Manual of Surgery Volume Second: Extremities—Head—Neck. Sixth Edition.

by Alexis Thomson; Alexander Miles

Fig. 100.—Compound Dislocation of the Talus.

When the foot is dorsiflexed at the moment of injury the displacement is backward, but this is rare, as is also dislocation to one or other side, and dislocation by rotation, in which the talus is rotated in its socket. In all these injuries the body of the talus loses its normal relationship with the malleoli.

An attempt should be made to reduce the dislocation under anæsthesia, the limb being placed in the same position as for reduction of dislocation of the ankle. While traction is made upon the foot, an assistant presses directly on the displaced bone and endeavours to manipulate it into position. In incomplete dislocations this usually succeeds, but it not infrequently fails in those which are complete, and under these circumstances it may be necessary to chisel through the lateral malleolus to admit of reduction, or to excise the talus. In most cases of compound dislocation also, this bone should be removed.

Sub-taloid Dislocation.—In this dislocation, which results from the same kinds of violence as the last, the talus retains its position in the tibio-fibular socket, and the calcaneus and navicular, with the rest of the foot, are carried away from it. The body of the talus, therefore, maintains its normal relationship with the malleoli—a point of importance in the differential diagnosis between this injury and dislocation of the talus. The displacement is usually incomplete, and the foot may either pass backward and medially, or backward and laterally. When the foot passes backward and medially, the head of the talus projects on the outer part of the dorsum, resting on the cuboid. The dorsum of the foot is shortened, the heel lengthened, the toes adducted, and the medial border of the foot raised. The lateral malleolus is unduly prominent, and reaches nearly to the sole.

Fig. 101.—Radiogram of Fracture-Dislocation of Talus.

In the backward and lateral variety, the medial malleolus and head of the talus project unduly towards the medial side of the foot, which is abducted and everted.