Stress X-p in the evaluation of anterio-posterior instability of the shoulder joint with the shoulderpositioning-Telos device was examined because the diagnosis of shoulder instability has not been established.
23 normal male joints without shoulder instability were evaluated. Their ages ranged from 19 to 38years with an average of 26.1 years. The device was positioned with its lower side on the edge of the x-ray table. The patient was seated and his 90°
abducted arm (in the scapular plane) was positioned in the device. Shoulder fixation pads were adjusted on the coracoid process and the spine of the scapula. Tho x-ray beam was directed in a 30°angle (frontal plane). For evaluation of anterior instability the pressure support was fixed dorsaly to the shoulder onto its base on the device and the pressure was gradually increased up to 15daN. A pressure support pad was positioned approx.2cm lateral to the edge of the acromion. For the evaluation of posterior instability the pressure support pad was positioned approx.7cm lateral to the edge of the coracoid process. The 60°external rotation of the upper arm was achieved by positioning the lower arm on the“lower arm positioner for 60°”We measured the translation fate of the head.
Shoulder 90°abduction⋅neutralrotation. Ant. instability. average 2.98±6.495(SD)%
Post. instability. average 3.89±5.43 (SD) %
Shoulder 90°abduction⋅60°external rotation. Ait. instability.
average 1.17±4.37 (SD) %
The shoulder-positioning-Telos device seems to be useful for evaluating shoulder instability.
