Fig. 1.

The midpoint of the upper surface of the talus was used to separate the medial joint space of the ankle from lateral. The narrowest distance between the upper surface of the talus and the distal end of the tibia was measured on the medial and lateral sides of this midpoint. This distance was not necessarily perpendicular to any bony surface. The narrower of the medial or lateral JSW was taken as the narrowest JSW of the ankle.