provided that the talar neck is in a reduced position. All displaced talar neck fractures require urgent reduction in the emergency room. Irreducible talar neck fractures should be taken to the operating room for open reduction and internal fixation on an urgent basis.
3.5.5 Percutaneous Fixation Percutaneous fixation should be reserved for truly nondisplaced fractures, in which fixation allows for early range of motion compared to casting. In displaced fractures, percutaneous fixation is indicated in the rare case in which an anatomic reduction can be performed and there is no significant comminution. Although low rates of osteonecrosis and malunion have previously been reported using closed reduction with Schanz pins followed by percutaneous fixation in Hawkins grades II-IV, it is not recommended.[21] Screw fixation can be placed from posteromedial, posterolateral, or anterior approaches.[22]
3.5.6 Open Reduction and Internal Fixation Dual anteromedial and anterolateral surgical approaches allow for full visualization of the talar neck. A medial malleolar osteotomy may be required to allow access to the talar body.[16, 23] Provisional reduction of the talar neck and body can be maintained with Kirschner wire fixation. Aligning the cortical margins without recognizing the degree of comminution will lead to improper varus and extension. One strategy to prevent this from occurring is performing an anterolateral exposure, which allows visualization and direct cortical reduction of the lateral talar neck. In addition, bone grafting of the medial neck may be required to provide mechanical support.[15] In all cases, subtalar debridement is critical to ensure that there is no block to reduction or loose fragments.
3.5.7 Screw Fixation Screw fixation alone was the predominant method of fixation of displaced talar neck fractures in most early series as well as several recent ones.[7, 14, 15, 22] Screws can be placed from anterior-to-posterior or posterior-to-anterior. Anterior-to-posterior screws (one medial and one lateral) are inserted adjacent to the articular surface of the talar head and directed posteriorly into the body. Anterior-to-posterior screws may interfere with talonavicular joint function when prominent. For that reason, it is recommended to countersink the screw head or use headless lag screws with this technique.
Posterior-to-anterior lag screw fixation has been shown to have superior biomechanical strength compared to anterior-to-posterior fixation.[24] These screws are typically placed from a posterolateral approach on either side of the flexor hallucis groove, and directed anteromedially. Potential disadvantages of posterior-to-anterior screw fixation include penetration of the subtalar joint, restriction of ankle plantar-flexion due to screw-head impingement, or injury to the FHL. Again, headless screws may avoid this risk and are biomechanically equivalent to standard screws.[25] For both anterior-toposterior and posterior-to-anterior screw fixation, it is important to remember that the use of lag screws in the setting of any comminution will lead to malalignment.[15] Position screws instead of lag screws can also be used to maintain an anatomic reduction on the medial side and avoid compressing a comminuted fracture into varus.
3.5.8 Screw and Plate Constructs Plate fixation of talar neck fractures has become more popular in the last decade, and is the recommended method of fixation by many authors.[2, 26-28] (Figure 5A-E) The major advantage of plate fixation over screw fixation is the ability to bridge areas of significant comminution.[26] This allows for a more precise reduction and avoids the potential risk of malalignment when using lag screw fixation across areas of comminution.[29] Areas of comminution should be packed with bone graft to provide structural support.[2, 15] The plate may be placed either medially or laterally depending on the location of comminution. Multiple studies have demonstrated that there is no difference in biomechanical strength between screw fixation alone and combination screw-plate constructs.[29, 30] Loose osteochondral fragments can be secured with minifragment screws with cruciform heads that are seated below the level of the articular cartilage, and are particularly useful for talar dome fractures.[16]
3.5.9 Postoperative management With stable fixation, early range of motion is encouraged once all wounds are healed. If there is concern regarding the integrity of the fixation, or in cases of significant ankle, subtalar, or talonavicular instability, casting for 6 weeks is recommended. The patient should remain non-weight-bearing until there is evidence of sufficient healing on radiographs, typically between 6 weeks and 3 months after injury.
4. TALAR BODY FRACTURES Fractures of the talar body involve both the tibiotalar and subtalar joints, and have the
highest incidence of arthritis among all talus fractures.[7] The accurate restoration of a congruent articular surface is therefore important to minimize the risk of this complication. Up to 50% of talar body fractures are associated with a talar neck fracture.[20] Radiologic evaluation of talar body fractures should always include a CT scan, as plain radiographs may underestimate the degree of articular injury. The treatment of talar body fractures adheres to many of the same principles as talar neck fixation; any displacement requires surgical management with open reduction and internal fixation. The surgical approaches for talar neck fractures may be used for open reduction and internal fixation of the talar body with minifragment or headless screws.[16] Medial malleolar osteotomy may be required for access to the talar dome.[23] It is important not to violate the deltoid ligament, which is an important source of blood supply to the talar body. Bone grafting should be considered when there is significant impaction of the talar dome.
4.1 Lateral Process Fractures Fractures of the lateral process are frequently missed on initial plain radiographs, as they may be subtle and difficult to visualize. This fracture is classically associated with a snowboarding injury.[31] Lateral process fractures are best seen on ankle mortise and internal oblique views, but CT scan is usually required to visualize the fracture and determine whether operative intervention is necessary. Small or nondisplaced lateral process fractures may be treated with immobilization and a period of non-weight bearing. Larger fractures and those with more than 2mm of displacement require fixation with lag screws or a minifragment plate.[32] Using either a posterolateral or anterolateral approach has been recommended.[2, 27] When lateral process fractures occur in the setting of a talar neck fracture, it is advised to stabilize the neck before fixing the lateral process.[2]
4.2 Posterior Process Fractures Posterior process fractures are best seen on lateral foot radiographs. It may be difficult to differentiate between a posterior process fracture of the talus and an os trigonum, which is an ossicle located behind the talus in up to 25% of the population.[33, 34] Os trigonum are generally round, oval, or triangular and may have a synchondrosis with the posterolateral talus. If the diagnosis cannot be made on plain radiographs, advanced imaging with either CT or MRI will allow for differentiation between os trigonum and posterior process fractures. Small and nondisplaced fractures of the posterior process may
be treated with immobilization and a period of non-weight-bearing. Larger fragments and those displaced more than 2mm are best treated with open reduction and internal fixation. The posteromedial approach allows access to the posterior process by utilizing the interval between the medial border of the Achilles tendon and the posterior edge of the medial malleolus. After fracture reduction, the fracture is stabilized with mini-fragment screws. While range of motion exercises may begin as soon as soft tissue swelling has subsided, it is recommended that patients remain non-weight bearing for 2 months after surgery.
5. TALAR HEAD FRACTURES Talar head fractures are rare, accounting for 2.6-10% of all talus fractures.[35] The natural history of talar head fractures is largely unknown, as only case reports are published in the literature.[35-40] (Table 2) These injuries are frequently associated with talonavicular dislocations, but can be easily missed when spontaneous reduction occurs before presentation. Standard radiographs should be supplemented with CT scan to assess the degree of articular displacement. Nondisplaced fractures may be treated with cast immobilization and non-weight bearing for 4-8 weeks after surgery. Ibrahim et al. recently suggested a treatment algorithm for displaced fractures on the basis of their systematic review; (1) displaced fractures with >50% talar head involvement or talonavicular joint instability should undergo open reduction and internal fixation with immobilization and non-weight bearing for 6-8 weeks postoperatively whereas (2) displaced fractures with <50% talar head involvement and no instability of the talonavicular joint may be treated with excision of fracture fragments, closure of the talonavicular joint capsule, and a period of immobilization and non-weight bearing.[35] An anteromedial approach to the talar head is most commonly used. Primary fusion of the talonavicular joint is an option in cases of severe talar head or navicular comminution, or as a salvage treatment for end-stage talonavicular post-traumatic arthritis.
6. TALUS FRACTURES IN CHILDREN Talus fractures in children are extremely rare. Compared to adult fractures, relatively little is known about the natural history of talus fractures in children, as there are only a small number of published case series.[41-47] The primary mechanism of injury for talus fractures in children appears to be dorsiflexion and axial loading, similar to the mechanism described in adults.[42, 44, 45] As in adults, talar neck fractures in children
are generally classified by the Hawkin’s classification, and follow similar treatment protocols. Nondisplaced fractures are generally treated non-operatively with cast immobilization,
whereas
displaced
fractures
are
treated
operatively.[41]
The
complications following talus fractures in children are similar to those found in adults, and
include
osteonecrosis,
post-traumatic
arthritis,
nonunion,
malunion,
and
infection.[41] One key difference between talus fractures in children and those in adults may be the rate of osteonecrosis after nondisplaced fractures.[47] Rammelt et al. found a rate of 16% of osteonecrosis after nondisplaced fractures, and proposed that this may be due to a greater susceptibility to circulatory disturbances in the pediatric talus.[47] It is important to maintain a high index of suspicion for the development of avascular necrosis following talus fracture in children, including those that are found to be nondisplaced.
