How To Evaluate And Treat Calcaneal Fractures

By Don Buddecke, DPM and Michael S. Lee, DPM

   Calcaneal fractures continue to be one of the most complicated injuries of the lower extremity. Satisfactory outcomes are difficult to achieve and require extensive experience and understanding in treating the injury. Calcaneal fractures are much like pilon fractures of the distal tibia in that they are severe soft tissue injuries complicated by fracture of the heel bone. The importance of the soft tissue envelope cannot be overstated.    There continues to be a wide range of treatment strategies despite the significant ongoing research on this injury. Cast immobilization, percutaneous pinning, limited open approaches, extensile open approaches and fine wire external fixation have all been reported. However, there is still no clear standard in the approach to these complex fractures.    Having a strong knowledge of the anatomy of the calcaneus is paramount to understanding the fracture patterns one may see with these injuries. The calcaneus has a thin cortical shell laterally with its interior consisting of cancellous bone. Medially, the sustentaculum tali is made up of dense cortical bone with strong ligamentous attachments to the talus. There is also very thick cortical bone that supports the facets on the superior surface of the calcaneus. This dense cortical bone forms an angle of 120 to 145 degrees (Gissane’s crucial angle). Directly under this dense bone is the neutral triangle, an area relatively void of trabecular patterns. This lies directly under the lateral process of the talus. Anteriorly, the calcaneus articulates with the cuboid and transitions to the lateral column of the foot.    Intraarticular calcaneal fractures are the result of an axial load with varying degrees of shear force. The shear forces are dictated by the position of the calcaneus in relation to the talus at the time of axial load. Calcaneal fractures typically result from a fall from varying heights or a motor vehicle accident. The characteristics of these fractures result from the amount of applied force, the quality of bone and the relationship of the talus and calcaneus (i.e. position of the foot).1,2 This talocalcaneal relationship may change throughout impact depending on the injuring force. This leads to the subtle variations in every fracture.    The initial axial load causes the impacting of the calcaneus into the talus. The lateral process of the talus then acts like a wedge into the dense cortical bone at the crucial angle of Gissane.3 Once the cortical bone has failed, the lack of dense bone in the neutral triangle offers little resistance to the applied forces. The resulting primary fracture line is oriented from superolateral to inferomedial, producing a posterolateral tuberosity fragment and a medial sustentacular fragment.2    Each main fragment will have a portion of the posterior facet. This primary fracture line will exit laterally beneath the lateral talar process or extend anteriorly and involve the calcaneocuboid joint. The tuberosity fragment is often plantarflexed (due to the Achilles tendon influence) and displaced laterally against the fibula. However, the sustentacular fragment is usually in anatomic alignment with respect to the talus due to the strong ligamentous attachments. Where the primary fracture line starts in the posterior facet is dependent on the relationship of the talus and calcaneus. An inverted foot will cause the fracture line to start more medially while an everted foot will cause the fracture line to begin laterally.4 The more eccentrically positioned the calcaneus is in relation to the talus, the more shear forces that are applied during axial load.

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