Fractures of the talus are extremely rare in children, with a reported frequency of 0.08% among all pediatric fractures1. Fractures of the body of the talus are even more uncommon in children, with very few cases reported in the literature2-4. Based on the understanding of the mechanisms of injury of various types of talar body fractures encountered in adults5,6, it has been suggested that displaced fractures of the talar body in children should be treated according to the same treatment principles for fractures in adults (i.e., by open reduction and internal fixation)4. However, no clear guidelines are available for treatment of the complications of these injuries in children, which include osteonecrosis and malunion3.
We report the successful treatment of a malunited, displaced coronal shear fracture of the body of the talus with osteonecrosis, fixed hindfoot varus, and impingement of the talus on the anterior tibial margin in a child. Revascularization of the avascular body of the talus appeared to be facilitated with a subtalar arthrodesis. The parents of the child were informed that data concerning the case would be submitted for publication, and they provided consent.
A seven-year-old boy had been involved in a traffic accident and had sustained injuries to the right knee and leg. An associated ankle injury had not been diagnosed at the time of admission, and during the period of hospitalization, he had not mentioned symptomatic pain in the region of the ankle. After convalescing at home for three months following discharge from the hospital, he complained of discomfort in the ankle.
The boy was referred to our center for treatment four months following the initial injury. The ankle was broadened, and there was a severe rigid varus deformity of the hindfoot. Subtalar motion was severely reduced, and dorsiflexion of the ankle was markedly limited. Radiographs revealed a Sneppen type-B (displaced) coronal shear fracture of the body of the talus (Fig. 1). The talar body was sclerotic, indicating that it was avascular. Examination of the ankle under fluoroscopy revealed that the entire talus moved in one piece during passive dorsiflexion and plantar flexion of the ankle, which indicated that the fracture had united in the grossly displaced position. Attempted passive dorsiflexion caused the distal displaced portion of the body of the talus to abut against the distal tibial margin.
It was decided to accept the position of union but to deal with the consequences of the malunion and the osteonecrosis. The osseous bump on the dorsum of the displaced portion of the body of the talus was resected down to the neck to relieve the impingement. A subtalar arthrodesis was performed to correct the varus deformity of the hindfoot and to potentially facilitate revascularization of the body of the talus from the vascular bed of the calcaneus. Sequential radiographs following the subtalar arthrodesis showed progressive reduction in the sclerosis of the body of the talus (Figs. 2 and 3). A displacement osteotomy of the calcaneus was performed a year later to correct some residual hindfoot varus that had not been corrected at the time of the arthrodesis (Fig. 4). At the time of final follow-up four years later, the body of the talus did not show any evidence of sclerosis, no collapse of the talar dome had occurred (Fig. 5), and the hindfoot varus had been corrected (Fig. 6). It was noted that 15° of plantar flexion and 15° of dorsiflexion of the ankle were possible. No discernible limp or calf atrophy was present, and the child had no pain on walking and running.
Recommendations for the optimal method of treatment for complications of displaced fractures of the body of the talus in children are not freely available. These injuries are very uncommon in children, and a large proportion of the few documented cases are undisplaced or minimally displaced fractures that heal without any complication3. Hence, one may be inclined to treat osteonecrosis of the talus in children in the same manner as recommended for adults, namely by core decompression and bone-grafting7. However, we opted to address both the severe fixed hindfoot varus deformity and the osteonecrosis by performing a subtalar arthrodesis. Excision of a laterally based wedge of bone from the calcaneus improved the deformity. Good contact between a large vascular cancellous surface of the calcaneum and the cancellous bone of the avascular talar body was ensured in an attempt to promote revascularization of the talus from the calcaneus. This apparently did occur as evidenced by the progressive resolution of the sclerosis of the body, which was noted on sequential radiographs. Collapse of the dome of the talus was averted; therefore, future satisfactory ankle function is possible.
The impingement of the talus on the tibia during dorsiflexion of the ankle was effectively treated by removing the offending osseous prominence. We acknowledge that we cannot be absolutely certain that revascularization of the talus would not have occurred spontaneously over a period of time. However, we believe that the subtalar fusion at least accelerated the rate of revascularization sufficiently to prevent collapse of the talar body.
This case presents an original approach to the treatment of osteonecrosis of the talus in a child, which may be considered a viable option in other pediatric patients.
Note: The clinical fellowship of Dr. Stéphane Tercier was supported by Swiss grants (Fonds du Département Médico-chirurgical de Pédiatrie et de Perfectionnement du CHUV, Fondation SICPA, Fondation de l’Hôpital Orthopédique de Lausanne, et Fonds de la Société Suisse d’Orthopédie et Traumatologie).
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