What is shoulder instability?
Shoulder instability is a condition where the head of the humerus is not well maintained in the socket of the scapula resulting in excess movement and frequently pathology in the shoulder. There is both passive and active movement deficiencies which result in instability. Passive structures that contribute to shoulder stability include the ligaments, capsule and labrum.
How did I get shoulder instability?
Damage may occur to the structures that contribute to stability as a result of trauma, overuse, poor technique or inefficiency of the active stabilisers (rotator cuff and peri scapular muscles). Anterior dislocation of the shoulder damages the ligaments and labrum at the front of the shoulder, allowing the humeral head to slide forward. Anterior capsule stretch can occur in baseball pitchers who over extend. Labral tears can occur as a result of excessive traction on the long head of biceps tendon. For active structures, overuse of the tendons of the rotator cuff or trauma may impair their function and result in poor control. Another group of patients that suffer from instability are those with hyper mobility disorders where there is global laxity of the capsule. There is a genetic component to this kind if instability and shoulder control tends to become fatigued resulting in pain.
What does shoulder instability feel like?
Patients will describe a feeling of apprehension at the ends of range or they may suffer from impingement type pain in the shoulder when lifting their arm up to their side depending on which structures are responsible for the instability. If the shoulder is very unstable frequent dislocations can occur.
How is shoulder instability diagnosed?
Clinical testing will demonstrate the instability on most occasions. MRI scanning will determine which structures are primarily responsible for the instability.
How do I fix shoulder instability?
Identification of the structures that are causing the instability is a must. Rotator cuff and peri scapular strengthening works well if there is a deficiency of the active stabilisers but might not make much difference if not. Surgical repair is indicated in some labral, ligament and capsule tears.
Will I need surgery?
If conservative measures do not work then surgery is often indicated. Long term instability in the shoulder can result in arthritis if not repaired or controlled. Hyper mobile shoulders don’t respond particularly well to surgery.
How do I stop shoulder instability coming back?
Good control of the scapula muscles and rotator cuff is a good way to prevent recurrence of instability. Avoidance of end range stressors where possible helps. Again it depends on the structures that are damaged here and surgery may be indicated.