7. COMPLICATIONS AND SALVAGE 7.1 Osteonecrosis The incidence of osteonecrosis after talar neck fracture increases with greater initial fracture displacement.[8, 12] (Table 1) The most cited rates of osteonecrosis come from Hawkins classic work, in which he reported an overall osteonecrosis rate of 58%, with rates of 0%, 42%, and 86% for Hawkins’ types I, II, and III, respectively.[8] Since the publication of this report in 1970, the standard of care has evolved to include the use of a more aggressive dual-incision open approach to all fractures.[11, 28] The reported rates of osteonecrosis have decreased with the evolution of treatment protocols in the past decade. (Table 3) In a meta-analysis of 26 studies including 980 talar neck fractures, Dodd et al. found that the overall rate of osteonecrosis was 31.2%; when looking at studies published after the year 2000, the rate drops to 24.9%.[12] In studies published after 2000, the authors also found that the rate of osteonecrosis for Hawkins Type II and Type III were 20.7% and 44.8%, respectively, which is roughly half the rate reported in Hawkins original series.[12] Osteonecrosis is also seen more commonly in open talus fractures.[14, 20] The diagnosis of osteonecrosis is commonly made on plain radiographs at anywhere from 4 weeks to 6 months after surgery.[8, 9] The radiographic criteria used to diagnose osteonecrosis are poorly defined, but it is generally indicated by a relative increase in the density of the talar body relative to adjacent structures. The presence of subchondral osteopenia at 6-8 weeks after injury, known as the Hawkins sign, is a reliable indicator that the development of osteonecrosis is unlikely.[48] The Hawkins sign has recently been shown to have a sensitivity of 100% and a specificity of
57.7%.[49] The converse, however, is not true; an absent Hawkins’ sign does not confirm the diagnosis of osteonecrosis.[48] In these cases, MRI can be used for the early diagnosis of osteonecrosis. Nearly half of all patients with osteonecrosis will undergo revascularization without collapse of the talar body, which may take up to 2 years following initial injury.[2, 10, 14, 20] There is no evidence that prolonged non-weight bearing during this time will help to prevent talar body collapse. It is important to note that many patients with talar body osteonecrosis are asymptomatic, and therefore the initial treatment is conservative. If conservative treatment fails and arthritis develops, arthrodesis of the involved joint is an effective means of eliminating pain. There are a variety of fusion techniques described in the literature to accomplish these goals.[50, 51] Motion preserving techniques have also been reported. Harnroongroj et al. recently reported the outcomes of 33 patients treated with implantation of a talar body prosthesis, 23 of which were implanted for talar body osteonecrosis.[52] Of the 33 talar body prosthesis, 28 were still implanted at final follow-up, ranging from 10 to 36 years post-operatively. The authors concluded that although early failure can occur, talar body prosthesis can provide satisfactory foot and ankle function at long-term follow up.[52]
7.2 Post-traumatic Arthritis Subtalar joint arthritis is the most common complication after talar neck fracture, developing in an average of 49% of patients in a recent meta-analysis of 16 included studies.[10-12, 14-16] (Table 3) When including only studies with a minimum of 2 year follow up, the authors found that this rate increased to 81%.[12] This complication is even more common after talar body fractures, where the reported rate is as high as 100%.[7, 14, 16] Post-traumatic arthritis may be treated conservatively with bracing and pain medication. End-stage arthritis recalcitrant to conservative treatment may require tibiotalar or subtalar arthrodesis for pain relief.[50, 51]
7.3 Malunion and Nonunion The rate of malunion after talar neck fracture is frequently reported in the range of 2030%, but is likely underestimated given the difficulty of identifying malignment by plain radiography alone.[14, 15, 53] (Table 3) Varus malunion is the most common deformity due to medial comminution. The dual incision approach and use of plates instead of lag screws alone both help to reduce the risk of this deformity. Varus malunion affects the biomechanics of the subtalar joint, which predisposes to the development of arthritis.[19]
Malunion should be evaluated with CT scan, and often requires corrective osteotomy.[54] Nonunion is rare after talar neck fracture, typically occurring in the 3-5% range.[10, 20, 28] If nonunion is associated with advanced arthritis, fusion may be required.
7.4 Skin Complications and Infection Soft tissue complications such as skin necrosis and deep infection are among the most disastrous complications after talar fracture. There are a number of principles aimed at minimizing the risk of these complications, including urgent reduction of dislocations, administration of antibiotics and surgical debridement for open fractures, and meticulous soft tissue handling during surgery. As stated previously, definitive surgical intervention should be delayed until adequate resolution of swelling has occurred, which may take up to 3 weeks after injury.[26]
8. SUMMARY The role for non-operative treatment of talar neck or body fractures is limited to nondisplaced or anatomically reduced fractures confirmed by CT scan. Any displacement requires meticulous anatomic reduction and fixation. The use of dual anteromedial and anterolateral approaches, plating, and bone grafting are paramount to a successful reduction. As a result of these surgical tactics, the reported rate of osteonecrosis following talar neck fracture has decreased over time, although it remains high. The current gold standard treatment for end stage tibiotalar or subtalar arthritis following talus fracture is arthrodesis of the involved joints. Lateral process fractures are easily missed, but prompt diagnosis and appropriate treatment are important to ensure a good outcome. Talar head fractures are rare, and depending on the percentage of talonavicular joint involved, may be either excised or anatomically fixed. Conflicts of Interest: There are no conflicts of interest to report.
Acknowledgements: None. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
REFERENCES [1]Santavirta S, Seitsalo S, Kiviluoto O, Myllynen P. Fractures of the talus. The Journal of trauma 24: 986, 1984 [2]Vallier HA. Fractures of the Talus: State of the Art. Journal of orthopaedic trauma 29: 385, 2015 [3]Fortin PT, Balazsy JE. Talus fractures: evaluation and treatment. The Journal of the American Academy of Orthopaedic Surgeons 9: 114, 2001 [4]Mulfinger GL, Trueta J. The blood supply of the talus. The Journal of bone and joint surgery British volume 52: 160, 1970 [5]Peterson L, Goldie IF. The arterial supply of the talus. A study on the relationship to experimental talar fractures. Acta orthopaedica Scandinavica 46: 1026, 1975 [6]Miller AN, Prasarn ML, Dyke JP, Helfet DL, Lorich DG. Quantitative assessment of the vascularity of the talus with gadolinium-enhanced magnetic resonance imaging. The Journal of bone and joint surgery American volume 93: 1116, 2011 [7]Elgafy H, Ebraheim NA, Tile M, Stephen D, Kase J. Fractures of the talus: experience of two level 1 trauma centers. Foot & ankle international 21: 1023, 2000 [8]Hawkins LG. Fractures of the neck of the talus. The Journal of bone and joint surgery American volume 52: 991, 1970 [9]Canale ST, Kelly FB, Jr. Fractures of the neck of the talus. Long-term evaluation of seventy-one cases. The Journal of bone and joint surgery American volume 60: 143, 1978 [10]Vallier HA, Reichard SG, Boyd AJ, Moore TA. A new look at the Hawkins classification for talar neck fractures: which features of injury and treatment are predictive of osteonecrosis? The Journal of bone and joint surgery American volume 96: 192, 2014 [11]Halvorson JJ, Winter SB, Teasdall RD, Scott AT. Talar neck fractures: a systematic review of the literature. The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons 52: 56, 2013 [12]Dodd A, Lefaivre KA. Outcomes of Talar Neck Fractures: A Systematic Review and Meta-analysis. Journal of orthopaedic trauma 29: 210, 2015 [13]Lin S, Hak DJ. Management of talar neck fractures. Orthopedics 34: 715, 2011 [14]Lindvall E, Haidukewych G, DiPasquale T, Herscovici D, Jr., Sanders R. Open reduction and stable fixation of isolated, displaced talar neck and body fractures. The Journal of bone and joint surgery American volume 86-A: 2229, 2004 [15]Sanders DW, Busam M, Hattwick E, Edwards JR, McAndrew MP, Johnson KD. Functional outcomes following displaced talar neck fractures. Journal of orthopaedic trauma 18: 265, 2004 [16]Vallier HA, Nork SE, Benirschke SK, Sangeorzan BJ. Surgical treatment of talar body fractures. The Journal of bone and joint surgery American volume 86-A Suppl 1: 180, 2004 [17]Gerken N, Yalamanchili R, Yalamanchili S, Penagaluru P, Md EM, Cox G. Talar revascularization after a complete talar extrusion. Journal of orthopaedic trauma 25: e107, 2011 [18]Thomas JL, Boyce BM. Radiographic analysis of the Canale view for displaced talar neck fractures. The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons 51: 187, 2012 [19]Sangeorzan BJ, Wagner UA, Harrington RM, Tencer AF. Contact characteristics of the subtalar joint: the effect of talar neck misalignment. Journal of orthopaedic research : official publication of the Orthopaedic Research Society 10: 544, 1992
