3. 1 Instability symptoms
- The classic instability symptom reported is one of apprehension and/or avoidance in a specific
position, such as abduction and ER 90° of elevation for anterior instability and flexion/HF
and IR for posterior instability. (ref). Patients with instability may also experience sharp pain
(plus or minus a sensation of the shoulder “giving way”) and weakness with quick or unguarded
movements, such as suddenly changing direction of a throw. - While apprehension (including avoidance) is typically with traumatic structural instability (ref)
(particularly anterior macro-instability) (ref), other sub-groups are more likely to experience
pain because of their GHJ instability. - Patients with micro-traumatic instability may experience sharp pain, catching, loss of control
and/or a loss of power with certain positions in their sport, such as the cocking phase of
the throw for anterior instability or the follow through phase of a serve/preparation for a backhand
in tennis for posterior instability. - Patients with atraumatic instability may also experience sharp pain, catching, and loss of
control in certain motions, but also report feeling subluxations and feelings of “looseness”
in the shoulder.