Primary Cause of Shoulder Pain and Treatment Options.
There are several causes of shoulder pain. In the elderly, shoulder pain is commonly associated with aging and can be traced to rotator cuff disease. In younger people, it is associated with throwing or overhead sporting activities that result in injury to the rotator cuff.
The rotator cuff is a band of four muscles and tendons at the shoulder joint, which grasp the end of the upper arm or humerus (HYU-mer-us, see figure), much like four fingers holding a baseball. The rotator cuff thus stabilizes the shoulder joint and provides exceptional mobility to the arm. Pinching, irritation, or tears of the rotator cuff are common causes of shoulder pain.
Rotator cuff tendons are separated from overlying bones by a soft tissue sac or bursa, allowing them to glide easily. According to one theory, repetitive motion of the arm causes pinching of this sac in the tight space between the acromion (a-KRO-me-un) and humerus (see figure), resulting in irritation, swelling and pain. This inflammation of the bursa and tendons is called impingement. The pain is characteristically worse when the arm is lifted and common at night.
Causes and Symptoms
The rotator cuff is frequently damaged by age related degeneration of the tendons. With advancing age, the blood supply to the rotator cuff diminishes, leading to weakness in the tendon and a decreased ability to repair micro tears occurring from every day use. Eventually a tear can develop. Of the four rotator cuff muscles, the supraspinatus (SOUP-ra-spin-ATE-us) is most frequently involved. Rotator cuff tendons can also be injured by constant rubbing across a bone spur.
Common symptoms include shoulder pain radiating to the neck or the arm. Pain increases while reaching overhead or behind the back, lifting, pulling, or sleeping on the affected side. Weakness of the arm is a common complaint. Most patients are able to perform activities required for daily living. However, patients with full thickness tears may be limited in their activities due to pain and weakness.
Diagnosing Rotator Cuff Disease
During a physical exam, the doctor will ask patients to perform various activities with their arm. Careful evaluations help the doctor diagnose impingement or rotator cuff tears. If your doctor suspects a tear, additional tests may be necessary to confirm and distinguish between a partial or complete tear.
An injection with a local anesthetic (eg lidocaine) can help the doctor distinguish between impingement syndrome, rotator cuff tears and other conditions, which mimic these. Radiographs can reveal signs of arthritis, fractures and bone spurs on the acromion causing irritation. Radiographs also reveal changes in position of the humerus and acromion suggestive of rotator cuff tears. However, radiographs cannot be used to visualize the rotator cuff itself or the underlying bursa, and advanced soft tissue imaging is frequently required. MRI is well suited for imaging soft tissues and to specifically evaluate the rotator cuff and the general shoulder.
Conservative Treatment May be Effective
Treating rotator cuff disease depends on the severity of symptoms and functional activity requirements. Dr Thomas F Holovacs, shoulder surgeon at the Massachusetts General Hospital and member of the Harvard Shoulder Service states, “a majority of patients will benefit from resting the shoulder, applying ice and using non-steroidal medications such as ibuprofen and naproxen to reduce pain. Subacromial injections of local anesthetic and corticosteroids can be effective in reducing shoulder inflammation.” A change in activities is often required.
Depending upon the type and level of injury, your doctor will coordinate with physical therapists and develop a customized protocol to strengthen the rotator cuff tendons and help you regain range of arm motion.
Some Patients May Need Surgery
A small percentage of patients with impingement, whose symptoms have not improved after conservative treatment, may benefit from minimally invasive surgical intervention. Using arthroscopic techniques performed through small ports in the shoulder, the irritated and inflamed bursa sac is removed, relieving pain and restoring function. During the procedure, the acromion bone is often smoothened to prevent impingement from reoccurring. Some surgeons believe that impingement is a sequelae of rotator cuff weakness, and in the case of a full-thickness rotator cuff tear, repairing the torn tendon is sufficient to relieve impingement.
Conservative treatments are less effective in patients with large rotator cuff tears, and in those with significant weakness in the arm and shoulder, hindering daily activities.
Often rotator cuff tears can be repaired using arthroscopy, a minimally invasive procedures. Successful repair reduces pain, and improves function and strength in greater than 80% of patients. Infection due to surgery and permanent stiffness remain complications in a small fraction of patients.
“Rotator cuff disease continues to plague our society for a variety of reasons including increased participation in sports and aging of our population. Frequently, rotator cuff disease can be managed conservatively. When conservative measures fail, arthroscopic surgery is a minimally invasive technique designed to return the patient to a painless, full, active lifestyle” adds Dr Holovacs.