[20]Vallier HA, Nork SE, Barei DP, Benirschke SK, Sangeorzan BJ. Talar neck fractures: results and outcomes. The Journal of bone and joint surgery American volume 86-A: 1616, 2004 [21]Abdelgaid SM, Ezzat FF. Percutaneous reduction and screw fixation of fracture neck talus. Foot and ankle surgery : official journal of the European Society of Foot and Ankle Surgeons 18: 219, 2012 [22]Abdelkafy A, Imam MA, Sokkar S, Hirschmann M. Antegrade-retrograde opposing lag screws for internal fixation of simple displaced talar neck fractures. The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons 54: 23, 2015 [23]van Bergen CJ, Tuijthof GJ, Sierevelt IN, van Dijk CN. Direction of the oblique medial malleolar osteotomy for exposure of the talus. Archives of orthopaedic and trauma surgery 131: 893, 2011 [24]Swanson TV, Bray TJ, Holmes GB, Jr. Fractures of the talar neck. A mechanical study of fixation. The Journal of bone and joint surgery American volume 74: 544, 1992 [25]Capelle JH, Couch CG, Wells KM, Morris RP, Buford WL, Jr., Merriman DJ, Panchbhavi VK. Fixation strength of anteriorly inserted headless screws for talar neck fractures. Foot & ankle international 34: 1012, 2013 [26]Fleuriau Chateau PB, Brokaw DS, Jelen BA, Scheid DK, Weber TG. Plate fixation of talar neck fractures: preliminary review of a new technique in twenty-three patients. Journal of orthopaedic trauma 16: 213, 2002 [27]Shakked RJ, Tejwani NC. Surgical treatment of talus fractures. The Orthopedic clinics of North America 44: 521, 2013 [28]Xue Y, Zhang H, Pei F, Tu C, Song Y, Fang Y, Liu L. Treatment of displaced talar neck fractures using delayed procedures of plate fixation through dual approaches. Int Orthop 38: 149, 2014 [29]Charlson MD, Parks BG, Weber TG, Guyton GP. Comparison of plate and screw fixation and screw fixation alone in a comminuted talar neck fracture model. Foot & ankle international 27: 340, 2006 [30]Attiah M, Sanders DW, Valdivia G, Cooper I, Ferreira L, MacLeod MD, Johnson JA. Comminuted talar neck fractures: a mechanical comparison of fixation techniques. Journal of orthopaedic trauma 21: 47, 2007 [31]Kramer IF, Brouwers L, Brink PR, Poeze M. Snowboarders' ankle. BMJ case reports 2014, 2014 [32]Perera A, Baker JF, Lui DF, Stephens MM. The management and outcome of lateral process fracture of the talus. Foot and ankle surgery : official journal of the European Society of Foot and Ankle Surgeons 16: 15, 2010 [33]Lawson JP. International Skeletal Society Lecture in honor of Howard D. Dorfman. Clinically significant radiologic anatomic variants of the skeleton. AJR Am J Roentgenol 163: 249, 1994 [34]Karasick D, Schweitzer ME. The os trigonum syndrome: imaging features. AJR Am J Roentgenol 166: 125, 1996 [35]Ibrahim MS, Jordan R, Lotfi N, Chapman AW. Talar head fracture: A case report, systematic review and suggested algorithm of treatment. Foot 25: 258, 2015 [36]Long NM, Zoga AC, Kier R, Kavanagh EC. Insufficiency and nondisplaced fractures of the talar head: MRI appearances. AJR Am J Roentgenol 199: W613, 2012 [37]Matsumura T, Sekiya H, Hoshino Y. Correction osteotomy for malunion of the talar head: a case report. J Orthop Surg (Hong Kong) 16: 96, 2008 [38]Mulligan ME. Horizontal fracture of the talar head. A case report. The American journal of sports medicine 14: 176, 1986
[39]Pehlivan O, Akmaz I, Solakoglu C, Rodop O. Medial peritalar dislocation. Arch Orthop Trauma Surg 122: 541, 2002 [40]Vlahovich AT, Mehin R, O'Brien PJ. An unusual fracture of the talus in a snowboarder. Journal of orthopaedic trauma 19: 498, 2005 [41]Smith JT, Curtis TA, Spencer S, Kasser JR, Mahan ST. Complications of talus fractures in children. J Pediatr Orthop 30: 779, 2010 [42]Jensen I, Wester JU, Rasmussen F, Lindequist S, Schantz K. Prognosis of fracture of the talus in children. 21 (7-34)-year follow-up of 14 cases. Acta Orthop Scand 65: 398, 1994 [43]Draijer F, Havemann D, Bielstein D. [Injury analysis of pediatric talus fractures]. Unfallchirurg 98: 130, 1995 [44]Mazel C, Rigault P, Padovani JP, Finidori G, Touzet P. [Fractures of the talus in children. Apropos of 23 cases]. Rev Chir Orthop Reparatrice Appar Mot 72: 183, 1986 [45]Letts RM, Gibeault D. Fractures of the neck of the talus in children. Foot Ankle 1: 74, 1980 [46]Eberl R, Singer G, Schalamon J, Hausbrandt P, Hoellwarth ME. Fractures of the talus--differences between children and adolescents. J Trauma 68: 126, 2010 [47]Rammelt S, Zwipp H, Gavlik JM. Avascular necrosis after minimally displaced talus fracture in a child. Foot Ankle Int 21: 1030, 2000 [48]Chen H, Liu W, Deng L, Song W. The prognostic value of the hawkins sign and diagnostic value of MRI after talar neck fractures. Foot & ankle international 35: 1255, 2014 [49]Tezval M, Dumont C, Sturmer KM. Prognostic reliability of the Hawkins sign in fractures of the talus. Journal of orthopaedic trauma 21: 538, 2007 [50]Easley ME, Trnka HJ, Schon LC, Myerson MS. Isolated subtalar arthrodesis. The Journal of bone and joint surgery American volume 82: 613, 2000 [51]Tenenbaum S, Stockton KG, Bariteau JT, Brodsky JW. Salvage of avascular necrosis of the talus by combined ankle and hindfoot arthrodesis without structural bone graft. Foot & ankle international 36: 282, 2015 [52]Harnroongroj T, Harnroongroj T. The Talar Body Prosthesis: Results at Ten to Thirty-six Years of Follow-up. The Journal of bone and joint surgery American volume 96: 1211, 2014 [53]Fournier A, Barba N, Steiger V, Lourdais A, Frin JM, Williams T, Falaise V, Pineau V, Salle de Chou E, Noailles T, Carvalhana G, Ruhlmann F, Huten D. Total talar fracture - long-term results of internal fixation of talar fractures. A multicentric study of 114 cases. Orthopaedics & traumatology, surgery & research : OTSR 98: S48, 2012 [54]Suter T, Barg A, Knupp M, Henninger H, Hintermann B. Surgical technique: talar neck osteotomy to lengthen the medial column after a malunited talar neck fracture. Clin Orthop Relat Res 471: 1356, 2013
Figure Legend: Figure 1. Superior and inferior views demonstrate the osseous anatomy of the talus. FHL = Flexor Hallucis Longus.
Figure 2. Arterial supply to the talus from dorsal and plantar views. The major arterial supplies are the 1) artery of the tarsal sinus (TS) from either the dorsalis pedis (DP) or peroneal artery, 2) the artery of the tarsal canal (TC) from the posterior tibial artery , 3) the deltoid artery from either the TC or the posterior tibial artery, 4) the posterior direct branches (PT) from the peroneal artery, and 5) the superomedial direct branches of the DP.
Figure 3A-E. Modified Hawkins classification system for talar neck fractures: (A) Type I - Nondisplaced talar neck fracture, (B) Type IIA – Talar neck fracture with subtalar subluxation (C) Type IIB – Talar neck fracture with subtalar dislocation , (D) Type III – Talar neck fracture with subtalar and tibiotalar dislocation, and (D) Type IV – Talar neck fracture with subtalar, tibiotalar, and talonavicular dislocations.
Figure 4. Clinical photograph of the incision used for the anterolateral approach to the talus.
Figure 5A-E. Anteroposterior (A) and lateral (B) radiographs of a Hawkins type II fracture with talar neck comminution and subtalar dislocation. Post-operative anteroposterior (C), Canale (D) and (E) lateral radiographs demonstrate dual plate fixation and reduction of the subtalar joint.
Table Legend Table 1. Avascular Necrosis Rates by Hawkins’ Type Table 1. Avascular Necrosis Rates by Hawkins’ Type Hawkins’ Type
Associated Joint Subluxation or Dislocation
Hawkins, 19708
Dodd et al., 201512 (Published after year 2000, n=14)*
I
None
0%
8.0%
II
Subtalar
42%
20.7%
III
Subtalar Tibiotalar
86%
44.8%
Subtalar IV Tibiotalar __ 36.5% Talonavicular *Authors performed a meta-analysis of all studies reporting the rate of avascular necrosis after talar neck fracture, and reported a separate rate for 14 studies published after 2000.
