Dislocations occur more frequently in the shoulder joint than in any other joint in the body. Reduction is, as a rule, readily accomplished, but if delayed beyond a few hours, is not easy. If deferred for days, it is quite difficult, and a delay of more than a week may mean that all attempts at reduction will fail. If the dislocation is associated with a fracture of the surgical neck of the humerus, unless reduction is accomplished by an open operation, the patient usually comes to a resection of the head of the bone later.
Habitual dislocations of the shoulder joint occur in cases in which reduction has been accomplished and the convalescence completed without incident, so that there is no cause for anxiety. The habit of easy dislocation is a sequela that cannot be foretold. A shoulder joint may be said to be subject to habitual or recurrent dislocations
HENDERSON MS. RECURRENT OR HABITUAL DISLOCATION OF THE SHOULDER. JAMA. 1918;70(1):1-4. doi:10.1001/jama.1918.02600010003001