The Dislocated Shoulder
Portions taken from the Harris Injury.
A shoulder dislocation is often confused with a shoulder separation, but these are two very different injuries! It is important to distinguish between these two problems because the issues with management, treatment, and rehabilitation are different. A shoulder dislocation injury affects the capsule that surrounds the actual glenohumeral joint, as explained below.
Anatomical Structures of the Shoulder
The capsule that surrounds the shoulder joint is a group of very strong ligaments that connect the humerus to the glenoid and help to keep the shoulder in the joint. These ligaments are the main source of stability for the shoulder and they keep the shoulder functioning normally. These ligaments are glenohumeral ligaments (GHL). Another ligament links the coracoid to the acromion - coracoacromial ligament (CAL). Two ligaments connect the clavicle to the scapula by attaching to the coracoid process, a bony ridge on the scapula - coracoclavicular ligaments (CCL).
Ligaments of the Shoulder Complex:
CCL - coracoclavicular ligaments
CAL - coracoacromial ligaments
SGHL - Superior GlenoHumeral Ligament
MGHL - Muperior GlenoHumeral Ligament
IGHL - Inferior GlenoHumeral Ligament
The tendons of the rotator cuff are the next layer in the shoulder joint. Tendons are much like ligaments, except that tendons attach muscles to bone. Muscles move the bones by pulling on the tendons. One important tendon that travels through the shoulder joint is the biceps tendon. The biceps tendon actually begins at the top of the shoulder socket (the glenoid) and then passes across the front of the shoulder to connect to the biceps muscle. The rotator cuff tendons are a group of four tendons that connect the deepest layer of muscles to the humerus. They are the tendons of the rotator cuff muscles.
Tendons of the shoulder complex:
* Subscapularis
* Biceps Tendon
* Supraspinatus
* Infraspinatus
* Teres Minor
Images and text taken from The Shoulder Doc UK
In most people it is very difficult to tear the ligaments of the capsule or pull the shoulder out of joint. These injuries usually occur only when a lot of force has been applied to the shoulder or the arm - like in a football game. If the shoulder slips partially out of joint, this is called "subluxation". A dislocated shoulder occurs when the shoulder comes completely out of joint.
A simple definition of the shoulder joint is an inverted golf ball on the tee. More below:
Anatomy of the Injury
The joint between the humerus and scapula, also called the glenohumeral joint, is a ball-and-socket joint- the ball is on the top of the humerus, and this fits into a socket of the shoulder blade called the glenoid. This joint is incredible because it allows us to move our shoulder though an amazing arc of motion- no joint in the body allows more motion than the glenohumeral joint. Unfortunately, by allowing this wide range of motion, the shoulder is not as stable as other joints. Because of this, shoulder dislocations are not uncommon injuries.
Image and text taken from About.com
Types of Shoulder Dislocations
There are two types of shoulder dislocations:
ANTERIOR DISLOCATION:
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 sling for four to six 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 sling immobilization, most 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 90% 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.
POSTERIOR DISLOCATION
Posterior dislocations constitute only two percent of all shoulder dislocations. Because they are so infrequent, this type of dislocation can often be missed on an initial visit to the emergency room or doctor’s office. Posterior dislocations can often be associated with electrical shocks or with seizures.
Recurrent posterior shoulder dislocation is unusual. In cases in which the dislocation is noted early after the injury, the ball can usually be placed back in the socket. Patients are immobilized and then started on an exercise program after they are removed from the sling. In some cases of posterior dislocation, the humeral head can be severely damaged. In some of these cases, surgical treatment may be required.
Symptoms
Patients with a shoulder dislocation are usually in significant pain. They know something is wrong, but may not know they have sustained a shoulder dislocation. Symptoms of shoulder dislocation include:
- Shoulder pain
- Arm held at the side, usually slightly away from the body with the forearm turned outward
- Loss of the normal rounded contour of the deltoid muscle
Diagnosis and Treatment
After the shoulder has been put back in the socket, the severe pain will stop almost immediately. The structures such as the labrum, bone, nerves, or ligaments were injured must be evaluated. The treatment that follows depends on what structures were injured, how many dislocations you have had, how unstable the shoulder is and how much pain you have. Immobilizization of the shoulder in a sling or sling and side pillow is done for a few weeks while the injury heals.
TREATMENT
Conservative nonoperative treatment including physical therapy to strengthen the muscles around the shoulder (rotator cuff) is best after the first dislocation. If you have had multiple dislocations or subluxations, surgery is suggested to repair or tighten the capsule and ligaments that hold the shoulder in place. If the labrum has been injured, it will need to be trimmed or sutured. The surgery is usually done arthoscopically, which is less invasive and offers quicker return to full activity. The surgery is performed with an arthroscope and small instruments introduced into the shoulder joint through hollow cannulas. Miniature anchors or screws with suture attached are inserted precisely into the socket edge of the shoulder, and the torn ligaments and labrum are reattached to the socket. Complete healing from this procedure takes approximately 4-6 months.
The older a patient is at the time of dislocation the lower the chances are for developing recurrent dislocations. Patients over 35-40 can tear the rotator cuff with a dislocation. Patients under the age of 25 with traumatic dislocations have a substantially higher rate of recurrence (greater than 80-90%).
From C. Thomas Vangsness, Jr., MD
Chief, Sports Medicine Service, LAC/USC Medical Center
Team Physician, USC Department of Athletics
X-ray images of the shoulder
The Normal, Anatomic Shoulder - after being relocated- popped back into place
The Anterior Dislocated Shoulder
Images from Leiden University Medical Center, the Netherlands
As Dr. Vangsness indicated above, patients under the age of 25 have a higher incidence of dislocation especially if the patient continues to participate in the type of activities that caused the initial dislocation leading to instability of the shoulder joint, instability can then lead to recurrent, multiple, dislocations thus requiring surgery. Some physicians will indicate surgery for these types of younger active patients.
Each type of dislocation has their own separate surgical repair and each of those can either be done "open", through a surgical incision, or arthroscopic with the use of an arthroscope attached to a camera.
Surgical Options
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.
Open Stabilization Procedures:
This stabilization technique has stood up well against the test of time. The likelihood of further instability after a properly performed open stabilization is less than 5%. The procedure requires a four inch scar on the front part of the shoulder. 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.
At the present time, most of our patients tend to prefer open stabilization techniques due to the low possibility of recurrence. We generally recommend this procedure exclusively in patients who participate in contact sports such as football, hockey, and lacrosse. We do not feel that arthroscopic stabilization techniques are appropriate in patients involved in these high-risk activities.
Arthroscopic Stabilization Techniques
Techniques of arthroscopic stabilization are still in their infancy. While we have a significant amount of experience with several different types of arthroscopic stabilization techniques, they 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. In addition, patients treated arthroscopically may require a long period of postoperative immobilization than patients treated by open techniques. A patient treated arthroscopically generally has a less secure repair and, therefore, needs to be protected in a sling for a longer period after surgery.
Throwing athletes and patients with only a small amount of shoulder laxity appear to be good candidates for arthroscopic stabilization procedures. In addition, new techniques are becoming available which may allow direct shrinkage of the capsule using a small radio frequency probe. While these techniques may prove to be extremely beneficial, they should, at present, be considered experimental. However, they may overcome one of the greatest disadvantages of arthroscopic stabilization procedures when compared to open stabilization procedures. While it is relatively straightforward to reattach the shoulder capsule to the socket using an arthroscopic technique, it is much more difficult to reduce capsular laxity. This technique of capsular shrinkage may, therefore, provide an excellent complement to currently available techniques.
Because Posterior dislocations are so infrequent there isn’t a whole lot written on the specific surgical repair these injuries but the surgical procedures are as follows and they are similar to the same procedures as the anterior repair.
Soft tissue injuries are much more common in posterior dislocations than bony injuries. Most procedures for posterior instability have been soft tissue reconstructions. These include:
1. Posterior Capsulolabral repair: repair of the soft tissue posterior bony Bankart lesion, often combined with a capsular shift.
2. Capsular Shift: A posterior capsular shift may be required for a hyperlax posterior capsule in the abscence of a labral injury.
3. Capsular Shrinkage: This is required as part of the rehabilitative programme for patients with laxity and proprioceptive instability (Polar II/III).
The Capsular Shift
Complications of the Shoulder Dislocation
Outside of the dislocation itself there are a few other complications that can arise.
The Bankart Lesion
This is one of the most common injures to occur with shoulder dislocations.
As discussed above, the shoulder joint is enclosed by a sheet of ligaments and other tough fibers called the capsule. During a shoulder dislocation, fibers in the capsule can pull on the labrum and cause it to tear. A Bankart lesion is the name for a tear that occurs in the inferior (lower) rim of the labrum. Once the labrum is torn, it’s much easier for the humerus to slip out of its socket. You may also have pain and feel as if your shoulder is slipping out of place. Diagnosing this injury will include imaging tests, such as an MRI or CT scan, as this will provide the surgeon a detailed view of the tissues inside your shoulder joint.
The Bankart Lesion
The Bony Bankart Lesion
A bony Bankart is a fracture of the anterior-inferior glenoid (front, lower portion of the glenoid). The presence of this fracture indicates that the labrum and ligaments in the front part of the shoulder are no longer attached to the glenoid.
The Hill-Sachs Lesion
The Hill-Sachs lesion is a common occurrence in the dislocated shoulder. This is an indentation or impaction fracture that is seen as an irregularity of the humeral head following anterior dislocation of the shoulder. When the shoulder dislocates, the smooth cartilage surface of the humerus hits or impinges against the rim of the scapula (glenoid) causing impaction or indentation of the posterolateral portion of the head of the humerus. This injury is diagnosed primarily with radiographs.
The Hill-Sachs Lesion Illustration
The Hill-Sachs Lesion x-rays
The Torn Rotator Cuff
Rotator cuff tears in younger patients are less frequent, some would say rare, than either a Bankart Lesion or a Hill-Sachs Lesion. See Above.
Recovery and Rehabilitation
Taken from The Steadman-Hawkins Clinic
* Patients who have a first dislocation, and do not develop recurrent instability, will often regain full motion from a four to six week course of physical therapy.
* Patients who do develop recurrent instability have a longer rehabilitation course and should concentrate on strengthening the shoulder muscles. Daily exercises in a home program may be recommended to help prevent instability events.
Operative Recovery
Following either arthroscopic or open operative repair and stabilization:
* The patient will usually wear a sling for the first four to six weeks. This immobilization protects the repaired labrum while it heals to the glenoid. Until the ligaments heal, the repair must depend on the sutures used to secure the labrum.
* During this immobilization period, elbow and wrist motion are maintained with gentle range of motion exercises.
* Once the initial healing process is complete, physical therapy may begin. Exercises stressing range of motion are done for approximately eight weeks after surgery, or until full strength is regained.
* Overhead sports, such as baseball or tennis, may resume about three months after surgery.
* Contact sports are restricted for six months.
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