Table 2. Case Reports of Talar Head Fracture Author, Year
Patie nt Age / Sex Ibrahim et 31/F al., 201535
Fracture Mechanis displaceme m nt
Treatment
Displaced
Locking plate and NWB in Symptomatic cast x 6 weeks hardware
12
Long et al., 45/M 201236 20/F 16/M
Nondisplac ed Nondisplac ed Nondisplac ed Displaced
Conservative Presentation) Conservative Presentation) Conservative Presentation) Cast x 4 weeks
NR NR NR
Matsumura 26/M et al., 200837
Mulligan et 27/M al., 198638 Pehlivan et 22/M al., 200239
Nondisplac ed Displaced
Inversion injury while walking NR NR Football
Wakeboard ing
Complications
(Delayed NR NR (Delayed NR (Delayed
Gymnastics Walking cast x 4 weeks Inversion injury while walking Snowboard ing
Follow -up (Mos.)
Malunion 18 (required medial talar head osteotomy and ICBG) None 21
ORIF with K-wire fixation Persistent 26 and NWB in cast x 6 weeks lateral hindfoot pain
Vlahovich 33/F Displaced ORIF with 2.7mm Persistent pain et al., compression screws and 200540 bone graft NR= Not Reported, ORIF = Open reduction and internal fixation, NWB = Non-weight bearing, ICBG = Iliac crest bone graft
3
Table 3. Complications After Surgical Treatment for Talar Neck Fracture
Author, Year
No. Talar Neck Fractures
Open Fractures
AVN
Malunion
Nonunion
PTA
Chateau et al., 200226
23
NR
4 (17.3%)
2 (8.7%)
0 (0%)
3 (13%)
Chen et al., 201434
48
NR
11/38 (28.9%)
NR
NR
NR
Elgafy et al., 20007
27
NR
7 (25.9%)
NR
NR
18 (66%)
Lindvall et al., 200414
16
NR
7/16 (43.7%)
NR
2/16 (12.5%)
16/16 100%
Sanders et al., 200415
70
10/70 (14.3%)
8/70 (11.4%)
21/70 (30%)
NR
54/70 (78%)
Tezval et al., 200749
41
11/41 (26.8%)
5/31 (16.1%)
NR
NR
NR
Vallier et al., 200420
102
24/102 (24%)
19/39 (49%)
NR
3/60 (5%)
21/39 (53.8%)
Vallier et al., 201410
81
24/81 (30%)
16/65 (25%)
NR
2/65 (3.1%)
35/65 (54%)
Xue et al., 201428
28
0 (0%)
6/28 (21%)
NR
1/28 (3.6%)
7/28 (25%)
NR= Not Reported, AVN = Avascular Necrosis, PTA = Post-traumatic arthritis, AOFAS = American Orthopaedic Foot and Ankle Society ankle-hindfoot score, AOS = Ankle Osteoarthritis Score, MFA = Musculoskeletal Function Assessment, SMFA = Short Musculoskeletal Function Assessment, FFI = Foot Function Index
S1268-7731(17)30086-3 http://dx.doi.org/doi:10.1016/j.fas.2017.04.008 FAS 1045
To appear in:
Foot and Ankle Surgery
Received date: Revised date: Accepted date:
6-1-2017 9-4-2017 14-4-2017
Please cite this article as: Buza John A, Leucht Philipp.Fractures of the talus: Current concepts and new developments.Foot and Ankle Surgery http://dx.doi.org/10.1016/j.fas.2017.04.008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Fractures of developments
the
talus:
Current
concepts
and
new
John A. Buza III, MD, MS, Philipp Leucht, MD, PhD 1
NYU Langone Medical Center, Hospital for Joint Diseases, 301 E. 17th St., New York,
NY 10003
Corresponding Author: Philipp Leucht, MD, PhD Assistant Professor, Departments of Orthopaedic Surgery and Cell Biology NYU Langone Medical Center, Hospital for Joint Diseases 301 E. 17th St, Suite 1500 New York, NY 10003 [email protected] P (646) 501-0291 F (646) 754-9825 Highlights: Fractures of the talus are challenging to manage with a high rate of complications Advanced imaging with CT scan is recommended in all talar neck fractures The Hawkin’s classification system predicts the rate of osteonecrosis Dual anteromedial and anterolateral surgical approaches may be beneficial Plate fixation often allows for precise reduction with decreased malalignment ABSTRACT Fractures of the talus are challenging to manage, with historically poor outcomes and a high rate of complications. The rare nature of this injury limits the number of studies available to guide treatment. Fortunately, a number of advancements have been made in the last decade. There is increased recognition regarding the importance of anatomic reconstruction of the osseous injury. Advanced imaging is used to assess the subtalar joint, where even slight displacement may predispose to arthritis. Increasing use of dual anteromedial and anterolateral approaches, along with plate fixation, has improved our ability to accurately restore the anatomy of the talus. Modification of the original Hawkins classification can both guide treatment and allow us to better predict which patients will develop avascular necrosis. Lastly, improved reconstructive techniques help address the most common complications after talus fracture, including arthritis, avascular necrosis, and malunion.
KEYWORDS: talus; fracture; Hawkins; osteonecrosis; post-traumatic arthritis
1. INTRODUCTION Fractures of the talus are uncommon, and typically occur after high-energy mechanisms such as a fall from a height or motor vehicle crash. While previous studies cite an incidence ranging from 0.1 – 2.5% of all fractures, the true incidence is not known.[1, 2] The infrequency of these injuries is in part responsible for the historically poor outcomes and high rate of complications, as there was little data to guide treatment. The majority of previous studies have been small case series, which has further limited our understanding of the proper treatment of these injuries. Fortunately, a number of advancements in our understanding of the treatment of talus fractures has improved outcomes and reduced complication rates. In the past decade, there have been improvements in the surgical techniques, timing, and instrumentation of talus fractures. These fractures are classified based on their primary fracture line into head, neck, body, or lateral/posterior process fractures. These fractures types have unique anatomy, presentation, and treatment, and will therefore be discussed separately. 2. RELEVANT ANATOMY The talus is unique in that over one half of its surface is covered by articular cartilage, and it has no muscular attachments. (Figure 1) The trochlea, or superior surface, articulates with the tibial plafond and is wider anteriorly such that maximal articular congruence of the ankle occurs in dorsiflexion. This superior articular surface extends both medially and laterally to articulate with the malleoli. The inferior aspect of the talus is predominantly covered with cartilage, and has posterior, middle, and anterior facets, which correspond to the articular facets of the calcaneus. The lateral process of the talus is completely covered by cartilage and articulates with the distal end of the fibula superiorly and the posterior facet of the calcaneus inferiorly. The posterior process of the talus is composed of both posteromedial and posterolateral tubercles, which form a groove that contains the flexor hallucis longus tendon. The neck of the talus is angled medially at a mean of 24 degrees (range, 10-44 degrees) and plantarly between 5 and 50 degrees.[3] Importantly, the neck is relatively devoid of articular cartilage and serves as a site of vascular inflow, particularly at the dorsal neck where capsular and ligamentous attachments originate.
2.1 BLOOD SUPPLY The talus has a rich network of extra- and intraosseous anastomoses that is vulnerable to disruption from trauma. (Figure 2) The extraosseous blood supply of the talus comes from three arteries including the anterior tibial, posterior tibial, and perforating peroneal artery.[4] The talar head is supplied by branches of the dorsalis pedis artery and the artery of the tarsal sinus. Early anatomical studies demonstrated that the main blood supply to the talar body is through an anastomotic sling located inferior to the talar neck in the tarsal canal. This sling is composed of the artery of the tarsal canal, which is a branch of the posterior tibial artery, and the artery of the tarsal sinus, which is a branch of the perforating peroneal artery.[5] This implied that the majority of the blood supply to the talus was through retrograde flow, which explained the high rate of AVN in talar neck fractures after disruption of this sling. A recent study using gadolinium-enhanced MRI found that the greatest blood supply to the talus enters posteriorly from the posterior tibial artery, contrasting earlier studies.[6] This finding, the authors concluded, might explain the low rates of osteonecrosis following talar neck fracture in the recent literature.[6] 3. TALAR NECK FRACTURES Fractures of the neck of the talus are the most common, accounting for 50% of all talus fractures.[7] The mechanism responsible for this injury is unknown, but is often ascribed to forced dorsiflexion of the foot, which drives the weak trabecular bone of the neck of the talus against the stronger anterior tibial plafond. With increasing dorsiflexion forces, disruption of the interosseous talocalcaneal ligament and posterior tibiotalar joint capsule leads to subluxation or complete dislocation of the talus. The talus will often rotate about the intact deltoid ligament and come to rest between the posterior aspect of the medial malleolus and the Achilles tendon, where neurovascular structures may be compromised. In extreme cases, the deltoid ligament may rupture, leading to talar extrusion. Twenty percent of talus fractures are open, and the rate of associated fractures is as high as 64%, including the foot, ankle, and spine.[8] In approximately 25% of these fractures, supination of the hindfoot leads to medial neck comminution and medial malleolus fracture.[8]
3.1 CLASSIFICATION The most commonly used classification system for talar neck fractures was originally
described by Hawkins and later modified by Canale and Kelly.[8, 9] (Figure 3) There are four types which are classified based on the radiographic appearance at the time of injury. Type I fractures are nondisplaced, with congruent ankle and subtalar joints. (Figure 3A) Even minimal displacement of 1 to 2 mm of the talar neck results in subtle incongruity of the subtalar joint, and should not be classified as a Type I. These fractures are difficult to identity on routine radiographs and may require CT for diagnosis. The rate of AVN in Type I fractures is less than 10%.[8, 9] (Table 1) Hawkins type II fractures refer to a talar neck fracture with either subluxation or dislocation of the subtalar joint. (Figure 3B-C) This is the most common type of talar neck fracture. In their original series, both Hawkins and Canale noted an AVN incidence of 42 to 50% for type II fractures.[8, 9] Vallier further subdivided the type II classification into two subtypes; IIA, those with a subluxated subtalar joint (Figure 3B), and IIB, those with a dislocated subtalar joint.[10] (Figure 3C) In their series of 81 talar neck fractures, 0 of the 19 (0%) Hawkins type IIA fractures developed osteonecrosis in contrast to 4 of 16 (25%) Hawkins type IIB fractures. In subtalar dislocations (type IIB) there is an increased risk of compromise to the remaining blood supply, which may account for the increased risk of osteonecrosis. The Hawkins type III fracture is characterized by a fracture of the neck with a dislocation of the tibiotalar joint in addition to the subtalar joint. (Figure 3D) The body is typically extruded posteromedially, which places the tibial neurovascular bundle at risk. Early cohorts had a reported AVN rate approaching 100%[8, 9], with more recent reviews citing an AVN rate of 44%.[11, 12] (Table 1) Given the degree of displacement, many of these fractures are open and are irreducible by closed means. Canale and Kelly added the type IV talar neck fracture to indicate an associated subluxation or dislocation of the talonavicular joint.[9] (Figure 3E) These fractures are extremely rare, representing only 4% of talar neck fractures.[11] The reported rate of AVN among these fractures is 12-48%, but this may not be an accurate estimate given the low number of reported type IV fractures in the literature.[11, 12]
3.2 CLINICAL EVALUATION Patients with talar neck fractures typically present after a high-energy injury such as a motor vehicle crash or fall from a height, and have foot swelling, pain, or deformity. For high-energy injuries, the patient should undergo a thorough physical examination to identify associated injuries.[13] When the talus is dislocated, an urgent reduction in the emergency room is indicated to reduce the risk of osteonecrosis and skin compromise.
