Talar Fractures

Background
     Referred to as the "universal joint of the foot," more than 60% of the talar surface is covered by articular cartilage.(1) Subsequently, minimal malalignment and loss of periarticular motion tends to create poor functional outcome. Furthermore, because of a large percentage of the surface area is articular, the vascular supply is mostly dependent on fascial structures that, when disrupted, may results in osteonecrosis.(2)
     Talar fractures are typically high-energy fractures, with 15-20% of all talus fractures being open and associated with multiple traumatic injuries in over 80% of cases. (1,2)  Attention must be paid to the spine and extremities, with a 58-86% reported incidence of associated fractures in these areas; the most common being the ipsilateral medial malleolus (up to 25%). (1,2,3)

Clinical Evaluation
     In the trauma setting, the exam of the foot must include evaluation of the soft tissues, tibial nerve, deep peroneal nerve, dorsal pedal and posterior tibial pulses. Significant swelling is nearly always present. However, skin tenting should be considered a surgical urgency and careful palpation should be performed to detect fracture fragments that place the skin under tension. Skin blanching and delayed capillary refill are signs of ischemia and mandate urgent reduction. Immediate reduction of an open dislocated talus is recommended. Although rare, large extruded bone fragments should be cleansed and saved for surgical reconstruction options.(1,2,3)

Imaging
     The Canale view is the recommended view, which is obtained by (1) maximally plantarflexing the ankle, (2) pronating the foot 15°, and (3) angling the imaging tube 15° caudal from vertical.(1) Standard AP, lateral, and oblique views are are always recommend. CT scan may also be used to further investigate fracture pattern and for operative planning.

Treatment
     Treatment of talar neck and body fractures are based on the Hawkins classification system. Fracture treatment within 8 hours is recommended and believed to lead result in superior functional functional outcome and lower incidences of AVN and post-traumatic arthritis. (1) Type I (non-displaced) may be treated non-operatively and Types II-IV are treated via immediate reduction, followed by (possibly delayed) ORIF.(1,2,3).

Complications
     Hight rates of osteonecrosis, post-traumatic arthritis, and malunion are found with displaced talar fractures, even with appropriate treatment. When excluding non-displaced talar fractures, recent litersture shows the rate of AVN climbs to as high as 35%. (1) Malunion is also common, occurring nearly 40% of the time.(1,3) Several studies have also shown post-traumatic arthritis to occur in approximately 50-80% of cases.(1) In cases of open talar fractures, infection risk greatly increases.

Summary
     Talar fractures are typically high-energy fractures associated with multiple traumatic injuries and high complication rates. Early fracture recognition through proper clinical and radiologic evalution, coupled with intervention may lower these complication rates.

from Dr. Bob Sershon