Shoulder Instability "Shoulder instability" is an all encompassing term that includes the entire range of disorders such as dislocation, subluxation, and "pathologic" laxity.
Translation is the movement of the humerus with respect to the glenoid articular surface. Laxity is the amount of translation that occurs. Some laxity is expected in normal shoulders. In fact, more than a centimeter,of posterior laxity is common, especially in athletes. Consequently, instability must be defined as unwanted translations of the GH joint experienced by the patient.
The ability of the examiner to translate the humerus greater than one cm or on to the rim of the glenoid is not equal to instability. However, if that maneuver reproduces the patient's symptoms, which they may describe describe as "slipping" or "giving-way" or "painful," then this is supportive evidence of GH joint instability.
We have already focused on the diagnosis and treatment of overhead athletes who have underlying microinstability that may predispose them to secondary impingement, internal impingement, rotator cuff tendinitis, and/or rotator cuff tears.
Classification of Shoulder Instability Frequency -Acute -Recurrent -Fixed (chronic) Cause -Traumatic event ( macrotrauma ) - Atraumatic event (voluntary, involuntary)
Recurrent anterior instability is the most common problem after a primary anterior dislocation. The most consistent and significant factor influencing recurrence is age at primary dislocation, but in reality, this may be a reflection of the activities more common in a younger population than an older population. Patients younger than 30 years have an average risk of approximately -70% of recurrent dislocation when treated with a nonsurgical rehabilitation program. Overall, the average recurrence rate is approximately 50% with nonoperative management.
One group was treated with a rehabilitation program and had a redislocation rate of 47%, and the other group was treated with an arthroscopic stabilization procedure and had a redislocation rate of 15% with an average follow-up of two years.
Conservative management of anterior shoulder instability has been associated with a more successful outcome in patients older than 30 years. Younger patients treated conservatively usually require a longer course of immobilization in hopes of achieving a successful outcome. However, it should be recognized that the length of immobilization has been only loosely associated with decreasing the risk of recurrence, with further scientific studies needed to prove its value. Because recurrence is the most common complication, the goal of the rehabilitation program is to optimize shoulder stability.