Closed reduction is attempted with knee flexion along with plantar flexion and inversion or eversion. Repeated forceful reduction attempts should be avoided. Irreducible injuries should be considered an indication of surgical urgency. Open fractures require urgent irrigation and debridement in the operating room.[14-16] In severe cases of complete or partial talar extrusion, the extruded bone fragments should be cleaned and saved to preserve all future surgical reconstruction options.[17]
3.4 RADIOGRAPHIC EVALUATION Initial radiographic views should include anteroposterior, lateral, and mortise views of the foot and ankle. While these views will allow assessment of the talar body, talar neck, and associated processes, they are often inadequate to assess the alignment and degree of comminution of the talar neck. Canale and Kelly described a view of the talar neck which is obtained by maximal plantarflexion at the ankle, 15o of eversion, and angling the beam 75o degrees from the horizontal.[9, 18] CT scans are invaluable to assess for comminution, intra-articular fragments, and congruent reduction of the tibiotalar, subtalar, and talonavicular joints.
3.5 TREATMENT The goals of treatment for talar neck fractures are anatomic reduction, restoration of articular and axial alignment, preservation of motion, and minimization of complications including AVN, post-traumatic arthritis, malunion, nonunion, and infection.
3.5.1 Non-operative Non-operative treatment is reserved for truly nondisplaced Hawkins Type I fractures. Biomechanical studies have demonstrated that as little as 2mm of displacement significantly alters subtalar contact forces, which may predispose to arthritis.[19] Thus, a CT scan should be used to assess displacement prior to selecting non-operative treatment. Treatment consists of non-weight bearing in a cast for 6 weeks or until radiographic union, which may take up to 12 weeks.
3.5.2 Operative The current standard of care for all displaced talar neck fractures is operative reduction and internal fixation. Closed reduction may be difficult, and when possible it is preferable to proceed directly to operative fixation to avoid multiple unsuccessful reduction attempts.
3.5.3 Surgical Approaches There are various surgical approaches to the talar neck. Regardless of approach, it is imperative that full-thickness flaps are created with no undermining to avoid soft tissue necrosis. The anteromedial approach to the talus involves making an incision medial to the anterior tibial tendon.[16] This incision may be extended proximally if a malleolar osteotomy is required, or in the presence of a medial malleolar fracture that requires operative fixation. The major disadvantage of this approach is the inability to visualize the lateral aspect of the talar neck, which is necessary to judge the quality of reduction. The anterolateral approach is performed with an incision between the tibia and fibula and in line with the fourth ray, just lateral to the extensor digitorum longus. (Figure 4) This incision is the distal extension of the Bohler incision, which is the extensile anterolateral approach to the foot and ankle.[16] When this incision is used in conjunction with the anteromedial approach, it is important to maintain an adequate skin bridge to avoid skin necrosis. This approach allows for anatomic reduction of the lateral talar neck. If needed, an anterolateral fibular osteotomy can be performed for gaining access to the proximal lateral talus. Often, there is a cortical fragment at the anterolateral corner of the talar neck near the margin with the lateral process, from which one can base an anatomic reduction. Dissection of the inferior neck, deltoid ligament, and sinus tarsi should all be avoided to maintain the vascular supply of the talar neck. The posterolateral approach involves making an incision just lateral to the Achilles tendon, and developing the interval between the flexor hallucis longus and peroneal muscles. This approach can be used to facilitate lag screw fixation, as the screw trajectory if perpendicular to the fracture line. Care should be taken to avoid injury to the peroneal artery and saphenous nerve.
3.5.4 Timing of Surgery Talar neck fractures were long thought to be orthopaedic emergencies, in which immediate reduction of the talar neck would minimize the incidence of osteonecrosis.[9] Recent studies have shown that this is not true, and that osteonecrosis may be more strongly correlated to other factors such as open fracture or comminution of the talar neck.[14, 20] Increased time between surgery and operative treatment did not increase the risk of complications or future surgery.[15] Timing of definitive surgery should be based on injury to the surrounding soft tissues, as the rate of soft tissue complications ranges between 2% and 10%.[10] Definitive surgery should be deferred until there is adequate
resolution of swelling, which may take up to 2 weeks after injury. It is critically important to remember that surgery should only be delayed provided that the talar neck is in a reduced position. All displaced talar neck fractures require urgent reduction in the emergency room. Irreducible talar neck fractures should be taken to the operating room for open reduction and internal fixation on an urgent basis.
3.5.5 Percutaneous Fixation Percutaneous fixation should be reserved for truly nondisplaced fractures, in which fixation allows for early range of motion compared to casting. In displaced fractures, percutaneous fixation is indicated in the rare case in which an anatomic reduction can be performed and there is no significant comminution. Although low rates of osteonecrosis and malunion have previously been reported using closed reduction with Schanz pins followed by percutaneous fixation in Hawkins grades II-IV, it is not recommended.[21] Screw fixation can be placed from posteromedial, posterolateral, or anterior approaches.[22]
3.5.6 Open Reduction and Internal Fixation Dual anteromedial and anterolateral surgical approaches allow for full visualization of the talar neck. A medial malleolar osteotomy may be required to allow access to the talar body.[16, 23] Provisional reduction of the talar neck and body can be maintained with Kirschner wire fixation. Aligning the cortical margins without recognizing the degree of comminution will lead to improper varus and extension. One strategy to prevent this from occurring is performing an anterolateral exposure, which allows visualization and direct cortical reduction of the lateral talar neck. In addition, bone grafting of the medial neck may be required to provide mechanical support.[15] In all cases, subtalar debridement is critical to ensure that there is no block to reduction or loose fragments.
3.5.7 Screw Fixation Screw fixation alone was the predominant method of fixation of displaced talar neck fractures in most early series as well as several recent ones.[7, 14, 15, 22] Screws can be placed from anterior-to-posterior or posterior-to-anterior. Anterior-to-posterior screws (one medial and one lateral) are inserted adjacent to the articular surface of the talar head and directed posteriorly into the body. Anterior-to-posterior screws may interfere with talonavicular joint function when prominent. For that reason, it is recommended to countersink the screw head or use headless lag screws with this technique.
Posterior-to-anterior lag screw fixation has been shown to have superior biomechanical strength compared to anterior-to-posterior fixation.[24] These screws are typically placed from a posterolateral approach on either side of the flexor hallucis groove, and directed anteromedially. Potential disadvantages of posterior-to-anterior screw fixation include penetration of the subtalar joint, restriction of ankle plantar-flexion due to screw-head impingement, or injury to the FHL. Again, headless screws may avoid this risk and are biomechanically equivalent to standard screws.[25] For both anterior-toposterior and posterior-to-anterior screw fixation, it is important to remember that the use of lag screws in the setting of any comminution will lead to malalignment.[15] Position screws instead of lag screws can also be used to maintain an anatomic reduction on the medial side and avoid compressing a comminuted fracture into varus.
