Patient Guide to Shoulder Instability

Anatomy

The shoulder is a combination of three bones: the humerus (upper arm bone), the clavicle (collarbone), and the scapula (shoulder blade). The ball-like head of the humerus fits into the cup-like end of the scapula known as the glenoid. This cup or glenoid is commonly referred to as the shoulder socket and is surrounded by a rim of soft tissue called the labrum. In order to maintain shoulder stability, the labrum acts like a bumper and is helped by the glenohumeral ligaments and capsule within the shoulder joint.

Definition

The head of the humerus may be forced out of the glenoid in a dislocation or can be forced partially out of the glenoid, which is known as a subluxation. Repeated dislocation or subluxation of the humerus out of the glenoid is known as instability. Instability is a weakening of the capsule and ligaments of the shoulder joint, which allows the ball to slip out of the socket, causing pain, frustration and doubt in the shoulder as a stable joint. Dislocations and some subluxations often happen from some sort of injury or trauma. Trauma often involves a high energy impact or may result from a fall onto an outstretched hand. Some patients may also have ‘loose’ shoulders that tend to sublux or even dislocate without trauma.

Repetitive overhead throwing can also cause subtle instability with secondary injury to the rotator cuff. Pain from instability can be from the unstable event or can be from overuse of the rotator cuff in an attempt to stabilize the loose shoulder. This is called instability-induced tendonitis, sometimes also called secondary impingement. Another type of instability is internal impingement, which is when the unstable shoulder rotates excessively (such as in a thrower). The rotator cuff bumps up against the glenoid, and it starts to tear the labrum (the tissue on the rim of the glenoid) and the posterior superior rotator cuff.

Both dislocations and subluxations can cause tears of the labrum, ligaments or capsule. They may also cause rotator cuff tears as well as fractures of the shoulder joint. When a traumatic dislocation occurs, and is associated with a tear of the labrum, it is often referred to as a, ‘Bankart lesion.’

Repeated dislocations may cause further tearing of these stabilizing structures and may cause the capsule to stretch out so much that the shoulder remains unstable.

The humerus may be forced out of the glenoid, (a dislocation), or overhead throwing sports may also injure the shoulder joint. Either may cause a Lesion, which stands for a tear in the Superior Labrum, Anterior to Posterior. In a SLAP Lesion, the labrum is torn from the front to the back. The superior labrum is the attachment for the biceps tendon, the strong muscle in the front of the arm. A sudden pull on this muscle can pull the superior labrum off of the bone.

History

Patients will commonly complain of symptoms of a loose shoulder joint. They may experience popping or grinding of the shoulder. There is often associated pain with certain positions of the arm. In patients who have a history of multiple dislocations, they may even re-dislocate while sleeping or getting dressed. Sometimes dislocations may be reduced by the patient themselves. This is often painful. More commonly, however, dislocations require a reduction in the emergency room supervised by a physician and require anesthesia. Most patients who have had even one dislocation will tell you that it is extremely uncomfortable.

A fall on an extended hand held close to the body presents the greatest risk of a SLAP lesion. Overhead sports, such as baseball, volleyball, swimming and weightlifting also increase the chance of the injury. A SLAP lesion may also occur as the result of an automobile accident. Additionally, those with above-average joint laxity, or looseness of the ligaments, stand at great risk of shoulder instability.

Treatment

After an initial dislocation is reduced, most patients are immobilized in a sling for a week or two and then started on a rehabilitation program. Some patients improve after immobilization followed by rehabilitation. One problem that affects younger patients more frequently is recurrence of dislocation. This means that patients will tend to re-dislocate, especially if they suffer their first dislocation between the ages of 15 and 25 years of age. For younger patients, the re-dislocation rate in the Orthopaedic literature ranges from 60-90%.

Patients older than 40 may suffer a rotator cuff tear with a dislocation rather than suffer recurrence of dislocations.

Strong rotator cuff muscles remain the best defense against shoulder dislocation, subluxation, and, thus, instability. Exercises that build up these muscles around the shoulder should be done. Adequate warm-up before activity and avoidance of high-contact sports may help prevent a recurrence of instability.

When non-operative treatment fails, there are many different surgical options to stabilize the shoulder. These treatments include both open and arthroscopic techniques. Recent Orthopaedic literature has shown that arthroscopic techniques can be as successful as open surgery.

HOW IS THE SHOULDER STABILIZED ?
The affected shoulder is first examined under anesthesia and tested for instability and relative laxity. This is then compared to the unaffected shoulder. A diagnostic arthroscopy is performed initially to assess the condition of the glenohumeral joint (ball & socket) and evaluate the extent of damage. The arthroscope is placed into the shoulder joint and the labral tear associated with a shoulder dislocation, often referred to as a ‘Bankart lesion’, is repaired. Often the capsule and associated ligaments are also torn or stretched out as well. In addition to the labral repair, the capsule and ligaments often need to be tightened up as well. If the shoulder instability is not secondary to a dislocation, but rather a subluxation, a labral tear may still be present. This is referred to as a SLAP tear and is associated with the Biceps tendon anchor or attachment. This anchor often requires stabilization.

