Shoulder subluxation is a partial or incomplete dislocation that usually occurs due to changes in the mechanical integrity of the joint. In subluxation, the head of the humerus comes out of the scapula as a result of weakness in the rotator cuff muscles or a blow to the shoulder area. Subluxation can be of three types: anterior (directed anteriorly), posterior (directed posteriorly) and inferior (directed downward).
Clinically Relevant Anatomy
Of all the joints, the shoulder (or glenohumeral) joint has the greatest range of motion. Since it is also the most commonly dislocated joint, it perfectly demonstrates the principle that stability must be sacrificed to achieve mobility.
The shoulder joint is formed by three bone structures: the humerus, the scapula and the clavicle. These bones make up a total of 3 synovial joints: the glenohumeral joint, the sternoclavicular joint, and the acromioclavicular joint. In addition, the subacromial and scapulothoracic joints are distinguished.
The size of the glenoid cavity is increased by the fibrous cartilaginous labrum, which continues beyond the bony edge of the glenoid cavity of the scapula. The bones of the shoulder girdle provide some stability at the top of the joint because the acromion and coracoid process extend laterally above the head of the humerus. However, most of the stability is provided by the surrounding skeletal muscles through their associated tendons and ligaments.
Friends, this and other questions will be discussed in detail at the seminar Diagnosis and treatment of problems of the glenohumeral complex.
The main ligaments that help stabilize the shoulder joint are the glenohumeral, coracohumeral, coracoacromial, and acromiohumeral ligaments. The acromioclavicular ligament strengthens the acromioclavicular joint capsule and supports the superior portion of the glenohumeral joint. The largest ligament is the glenohumeral ligament, which is usually damaged or strained when the shoulder joint is subluxated.
The muscles that move the humerus stabilize the shoulder more than all the ligaments and capsular fibers combined. Muscles originating in the trunk, shoulder girdle, and humerus cover the anterior, superior, and posterior surfaces of the capsule. The supraspinatus, infraspinatus, teres minor, and subscapularis tendons strengthen the joint capsule and limit range of motion. These muscles, known as the rotator cuff, are the primary mechanism for supporting the shoulder joint and limiting range of motion.
Basic treatment methods
What to do if the shoulder joint pops out, the traumatologist decides after studying the results of instrumental studies. Conservative treatment methods are most often used. Pharmacological drugs are used to eliminate painful sensations. Traumatologists prescribe NSAIDs in tablets and ointments (Voltaren, Nurofen, Fastum), and external agents with a warming effect (Capsicam, Viprosal, Apizartron). Patients are advised to take a long-term course of chondroprotectors (Teraflex, Artra, Chondroxide), which stimulate the strengthening of the ligamentous-tendon apparatus.
Chondroprotectors.
Therapy for chronic instability involves changing the nature of physical activity. Movements that place stress on the shoulder joint should be minimized. These include:
- throws with a wide swing;
- bench press;
- intense rotation of the joint.
If painful or other uncomfortable sensations arise during movement, they should be done as rarely as possible. Changing your physical activity helps prevent further tissue damage.
Physiotherapeutic procedures are also used in the treatment of the disease - UHF therapy, acupuncture, magnetic therapy, laser therapy, applications with ozokerite and paraffin. Patients are advised to perform special exercises daily to build muscle corset, strengthen ligaments and tendons. And only if conservative treatment is ineffective, surgery is performed.
| Surgery to correct chronic shoulder instability | Surgical technique |
| Open surgery | It is performed in cases of severe damage to articular elements and the development of complications. A wide dissection of the connective tissue structures is performed to provide access to the surgical field. Torn ligaments are repaired to improve the fixation of the shoulder |
| Arthroscopy | The soft tissue is repaired through microscopic incisions using arthroscopic instruments. In most cases, minimally invasive surgery is performed on an outpatient basis. The patient is immediately discharged for further rehabilitation at home. |
Animation of a surgical operation:
A person suffering from chronic instability often moves the joint back into place on their own. Traumatologists strongly do not recommend doing this. The pathology is characterized by a recurrent course, so another attempt to straighten the shoulder may result in the development of severe complications. Self-medication leads to damage to large vessels, bleeding, capsule rupture, compression or injury to nerve trunks.
