S P P S Rao, Mazin S Ibrahim*, Gurdip Chahal and James Ramos
Heart of England NHS trust, UK
Received: 16 April, 2014; Accepted: 15 July, 2014; Published: 17 July, 2014
Mazin S Ibrahim, Heart of England NHS trust, UK, Email: [email protected]
Rao SPPS, Ibrahim MS, Chahal G, Ramos J (2014) Talar Neck Fractures: An Overview. J Nov Physiother Phys Rehabil 1(1): 013-018. DOI: 10.17352/2455-5487.000003
© 2014 Rao SPPS, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Talar injuries are infrequently encountered in practice as the majority require a high energy force such as road traffic accident or fall from height and they are often presented as complex injuries. Talar neck fracture accounts for half of these injuries. Because of the high rate of avascular necrosis (AVN) and posttraumatic arthritis associated with these injuries, it is difficult to predict the prognosis of AVN with the current classification systems. The anatomical position, difficulty of surgical approaches and its complex blood supply add to the challenges. Early recognition and a robust management plan are essential in treating such injuries. Failure to recognize a displaced talus fracture can result in Osteonecrosis, osteoarthritis, malunion or non-union which affects the hind foot function and results in pain, loss of motion and deformity. The integrity of this bone is vital for the function of the ankle, subtalar and mid tarsal joints. This article is an overview of this challenging injury including the mechanism of injury, classification, management and rehabilitation.
Talus fractures and dislocations are infrequently encountered in practice, therefore; scarce evidence is available in the literature on these fractures and their management. However, talar neck fracture accounts for 50% of these injuries [1-3] making its management clearer in the literature. However, a recent study on the patterns of talus fractures showed that the most common talus injury is talus body fracture (61%) . The anatomical position of this bone and its complex blood supply render this bone prone to avascular necrosis and osteoarthritis following injury especially to its neck. Talus fractures are second in frequency after calcaneum fractures of all tarsal bone injuries . Talus fractures account for 6% of all foot injuries . Half of the talus injuries are secondary to road traffic accidence (RTA) [2,3,5]. However, Santavirta et al. , found in his series that the most common cause of injury is falling from height followed by RTAs. The incidence of talus fractures ranges from 0.1% to 0.85% of all fractures [1-3,5,6].
This article presents a thorough evidence-based review of talus neck fractures, their management and their rehabilitation.
Mechanism of Injury
The mechanism of injury of talar neck fracture involves mostly acute dorsiflexion force directed at the midpoint of forefoot especially during falls, motor car accident and airplane crash. In 1919, Anderson in his 8 cases review, highlighted that forced dorsiflexion of the foot was the main mechanism of injury of what he described” aviator’s astragalus” .
With forced dorsiflexion, the anterior tibial edge compress the thin trabecular bone of the talar neck and causes the fracture, with more dorsiflexion , the talocalcaneal ligament and the ligamentous complex of the posterior ankle and subtalar joints will be disrupted causing subluxation or dislocation of the body from its articulation. If forced supination accompanied this, a medial talar neck comminution and subluxation of subtalar joint will occur [1,3].
Medial malleolus fracture is associated with talar neck fracture in 19-28% of cases . In Hawkins study in 1970; found that 26% of talar neck fractures are associated with medial malleolus fracture, and Canale and Kelly found the incidence to be of 15% of talar neck fractures. This highlights the presence of rotational forces associated with these injuries [2,3,5-7].
Lumbar spines fractures are less commonly encountered with this injury but have been found to be associated [2,3,5].
Blood supply of the talus comes from three arteries
These form extra osseous circulation as described by Wildenaur around the talar neck and sinus tarsi1.
Anterior tibial artery gives off the medial tarsal artery branches and anterior medial malleolar branches to supply the superior aspect of the talar neck at the level of ankle joint. The dorsalis pedis artery which is the continuation of anterior tibial artery, gives off the tarsal sinus artery, together with the lateral malleolar branch of the peroneal artery , they supply the talar head and distal talar body before anastomosing with tarsal canal artery .
Posterior tibial artery branches are divided into calcaneal branches which supply the periosteum and most of the posterior aspect of the talus. It also divides to form artery of tarsal canal, 2 cm below the ankle and passes through the deltoid ligament to give off the deltoid branch to supply the medial talar body and then anastomose with dorsalis pedis over the neck of the talus and also it supplies the middle of talar body as it passes through thesuperior part of the tarsal canal [2,5].
Perforating branch of peroneal artery gives small branches to anastomose with both calcaneal branches of posterior tibial artery and to dorsalis pedis to form the artery of tarsal sinus .
Fortin et al. described the arteries of tarsal canal and tarsal sinus as discrete blood vessels that form anastomotic sling inferior to the talus; these give branches to the talar neck. He described that the body is mainly supplied by the branches of the tarsal canal artery while the neck and head supplied mainly by the artery of tarsal sinus and dorsalis pedis artery . Deltoid artery is an important source of blood to talar body, it comes from the tarsal canal artery which arises from posterior tibial artery within the deltoid ligament below medial malleolus, therefore; it is essential to preserve the deltoid ligament during reduction or fixation of the talar neck and body .
There is intraosseous circulation between all parts of the talus which has been found in 60% of the anatomic specimens . The intraosseous circulation of the talar head comes from dorsalis pedis and the tarsal sinus arteries while those of the body comes from the artery of the tarsal canal inferiorly, deltoid artery medially and tarsal sinus artery network inferolaterally and posteriorly .
The anterolateral surface of the body and the posterior tubercles of the talus are relatively avascular .
The head has a rich blood supply comes from the anterior tibial artery, the tarsal sinus artery, and the lateral tarsal artery [1,3,5].
The posterior part of the talus is supplied by branches of the posterior tibial artery via calcaneal branches that enter through the posterior tubercle. During injuries of the talus, initial fracture displacement, timing of the reduction and soft tissue handling at the time of surgery are all factors can affect integrity of talar blood supply .
These injuries usually present with swelling and haematoma over the ankle with Painful and restricted movements of ankle, subtalar and midtarsal joints . Difficulty in weight bearing and ankle deformity are other signs. The presence of wound over the ankle area should raise suspicion of open fractures.
There is a special oblique view described by Canale and Kelly which provides a good evaluation of the talar neck angulation, shortening and comminution. The technique requires maximum equinus, the foot should be pronated at 15 degree and he the X-ray tube should be directed cephalad at 75 degree from the surface top (Figure 1). In the acute situation is difficult to perform this technique and the CT supplies this radiographic view. The Canale view is useful in the patient follow-up to detect talar neck consolidation in varus [7-9].