Dislocated shoulder | |
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Anterior dislocation of the left shoulder. | |
Specialty | Emergency medicine, orthopedics |
Symptoms | Shoulder pain |
Complications | Bankart lesion, Hill-Sachs lesion, rotator cuff tear, axillary nerve injury [1] |
Types | Anterior, posterior, inferior, superior [2] [1] |
Causes | Fall onto an outstretched arm or the shoulder. [3] |
Diagnostic method | Based on symptoms, X-rays [2] |
Treatment | Shoulder reduction, arm sling [1] [2] |
Medication | Procedural sedation and analgesia, intraarticular lidocaine [4] |
Prognosis | Recurrence common in young people [3] |
Frequency | 24 per 100,000 per year (US) [1] |
A dislocated shoulder is a condition in which the head of the humerus is detached from the glenoid fossa. [2] Symptoms include shoulder pain and instability. [2] Complications may include a Bankart lesion, Hill-Sachs lesion, rotator cuff tear, or injury to the axillary nerve. [1]
A shoulder dislocation often occurs as a result of a fall onto an outstretched arm or onto the shoulder. [3] Diagnosis is typically based on symptoms and confirmed by X-rays. [2] They are classified as anterior, posterior, inferior, and superior with most being anterior. [2] [1]
Treatment is by shoulder reduction which may be accomplished by a number of techniques. [1] These include traction-countertraction, external rotation, scapular manipulation, and the Stimson technique. [1] After reduction X-rays are recommended for verification. [1] The arm may then be placed in a sling for a few weeks. [2] Surgery may be recommended in those with recurrent dislocations. [2]
Not all patients require surgery following a shoulder dislocation. There is moderate quality evidence that patients who receive physical therapy after an acute shoulder dislocation will not experience recurrent dislocations. [5] It has been shown that patients who do not receive surgery after a shoulder dislocation do not experience recurrent dislocations within two years of the initial injury. [5]
About 1.7% of people have a shoulder dislocation within their lifetime. [3] In the United States this is about 24 per 100,000 people per year. [1] They make up about half of major joint dislocations seen in emergency departments. [1] Males are affected more often than females. [1] Most shoulder dislocations occur as a result of sports injuries. [5]
A diagnosis of shoulder dislocation is often suspected based on the person's history and physical examination. Radiographs are made to confirm the diagnosis. Most dislocations are apparent on radiographs showing incongruence of the glenohumeral joint. Posterior dislocations may be hard to detect on standard AP radiographs, but are more readily detected on other views. After reduction, radiographs are usually repeated to confirm successful reduction and to detect bone damage. After repeated shoulder dislocations, an MRI scan may be used to assess soft tissue damage. In regards to recurrent dislocations, the apprehension test (anterior instability) and sulcus sign (inferior instability) are useful methods for determining predisposition to future dislocation.[ citation needed ]
There are three main types of dislocations: anterior, posterior, and inferior. [7]
In over 95% of shoulder dislocations, the humerus is displaced anteriorly. [8] In most of those, the head of the humerus comes to rest under the coracoid process, referred to as sub-coracoid dislocation. Sub-glenoid, subclavicular, and, very rarely, intrathoracic or retroperitoneal dislocations may also occur. [9]
Anterior dislocations are usually caused by a direct blow to, or fall on, an outstretched arm. The person typically holds his/her arm externally rotated and slightly abducted. [10]
A Hill–Sachs lesion is an impaction of the head of the humerus left by the glenoid rim during dislocation. [6] Hill-Sachs deformities occur in 35–40% of anterior dislocations. They can be seen on a front-facing X-ray when the arm is in internal rotation. [11] Bankart lesions are disruptions of the glenoid labrum with or without an avulsion of bone fragment. [12]
Damage to the axillary artery [13] and axillary nerve (C5, C6) may result. The axillary nerve is injured in 37% making it the most commonly injured structure with this type of injury. [14] Other common, associated, nerve injuries include injury to the suprascapular nerve (29%) and the radial nerve (22%). [14] Axillary nerve damage results in a weakened or paralyzed deltoid muscle and as the deltoid atrophies unilaterally, the normal rounded contour of the shoulder is lost. A person with injury to the axillary nerve will have difficulty in abducting the arm from approximately 15° away from the body. The supraspinatus muscle initiates abduction from a fully adducted position.[ citation needed ]
Posterior dislocations are uncommon, and are typically due to the muscle contraction from electric shock or seizure. [6] They may be caused by strength imbalance of the rotator cuff muscles. People with dislocated shoulders typically present holding their arm internally rotated and adducted, and exhibiting flattening of the anterior shoulder with a prominent coracoid process.[ citation needed ]
Posterior dislocations may go unrecognized, especially in an elderly person [15] and in people who are in the state of unconscious trauma. [16] An average interval of 1 year was noted between injury and diagnosis in a series of 40 people. [17]
Inferior dislocation is the least likely, occurring in less than 1%. This condition is also called luxatio erecta because the arm appears to be permanently held upward or behind the head. [18] It is caused by a hyper abduction of the arm that forces the humeral head against the acromion. [19] Such injuries have a high complication rate as many vascular, neurological, tendon, and ligament injuries are likely to occur from this mechanism of injury.
Prompt medical treatment should be sought for suspected dislocation. Usually, the shoulder is kept in its current position by use of a splint or sling. A pillow between the arm and torso may provide support and increase comfort. Strong analgesics are needed to allay the pain of a dislocation and the distress associated with it.[ citation needed ]
Shoulder reduction may be accomplished with a number of techniques including traction-countertraction, external rotation, scapular manipulation, Stimson technique, Cunningham technique, or Milch technique. [1] [3] Pain can be managed during the procedures either by procedural sedation and analgesia or injected lidocaine into the shoulder joint. [20] Injecting lidocaine into the joint may be less expensive and faster. [4] If a shoulder cannot be relocated in the emergency room, relocation in the operating room may be required. [1] This situation occurs in about 7% of cases. [1]
[21] Stimson procedure is the least painful, widely used shoulder reduction technique. In this procedure a weight is attached to the wrist while the injured arm is hanging off an examination table for between 20 and 30 minutes. The arm is then slowly rotated until the shoulder is relocated. Sedatives are used in Stimson procedure and first time Stimson reduction for acute shoulder dislocation requires wearing arm slings for between 2 and 4 weeks.
There is no strong evidence of a difference in outcomes when the arm is immobilized in internal versus external rotation following an anterior shoulder dislocation. [22] [23] A 2008 study of 300 people for almost six years found that conventional shoulder immobilisation in a sling offered no benefit. [24]
In young adults engaged in highly demanding activities shoulder surgery may be considered. [25] Arthroscopic surgery techniques may be used to repair the glenoidal labrum, capsular ligaments, biceps long head anchor or SLAP lesion or to tighten the shoulder capsule. [26]
Arthroscopic stabilization surgery has evolved from the Bankart repair, a time-honored surgical treatment for recurrent anterior instability of the shoulder. [27] However, the failure rate following Bankart repair has been shown to increase markedly in people with significant bone loss from the glenoid (socket). [28] In such cases, improved results have been reported with some form of bone augmentation of the glenoid such as the Latarjet operation. [29] [30] [31]
Although posterior dislocation is much less common, instability following it is no less challenging and, again, some form of bone augmentation may be required to control instability. [32] Damaged ligaments, including labral tears, occurring as a result of posterior dislocations may be treated arthroscopically.[ citation needed ]
There remains those situations characterized by multidirectional instability, which have failed to respond satisfactorily to rehabilitation, falling under the AMBRI classification previously noted. This is usually due to an overstretched and redundant capsule which no longer offers stability or support. Traditionally, this has responded well to a 'reefing' procedure known as an open inferior capsular shift. [33] More recently, the procedure has been carried out as an arthroscopic procedure, rather than open surgery, again with comparable results. [33] Most recently, the procedure has been carried out using radio frequency technology to shrink the redundant shoulder capsule (thermal capsular shrinkage); [34] while long-term results of this development are currently unproven, recent studies show thermal capsular shrinkage have higher failure rates with the highest number of cases of instability recurrence and re-operation. [31]
Following shoulder reduction, most people are given self-management advice on recovery, such as home exercises, but some receive additional physiotherapy. A randomised controlled trial showed similar shoulder function after 6 months between those who received self-management advice only and those who had extra physiotherapy. Both groups also had a similar number of complications. [35] [36]
After an anterior shoulder dislocation, the risk of a future dislocation is about 20%. This risk is greater in males than females. [37]
The rotator cuff is a group of muscles and their tendons that act to stabilize the human shoulder and allow for its extensive range of motion. Of the seven scapulohumeral muscles, four make up the rotator cuff. The four muscles are:
The axillary nerve or the circumflex nerve is a nerve of the human body, that originates from the brachial plexus at the level of the axilla (armpit) and carries nerve fibers from C5 and C6. The axillary nerve travels through the quadrangular space with the posterior circumflex humeral artery and vein to innervate the deltoid and teres minor.
Shoulder problems including pain, are one of the more common reasons for physician visits for musculoskeletal symptoms. The shoulder is the most movable joint in the body. However, it is an unstable joint because of the range of motion allowed. This instability increases the likelihood of joint injury, often leading to a degenerative process in which tissues break down and no longer function well.
The human shoulder is made up of three bones: the clavicle (collarbone), the scapula, and the humerus as well as associated muscles, ligaments and tendons.
A joint dislocation, also called luxation, occurs when there is an abnormal separation in the joint, where two or more bones meet. A partial dislocation is referred to as a subluxation. Dislocations are often caused by sudden trauma on the joint like an impact or fall. A joint dislocation can cause damage to the surrounding ligaments, tendons, muscles, and nerves. Dislocations can occur in any major joint or minor joint. The most common joint dislocation is a shoulder dislocation.