Clinical picture
The main problem with shoulder subluxation is instability of the glenohumeral joint. The anatomy of this joint allows for a large range of motion, which is accompanied by a loss of stability. A study conducted by Basmajian determined that the supraspinatus muscle and also the posterior fibers of the deltoid muscle play a key role in preventing humeral subluxation. Chaco and Wolf also confirmed in their study that the supraspinatus muscle is very important in preventing inferior subluxation of the humerus. Shoulder subluxation occurs during abduction and external rotation.
Other studies indicate that the most important ligamentous structure for maintaining proper alignment of the humerus and also for preventing shoulder subluxation is the inferior glenohumeral ligament. This ligament is most important in external rotation and abduction during the throwing movement.
Shoulder subluxation can lead to soft tissue damage because traction can occur due to gravitational forces and a weak shoulder provides poor protection. This is usually quite painful and may be accompanied by partial numbness in the shoulder, arm and hand.
Characteristic features of the pathology
A condition where the shoulder frequently pops out of the socket is called chronic instability due to decreased function of the joint. There is a weakening of connective tissue structures, usually the joint capsule and the ligamentous-tendon apparatus. This leads to excessive range of motion of the bones that form the shoulder joint. The structure of the joint resembles a ball joint. The rosette of the joint is formed by the articular fossa of the scapula, and the head of the humerus bone serves as the spherical support. The elements of the articulation are lined with strong connective tissue - the joint capsule, and are fastened together by ligaments. Holding the shoulder in place while increasing its stability is the rotator cuff, a group of muscles.
A person performing movements with his hands (for example, throwing a heavy object) can injure his shoulder. This situation also occurs with a direct blow, falling forward with emphasis on an outstretched arm. The joint capsule, ligaments, and muscle tissue are affected by a force that significantly exceeds their strength limits. Frequent microtrauma of connective tissue structures causes a violation of their integrity. They lose strength and cease to fully stabilize the joint.
An excessive increase in the range of motion is a prerequisite for constant, habitual dislocations and subluxations. The head of the bone slips out of the articular fossa, shifting relative to the other elements of the articulation.
Report from a conference of traumatologists on the problem under consideration:
Differential diagnosis
Damage to the acromioclavicular joint
AC joint injuries are common and often occur after falls from bicycles, during contact sports, and as a result of automobile accidents. The acromioclavicular joint is located at the top of the shoulder where the acromion and collarbone are located, forming the joint. Several ligaments surround this joint, and depending on the severity of the injury, a person may tear one or all of the ligaments. Damaged ligaments lead to stretching of the acromioclavicular joint or disruption of its integrity.
Recovery after a dislocated shoulder.
Rehabilitation measures take place in several stages. At the initial stage, in the first week after the injury, the patient is given rest with limitation of any actions in the shoulder joint, cold compresses are used, and the doctor prescribes electrophoresis. It is recommended to lightly warm up the hands and wrists (to prevent future atrophy of the arm muscles). At the next stages, exercises for developing the arm are gradually strengthened (a set of exercises is selected individually for each patient), and various physiotherapeutic procedures are prescribed. By strictly following all the recommendations of your doctor, continuing to do gymnastics to develop the joint and observing basic safety requirements, you can avoid serious consequences (for example, repeated dislocation, etc.)
Diagnostics
Symptoms
Patients with shoulder subluxation usually have:
- Pain in the shoulder area.
- Decreased range of motion.
- A palpable gap between the acromion and the head of the humerus (conventionally, this can be measured by the width of the fingers).
Functional tests
- Subluxation test is positive = resistance is encountered when the patient brings the arm into a throwing position, in the direction of internal rotation.
- Pain in the anterior capsule indicates anterior shoulder injury.
- Pressure on the back of the joint (during a resistance test) can cause it to move anteriorly, which can cause anterior subluxation and severe pain. This can be performed at various degrees of shoulder abduction, with or without shoulder support.
X-ray examination is considered the most accurate way to assess the extent of subluxation.
First aid
Timely first aid will help avoid the formation of inflammatory edema, which significantly increases pain. The victim needs to be laid down or sat down, given a non-steroidal anti-inflammatory drug (NSAID) tablet - Nise, Ketorol, Ibuprofen. What to do next if the shoulder joint is knocked out:
- immobilize (immobilize) the shoulder. To do this, use any available means: elastic or gauze bandage, scarf, scarf;
- provide the joint with functional rest. You cannot make movements that provoke an even greater displacement of the shoulder structures - flexion or extension of the elbow, rotation of the hand;
- apply a cold compress. A plastic bag filled with ice cubes and wrapped in thick cloth will help eliminate pain and prevent the formation of edema and hematoma. It is applied to the joint for 10-15 minutes. The procedure is repeated after an hour.