3.5.8 Screw and Plate Constructs Plate fixation of talar neck fractures has become more popular in the last decade, and is the recommended method of fixation by many authors.[2, 26-28] (Figure 5A-E) The major advantage of plate fixation over screw fixation is the ability to bridge areas of significant comminution.[26] This allows for a more precise reduction and avoids the potential risk of malalignment when using lag screw fixation across areas of comminution.[29] Areas of comminution should be packed with bone graft to provide structural support.[2, 15] The plate may be placed either medially or laterally depending on the location of comminution. Multiple studies have demonstrated that there is no difference in biomechanical strength between screw fixation alone and combination screw-plate constructs.[29, 30] Loose osteochondral fragments can be secured with minifragment screws with cruciform heads that are seated below the level of the articular cartilage, and are particularly useful for talar dome fractures.[16]
3.5.9 Postoperative management With stable fixation, early range of motion is encouraged once all wounds are healed. If there is concern regarding the integrity of the fixation, or in cases of significant ankle, subtalar, or talonavicular instability, casting for 6 weeks is recommended. The patient should remain non-weight-bearing until there is evidence of sufficient healing on radiographs, typically between 6 weeks and 3 months after injury.
4. TALAR BODY FRACTURES Fractures of the talar body involve both the tibiotalar and subtalar joints, and have the
highest incidence of arthritis among all talus fractures.[7] The accurate restoration of a congruent articular surface is therefore important to minimize the risk of this complication. Up to 50% of talar body fractures are associated with a talar neck fracture.[20] Radiologic evaluation of talar body fractures should always include a CT scan, as plain radiographs may underestimate the degree of articular injury. The treatment of talar body fractures adheres to many of the same principles as talar neck fixation; any displacement requires surgical management with open reduction and internal fixation. The surgical approaches for talar neck fractures may be used for open reduction and internal fixation of the talar body with minifragment or headless screws.[16] Medial malleolar osteotomy may be required for access to the talar dome.[23] It is important not to violate the deltoid ligament, which is an important source of blood supply to the talar body. Bone grafting should be considered when there is significant impaction of the talar dome.
4.1 Lateral Process Fractures Fractures of the lateral process are frequently missed on initial plain radiographs, as they may be subtle and difficult to visualize. This fracture is classically associated with a snowboarding injury.[31] Lateral process fractures are best seen on ankle mortise and internal oblique views, but CT scan is usually required to visualize the fracture and determine whether operative intervention is necessary. Small or nondisplaced lateral process fractures may be treated with immobilization and a period of non-weight bearing. Larger fractures and those with more than 2mm of displacement require fixation with lag screws or a minifragment plate.[32] Using either a posterolateral or anterolateral approach has been recommended.[2, 27] When lateral process fractures occur in the setting of a talar neck fracture, it is advised to stabilize the neck before fixing the lateral process.[2]
4.2 Posterior Process Fractures Posterior process fractures are best seen on lateral foot radiographs. It may be difficult to differentiate between a posterior process fracture of the talus and an os trigonum, which is an ossicle located behind the talus in up to 25% of the population.[33, 34] Os trigonum are generally round, oval, or triangular and may have a synchondrosis with the posterolateral talus. If the diagnosis cannot be made on plain radiographs, advanced imaging with either CT or MRI will allow for differentiation between os trigonum and posterior process fractures. Small and nondisplaced fractures of the posterior process may
be treated with immobilization and a period of non-weight-bearing. Larger fragments and those displaced more than 2mm are best treated with open reduction and internal fixation. The posteromedial approach allows access to the posterior process by utilizing the interval between the medial border of the Achilles tendon and the posterior edge of the medial malleolus. After fracture reduction, the fracture is stabilized with mini-fragment screws. While range of motion exercises may begin as soon as soft tissue swelling has subsided, it is recommended that patients remain non-weight bearing for 2 months after surgery.
5. TALAR HEAD FRACTURES Talar head fractures are rare, accounting for 2.6-10% of all talus fractures.[35] The natural history of talar head fractures is largely unknown, as only case reports are published in the literature.[35-40] (Table 2) These injuries are frequently associated with talonavicular dislocations, but can be easily missed when spontaneous reduction occurs before presentation. Standard radiographs should be supplemented with CT scan to assess the degree of articular displacement. Nondisplaced fractures may be treated with cast immobilization and non-weight bearing for 4-8 weeks after surgery. Ibrahim et al. recently suggested a treatment algorithm for displaced fractures on the basis of their systematic review; (1) displaced fractures with >50% talar head involvement or talonavicular joint instability should undergo open reduction and internal fixation with immobilization and non-weight bearing for 6-8 weeks postoperatively whereas (2) displaced fractures with <50% talar head involvement and no instability of the talonavicular joint may be treated with excision of fracture fragments, closure of the talonavicular joint capsule, and a period of immobilization and non-weight bearing.[35] An anteromedial approach to the talar head is most commonly used. Primary fusion of the talonavicular joint is an option in cases of severe talar head or navicular comminution, or as a salvage treatment for end-stage talonavicular post-traumatic arthritis.
6. TALUS FRACTURES IN CHILDREN Talus fractures in children are extremely rare. Compared to adult fractures, relatively little is known about the natural history of talus fractures in children, as there are only a small number of published case series.[41-47] The primary mechanism of injury for talus fractures in children appears to be dorsiflexion and axial loading, similar to the mechanism described in adults.[42, 44, 45] As in adults, talar neck fractures in children
are generally classified by the Hawkin’s classification, and follow similar treatment protocols. Nondisplaced fractures are generally treated non-operatively with cast immobilization,
whereas
displaced
fractures
are
treated
operatively.[41]
The
complications following talus fractures in children are similar to those found in adults, and
include
osteonecrosis,
post-traumatic
arthritis,
nonunion,
malunion,
and
infection.[41] One key difference between talus fractures in children and those in adults may be the rate of osteonecrosis after nondisplaced fractures.[47] Rammelt et al. found a rate of 16% of osteonecrosis after nondisplaced fractures, and proposed that this may be due to a greater susceptibility to circulatory disturbances in the pediatric talus.[47] It is important to maintain a high index of suspicion for the development of avascular necrosis following talus fracture in children, including those that are found to be nondisplaced.
7. COMPLICATIONS AND SALVAGE 7.1 Osteonecrosis The incidence of osteonecrosis after talar neck fracture increases with greater initial fracture displacement.[8, 12] (Table 1) The most cited rates of osteonecrosis come from Hawkins classic work, in which he reported an overall osteonecrosis rate of 58%, with rates of 0%, 42%, and 86% for Hawkins’ types I, II, and III, respectively.[8] Since the publication of this report in 1970, the standard of care has evolved to include the use of a more aggressive dual-incision open approach to all fractures.[11, 28] The reported rates of osteonecrosis have decreased with the evolution of treatment protocols in the past decade. (Table 3) In a meta-analysis of 26 studies including 980 talar neck fractures, Dodd et al. found that the overall rate of osteonecrosis was 31.2%; when looking at studies published after the year 2000, the rate drops to 24.9%.[12] In studies published after 2000, the authors also found that the rate of osteonecrosis for Hawkins Type II and Type III were 20.7% and 44.8%, respectively, which is roughly half the rate reported in Hawkins original series.[12] Osteonecrosis is also seen more commonly in open talus fractures.[14, 20] The diagnosis of osteonecrosis is commonly made on plain radiographs at anywhere from 4 weeks to 6 months after surgery.[8, 9] The radiographic criteria used to diagnose osteonecrosis are poorly defined, but it is generally indicated by a relative increase in the density of the talar body relative to adjacent structures. The presence of subchondral osteopenia at 6-8 weeks after injury, known as the Hawkins sign, is a reliable indicator that the development of osteonecrosis is unlikely.[48] The Hawkins sign has recently been shown to have a sensitivity of 100% and a specificity of
57.7%.[49] The converse, however, is not true; an absent Hawkins’ sign does not confirm the diagnosis of osteonecrosis.[48] In these cases, MRI can be used for the early diagnosis of osteonecrosis. Nearly half of all patients with osteonecrosis will undergo revascularization without collapse of the talar body, which may take up to 2 years following initial injury.[2, 10, 14, 20] There is no evidence that prolonged non-weight bearing during this time will help to prevent talar body collapse. It is important to note that many patients with talar body osteonecrosis are asymptomatic, and therefore the initial treatment is conservative. If conservative treatment fails and arthritis develops, arthrodesis of the involved joint is an effective means of eliminating pain. There are a variety of fusion techniques described in the literature to accomplish these goals.[50, 51] Motion preserving techniques have also been reported. Harnroongroj et al. recently reported the outcomes of 33 patients treated with implantation of a talar body prosthesis, 23 of which were implanted for talar body osteonecrosis.[52] Of the 33 talar body prosthesis, 28 were still implanted at final follow-up, ranging from 10 to 36 years post-operatively. The authors concluded that although early failure can occur, talar body prosthesis can provide satisfactory foot and ankle function at long-term follow up.[52]
7.2 Post-traumatic Arthritis Subtalar joint arthritis is the most common complication after talar neck fracture, developing in an average of 49% of patients in a recent meta-analysis of 16 included studies.[10-12, 14-16] (Table 3) When including only studies with a minimum of 2 year follow up, the authors found that this rate increased to 81%.[12] This complication is even more common after talar body fractures, where the reported rate is as high as 100%.[7, 14, 16] Post-traumatic arthritis may be treated conservatively with bracing and pain medication. End-stage arthritis recalcitrant to conservative treatment may require tibiotalar or subtalar arthrodesis for pain relief.[50, 51]
7.3 Malunion and Nonunion The rate of malunion after talar neck fracture is frequently reported in the range of 2030%, but is likely underestimated given the difficulty of identifying malignment by plain radiography alone.[14, 15, 53] (Table 3) Varus malunion is the most common deformity due to medial comminution. The dual incision approach and use of plates instead of lag screws alone both help to reduce the risk of this deformity. Varus malunion affects the biomechanics of the subtalar joint, which predisposes to the development of arthritis.[19]
Malunion should be evaluated with CT scan, and often requires corrective osteotomy.[54] Nonunion is rare after talar neck fracture, typically occurring in the 3-5% range.[10, 20, 28] If nonunion is associated with advanced arthritis, fusion may be required.