The teres minor is a narrow, elongated muscle of the rotator cuff. The muscle originates from the lateral border and adjacent posterior surface of the corresponding right or left scapula and inserts at both the greater tubercle of the humerus and the posterior surface of the joint capsule.
The shoulder joint is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint. It involves an articulation between the glenoid fossa of the scapula and the head of the humerus. Due to the very loose joint capsule ,that gives a limited interface of the humerus and scapula, it is the most mobile joint of the human body.
Dead arm syndrome starts with repetitive motion and forces on the posterior capsule of the shoulder. The posterior capsule is a band of fibrous tissue that interconnects with tendons of the rotator cuff of the shoulder. Four muscles and their tendons make up the rotator cuff. They cover the outside of the shoulder to hold, protect and move the joint.
A SLAP tear or SLAP lesion is an injury to the superior glenoid labrum that initiates in the back of the labrum and stretches toward the front into the attachment point of the long head of the biceps tendon. SLAP is an acronym for "Superior Labrum Anterior and Posterior". SLAP lesions are commonly seen in overhead throwing athletes but middle-aged labor workers can also be affected, and they can be caused by chronic overuse or an acute stretch injury of the shoulder.
The glenoid labrum is a fibrocartilaginous structure attached around the rim of the glenoid cavity on the shoulder blade. The shoulder joint is considered a ball-and-socket joint. However, in bony terms the 'socket' is quite shallow and small, covering at most only a third of the 'ball'. The socket is deepened by the glenoid labrum, stabilizing the shoulder joint.
A separated shoulder, also known as acromioclavicular joint injury, is a common injury to the acromioclavicular joint. The AC joint is located at the outer end of the clavicle where it attaches to the acromion of the scapula. Symptoms include non-radiating pain which may make it difficult to move the shoulder. The presence of swelling or bruising and a deformity in the shoulder is also common depending on how severe the dislocation is.
Shoulder surgery is a means of treating injured shoulders. Many surgeries have been developed to repair the muscles, connective tissue, or damaged joints that can arise from traumatic or overuse injuries to the shoulder.
A Bankart lesion is a type of shoulder injury that occurs following a dislocated shoulder. It is an injury of the anterior (inferior) glenoid labrum of the shoulder. When this happens, a pocket at the front of the glenoid forms that allows the humeral head to dislocate into it. It is an indication for surgery and often accompanied by a Hill-Sachs lesion, damage to the posterior humeral head.
A Hill–Sachs lesion, or Hill–Sachs fracture, is a cortical depression in the posterolateral head of the humerus. It results from forceful impaction of the humeral head against the anteroinferior glenoid rim when the shoulder is dislocated anteriorly.
The elbow is the region between the upper arm and the forearm that surrounds the elbow joint. The elbow includes prominent landmarks such as the olecranon, the cubital fossa, and the lateral and the medial epicondyles of the humerus. The elbow joint is a hinge joint between the arm and the forearm; more specifically between the humerus in the upper arm and the radius and ulna in the forearm which allows the forearm and hand to be moved towards and away from the body. The term elbow is specifically used for humans and other primates, and in other vertebrates it is not used. In those cases, forelimb plus joint is used.
Humeral avulsion of the glenohumeral ligament (HAGL) is defined as an avulsion of the inferior glenohumeral ligament from the anatomic neck of the humerus. In other words, it occurs when we have disruption of the ligaments that join the humerus to the glenoid. HAGL tends to occur in 7.5-9.3% of cases of anterior shoulder instability. Making it an uncommon cause of anterior shoulder instability. Avulsion of this ligamentous complex may occur in three sites: glenoid insertion (40%), the midsubstance (35%) and the humeral insertion (25%). Bony humeral avulsion of the glenohumeral ligament (BHAGL) refers when we have HAGL with bony fracture.
Glenolabral articular disruption (GLAD) lesion is a type of shoulder injury. It is difficult to diagnose clinically, and requires surgical repair to correct the damage to the shoulder.
The Latarjet operation, also known as the Latarjet-Bristow procedure, is a surgical procedure used to treat recurrent shoulder dislocations, typically caused by bone loss or a fracture of the glenoid. The procedure was first described by French surgeon Dr. Michel Latarjet in 1954.
Shoulder reduction is the process of returning the shoulder to its normal position following a shoulder dislocation. Normally, closed reduction, in which the relationship of bone and joint is manipulated externally without surgical intervention, is used. A variety of techniques exist, but some are preferred due to fewer complications or easier execution. In cases where closed reduction is not successful, open (surgical) reduction may be needed. X-rays are often used to confirm success and absence of associated fractures. The arm should be kept in a sling or immobilizer for several days, prior to supervised recovery of motion and strength.
A proximal humerus fracture is a break of the upper part of the bone of the arm (humerus). Symptoms include pain, swelling, and a decreased ability to move the shoulder. Complications may include axillary nerve or axillary artery injury.
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