Now the victim needs to be taken to the emergency room or an ambulance is called.
Rating scales
Oxford Shoulder Instability Test (OISS)
The OISS is a 12-item questionnaire with five correct Likert responses for each question and has a range from 0 to 48 (with a score of 48 indicating better shoulder function). The OISS was developed and validated to assess shoulder instability and has also been tested to assess sensation in patients with shoulder instability.
Western Ontario Shoulder Instability Index (WOSI)
The WOSI is a 21-item questionnaire with a 100 mm horizontal visual analogue scale below each patient response question and ranges from 0 to 2100 as a percentage, with 100% representing the best possible shoulder-related quality of life. The WOSI is a carefully developed and evaluated instrument for patients with shoulder instability that has been demonstrated to have excellent sensitivity for posterior instability.
Treatment of habitual dislocation
Patients with habitual shoulder dislocations should undergo surgical treatment, since conservative methods in this case are completely ineffective.
Habitual dislocation differs in that stabilization of the shoulder joint can be done openly by making an incision on the anterior surface of the shoulder, as well as arthroscopically, without making incisions, that is, through punctures. A special optical device called an arthroscope . It allows you to examine the joint to identify the presence of damage to the ligamentous apparatus of the joint and determine the specific cause of instability. Through another puncture, special instruments are introduced into the joint cavity, which make it possible to attach the previously torn labrum. Fixation of the articular labrum is carried out using special absorbable clamps - anchors.
Survey
First, the researcher should ask the patient about the medical history. He can then perform an examination, comparing the affected shoulder with the unaffected side. To do this, you can use the following tests.
- Load and displacement test
In this test, the therapist stabilizes the scapula and moves the humeral head posteriorly and anteriorly. This test can determine whether the humeral head will subluxate.
- Push-pull test
The patient's arm is in a position of 90 degrees of abduction and 30 degrees of forward flexion. The examiner grasps the midsection of the patient's shoulder and applies posterior pressure. This test is used to evaluate posterior shoulder instability.
- Protzman test
This test is similar to the load and displacement test, but the examiner's second hand is placed in the axilla to feel the movement of the humeral head as close to the glenoid cavity of the scapula as possible.
Prevention
In order to avoid such injury and long-term treatment, you must follow simple rules of prevention:
- strengthen muscles, joints and ligaments, for which you need to do exercises daily, or better yet, choose a set of exercises for the shoulder girdle,
- avoid excessive stress,
- replenish the body’s reserves with useful substances (calcium, vitamin D, collagen, B vitamins are especially necessary),
- stop smoking and drinking alcohol, as they impair tissue nutrition,
- Since no one is immune from falls, it is advisable to learn how to properly group yourself when falling, which will minimize the risk of injury.
also promptly consult a doctor if shoulder discomfort occurs.
Physical therapy
In patients with hemiplegia
Sling/support
Traditionally, support devices in the form of slings or orthoses have been used to manage patients with shoulder subluxation after stroke. The goal is to support the arm by preventing/minimizing downward displacement of the humerus and reducing stretching of the joint capsule. A 2009 Cochrane review concluded that there is insufficient evidence to conclude whether assistive devices are beneficial.
About shoulder subluxation with hemiplegia, see here.
Electrical stimulation
Also, one Cochrane review found that functional electrical stimulation increased pain-free passive external rotation of the humerus and reduced the degree of shoulder subluxation, but did not find a significant effect on upper limb motor recovery.
What to do if these symptoms occur?
If the patient has every reason to believe that he has a dislocation, then the first step is to contact a specialist. You cannot adjust the joint yourself, as this can lead to dire consequences: even greater trauma to the joint tissue, nerve damage, loss of motor function and sensitivity of the upper limb. Only a specialist can correctly assess the injury and prescribe the appropriate course of treatment. The sooner the victim is seen, the easier it is to solve the problem and the greater the chance of avoiding complications. As the day passes, muscle contraction will occur, making it more difficult to act promptly on the affected area. When transporting the patient to a doctor's appointment, the limb should be fixed in the position in which it was dislocated. You should not perform a reduction if the victim cannot return it to the reverse position on his own. To reduce pain, apply a cold compress to the injury site. To make an accurate diagnosis, it is necessary to explain in detail how exactly the incident happened.