What Is a Dislocated Shoulder?

Dislocation of the shoulder joint is the most common, accounting for about 50% of systemic joint dislocations. This is related to the anatomical and physiological characteristics of the shoulder joint, such as large humeral head, shallow and small glenoid, loose joint capsule, weak anterior and inferior tissue, and range of joint motion. Large, many opportunities to suffer external forces. Dislocation of the shoulder joint occurs mostly in young adults and males.

Basic Information

English name: scapular dislocation
Visiting department: orthopedics
Multiple groups: Young male

Common causes: Indirect violence
Common symptoms: Injured shoulders, swelling, pain, restricted active and passive movements
Contagious: no

Causes of Shoulder Dislocation

Dislocation of the shoulder joint is divided into anterior dislocation and posterior dislocation according to the position of the humeral head. Anterior dislocation of the shoulder joint is very common, often caused by indirect violence, such as upper abduction abduction, palm or elbow landing when falling, external force impacts along the longitudinal axis of the humerus, and the humerus head is between the subscapularis and great round muscles. The weak part avulses the joint capsule and prolapses forward and backward, forming anterior dislocation. The humeral head is pushed below the coracoid process of the scapula to form a subcoracoid dislocation. If the violence is greater, the humerus head moves forward to cause the subclavian dislocation. Posterior dislocations are rare, mostly due to shoulder-to-back violent action or hand landing when the shoulder is in adduction and adduction position. Posterior dislocations can be divided into subscapular and subscapular dislocations. Should the dislocation of the shoulder joints be inappropriately treated in the initial stage, habitual dislocations can occur.

Clinical manifestations of shoulder dislocation

1. Injured shoulder, swelling, pain, limited active and passive movement.

2. The affected limb is elastically fixed in a light external booth, and the healthy arm is often used to support the affected arm. The head and trunk are inclined toward the affected side.

3. The deltoid muscle of the shoulder collapses and is deformed as a square shoulder. The displaced humeral head can be reached in the axilla, subcoracoid process or subclavian, and the glenoid cavity is empty.

4. Shoulder test is positive. When the affected side rests on the chest, the palm cannot rest on the contralateral shoulder.

Dislocation of shoulder

Conventional anterior and posterior X-rays of the shoulder joint are often negative during posterior dislocation of the shoulder. Subhumeral posterior dislocations are the most common, and the general positional relationship between the humeral head and the glenoid and acromion remains when anterior and posterior shoulder X-rays are taken. Therefore, radiographs are often negative. However, if you read the film carefully, you can still find the following abnormal characteristics: Because the humeral head is in the forced internal rotation position, even if the forearm is in the neutral position, the humeral neck can be found to be "shortened" or "disappeared", and the images of large and small nodules overlap; The gap between the inner edge of the humeral head and the anterior edge of the scapula widens, and it is generally considered that the gap is greater than 6mm, which can be diagnosed as an abnormality. The oval overlapping shadow of the normal humeral head and the scapula disappears; The relationship between the humeral head and the scapula Symmetric, showing high or low, and not parallel to the anterior edge of the glenoid.

It is highly suspected that when the posterior dislocation of the shoulder joint is taken, an axillary film or a thoracotomy should be taken, and the humeral head prolapse can be found on the posterior side of the scapula. If necessary, a CT scan of both shoulders can clearly show that the humeral head is facing backwards and protrudes from the posterior margin of the glenoid; sometimes a recessed fracture of the humeral head can be found and entrapment with the posterior margin of the glenoid can affect the reduction, or the glenoid Fracture of the trailing edge.

Shoulder Dislocation Diagnosis

1. History of shoulder or upper limb trauma.

2. According to the above symptoms and signs.

3. X-rays can clearly identify the type of dislocation and whether there is a fracture.

Differential diagnosis of shoulder dislocation

The disease needs to be distinguished from periarthritis of the shoulder. Both periarthritis and dislocation of the shoulder joint have severe shoulder pain and significantly limited shoulder function. Periarthritis is a chronic degenerative inflammation of the soft tissue of the shoulder, with severe pain in the early stages and dysfunction in the middle and late stages. Shoulder dislocations often have a history of acute injuries, such as excessive force or sudden violent pulls and collisions, and the palms and elbows touch the ground during a fall. The sudden violent impact on the humerus causes the humeral head to escape from the glenoid.

In addition, it is necessary to identify the type of dislocation. After dislocation, it can be divided into 3 types according to the position of the humeral head: subpelvic type: the humeral head is located below the glenoid, which is rare; subgangular type: the humeral head is located in the scapula This type is also rare; subacromial type: the humeral head is still below the acromion, but the articular face is behind and is behind the scapula.

Shoulder Dislocation Treatment

Manual reset

After dislocation, it should be reset as soon as possible, and appropriate anesthesia (brachial plexus anesthesia or general anesthesia) should be selected to relax the muscles and make the reduction painless. Elderly or weak muscles can also be performed under analgesics. Habitual dislocations do not require anesthesia. The resetting method should be gentle, and crude methods should be disabled to avoid additional injuries such as fractures or nerve damage. There are three common reset methods.

