Stress fractures occur in the osteoporotic and occasionally in athletes. Fracture of the os calcis after excision of a heel spur has been described. Fractures in toddlers with no history of injury have been reported, and do well without treatment.
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Major body fractures are usually caused by a fall from a height (about 75% of most series) with RTA making up most of the rest. |
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The lateral process of the talus drives into angle of Gissane and splits the os calcis to produce primary fracture line (Fig 1). This runs from anterosuperomedial to posteroinferolateral. In 60-80% of body fractures this splits the posterior subtalar joint and may run into the calcaneocuboid joint also. Position of this fracture line depends on the hindfoot position at impact: the more valgus the hindfoot, the more lateral the fracture line. |
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Continuing descent of the talus and impaction against the medial fragment may split off one or more further joint fragments, and pushes the joint surface down. This shows secondary fracture lines emerging from the superior surface of the calcaneum; they may also emerge posteriorly - see the Essex-Lopresti classification illustrations. On release of force, the talus recoils upwards, drawing the medial calcaneal fragment with it because of ligamentous attachment.
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The peroneal tendons may become entrapped in the fracture site and may suffer partial rupture.
