Did You Know?
One of the most common causes for shoulder pain is impingement syndrome. Commonly referred to as “bursitis” or subacromial impingement, this shoulder condition occurs in patients who frequently perform overhead activities. Most patients complain of anterior or lateral shoulder pain that is worse with elevation of the arm and working overhead. Patients classically complain of pain at night, particularly when lying on the affected shoulder.
Impingement of the greater tuberosity of the humerus on the undersurface of the acromion is the key feature of this syndrome. This impingement is exacerbated with forward elevation of the arm and internal rotation of the shoulder. This position brings the greater tuberosity closest to the anterolateral corner of the acromion, pinching the subacromial bursa and rotator cuff. Repetition can cause inflammation and thickening of the subacromial bursa, further increasing impingement.
Evaluation is Necessary
The many other causes of shoulder pain must also be evaluated as they may require different treatments. An arthritic acromioclavicular joint, rotator cuff tendonopathy alone or biceps tendonitis may also present with symptoms similar to impingement. Impingement syndrome may also be a precursor to a rotator cuff tear. The constant impingement of these tendons may cause progressive tendonopathy and degeneration, eventually leading to a full thickness tear.
Looking at History When Diagnosing
History is important in diagnosing impingement syndrome. The classic history is one of pain with overhead activities and at night. A preceding traumatic event is uncommon. The patient will usually have full motion of the shoulder but can have a painful arc during abduction. Palpation along the anterior and lateral borders of the acromion may produce pain. Strength testing is normal and weakness may indicate a rotator cuff tear. Specific impingement tests can aid in diagnosing impingement. The Hawkins and Neer impingement signs produce pain by causing subacromial impingement. Relief of this pain with a subacromial injection of an anesthetic confirms the diagnosis.
Initial treatment of impingement syndrome is conservative. Physical therapy to maximize flexibility and to strengthen the rotator cuff is very successful, especially early. The addition of NSAIDs and a subacromial corticosteroid injection are also highly effective, particularly if the patient is progressing slowly with therapy. Patients are also encouraged to limit overhead activities, especially lifting, to decrease bursal and tendon impingement.
When Surgery is Necessary
If a patient fails a full course of physical therapy and injections, this patient may be a candidate for surgical decompression. Arthroscopic decompression of the subacromial space is the most common surgical procedure performed on the shoulder. Through three small incisions, the hypertrophic bursa can be excised and the undersurface of the acromion resected to increase space for the rotator cuff tendons. Arthroscopy also allows for direct examination and treatment of other causes of shoulder pain. Pain relief is reliable, patient recovery is quick (approximately 4-6 weeks) and symptoms rarely recur.