Pathoanatomy: (The Problem)
Inflammation of the subacromial bursa and the rotator cuff tendon results in pain and swelling. The swelling causes further impingement and inflammation, setting up a vicious cycle. Occasionally the boney anatomy contributes to the problem due to bone spurs further causing damage. Secondary impingement from instability can also occur, further complicating the matter.
With repeated irritation and rubbing, the tendon of the rotator cuff may become thin and weak and eventually tear. Tears of the cuff may also occur as result of acute trauma such as a fall skiing, instead of occurring as a gradual, progressive tearing.
Symptoms and Signs: (What it feels like)
At first the patient may experience pain only with overhead use of the arm or when reaching. This progresses to an aching pain felt all the time and making sleep difficult. Patients often awaken at night when they roll onto their affected shoulder. The pain is usually worsened by further reaching or overhead use of the arm.
A catching or popping sensation is sometimes felt with pain at the top of the shoulder during motion. Many patients describe the pain radiating down the arm and up to the base of the neck.
If the rotator cuff is torn, the shoulder will be somewhat weak and it may be difficult to elevate the arm over the head.
Natural History: (What happens with no treatment)
Many cases of impingement syndrome will resolve spontaneously over time as the patient rests the shoulder from the activities that caused the problem. In some, certain conservative treatments can speed this process.
Unfortunately, for others the process continues despite rest. The pain and aching continue and may even worsen. In the worst cases the rotator cuff will continue to be damaged by the rubbing and will eventually tear.
Treatment and Options:
Initially, rest from aggravating activities is very important. Next, if the patient can tolerate such medication, an anti-inflammatory can be taken to decrease both the pain and the inflammation in the subacromial area (where the bursa is). Finally, in order to dynamically decrease the rubbing, the shoulder capsule needs to be stretched and the shoulder muscles strengthened. This is usually done by physical therapy in combination with a home program for the patient.
If this does not solve the problem–as it will in the majority of patients–more aggressive steps can be considered. Some physicians will inject cortisone or steroid into the area to decrease the inflammation and swelling. This has both pros and cons but is occasionally quite effective.
Such treatment may have only temporary effects, however, and in the face of a weak or partially torn rotator cuff may be less advisable.
As a last resort, arthroscopy can be performed to help in the determination of the nature of the rubbing and to try to eliminate it. This sometimes requires repairing a tear in the rotator cuff (see below) or removal of a portion of the acromion bone where the rubbing is occurring.
Surgical Intervention:
(See the Appendix on Arthroscopy for general information.) Once it has been determined that the problem is unresponsive to more conservative care, an outpatient arthroscopy is scheduled. The patient will be asleep lying on his/her side during the 30 to 60 minute procedure. When the rotator cuff is not completely torn, the source of the impingement is treated by decompression. Decompression is when some of the bone which is rubbing on the rotator cuff tendon is removed. If a repairable rotator cuff tear is found, a small incision will be made along the side of the shoulder for the repair. The torn tendon may then be sutured down into a small trough created in the bone. The shoulder must then be protected from certain stresses while the cuff heals back down to bone. This healing process can take 8 to 10 weeks.
Some rotator cuff tears cannot be repaired but are debrided to decrease the amount of rubbing and catching they cause. This is more common in neglected tears that over time have become very large and the tissue, very thin and weak.
The amount of pain the patient experiences and the rehabilitation time will depend on the extent of the procedure. For several days after the surgery, the shoulder will be swollen and sore. Physical therapy is begun immediately to prevent shoulder stiffening and to speed up the recovery process. If no rotator cuff repair has been necessary, the patient is allowed to return to using the shoulder as soon as the comfort level allows. The risks of surgery include infection, bleeding, nerve or blood vessel damage, and failure of the procedure to prevent recurrence. The long-term outcome is usually quite good, with many patients regaining what feels to them to be a nearly normal shoulder.