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Shoulder Instability and Dislocations

What is Shoulder Instability?


The shoulder is a ball-and-socket joint that is naturally very mobile. Instability occurs when the ball (humeral head) does not stay centered in the socket (glenoid).


What is This Condition?


  • Dislocation: the ball comes completely out of the socket.

  • Subluxation: the ball partially slips out.

  • Instability may be caused by trauma, overuse, or naturally loose ligaments.


What Causes It?


  • A fall, collision, or sudden force (common in sports)

  • Repetitive overhead activity (throwing, swimming)

  • Loose ligaments or hypermobility (sometimes genetic)

  • Prior dislocations that stretched or tore supporting structures


What are the Symptoms?


  • Sensation of the shoulder “slipping out” or feeling loose

  • Sudden pain and visible deformity with a dislocation

  • Swelling, bruising, and limited ability to move the arm after injury

  • Numbness or tingling down the arm if nerves are stretched

  • Recurrent dislocations with overhead or sports activity


How is It Diagnosed?


  • History: patients often describe a shoulder “slipping out”

  • Exam: checking laxity and stability of the joint

  • X-rays: show dislocation or bone injury

  • MRI or CT: reveal labral tears, ligament injuries, or bone loss


How is It Treated?


Non-surgical treatment:


  • After a dislocation, the shoulder is reduced (put back in place) and often supported in a sling.

  • Physical therapy is the cornerstone of care. Strengthening the rotator cuff and shoulder blade muscles helps keep the joint stable and lowers the risk of future dislocations. Therapy also improves posture, flexibility, and control of movement.

  • Many patients, especially those who are older or less active, do very well with rehab alone.


Surgical treatment:


  • Surgery is considered if instability recurs despite therapy.

  • Some first-time dislocators may need surgery right away — particularly young athletes, or patients with significant bone loss or large labral tears.

  • Surgical options include arthroscopic labral repair, capsular tightening, and bone graft procedures (such as the Latarjet) when bone is missing.


The goal is to restore stability, prevent future dislocations, and allow patients to return safely to their activities.

​​Learn more from AAOS (OrthoInfo):

https://orthoinfo.aaos.org/en/diseases--conditions/chronic-shoulder-instability/

https://orthoinfo.aaos.org/en/diseases--conditions/dislocated-shoulder/

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