(1) The patient is supine, with the operator lying on the affected side, holding the wrist of the affected limb with both hands, and placing the heel on the axillary side of the affected side. Both hands are pulled with a steady and continuous force. During the traction, the heel pushes the humeral head outward. Rotate at the same time, and the adducted upper arm can be reset. An audible sound is heard during reset.

(2) Coriolis method This method is easy to perform under muscle relaxation. Do not use too much force to prevent the humerus neck from receiving excessive torsion and fracture. Manipulative steps: Hold the wrist in one hand and bend the elbow to 90 degrees to relax the biceps. Hold the elbow in the other hand and continue traction, gently abduct, gradually rotate the upper arm outward, and then bring the elbow closer to the chest wall. Centerline, and then rotate the upper arm inward, you can reset. And you can hear the sound.

(3) Traumatic massage method lies on the back, one assistant covers the thorax with a cloth sheet and pulls to the healthy side. The second assistant uses the cloth sheet to pull the affected limb outward and upward through the armpit, and the third assistant holds the wrist of the affected limb. Towing downwards and adducting externally, the three aspects continue to slowly traction. The surgeon pushed the humeral head outwards under the armpit to reset it. They can also do traction reduction.

After the reduction, the shoulder was restored to the normal shape of the blunt garden. The dislocated humeral head could no longer be touched under the axilla, subcoracoid process, or subclavian bone. The shoulder test became negative. X-ray examination of the humeral head was normal. If combined with avulsion fractures of the humerus tuberosus, the fractures and humeral shaft are often connected by periosteum. In most cases, the avulsion of the large tuberosity bone fragments after shoulder dislocation is also reduced.

Post-reduction treatment: After the anterior dislocation of the shoulder joint is reset, the affected limb should be kept in the adduction and internal rotation position, cotton pads should be placed on the armpit, and then fixed on the chest with a triangle towel, bandage or plaster. Rotate activities, but to prevent excessive abduction and external rotation to prevent dislocation. After the posterior dislocation is reset, it is fixed in the opposite position (ie abduction, external rotation and posterior extension).

2. Surgical reduction

A small number of shoulder dislocations require surgical reduction. The indications are: anterior dislocation of the shoulder joint with biceps brachii longus tendon slippage hindering manual reduction; large humeral tuberosity avulsion fracture, and the fracture piece stuck to the humeral head and joint Those who affected the reduction between the glenoids; those with surgical neck fractures of the humerus who could not be rehabilitated; those with coracoid processes, acromion, or shoulder glenoid fractures with significant displacement; those with large axillary injury.

3. Treatment of old shoulder dislocation

Shoulder joint dislocation that has not been reset more than three weeks after the dislocation is an old dislocation. The joint cavity is full of scar tissue, there is adhesion to surrounding tissues, contraction of surrounding muscles occurs, and those with fractures form epiphyses or deformity healing. These pathological changes prevent the humeral head from resetting.

Treatment of old shoulder dislocations: Dislocation within three months, young and strong, dislocated joints still have a certain range of motion. X-ray films without osteoporosis and ossification inside and outside the joint can be tried by manual reduction. Before reduction, the affected ulna olecranon can be traction for 1 to 2 weeks; if the dislocation time is short, the joint movement disorder can be light or not. Reduction is performed under general anesthesia. Shoulder massage and gentle rocking activities are performed first to relieve adhesions, relieve muscle spasms, and facilitate reduction. The reset operation adopts traction massage method or foot pedal method, and the treatment after reset is the same as that of fresh dislocation. It must be noted that the operation must not be rough to avoid fractures and axillary neurovascular damage. If manual reduction fails, or the dislocation has been more than three months, surgical reduction may be considered for young and injured casualties. Should the articular surface of the humerus head be severely damaged, shoulder joint fusion or artificial joint replacement should be considered. After shoulder joint reduction surgery, the movement function is often unsatisfactory. For elderly patients, surgical treatment is not recommended, and patients are encouraged to strengthen shoulder activities.

4. Treatment of habitual shoulder dislocation

The habitual dislocation of the shoulder joint is more common in young adults. The reason is generally believed that the injury was caused after the first dislocation of the trauma. Although it was reset, it was not properly and effectively fixed and rested. Due to the tearing or avulsion of the articular capsule and the damage to the cartilage labrum and labrum, the depression of the posterolateral humeral head has become equal to the pathological changes and the joints become loose. Dislocations may occur repeatedly under slight external force or during certain movements, such as upper abduction abduction and extension. The diagnosis of habitual dislocation of the shoulder joint is relatively easy. During X-ray examination, in addition to the plain radiographs of the shoulders, anterior and posterior X-rays of the upper arm in 60 ° 70 ° rotation should be taken. display.