Shoulder impingement is a common shoulder condition in adults involved in activities that involve repetitive overhead motion. Shoulder impingement can occur when the rotator cuff tendon and overlying lubricating sac, or bursa, are contacted by two bones of the shoulder with overhead motion. The condition can be an important cause of shoulder bursitis and/or rotator cuff tendinitis.
Your shoulder is made up of three bones: your upper arm bone (humerus), your shoulder blade (scapula), and your collarbone (clavicle). The muscles and tendons that make up your rotator cuff form a covering around the head of the humerus and attach it to your scapula. A lubricating sac called a bursa is situated between the rotator cuff and the top of your shoulder bone (acromion) which allows the rotator cuff tendons to glide freely when the arm is in motion.
Causes of shoulder impingement
Shoulder impingement can occur with activities that require repetitive overhead motions such as painting, construction, swimming, baseball, and tennis. Bone and joint abnormalities can also cause shoulder impingement. When your arm is raised to shoulder height or above, the space between the acromion and rotator cuff narrows. The acromion can rub against (or “impinge” on) the tendon and the bursa, causing irritation and pain.
Signs and symptoms of shoulder impingement
Early symptoms of shoulder impingement may be mild. With time, however, the pain is persistent, and can affect every day activities such as putting on a coat or blouse, reaching overhead, and sleeping. Pain may radiate down the arm from the front or the side of the shoulder down towards the elbow. Any shoulder motion can be painful, particularly reaching above shoulder level and behind the back. As the condition progresses, the rotator cuff tendon can fray and eventually tear.
A physician will examine the shoulder and the arm’s range of motion and may order an X-ray to rule out arthritis or bone spurs that may impact treatment. MRI and ultrasound are used for images of soft tissues like the rotator cuff tendons and can show fluid or inflammation in the bursa and rotator cuff. In some cases, partial or complete tearing of the rotator cuff or of the biceps tendon will be seen.
Treatment for shoulder impingement
Nonsurgical treatment may take several weeks to months, but many patients experience a gradual improvement and return to function following:
- Rest and activity modification to avoid overhead motion.
- Non-steroidal and anti-inflammatories such as ibuprofen and naproxen can help reduce pain and swelling.
- Physical therapy including stretching exercises to improve range of motion, and once pain is resolved, strengthening of the rotator cuff and the muscles that support the shoulder blade.
- Steroid injections only if rest, medications, and physical therapy do not relieve the pain.
If nonsurgical treatments do not resolve the condition, your physician may discuss surgery. The procedure is performed arthroscopically, and serves to remove the inflamed bursal tissue and the bone spur, and contour the acromion to provide more space for the rotator cuff.