Dome fracture of the talus. A report of ten cases.

The dome of the talus is the part that articulates with the ankle mortice formed by the lower articular surfaces of tibia and fibula. A fracture of this part of the talus may be called a dome fracture. Such fractures are not common and the significance of the original radiographic appearance is not always appreciated. Definitive treatment is therefore often unnecessarily delayed ; this has been true in our cases as well as in most published series. For this reason we think it is worth reporting a consecutive series of ten cases at Glasgow Royal Infirmary between September 1969 and March 1972. The total number of cases of fracture and dislocation of the ankle over this period was 1,282. Alexander Monro first reported loose cartilaginous bodies in the knee joint in 1737 and ascribed them to trauma, but it was 1932 before Rendu reported an intra-articular fracture of the talus. In 1943 Watson-Jones noted eight chip fractures of the talus among ninety-seven cases of fracture and fracture-dislocation of the talus and navicular. Of twenty-nine cases of fracture of the talus reported by Kleiger in 1948, six affected the dome. In 1952 Coltart reviewed the statistics ofthe Royal Air Force from 1940 to 1945 recording 25,000 fractures ofall bones. Among 4,000 fractures of the ankle and foot were fifty-six chip fractures of the talus. Marks (1952), R#{246}d#{233}n, Tilleg#{227}rd and Unander-Scharin (1954) and Nisbet (1954) reported fractures of the dome, and Cameron (1956) reported a medial lesion which healed with prolonged rest and would seem to have been a dome fracture. Berndt and Harty (1959) in an authoritative article reported twenty-four cases and found another 190 in the literature. They investigated the mechanism of injury and produced some experimental evidence in support of their theory that all dome fractures are caused by an inversion injury of the ankle. Lateral dome fractures, they say, are caused by inversion and dorsiflexion and affect the anterior part of the dome; medial fractures are due to plantar flexion of the ankle, slight anterior displacement of tibia upon talus, inversion of the ankle, and lateral rotation of tibia upon talus. By this latter mechanism it is the more posterior part of the dome that fractures, and radiographs may require to be taken in plantar flexion. Berndt and Harty were the first to classify dome fractures according to site and also to stage them according to displacement : Stage I-a small area of compression of subchondral bone ; Stage 11-a partially detached osteochondral fragment ; Stage 111-a completely detached osteochondral fragment remaining in place ; and Stage IV-a displaced osteochondral fragment. Most writers now agree with their views. Since they wrote in 1959, dome fractures of the talus have been reported by Rosenberg (1965), by Davidson, Steele, Mackenzie and Penny (1967) and by Gustilo and Gordon (1968).