Dislocation Of The Shoulder Joint

2023 Author: Wallace Forman | [email protected]. Last modified: 2023-11-27 18:19

The shoulder joint is the joint in the body with the greatest range of motion. The arm connected to the shoulder girdle can be moved in almost all directions. This is ensured by the complicated structure of the surrounding structures. The shoulder joint is mainly stabilized by muscles, ligaments and tendons. Due to the relatively small, flat socket, the shoulder joint is not as stable as other joints. The risk of dislocations and injuries is therefore higher.

Around 30 percent of all acute shoulder injuries are dislocations (dislocations) of the shoulder joint. An acute dislocation of the shoulder can be associated with accompanying injuries in the shoulder girdle area. The collarbone is also often affected.

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How is the shoulder joint structured?

The shoulder joint is part of the shoulder girdle. This consists of three real joints as well as bones (collarbone, shoulder blade), muscles, tendons and ligaments (see illustration: anatomy of the shoulder).

Anantomy shoulder joint, view from the front and back © bilderzwerg

The three joints form a functional unit with the collarbone and shoulder blade and are involved in most of the movements of the arm. The two fake joints are shifting layers in order to reduce the friction between the moving parts (e.g. between muscles and bones).

The shoulder joint (glenohumeral joint, main joint of the shoulder) connects the head of the upper arm bone (humerus) with the flat joint socket (glenoid) of the shoulder blade bone (scapula). This ball joint is enclosed by a solid fiber layer, the joint capsule.
The shoulder-clavicle joint (acromioclavicular joint) connects the collarbone (clavicle) with the upper end of the shoulder blade (shoulder roof or acromion).
The sternum-clavicle joint (sternoclavicular joint) connects the breastbone (sternum) and clavicle. It can be easily felt through the skin.
The subacromial secondary joint is a sliding layer between the roof of the shoulder and the rotator cuff, which is lined by bursa. The bursa reduce friction, for example between muscles and bones.
The Thorakoskapulargelenk is a spurious joint, a sliding layer is provided between the chest wall and shoulder blade.
The rotator cuff is a muscle-tendon cap that surrounds, stabilizes and protects the shoulder joint.

How to prevent a shoulder dislocation

Experts recommend the following preventive measures, among others:

Muscle building training and coordination training,
Warming up the muscles before exercise, e.g. through mobilization exercises,
Moderate exercise of sports that put stress on the shoulder joint, such as handball, basketball.

What causes a shoulder dislocation and shoulder instability?

A common cause of a shoulder dislocation is an acute injury (trauma) to the shoulder when the arm rotates or spreads apart, from a fall on the extended arm, from the application of external forces or from absorbing the entire body weight with the arm.

Repeated microtraumas can also lead to instability of the shoulder joint and repeated dislocations. An existing shoulder instability (habitual dislocation) can also have other causes, e.g. dysplasia of the shoulder joint, structural joint damage, muscular malfunctions or weaknesses, etc.

What types of shoulder dislocation are there?

Depending on the severity of the accident, the joint may be sprained (distorted) or dislocated (dislocated) or dislocated. An incomplete dislocation is called a subluxation.

A sprain causes some fibers to stretch and injure, and the capsule remains intact. A dislocation results in more or less severe injuries to the capsule ligament.

In a Bankart lesion, the lip (labrum) of the joint socket at the edge of the socket is partially or completely torn off. A Hill-Sachs lesion is a deformation in the head of the humerus, usually as a result of repeated dislocations

In more than 90 percent of shoulder dislocations there is a forward dislocation, in around three percent there is a backward dislocation and in around two percent there is general instability of the joint.

What are the symptoms?

In the case of a dislocation, the affected shoulder is usually very painful. The arm can hardly be moved and is held close to the body in a relieving position. The normal shape of the shoulder is changed. Depending on the injury, bruising and swelling may also occur. There may also be a loss of sensitivity in the arm area. The head of the humerus can often be felt by the doctor during the clinical examination.

First aid measures

If a shoulder dislocation is suspected, rapid medical help is necessary.
Until medical treatment, the arm on the upper body is immobilized and fixed with the elbow joint bent, for example with a wide elastic bandage.
The arm should not be moved or adjusted by laypeople. This can damage the joint and the surrounding nerves, blood vessels, muscles or ligaments.

For more information, see: Emergency: Injuries

How is the diagnosis made?

At the beginning the doctor collects the medical history and asks about previous injuries as well as the course of the acute injury (e.g. direct impact, impact, indirect trauma). The shoulder is then examined for any external signs. The doctor checks stability, pressure pain and restrictions in shoulder mobility with special grips. The blood circulation and sensitivity of the shoulder are also examined. An important criterion for the classification of a shoulder dislocation is the looseness of the joint (laxity).

X-rays in different planes provide more precise information about the shape and degree of the injury. Further examinations may be necessary to clarify possible accompanying injuries, e.g. MRI if injuries to the ligaments are suspected, CT in bony injuries.

How is a shoulder dislocation treated?

Medical treatment depends on the type and severity of the dislocation and possible accompanying injuries.

Reduction

The doctor performs the reduction in a special grip maneuver with pull and pull. It takes place under pain treatment or, if necessary, under anesthesia. Another x-ray is taken as a check. Then the shoulder joint is immobilized with a bandage for about two weeks. Rare complications when straightening are injuries to the nerves or blood vessels.

After a shoulder dislocation, the risk of a new dislocation is increased. The recurrence rate in patients under 30 is around 80 percent. It decreases with age.

surgery

In the case of certain forms of shoulder dislocation, surgery is indicated, e.g. if a reduction is not possible or in the case of a Bankart lesion with an osseous avulsion. Depending on the injury, an arthroscopic or open procedure can be performed for the operation. During the operation, the stability of the joint is restored, for example by reconstructing the joint capsule or the capsule-ligament apparatus, reducing the capsule volume or by other measures.

Surgery may also be indicated after repeated dislocations to correct the cause of the instability. This is intended to avoid permanent damage to the joint (e.g. arthrosis) or restriction of mobility (impingement).

After the operation, the shoulder is immobilized with a special shoulder-arm bandage for about four weeks.

How is follow-up treatment and rehabilitation carried out?

Usually the doctor will prescribe functional physiotherapy. Following instructions, the patient independently performs exercises to mobilize the joint, strengthen the shoulder muscles and do coordination training. The exercises are also designed to reduce the risk of repeated dislocations.

Whom can I ask?

If you have an acute shoulder injury and you suspect a dislocation, call the ambulance (144) or go to a hospital.

After the acute treatment, exercise therapy can be carried out on an outpatient basis according to a doctor's prescription, e.g. in the hospital outpatient department or by resident physiotherapists or occupational therapists.

How are the costs going to be covered?

The e-card is your personal key to the benefits of the statutory health insurance. All necessary and appropriate diagnostic and therapeutic measures are taken over by your responsible social insurance agency. A deductible or contribution to costs may apply for certain services. You can obtain detailed information from your social security agency. Further information can also be found at: