Chronic Shoulder Instability is a condition where the head or top of the arm bone (humerus) repeatedly slips out of the shoulder socket (glenoid).

Common Symptoms

• Pain caused by shoulder injury
• Repeated shoulder dislocations or subluxations (partial dislocations)
• Persistent sensation of the shoulder feeling loose or slipping in and out of the joint
• Shoulder weakness, especially during activity
• Decreased range of motion

Cause & Anatomy

Causes of Chronic Shoulder Instability:

• Severe trauma or injury causing an initial shoulder dislocation that damages the ligaments and capsule
• Repetitive overhead motions like throwing that loosen the shoulder capsule over time
• Genetic condition of loose ligaments (hyperlaxity) leading to instability without injury

Anatomy of Chronic Shoulder Instability:

• Humerus (upper arm bone)
• Glenoid (shallow socket in the shoulder blade)
• Shoulder capsule and ligaments that keep the humerus centered in the glenoid
• Rotator cuff and other shoulder muscles that dynamically stabilize the joint

Diagnosis

• Physical exam to check for looseness, weakness, range of motion
• Imaging tests like MRI or CT scan, sometimes with contrast dye injection (arthrogram)
• Examination under anesthesia followed by arthroscopy

Prevention

Strengthening shoulder muscles and improving motor control through physical therapy can help prevent instability, especially after an initial dislocation.

Non-Surgical Treatment

• Activity modification, anti-inflammatory medication
• Physical therapy to strengthen muscles and improve control

Surgery

Surgical (if nonsurgical treatment fails):

• Arthroscopic or open repair of torn ligaments and capsule to stabilize the joint

Post Surgical Rehabilitation

• Immobilization with a sling for several weeks
• Physical therapy to regain range of motion and prevent scarring
• Gradually progressing to strengthening exercises as healing allows
• Commitment to rehab is crucial for a successful outcome