[The "positioned image" of the talo-calcaneus joint in instability of the posterior distal ankle joint].

With regard to the very common disease of sprained ankles the combined tear with ruptures of ligaments of the subtalar joint are possible. Even an isolated instability is known as the reason of long lasting post-traumatic complaints. Using the apparatus of Scheuba, well-known in diagnosing instabilities of the knee and ankle joint, a new standardized method controlling instabilities of the subtalar talo-calcanear joint is introduced. In an experimental investigation this radiological technique has been tested out in cadaveric ankle joints (nine joints) with artificial ligamentous lesions. The results show that in all cases an instability is recognizable radiologically using this technique. For clinical use the bilateral examination is recommended failing standardized values for unilateral use.