Impingement is a very common problem in which tendons of the shoulder rotator cuff (predominantly supraspinatus) rub on the underside of the acromion. This causes pain due to the repeated rubbing of those tendons and it is especially bad in certain positions of the arm. In particular it is difficult to put the arm behind the back and to use it in the elevated position. This makes it difficult to drive, change gears, hang clothes, comb one’s hair, and even lie on the affected shoulder.
The shoulder rotator cuff is a group of flat tendons which fuse together and surround the front, back and top of the shoulder joint like a cuff on a shirt sleeve. These tendons are connected individually to short , but very important muscles that originate from the scapula. When the muscles contract, they pull on the rotator cuff tendon, causing the shoulder to rotate upward, inward or outward, hence the name “rotator cuff”.
Impingement syndrome, rotator cuff tendonitis and rotator cuff tear represents a single pathological process at increasing stages of progression. The uppermost tendon of the rotator cuff, the supraspinatus tendon, passes beneath the bone on top of the shoulder, called the acromion. “Impingement syndrome” has also been termed “subacromial bursitis” and “supraspinatus tendonitis”.
Essentially these terms refer to a condition in which the tissue above the shoulder joint, in the sub-acromial space, rub against the overlying bone, the acromion, resulting in pain which is generally made worse by elevating the arm. It is a spectrum ranging from mild inflammation of the bursa, or lubricating sac, overlying the muscle, to inflammation of the muscle itself and finally to tearing of the tendon of the muscle resulting in weakness and dysfunction of the shoulder.
The exact cause of this condition is not known. In some individuals it is clearly a traumatic event usually secondary to a wrenching type injury of the shoulder. In most individuals the cause is less obvious. Some individuals do seem to be predisposed to this condition due to the shape of the overlying acromion and the presence of acromial spurs. It is more common in individuals who do repetitive overhead activities such as ceiling plasterers, swimmers and baseball pitchers.
Symptoms of rotator cuff injury
The most common complaint is aching located in the top and front of the shoulder, or on the outer side of the upper arm (deltoid area). The pain is usually increased when the arm is lifted to the overhead position. Frequently, the pain seems to be worse at night, and often interrupts sleep. Depending on the severity of the injury, there may also be weakness in the arm and with some complete rotator cuff tears, the arm cannot be lifted in the forward or outward direction at all.
Diagnosing rotator cuff disease
The diagnosis of rotator cuff tendon disease includes a careful history taken and reviewed by the physician, an x-ray to visualize the anatomy of the bones of the shoulder, specifically looking for acromial spur, and a physical examination. Atrophy may be present, along with weakness, if the rotator cuff tendons are injured, and special impingement tests can suggest that impingement syndrome is involved. An ultrasound or MRI (magnetic resonance imaging) scan frequently gives further evidence of the status of the rotator cuff tendon. Although none of these tests is guaranteed accurate, most rotator cuff injuries can be diagnosed using this combination of exams.
Treating Impingement Syndrome
If minor impingement or rotator cuff tendinitis is diagnosed, a period of rest coupled with medicines taken by mouth, and physical therapy will frequently decrease the inflammation and restore the tone to the atrophied muscles. Activities causing the pain should be slowly resumed only when the pain is gone. Sometimes a cortisone injection into the bursal space above the rotator cuff tendon is helpful to relieve swelling and inflammation. Application of ice to the tender area three or four times a day for 15 minutes is also helpful.
Surgical Treatment of Impingement Syndrome
If there is a thickened acromion or acromial bone spur causing impingement, it can be removed with a burr using shoulder arthroscopy. The procedure is performed in hospital under a general anaesthetic, and at the same time, any minor damage and fraying to the rotator cuff tendon and scarred bursal tissue can be removed. Often this will completely cure the impingement and prevent progressive rotator cuff injury.
Treatment of rotator cuff tears
A torn tendon cannot heal without the intervention of surgery. The choice of shoulder surgery, of course, depends on the severity of the symptoms, the health of the patient, and the functional requirements for that shoulder. In young working individuals, repair of the tendon is most often suggested. In some older individuals who do not require significant overhead lifting ability, surgical repair may not be as important. If chronic pain and disability are present at any age, consideration for repair of the rotator cuff should be given.
Consequences of not repairing rotator cuff tears
In some situations, the bursa overlying the rotator cuff may form a patch to close the defect in the tendon. Although this is not true tendon healing, it may decrease the pain to an acceptable level. If the tendon edges become fragmented and severely worn, and the muscle contracts and atrophies, repair at that point may not be possible.
Sometimes in this situation, the only beneficial surgical procedure would be an arthroscopic operation to remove bone spurs and fragments of torn tissue that catch when the arm is rotated. This will certainly not restore normal power or strength to the shoulder, but often will relieve pain.
Surgical Treatment of rotator cuff tears
The arthroscope is extremely helpful when repairing rotator cuff tendons, but sometimes it is necessary to add a “mini-open” procedure if the tendon is completely torn. Using the arthroscope at the beginning of the case allows visualization of the anterior joint to facilitate trimming and removal of fragments of torn rotator cuff tendon and biceps tendon. The next step utilizes the arthroscope to visualize the spur and thickened ligament beneath the acromial bone, while they are removed with miniature cutting and grinding instruments. If it is necessary to suture a rotator cuff tear which has pulled off the bone, a two-inch incision can be made directly over the tear that has been visualized and localized using the arthroscope. The deltoid muscle fibres can be spread apart so that strong stitches can attach the rotator cuff tendon back to the bone. If the tear is minimally retracted, small suture screw anchors may be used arthroscopically or open.
Post Operative Management
In a minor operation for impingement, the shoulder is placed in a simple sling. If a full thickness tear of the rotator cuff was present and repaired, then the shoulder will be supported by a shoulder immobilzer sling. The brace is very helpful because it will allow exercise of the elbow, wrist and hand at all times, and places the arm in a position that promotes better blood circulation and relieves stress on the repaired rotator cuff tissues. In addition, the shoulder can be exercised in the brace much easier than when it is at the side in an immobilizer.
Post Operative Rehabilitation
Depending on the type of surgery performed, the program will allow a period of time for healing of the soft tissues followed by time to regain a motion and then strengthen the shoulder muscles, but particularly the rotator cuff. In minor tendinitis and impingement syndrome, the program takes approximately two to three months. If the rotator cuff tendon has been completely torn, it may take six months or more before the atrophied muscles can resume their function and the range of motion of the arm is restored. Frequently, pain relief is much quicker and return to daily activities is often possible by two to three months.
Results of surgery for Impingement and rotator cuff tears
Again, every case is unique. In the young healthy person with a minor rotator cuff impingement, surgery is predictably successful. As the injury becomes more severe, such as with a large bone spur and fragmentation of the tendon, then a perfect result cannot be expected. Since it is necessary to trim back the unhealthy tendon before reattaching it to the bone, a decreased range of motion of the shoulder will often result. Despite this, pain relief and return of strength are usually well worth the minor decreased mobility. The final outcome often depends on the willingness and ability of an individual patient to work on their postoperative physical therapy programme. The incidence of major complications from the above operation is very small, however risks exist with all surgical procedures and these should be discussed and clearly understood by yourself before you proceed with surgery. Return to work and sport will depend to a large extent on the activities required and the extent of the cuff tear. This may be considerable and the full extent of any cuff tear may only be known after surgery.