The ability to stabilize the shoulder is assessed arthroscopically and a determination is made based on bone stock as well as tear pattern, size, shape, scarring and tissue quality, whether an arthroscopic versus open repair will be performed. A variety of different instruments, implants, sutures and techniques are employed to complete the repair.

WHAT KIND OF FUNCTION CAN I EXPECT FROM A SHOULDER STABILIZATION ?
The goal of shoulder stabilization is to restore stability, strength, function and provide pain relief. The final result depends on many factors, including: the severity of the initial injury (whether it is associated with a fracture of the ball and/or socket), the amount of times the shoulder has dislocated (this will affect how loose the shoulder structures become), the quality of the tissue (labrum, ligaments and capsule), the strength of the repair and finally, the motion and strength that is ultimately able to be achieved by the patient in rehabilitation.

These instability injuries vary from subtle subluxations to dislocations. The rotator cuff may also be affected secondarily.

WHAT IS SPECIAL ABOUT OUR APPROACH AND TECHNIQUES ?
Our goal is always to reconstruct and stabilize the shoulder joint. We prefer to complete the procedure arthroscopically. This technique allows the surgeon to fully evaluate the shoulder joint and pathology associated with the shoulder instability. This arthroscopic procedure leaves a much smaller scar, thus reducing postoperative pain, avoids incision of an uninjured, healthy subscapularis muscle, improves speed and comfort of rehabilitation and decreases the chance of infection.

DO I NEED TO HAVE ANY TESTS PRIOR TO SURGERY?
Depending on your overall medical condition, you may need specific tests and/or a medical evaluation by your primary care physician. Within two weeks of your surgery, you may need several medical tests. These are done on an outpatient basis. Some people require blood tests and urinalysis. A chest X-Ray and an EKG are required if you are over 50. If you have had a heart attack or significant heart disease a stress test may be required. In select cases, a MRI (magnetic resonance image) is useful to assess the soft tissue structures around the shoulder and may help in predicting the severity of injury and in preoperative planning.

You should STOP taking any medication 2 weeks prior to surgery that may cause excessive bleeding. These include: Aspirin, NSAIDs (Non-steroidals) like Ibuprofen, Naprosyn, and Daypro. Tylenol is okay to continue.

WHAT TYPE OF ANESTHESIA IS USED?
A regional block to make the shoulder numb is often combined with general anesthesia for most shoulder repairs. Prior to surgery you will meet a member of the Anesthesia Department who will explain your anesthesia alternatives and address questions that you may have concerning anesthesia. On the morning of surgery, a member of the Anesthesia Department will again review your anesthesia options with you and your family.

WHAT HAPPENS THE DAY OF SURGERY?
You will arrive at the hospital approximately one hour before your scheduled surgery. The surgery will take approximately two to three hours and you will be in the recovery room for one hour so that your recovery from the anesthesia can be monitored. You will then go home.

NOTE: YOU MAY NOT EAT OR DRINK ANYTHING BEGINNING AT MIDNIGHT THE NIGHT PRIOR TO THE SURGERY. If you must take medicines daily you should do so with just a sip of water. This should be cleared by the operating surgeon or by the anesthesiologist prior to the day of surgery.

WHAT HAPPENS AFTER SURGERY?
Following surgery, you will have a bandage over your incision and your arm will be placed in a sling or a brace so that the repaired tissues can heal (this takes 6 weeks). Ice and a prescription for medications will be provided for your comfort. You should keep a pillow under your elbow on the operated side while lying in bed. Also keep a pad in your armpit to avoid skin maceration from sweating.

HOW DO I CARE FOR MY SHOULDER?
Two days after you go home, the bandage may be removed. You will see an incision covered with suture. Remove the surgical dressing and replace it with the 4×4 gauze dressings and tape. You may later change this to bandaids or a tegaderm dressing. You will then be able to shower. Remove the sling and keep your arm at your side while showering. To give your wound time to heal, please DO NOT SOAK or SUBMERGE your operated shoulder under water, i.e., in a tub or whirlpool.

After your surgery call the office to make a follow-up appointment for approximately seven to ten days following your surgery. At that time, the stitches will be removed and you will again be instructed in what activities you may do.

WHAT CAN I DO AFTER SURGERY?
YOU WILL NEED TO WEAR THE SLING FOR APPROXIMATELY 6 WEEKS so that the tissues can heal. During this time, you are permitted to use your elbow, wrist and hand below shoulder level, i.e. to feed yourself, write or type on the computer. You MUST do the gentle PASSIVE ONLY range of motion exercises 5X a day, while lying flat, as instructed by your physician. It is suggested that you avoid driving during the time you wear the sling, for safety reasons and to prevent injury to the operated area.

Many people can return to a desk job within seven days following surgery. Returning to a job that is more strenuous will require more time. You are not permitted to lift anything greater than one or two pounds for the first six weeks and nothing overhead.

WHEN CAN I EXPECT TO RETURN TO MY PREVIOUS LEVEL OF ACTIVITY?
There are a rehabilitation protocols for the different types of shoulder stabilization. For the first 6 weeks, you will be doing passive motion with your shoulder. The key is allowing the tissues to heal properly while balancing the return of motion and strength. The end result depends on the quality of the tissue and the repair, but also how much time and effort you can devote to your rehabilitation.