[Fractures and dislocations of the talus]

Some of the peculiarities of the anatomy of the talus are of special interest: the lack of muscle insertions, the vulnerability of the blood supply, and the fact that about 60% of the surface is covered by hyaline cartilage. This implies that most of the fractures are intra-articular. In 1983, the results of 262 talus fractures were published. Kuner and Lindenmaier found post-traumatic arthritis in about 50% of the cases. A subdivision of peripheral and central fractures is useful; complications like avascular necrosis are found in about 18% of fracture cases of the central talus. Magnetic resonance imaging may be helpful in the early diagnosis of talus necrosis. Hawkins' sign in an anteroposterior roentgenogram after 6 or 8 weeks of fracture dislocation and non-weight-bearing shows that subchondral atrophy is present in the dome of the talus. This excludes the diagnosis of avascular necrosis. Absence of subchondral atrophy in the early months and then later density of the dead bone and atrophy of the surrounding bones imply avascular necrosis. Dislocations around the talus without fractures are classified into three types: talocrural dislocation (i.e., luxatio pedis cum talo), subtalar dislocation (i.e., luxatio pedis sub talo), and the extremely unusual total dislocation of the talar body. The dislocations should be reduced promptly to avoid breakdown of the skin and distal circulatory compromise.