This study determined changes in shoulder function associated with increasing age. We studied the range of motion, inferior instability and intra-articular pressure of the shoulder according to patient's age.
We examined 50 normal shoulders by elevating them from 60 degrees to 150 degrees in 30 degree increments in both the coronary and sagittal plans, and measured their range of motion from the most internally rotated to the most externally rotated position. We measured inferior instability of 35 shoulders and intra-articular pressure of 11 shoulders.
When age and degree of elevation were high, range of motion of the shoulder was decreased. Inferior instability was independent of age. When an increased volume of normal saline was injected intra-articularly the shoulder, the intra-articular pressure was higher. We concluded that the capacity of the shoulder capsule in younger subjects was larger than in the old.
