Talar body fractures are extremely rarer still. The body of the talus articulates with tibia, fibula and the calcaneus. Complexity in the blood supply to the talus itself makes it one of the bones in the body vulnerable to avascular necrosis [17]. Arthritis in the ankle and subtalar joints can occur in the absence of avascular necrosis of the talus and joint incongruity [6, 16].
The reported incidence of avascular necrosis for severely comminuted talar body fracture is around 50%-75% [5, 10, 12, 20]-[22]. Vallier et al. reporting on radiographic findings of 26 talar body fractures with a minimum follow-up of 1 year, noted a 38% incidence of AVN, 65% incidence of post-traumatic tibiotalar arthritis and 34% incidence of posttraumatic subtalar arthritis. Worse outcomes were noted in association with comminuted fractures, associated talar neck fractures and open fractures [4]. Lindvall et al., in 2004, reported on 26 isolated cases of talar neck and body fractures with a minimum follow-up of 48 months and found a 50% incidence of AVN and 100% incidence of post-traumatic arthritis. Timing of fixation did not seem to affect the outcome, union or prevalence of AVN in the later study [10].
The appearance of a radiolucent zone 4-8 weeks after the injury at the subcortical bone of the talar dome indicating bone remodelling "Hawkins' sign" is highly predictive of a revitalisation of the talar body after a fracture. We had not seen AVN in our patients. All cases with a positive Hawkins sign. Thirteen months (mean follow-up period) after the initial injury, our patient made full recovery with no evidence of avascular necrosis or collapse radiologically and clinically. The reason for not seeing avascular necrosis, however, could be our short follow-up period. The mild osteo-arthritic changes seen at the 3 years follow-up are expected in our patient, since the incidence of degenerative changes after talar body fractures is high, affecting more often the tibiotalar than the subtalar joint.
Talar body fractures are produced by an axial compression of the talus between the tibial plafond and calcaneus [6, 12]. In cases with a combined medial malleolar fracture, an additional inversion torque seems to distribute this force to the medial structures, producing a vertical split of the talar body and the medial malleolar fracture [8]. A lateral side talar body fracture could be produced by pronation-external rotation [7]. Recently, Frawley et al. showed in their series of 26 talar fracture patients, 15 talar fractures in the right feet, which push brake pedals, in 16 car drivers [23]. Fractures in the neck and the lateral process of the talus were believed to occur when both the foot and ankle are hyperdorsiflexed [9]. The fracture pattern in our cases suggests an inversion, axial loading, and external rotation mechanism.
In our patients, open reduction and internal fixation was performed with the use of 4.5 mm AO cannulated or headless cannulated (acutrak®, Acumed) screws. We performed surgery through three different (single) approach individually (case1, anteromedial; case 2, anterolateral; case 3, anterior approach). The screws are introduced into the posterior part of the talar body in order to achieve maximum purchase. On the other hand, additional screw was inserted percutaneously. Because posteroanterior screw position gave more stability in a biomechanical trial [19].
Open reduction and internal fixation may restore the joint congruity allowing early range of movement in the tibio-talar and subtalar joints. Plaster cast application was not used and range of motion exercise was encouraged at the early post-operative period but full weight bearing was allowed at 12 weeks [8].