The role of proprioception inshoulder instability

Abstract

Stability of the shoulder joint is derived from a number of different mechanisms involving the articular geometry,dynamic (muscular) stabilizers, static capsuloligamentous tissues, and intra-articular forces (negative intraarticular pressure, surface forces of adhesion and cohesion). Capsuloligamentous structures might contribute to the joint stability by providing an afferent feedback for reflexive muscular contraction of rotator cuff and the biceps brachii. The role of proprioception in allowing a feedback mechanism to work, which in turn allows a synergistic contraction of muscle groups, may be vital both for normal functioning of the muscle groups of the shoulder joint and in protecting the shoulder against potential instability. Significant proprioceptive deficits have been reported in patients who had chronic, traumatic anterior shoulder instability and surgical stabilization of such shoulders restored proprioceptive deficits. Whereas the many studies done on proprioceptors and their distribution patterns are relatively free of controversy, the relationship between proprioception deficit and instability is still not crystal clear. However, most studies have shown that proprioception may play an important role in contributing to joint stability. Future work needs to look at the exact mechanisms of proprioception, whether proprioceptive sensibilities are congenital or acquired factors, and whether there is any role for proprioceptive prophylaxis in modern day injury prevention.