Multidirectional instability of the shoulder

Abstract

Multidirectional instability (MDI) represents a wide spectrum of disease, but is defined as symptomatic, involuntary, and uncontrollable subluxation or dislocation of the glenohumeral joint in two or more directions. Instability should be differentiated from laxity, in which no symptoms are present. Due to its inconsistent definition in the literature, it is difficult to reliably determine its actual incidence. MDI likely represents a less common clinical entity than anterior traumatic instability, representing 7-10 % of all instability cases.