The shoulder is a very complex joint that plays a critical role for upper extremity function. The shoulder is a highly mobile ball and socket joint. The ball of the upper arm bone (humerus) is held in place at the socket (glenoid) by several anatomic structures including a fibrocartilage called labrum, a group of ligaments, the fibrous envelope called capsule as well as by the dynamic pull of the rotator cuff muscles surrounding the joint. The stability of the shoulder can be affected by either acute traumatic injuries, chronic overuse injury, or anatomic abnormalities and can result in significant limitation of occupational, recreational, and athletic activities. Besides a full separation of the ball and socket (dislocation), instability can be encountered from the ball partially moving out of the glenoid (subluxation). Instability of the shoulder is a complex condition that can be very disabling and requires a comprehensive treatment approach to not only restore stability but also prevent secondary complications such as secondary shoulder osteoarthritis.
Causes of Shoulder Instability
A dislocation occurs when the end of the humerus (the ball portion) partially or completely dislocates from the glenoid (the socket portion) of the shoulder. A partial dislocation is referred to as a subluxation whereas a complete separation is referred to as a dislocation.
Risk Factors of Shoulder Instability
The risk factors that increase the chances of developing shoulder instability include:
- Injury or trauma to the shoulder
- Falling on an outstretched hand
- Repetitive overhead sports such as baseball, swimming, volleyball or weightlifting
- Loose shoulder ligaments or an enlarged capsule
Symptoms of Shoulder Instability
The common symptoms of shoulder instability include pain with certain movements of the shoulder; popping or grinding sound may be heard or felt, swelling and bruising of the shoulder may be seen immediately following subluxation or dislocation. Visible deformity and loss of function of the shoulder occurs after subluxation or sensation changes such as numbness or even partial paralysis can occur below the dislocation because of pressure on nerves and blood vessels.
Treatment Options for Shoulder Instability
Conservative Treatments for Shoulder Instability
The goal of conservative treatment for shoulder instability is to restore stability, strength, and full range of motion. Conservative treatment measures may include the following:
- Closed reduction: Following a dislocation, your surgeon can often manipulate the shoulder joint, usually under anesthesia, realigning it into proper position. Surgery may be necessary to restore normal function depending on your condition.
- Medications: Over the counter pain medications and NSAIDs can help reduce the pain and swelling. Steroidal injections may also be administered to decrease swelling.
- Rest: Rest the injured shoulder and avoid activities that require overhead motion. A sling may be worn for 2 weeks to facilitate healing.
- Ice: Ice packs should be applied to the affected area for 20 minutes every hour.