7.4 Skin Complications and Infection Soft tissue complications such as skin necrosis and deep infection are among the most disastrous complications after talar fracture. There are a number of principles aimed at minimizing the risk of these complications, including urgent reduction of dislocations, administration of antibiotics and surgical debridement for open fractures, and meticulous soft tissue handling during surgery. As stated previously, definitive surgical intervention should be delayed until adequate resolution of swelling has occurred, which may take up to 3 weeks after injury.[26]
8. SUMMARY The role for non-operative treatment of talar neck or body fractures is limited to nondisplaced or anatomically reduced fractures confirmed by CT scan. Any displacement requires meticulous anatomic reduction and fixation. The use of dual anteromedial and anterolateral approaches, plating, and bone grafting are paramount to a successful reduction. As a result of these surgical tactics, the reported rate of osteonecrosis following talar neck fracture has decreased over time, although it remains high. The current gold standard treatment for end stage tibiotalar or subtalar arthritis following talus fracture is arthrodesis of the involved joints. Lateral process fractures are easily missed, but prompt diagnosis and appropriate treatment are important to ensure a good outcome. Talar head fractures are rare, and depending on the percentage of talonavicular joint involved, may be either excised or anatomically fixed. Conflicts of Interest: There are no conflicts of interest to report.
Acknowledgements: None. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
REFERENCES [1]Santavirta S, Seitsalo S, Kiviluoto O, Myllynen P. Fractures of the talus. The Journal of trauma 24: 986, 1984 [2]Vallier HA. Fractures of the Talus: State of the Art. Journal of orthopaedic trauma 29: 385, 2015 [3]Fortin PT, Balazsy JE. Talus fractures: evaluation and treatment. The Journal of the American Academy of Orthopaedic Surgeons 9: 114, 2001 [4]Mulfinger GL, Trueta J. The blood supply of the talus. The Journal of bone and joint surgery British volume 52: 160, 1970 [5]Peterson L, Goldie IF. The arterial supply of the talus. A study on the relationship to experimental talar fractures. Acta orthopaedica Scandinavica 46: 1026, 1975 [6]Miller AN, Prasarn ML, Dyke JP, Helfet DL, Lorich DG. Quantitative assessment of the vascularity of the talus with gadolinium-enhanced magnetic resonance imaging. The Journal of bone and joint surgery American volume 93: 1116, 2011 [7]Elgafy H, Ebraheim NA, Tile M, Stephen D, Kase J. Fractures of the talus: experience of two level 1 trauma centers. Foot & ankle international 21: 1023, 2000 [8]Hawkins LG. Fractures of the neck of the talus. The Journal of bone and joint surgery American volume 52: 991, 1970 [9]Canale ST, Kelly FB, Jr. Fractures of the neck of the talus. Long-term evaluation of seventy-one cases. The Journal of bone and joint surgery American volume 60: 143, 1978 [10]Vallier HA, Reichard SG, Boyd AJ, Moore TA. A new look at the Hawkins classification for talar neck fractures: which features of injury and treatment are predictive of osteonecrosis? The Journal of bone and joint surgery American volume 96: 192, 2014 [11]Halvorson JJ, Winter SB, Teasdall RD, Scott AT. Talar neck fractures: a systematic review of the literature. The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons 52: 56, 2013 [12]Dodd A, Lefaivre KA. Outcomes of Talar Neck Fractures: A Systematic Review and Meta-analysis. Journal of orthopaedic trauma 29: 210, 2015 [13]Lin S, Hak DJ. Management of talar neck fractures. Orthopedics 34: 715, 2011 [14]Lindvall E, Haidukewych G, DiPasquale T, Herscovici D, Jr., Sanders R. Open reduction and stable fixation of isolated, displaced talar neck and body fractures. The Journal of bone and joint surgery American volume 86-A: 2229, 2004 [15]Sanders DW, Busam M, Hattwick E, Edwards JR, McAndrew MP, Johnson KD. Functional outcomes following displaced talar neck fractures. Journal of orthopaedic trauma 18: 265, 2004 [16]Vallier HA, Nork SE, Benirschke SK, Sangeorzan BJ. Surgical treatment of talar body fractures. The Journal of bone and joint surgery American volume 86-A Suppl 1: 180, 2004 [17]Gerken N, Yalamanchili R, Yalamanchili S, Penagaluru P, Md EM, Cox G. Talar revascularization after a complete talar extrusion. Journal of orthopaedic trauma 25: e107, 2011 [18]Thomas JL, Boyce BM. Radiographic analysis of the Canale view for displaced talar neck fractures. The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons 51: 187, 2012 [19]Sangeorzan BJ, Wagner UA, Harrington RM, Tencer AF. Contact characteristics of the subtalar joint: the effect of talar neck misalignment. Journal of orthopaedic research : official publication of the Orthopaedic Research Society 10: 544, 1992
[20]Vallier HA, Nork SE, Barei DP, Benirschke SK, Sangeorzan BJ. Talar neck fractures: results and outcomes. The Journal of bone and joint surgery American volume 86-A: 1616, 2004 [21]Abdelgaid SM, Ezzat FF. Percutaneous reduction and screw fixation of fracture neck talus. Foot and ankle surgery : official journal of the European Society of Foot and Ankle Surgeons 18: 219, 2012 [22]Abdelkafy A, Imam MA, Sokkar S, Hirschmann M. Antegrade-retrograde opposing lag screws for internal fixation of simple displaced talar neck fractures. The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons 54: 23, 2015 [23]van Bergen CJ, Tuijthof GJ, Sierevelt IN, van Dijk CN. Direction of the oblique medial malleolar osteotomy for exposure of the talus. Archives of orthopaedic and trauma surgery 131: 893, 2011 [24]Swanson TV, Bray TJ, Holmes GB, Jr. Fractures of the talar neck. A mechanical study of fixation. The Journal of bone and joint surgery American volume 74: 544, 1992 [25]Capelle JH, Couch CG, Wells KM, Morris RP, Buford WL, Jr., Merriman DJ, Panchbhavi VK. Fixation strength of anteriorly inserted headless screws for talar neck fractures. Foot & ankle international 34: 1012, 2013 [26]Fleuriau Chateau PB, Brokaw DS, Jelen BA, Scheid DK, Weber TG. Plate fixation of talar neck fractures: preliminary review of a new technique in twenty-three patients. Journal of orthopaedic trauma 16: 213, 2002 [27]Shakked RJ, Tejwani NC. Surgical treatment of talus fractures. The Orthopedic clinics of North America 44: 521, 2013 [28]Xue Y, Zhang H, Pei F, Tu C, Song Y, Fang Y, Liu L. Treatment of displaced talar neck fractures using delayed procedures of plate fixation through dual approaches. Int Orthop 38: 149, 2014 [29]Charlson MD, Parks BG, Weber TG, Guyton GP. Comparison of plate and screw fixation and screw fixation alone in a comminuted talar neck fracture model. Foot & ankle international 27: 340, 2006 [30]Attiah M, Sanders DW, Valdivia G, Cooper I, Ferreira L, MacLeod MD, Johnson JA. Comminuted talar neck fractures: a mechanical comparison of fixation techniques. Journal of orthopaedic trauma 21: 47, 2007 [31]Kramer IF, Brouwers L, Brink PR, Poeze M. Snowboarders' ankle. BMJ case reports 2014, 2014 [32]Perera A, Baker JF, Lui DF, Stephens MM. The management and outcome of lateral process fracture of the talus. Foot and ankle surgery : official journal of the European Society of Foot and Ankle Surgeons 16: 15, 2010 [33]Lawson JP. International Skeletal Society Lecture in honor of Howard D. Dorfman. Clinically significant radiologic anatomic variants of the skeleton. AJR Am J Roentgenol 163: 249, 1994 [34]Karasick D, Schweitzer ME. The os trigonum syndrome: imaging features. AJR Am J Roentgenol 166: 125, 1996 [35]Ibrahim MS, Jordan R, Lotfi N, Chapman AW. Talar head fracture: A case report, systematic review and suggested algorithm of treatment. Foot 25: 258, 2015 [36]Long NM, Zoga AC, Kier R, Kavanagh EC. Insufficiency and nondisplaced fractures of the talar head: MRI appearances. AJR Am J Roentgenol 199: W613, 2012 [37]Matsumura T, Sekiya H, Hoshino Y. Correction osteotomy for malunion of the talar head: a case report. J Orthop Surg (Hong Kong) 16: 96, 2008 [38]Mulligan ME. Horizontal fracture of the talar head. A case report. The American journal of sports medicine 14: 176, 1986
