"Zero-position" functional shoulder orthosis

The "zero-position" of the shoulder joint described by Saha (1961) is recognized as a mechanical position between scapula and humerus, and the "scapular plane" is widely accepted as a mechanical plane at the shoulder joint. On the basis of biomechanical concepts of the "zero-position" and the "scapular plane", the authors designed the "zero-position" functional shoulder orthosis. This orthosis has been successfully fitted to more than 75 patients for the postoperative management of rotator cuff injuries, and to 3 patients for the treatment of scapular neck fractures. It is introduced here, together with biomechanical considerations, structure, functional and clinical results.