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This article presents two case studies of talar body fractures. It describes the historical significance, the mechanism of injury, radiographic appearances and treatment. The objective of the article is to highlight this often subtle injury, in the hope that it doesn't get overlooked.
Aviator's astragalus is an old, almost obsolete term for a pattern of isolated fracture plus or minus dislocation injury of the talus1.
It was in 1919 that a consulting surgeon to the Royal Flying Corps, Henry Graeme Anderson, made the link between talar fractures and aviation crashes, thus the term Aviators Astragalus. He described 18 fractures and/or dislocations of the talus. At that time the mechanism of injury was described as 'when the aircraft strikes the ground at an angle, with the sole of the foot resting on the rudder bar, on impact the talus gets pressed into the instep just in front of the heel. The talus takes most of the force and becomes the seat of the fracture. Before the actual fracture occurs, the foot may be in a position of acute dorsiflexion, plantar flexion or may be inverted'2.
Coltart3 followed up Anderson's work following World War II where out of 4000 ankle injuries, 228 (6%) involved the talus. 70% of the severe talar injuries could be attributed to flying injuries.
Nowadays, the speed of planes is such that crashes tend to be fatal, so this injury is not seen in pilots. However, a similar mechanism of severe forced dorsiflexion following a fall from a height or a motor accident can cause the same type of fracture pattern.
ANATOMY
The talus is the second largest tarsal bone after the calcaneum4. It consists of three main portions: the body, the neck and the head. The body of the talus is cuboidal; its superior surface has a semicylindrical joint surface, called the trochlea, which articulates with the distal tibia. The dome of the talus is convex from anterior to posterior, and slightly concave from side to side. The inferior surface of the body is mostly made up of the articulation with the calcaneus. Approximately 60% of the talus is covered by articular cartilage. Distal to the body of the talus the bone constricts to form the neck, and then expands...