Shoulder instability is a condition characterized by a loose, or unstable shoulder joint caused by weakened and stretched surrounding ligaments. This may become a chronic condition after a shoulder dislocation, which occurs when the ball of the upper arm bone comes out of the socket. Chronic instability may produce frequent slipping, or partial dislocation, known as subluxation.
A shoulder dislocation may occur after an acute traumatic injury to the shoulder. This usually occurs during a contact sport such as football, or hockey, but can also occur from a fall onto an outstretched arm.
An unstable shoulder may also be the result of repetitive overuse in an overhead athlete, such as tennis, volleyball, and swimming.
The shoulder is more susceptible to this type of condition than other joints because it provides the arm with a tremendous range of motion. If a dislocation takes place, the muscles, tendons and ligaments of the shoulder may tear or loosen, resulting in the persistent slippage associated with instability.
Symptoms of Shoulder Instability
People with unstable shoulders may experience pain and limited motion in the joint and additional symptoms may include:
- Numbness in the arm
Symptoms of shoulder instability may discourage participation in sports that require stretching the arm overhead.
Diagnosis of Shoulder Instability
Shoulder instability can be diagnosed after a medical history has been taken and a physical examination performed. The exam may include certain tests of movement in order to evaluate potential shoulder instability. Additionally, imaging tests such as X-rays or MRI scans may be necessary to provide clear visualization of the bones and tissues around the shoulder.
Treatment of Shoulder Instability
Treatment for shoulder instability usually begins with conservative measures including resting the affected arm, physical therapy and use of non-steroidal anti-inflammatory medications. However, for some people these approaches may fail to provide relief. At that point, surgical treatment may be recommended. Instability surgery varies depending on the cause of the condition, but usually aims to tighten the loose ligaments of the shoulder. The two most common types of instability surgery include Bankart repair and capsular shift procedures, which may be performed in combination.
Bankart repair is an arthroscopic surgery procedure, where the surgeon places a small camera into the shoulder through a portal. Other portals are used to place small anchors in the socket with strong sutures attached. These sutures are then passed around the torn labrum and ligament to repair the tear and restore stability to the shoulder joint.
Capsular shift is used to decrease and tighten the joint capsule, which is the lining of the joint, when it is too large. This is accomplished by folding the affected ligaments over on themselves and suturing them in this more layered position.
Both of these outpatient surgeries can often be performed through arthroscopy, which allows for minimally invasive procedures with smaller incisions and shorter recovery times.
Risks of Shoulder Instability Surgery
As with any type of surgery, shoulder repair surgery may pose a risk of complications. Although uncommon, risks may include:
- Blood clot
- Shoulder stiffness
- Shoulder weakness
- Nerve or blood vessel damage
In some cases, the shoulder may fail to heal after surgery.
Recovery from Shoulder Instability Surgery
Patients are required to wear a sling or another immobilization device for 5 days after surgery until their first postoperative visit. Depending upon the procedure performed and the severity of the tear, physical therapy will usually begin 5 days after surgery. Sling use will be gradually weaned as function improves to reduce the risk of postoperative stiffness. Pain medication and applications of ice may be necessary for at least a few days following the procedure. Physical therapy can be very effective in restoring the flexibility and strength to the shoulder. Recovery periods vary depending on the extent of the shoulder damage, but full recovery typically takes several months.