[39]Pehlivan O, Akmaz I, Solakoglu C, Rodop O. Medial peritalar dislocation. Arch Orthop Trauma Surg 122: 541, 2002 [40]Vlahovich AT, Mehin R, O'Brien PJ. An unusual fracture of the talus in a snowboarder. Journal of orthopaedic trauma 19: 498, 2005 [41]Smith JT, Curtis TA, Spencer S, Kasser JR, Mahan ST. Complications of talus fractures in children. J Pediatr Orthop 30: 779, 2010 [42]Jensen I, Wester JU, Rasmussen F, Lindequist S, Schantz K. Prognosis of fracture of the talus in children. 21 (7-34)-year follow-up of 14 cases. Acta Orthop Scand 65: 398, 1994 [43]Draijer F, Havemann D, Bielstein D. [Injury analysis of pediatric talus fractures]. Unfallchirurg 98: 130, 1995 [44]Mazel C, Rigault P, Padovani JP, Finidori G, Touzet P. [Fractures of the talus in children. Apropos of 23 cases]. Rev Chir Orthop Reparatrice Appar Mot 72: 183, 1986 [45]Letts RM, Gibeault D. Fractures of the neck of the talus in children. Foot Ankle 1: 74, 1980 [46]Eberl R, Singer G, Schalamon J, Hausbrandt P, Hoellwarth ME. Fractures of the talus--differences between children and adolescents. J Trauma 68: 126, 2010 [47]Rammelt S, Zwipp H, Gavlik JM. Avascular necrosis after minimally displaced talus fracture in a child. Foot Ankle Int 21: 1030, 2000 [48]Chen H, Liu W, Deng L, Song W. The prognostic value of the hawkins sign and diagnostic value of MRI after talar neck fractures. Foot & ankle international 35: 1255, 2014 [49]Tezval M, Dumont C, Sturmer KM. Prognostic reliability of the Hawkins sign in fractures of the talus. Journal of orthopaedic trauma 21: 538, 2007 [50]Easley ME, Trnka HJ, Schon LC, Myerson MS. Isolated subtalar arthrodesis. The Journal of bone and joint surgery American volume 82: 613, 2000 [51]Tenenbaum S, Stockton KG, Bariteau JT, Brodsky JW. Salvage of avascular necrosis of the talus by combined ankle and hindfoot arthrodesis without structural bone graft. Foot & ankle international 36: 282, 2015 [52]Harnroongroj T, Harnroongroj T. The Talar Body Prosthesis: Results at Ten to Thirty-six Years of Follow-up. The Journal of bone and joint surgery American volume 96: 1211, 2014 [53]Fournier A, Barba N, Steiger V, Lourdais A, Frin JM, Williams T, Falaise V, Pineau V, Salle de Chou E, Noailles T, Carvalhana G, Ruhlmann F, Huten D. Total talar fracture - long-term results of internal fixation of talar fractures. A multicentric study of 114 cases. Orthopaedics & traumatology, surgery & research : OTSR 98: S48, 2012 [54]Suter T, Barg A, Knupp M, Henninger H, Hintermann B. Surgical technique: talar neck osteotomy to lengthen the medial column after a malunited talar neck fracture. Clin Orthop Relat Res 471: 1356, 2013
Figure Legend: Figure 1. Superior and inferior views demonstrate the osseous anatomy of the talus. FHL = Flexor Hallucis Longus.
Figure 2. Arterial supply to the talus from dorsal and plantar views. The major arterial supplies are the 1) artery of the tarsal sinus (TS) from either the dorsalis pedis (DP) or peroneal artery, 2) the artery of the tarsal canal (TC) from the posterior tibial artery , 3) the deltoid artery from either the TC or the posterior tibial artery, 4) the posterior direct branches (PT) from the peroneal artery, and 5) the superomedial direct branches of the DP.
Figure 3A-E. Modified Hawkins classification system for talar neck fractures: (A) Type I - Nondisplaced talar neck fracture, (B) Type IIA – Talar neck fracture with subtalar subluxation (C) Type IIB – Talar neck fracture with subtalar dislocation , (D) Type III – Talar neck fracture with subtalar and tibiotalar dislocation, and (D) Type IV – Talar neck fracture with subtalar, tibiotalar, and talonavicular dislocations.
Figure 4. Clinical photograph of the incision used for the anterolateral approach to the talus.
Figure 5A-E. Anteroposterior (A) and lateral (B) radiographs of a Hawkins type II fracture with talar neck comminution and subtalar dislocation. Post-operative anteroposterior (C), Canale (D) and (E) lateral radiographs demonstrate dual plate fixation and reduction of the subtalar joint.
Table Legend Table 1. Avascular Necrosis Rates by Hawkins’ Type Table 1. Avascular Necrosis Rates by Hawkins’ Type Hawkins’ Type
Associated Joint Subluxation or Dislocation
Hawkins, 19708
Dodd et al., 201512 (Published after year 2000, n=14)*
I
None
0%
8.0%
II
Subtalar
42%
20.7%
III
Subtalar Tibiotalar
86%
44.8%
Subtalar IV Tibiotalar __ 36.5% Talonavicular *Authors performed a meta-analysis of all studies reporting the rate of avascular necrosis after talar neck fracture, and reported a separate rate for 14 studies published after 2000.
Table 2. Case Reports of Talar Head Fracture Author, Year
Patie nt Age / Sex Ibrahim et 31/F al., 201535
Fracture Mechanis displaceme m nt
Treatment
Displaced
Locking plate and NWB in Symptomatic cast x 6 weeks hardware
12
Long et al., 45/M 201236 20/F 16/M
Nondisplac ed Nondisplac ed Nondisplac ed Displaced
Conservative Presentation) Conservative Presentation) Conservative Presentation) Cast x 4 weeks
NR NR NR
Matsumura 26/M et al., 200837
Mulligan et 27/M al., 198638 Pehlivan et 22/M al., 200239
Nondisplac ed Displaced
Inversion injury while walking NR NR Football
Wakeboard ing
Complications
(Delayed NR NR (Delayed NR (Delayed
Gymnastics Walking cast x 4 weeks Inversion injury while walking Snowboard ing
Follow -up (Mos.)
Malunion 18 (required medial talar head osteotomy and ICBG) None 21
ORIF with K-wire fixation Persistent 26 and NWB in cast x 6 weeks lateral hindfoot pain
Vlahovich 33/F Displaced ORIF with 2.7mm Persistent pain et al., compression screws and 200540 bone graft NR= Not Reported, ORIF = Open reduction and internal fixation, NWB = Non-weight bearing, ICBG = Iliac crest bone graft
3
Table 3. Complications After Surgical Treatment for Talar Neck Fracture
Author, Year
No. Talar Neck Fractures
Open Fractures
AVN
Malunion
Nonunion
PTA
Chateau et al., 200226
23
NR
4 (17.3%)
2 (8.7%)
0 (0%)
3 (13%)
Chen et al., 201434
48
NR
11/38 (28.9%)
NR
NR
NR
Elgafy et al., 20007
27
NR
7 (25.9%)
NR
NR
18 (66%)
Lindvall et al., 200414
16
NR
7/16 (43.7%)
NR
2/16 (12.5%)
16/16 100%
Sanders et al., 200415
70
10/70 (14.3%)
8/70 (11.4%)
21/70 (30%)
NR
54/70 (78%)
Tezval et al., 200749
41
11/41 (26.8%)
5/31 (16.1%)
NR
NR
NR
Vallier et al., 200420
102
24/102 (24%)
19/39 (49%)
NR
3/60 (5%)
21/39 (53.8%)
Vallier et al., 201410
81
24/81 (30%)
16/65 (25%)
NR
2/65 (3.1%)
35/65 (54%)
Xue et al., 201428
28
0 (0%)
6/28 (21%)
NR
1/28 (3.6%)
7/28 (25%)
NR= Not Reported, AVN = Avascular Necrosis, PTA = Post-traumatic arthritis, AOFAS = American Orthopaedic Foot and Ankle Society ankle-hindfoot score, AOS = Ankle Osteoarthritis Score, MFA = Musculoskeletal Function Assessment, SMFA = Short Musculoskeletal Function Assessment, FFI = Foot Function Index