SPORTS MEDICINE  ·  SURGERY OF THE KNEE  ·  SURGERY OF THE SHOULDER  

Anterior Dislocation Print

More than 98% of shoulder dislocations occur in the anterior (frontward) direction. The most common cause of an anterior dislocation is an indirect force applied to the arm in which it is forced away from the body and rotated over the head. However, four percent of anterior dislocations may occur without trauma.

The diagnosis of an anterior dislocation is usually fairly straightforward. The arm is kept at the side with the hand rotated away from the body. The arm cannot be rotated inward and cannot be lifted away from the body. The ball of the shoulder may be felt in the armpit and the back of the shoulder may feel hollow.

If an injury of this type is encountered by a knowledgeable health care professional, immediate reduction of the ball back into the socket is recommended. If there is no one with experience in reducing dislocations present, the patient should be transported immediately to the nearest emergency room.

After an initial dislocation, most experts recommend that the patient be placed in a brace with hand facing forward for four weeks. The available basic science data suggests that immobilization of this duration is required for any chance of proper capsular healing. This period is followed by a rehabilitative program that emphasizes strengthening of the rotator cuff and the muscles that attach to the shoulder blade. Positions of extreme motion are limited for three months after the removal of the sling.

Despite brace immobilization, many young patients who experience a dislocation that is associated with trauma will continue to have problems with the shoulder. Several studies have shown that patients under the age of twenty who suffer an initial dislocation have an approximately 50% chance of suffering another dislocation. In patients over forty years of age, the risk of another episode of dislocation is much lower. This is probably due to changes in activity in individuals as they age. Because of the high risk of recurrent dislocation in young people, some authors have advocated consideration of surgical treatment in initial dislocation to try to prevent further episodes in the future. Early intervention is especially applicable to throwing athletes and those who participate in overhead sports such as tennis and racquetball.

 

Recurrent Anterior Dislocation

As mentioned, it is very common, particularly in younger people, for an initial dislocation to result in a situation in which there are several repeated episodes in which the ball comes out of the socket. After an initial dislocation, prolonged immobilization in a brace or sling is of no apparent value. The patient is simply immobilized until the pain resolves and then started on a rotator cuff and shoulder blade musculature strengthening program.

A rehabilitation program which emphasizes strengthening of the rotator cuff in the shoulder blade musculature is much more likely to be successful in patients who have instability without a specific episode of trauma. Studies have shown that in these patients, exercises will help resolve symptoms in more than 80%. On the other hand, patients who have had a specific traumatic episode which led to problems with the shoulder, exercises are helpful in only 15 to 20%. Many of these patients with traumatic injuries will end up requiring surgical treatment to control their problems with instability.

 

Operative Treatment for Anterior Shoulder Instability

The indications for surgical treatment of recurrent anterior shoulder instability are highly subjective. They include a desire of the patient to avoid recurrent problems with instability, (including the necessity of reporting to the emergency room on a frequent basis to have the shoulder reduced), problems with recurrent pain, or an inability to perform certain activities because of a fear of further shoulder instability. Failure of a thorough trial of nonoperative treatment can also be considered an indication for surgical treatment.

If it is decided to proceed with surgical treatment, the goals of treatment are similar regardless of the technique utilized to stabilize the shoulder. The primary goals should be to restore shoulder stability and to provide the patient with full pain-free motion. Older techniques of shoulder stabilization tended to limit shoulder range of motion in exchange for providing stability to the shoulder. We now understand that it is probably more important to preserve motion than it is to stabilize the shoulder. Techniques which limit shoulder motion often lead to osteoarthritis while it is unlikely that recurrent dislocation itself leads directly to osteoarthritis. As a result, current methods are designed to provide both full functional use of the shoulder as well as normal stability.

Our basic procedure for the open surgical treatment of recurrent anterior instability involves repair of the anterior capsule and labrum to the glenoid socket, but In most cases of instability, the capsular ligaments of the shoulder are either stretched or detached from the glenoid socket. The stabilization procedure is designed to reattach the ligaments and to remove any abnormal laxity. The procedure is performed with the anticipation that the shoulder should not be overtightened and that, eventually, the patient will regain full range of motion which is symmetrical with the opposite side.

The likelihood of further instability after a properly performed arthroscopic stabilization is approximately 5%. The procedure is performed arthroscopically through three small incisions. After the operation, the patient is maintained in a sling for two to four weeks. Initially, the patient is begun on a range of motion program and then begins a strengthening program. Generally, four to six months are required before the patient can return to full activity.

Open stabilization techniques may be recommended in patients who have failed arthroscopic reconstruction or who participate in contact sports such as football, hockey, and lacrosse.

 

Arthroscopic Stabilization Techniques

Arthroscopic stabilization techniques have stimulated a great deal of interest since their introduction in the early 1980's. Arthroscopic techniques have the advantages of less initial postoperative pain and smaller surgical scars. Initially, the risks of recurrence after an arthroscopic stabilization were higher than that of an open procedure. Now with inproved techniques, the recurrence rate is approximately the same for open and arthroscopic shoulder stabilization.

Techniques of arthroscopic stabilization should generally be performed only by experienced arthroscopists in well-selected patients. A well-performed open stabilization procedure is certainly preferable to a failed arthroscopic procedure.

Figure 1A demonstrates a torn labrum that is displaced from the socket and Figure 1B shows an athroscopic view of a torn and displaced labrum. (large arrow). The glenoid has been roughened to enhance healing (small arrow). The labrum has been repaired in Figure C.

 

shoulder, dislocation, Dr. Allen F. Anderson, nashville, orthopaedic surgery, sports medicine, figure 4a shoulder, dislocation, Dr. Allen F. Anderson, nashville, orthopaedic surgery, sports medicine, figure 4b
Figure 1A Figure 1B

 

shoulder, dislocation, Dr. Allen F. Anderson, nashville, orthopaedic surgery, sports medicine, figure 6b
Figure 1C

 

Drawings of a Labral Tear

Fig. 2A shows a probe in the tear. The labrum is reattached with bioabsorable suture anchors in the bone.

The final repair is demonstrated in Fig. 2C 

Anterior Dislocation, Dr. Allen F. Anderson, Nashville, Orthopaedic Sports Medicine, Figure 4A

Anterior Dislocation, Dr. Allen F. Anderson, Nashville, Orthopaedic Sports Medicine, Figure 5

Anterior Dislocation, Dr. Allen F. Anderson, Nashville, Orthopaedic Sports Medicine, Figure 6A

Figure 2A Figure 2B Figure 2C

 

 
© Allen F. Anderson, M.D. 2014