Changes in tibiotalar area of contact caused by lateral talar shift.

A carbon black transference technique was used to determine the contact area in twenty-three dissected tibiotalar articulations, with the talus in neutral position and displaced one, two, four, and six millimeters laterally. The greatest reduction in contact area occurred during the initial one millimeter of lateral displacement, the average reduction being 42 per cent. With further lateral displacement of the talus the contact area was progressively reduced but the rate of change for each increment of shift was less marked.