Shoulder Impingement Syndrome/Bursiitis
Impingement syndrome is a common condition causing pain, loss of motion, and limitation of function in the shoulder. It may be due to an injury, such as a fall, or more commonly from overuse of the shoulder, particularly from repetitive overhead arm motions. Most cases of impingement syndrome can be treated successfully with rest, use of anti-inflammatory medicine, cortisone injections, and physical therapy exercises. In certain severe cases surgery is required to alleviate the condition.
The shoulder is a “ball & socket” joint. The upper part of the arm bone (or “humerus”) forms a ball shape and this fits into a small cup or socket (called the “glenoid”) on the outside of the shoulder blade. The ball is much larger than the socket and therefore very unconstrained, which is what allows us to move our shoulders over such a wide area. In order to help stabilize the shoulder joint, we have a series of tendons that surround the shoulder and form a sleeve or “cuff” that contains the ball and the socket. This series of tendons is called the “rotator cuff” and arises from four muscles that all originate on the shoulder blade.
As we move our shoulders the tendons of the rotator cuff need to slide underneath a bone at the top over the shoulder called the acromion. The acromion is also part of the shoulder blade and is the attachment site for several muscles, such as the deltoid that provides power and strength for arm motion. To assist the rotator cuff tendons in sliding smoothly under the acromion there is a slippery layer of tissue called the bursa that sits on top of the tendons and under the acromion. When the bursa becomes irritated and swollen this is termed “bursitis.”
In impingement syndrome, the tendons and bursa become pinched (or impinged upon) by the overlying acromion. There may be an accentuated curvature of the acromion that predisposes a narrower space for the tendons to slide under. Bone spurs may develop overtime that further irritate and inflame the tendons. Alternatively, the tendons and bursa may become irritated and swollen from overuse. There may be an imbalance in the pull of the rotator cuff tendons that causes the ball to ride up in the socket slightly, which can lead to further irritation. When this happens, pain occurs when the arm is brought overhead, to the side or behind the back, as the inflamed tissue is pinched under the acromion.
Symptoms of impingement syndrome include gradually worsening pain, particularly when the arm is raised overhead. Pain at night is worse when sleeping on the involved arm. There may be a rubbing, popping, or catching sensation when the arm is moved. Stiffness of the shoulder may occur overtime as certain painful motions are limited and the shoulder seizes up. Pain is usually felt in the side of the shoulder and may radiate to the elbow and into the hand. It may feel like the hands to go numb at certain times.
Diagnosis of impingement syndrome is typically made by a combination of a history of symptoms, physical examination findings and x-rays. An MRI may be used to confirm the diagnosis or to make sure there is not an associated tear of the rotator cuff.
Treatment of impingement syndrome initially focuses on alleviating irritation in the tendons and bursa and correcting any imbalance in the pull of the rotator cuff tendons so that they function better at containing the ball in the socket of the joint. Resting the arm, taking anti-inflammatory pills and cortisone injections are used to help alleviate inflammation. Specific strengthening exercises for the rotator cuff may be prescribed to help improve rotator cuff function. If this initial treatment approach fails to relieve symptoms, surgery is generally recommended. The procedure is done arthroscopically and involves removal of the inflamed bursa as well as shaving of bone spurs or excess bone on the underside of the acromion to increase the space available for the rotator cuff tendons to slide smoothly as the arm is raised. It may take several weeks to recover fully, but patients ultimately experience good pain relief and highly successful results
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