STRESS RADIOGRAPHY OF THE TALOCRURAL AND SUBTALAR JOINTS

The object of this investigation was to determine a possible subtalar component in a group of 33 patients with chronic ankle instability. A group of 10 subjects without ankle/foot symptoms acted as controls. A standardized radiographic assessment of talar and simultaneous subtala r tilt was made. A hinge device to stress the joints and a specific su btalar stress view (Broden view) were used under fluoroscopic control. Radiographs were made with the feet: (1) in neutral position, (2) aft er inversion with moderate force until the point of fair restraint (st ep 1), and (3) after inverting with more force as far as the condition s would allow (step 2). An increase of talar tilt between step 1 and s tep 2 was only found in feet that were symptomatic. This suggests that this increase is only possible when lateral ligaments are damaged. Fu rther research is necessary to determine whether this finding can serv e as a parameter to discriminate between physiological and abnormal ta lar tilt. A wide range of subtalar motion was found in both symptomati c and asymptomatic feet. With the present method, practically all subt alar joints showed some loss of congruity and medial shift of the calc aneus in relation to the talus. This could not be correlated with ankl e instability at the talocrural joint. The consequence of the use of d ifferent subtalar stress methods has so far received little attention and is discussed.