Shoulder Impingement Syndrome

The shoulder is the most mobile joint in the body. This flexibility makes it prone to both sudden injury and chronic wear and tear. Shoulder injuries usually occur in active younger people, especially children and athletes. After age twenty-five, many people get shoulder pain from the wear and tear of routine activities. By middle age, people who use their upper extremities repetitively, at work or play, are particularly susceptible to developing shoulder problems.

Anatomy

The shoulder joint consists of three bones:

1. the clavicle (1)
2. scapula (2)
3. and humerus (3)

held together by muscles, tendons, and ligaments. The coracoid, acromion and glenoid with their attaching ligaments, combine to form a shallow socket called the glenoid fossa (4). The ball-like head of the humerus is cradled in the fossa forming the glenohumeral or shoulder joint. This shallow ball and socket joint, the most mobile joint in the body, is primarily held together by the rotator cuff tendons. The subacromial bursa is a fluid-filled sack which acts to cushion and lubricate the rotator cuff as it moves below the acromial arch or roof of the shoulder joint.

When the shoulder is moved in any direction, the rotator cuff and the associated bursa are squeezed under the acromial arch. Over the years, this repetitive friction can wear down the tendons and bursa causing inflammation and at times, rotator cuff tears. Excessive wear and tear, improper conditioning and inadequate warm up before exercise can result in inflammation in the bursa (bursitis) or in the rotator cuff and bice tendon (tendonitis). Calcification may form the rotator cuff tendons or in the bursa as a result of chronic inflammation.

Impingement Syndrome of the shoulder a term used to describe either rotator cuff tendonitis or subacromial bursitis. It is difficult, and often unnecessary, to differentiate between the two. Patients with Impingement Syndrome can present with shoulder, arm, hand and/or neck pain. The symptoms may have a gradual or sudden onset. Pain may occur at rest or with activity and patients often wake in the middle of the night as a result shoulder pain. Pain may be refereed to the insertion of the deltoid the mid-humerus Physical examination often demonstrates tenderness along the lateral aspect of the shoulder or over the acromioclavicular joint.

Limited motion, abduction and internal rotation are common with motion, grinding or clicking may be felt in the shoulder. A rotator cuff tear should be suspected when abduction weakness is found or when normal passive abduction is associated with limited active motion of the shoulder.

The cycle of disuse produces limited motion. Patients avoid using there painful shoulders which results in the development of adhesions within the joint. This eventually produces adhesive capsulitis called a frozen shoulder.

The Impingement Sign is elicited when shoulder pain is reproduced as the examiner flexes the shoulder. This forces the greater tuberosity against the anteroinferior surface of the acromion. Internally rotating the arm with the shoulder flexing to 90 degrees will increase the discomfort if the sign is positive.

The Impingement Test is useful in confirming the diagnosis. The examiner injects Lidocaine into the subacromial space. If this injection temporarily relieves the discomfort, the patient is likely to be suffering from Impingement Syndrome. Radiographs should always be obtained. Request AP (internal and external rotation), outlet and axillary views. If a rotator cuff tear is suspected, an MRI or an arthrogram is indicated.

Treatment

Initial treatment should be directed at the inflammatory response with the use of rest, ice and anti-inflammatory medication. If resistant to first line therapy, ultrasound with a cortisone cream or a subacromial corticosteroid injection may be therapeutic As inflammation decreases, emphasis is placed on increasing range of motion and total arm strength. The final rehabilitation step for impingement syndrome is correction or modification of pathomechanical activity that created the overuse injury. Warm up and stretching before exercise or work is essential. Working With arms overhead for extended periods of the should be avoided. If after six months, the patient fails to improve with non-operative treatment, surgical intervention may be required.

Clinical Features

1. Pain at rest or with activity
2. Can present as shoulder, arm hand or neck pain
3. Caused by "wear & tear"
4. Gradual or sudden onset
5. Limited shoulder motion

Treatment

1. Rest
2. Ice, NSAID
3. Improve
4. Increase strength
5. Ultrasound
6. Limited use of steroid injections
7. Surgery