
A dislocated shoulder is a condition in which the head of the
humerus
The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...
is detached from the
glenoid fossa.
Symptoms include shoulder pain and instability.
[ Complications may include a Bankart lesion, Hill-Sachs lesion, rotator cuff tear, or ]injury
Injury is physiological damage to the living tissue of any organism, whether in humans, in other animals, or in plants.
Injuries can be caused in many ways, including mechanically with penetration by sharp objects such as teeth or with ...
to the axillary nerve
The axillary nerve or the circumflex nerve is a nerve of the human body, that originates from the brachial plexus ( upper trunk, posterior division, posterior cord) at the level of the axilla (armpit) and carries nerve fibers from C5 and C6. ...
.[
A shoulder dislocation often occurs as a result of a fall onto an outstretched arm or onto the shoulder.][ Diagnosis is typically based on symptoms and confirmed by ]X-rays
An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...
.[ They are classified as anterior, posterior, inferior, and superior with most being anterior.][
Treatment is by shoulder reduction which may be accomplished by a number of techniques.][ These include traction-countertraction, external rotation, scapular manipulation, and the Stimson technique.][ After reduction X-rays are recommended for verification.][ The arm may then be placed in a sling for a few weeks.][ Surgery may be recommended in those with recurrent dislocations.][
Not all patients require surgery following a shoulder dislocation. There is moderate quality evidence that patients who receive ]physical therapy
Physical therapy (PT), also known as physiotherapy, is a healthcare profession, as well as the care provided by physical therapists who promote, maintain, or restore health through patient education, physical intervention, disease preventio ...
after an acute shoulder dislocation will not experience recurrent dislocations. 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.
About 1.7% of people have a shoulder dislocation within their lifetime. In the United States this is about 24 per 100,000 people per year. They make up about half of major joint dislocations seen in emergency department
An emergency department (ED), also known as an accident and emergency department (A&E), emergency room (ER), emergency ward (EW) or casualty department, is a medical treatment facility specializing in emergency medicine, the Acute (medicine), ...
s. Males are affected more often than females. Most shoulder dislocations occur as a result of sports injuries.
Signs and symptoms
* Significant pain
Pain is a distressing feeling often caused by intense or damaging Stimulus (physiology), stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sense, sensory and emotional experience associated with, or res ...
, sometimes felt along the arm past the shoulder
The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons.
The articulations between the bones of the shoulder m ...
.
* Sensation that the shoulder is slipping out of the joint during abduction and external rotation.
* Shoulder and arm held in external rotation (anterior dislocation), or adduction and internal rotation (posterior dislocation). Resistance of all movement.
* Numbness
Hypoesthesia or numbness is a common side effect of various medical conditions that manifests as a reduced sense of touch or sensation, or a partial loss of sensitivity to Sensory receptor, sensory stimuli. In everyday speech this is generally r ...
of the arm.
* Visibly displaced shoulder. Some dislocations result in the shoulder appearing unusually square.
* No palpable bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...
on the side of the shoulder.
Diagnosis
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
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ra ...
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.
There are three main types of dislocations: anterior, posterior, and inferior.
Anterior (forward)
In over 95% of shoulder
The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons.
The articulations between the bones of the shoulder m ...
dislocations, the humerus is displaced anteriorly
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Thi ...
. In most of those, the head of the humerus comes to rest under the coracoid process
The coracoid process (from Greek κόραξ, raven) is a small hook-like structure on the lateral edge of the superior anterior portion of the scapula (hence: coracoid, or "like a raven's beak"). Pointing laterally forward, it, together with the ...
, referred to as sub-coracoid dislocation. Sub- glenoid, sub clavicular, and, very rarely, intrathoracic
The thoracic cavity (or chest cavity) is the chamber of the body of vertebrates that is protected by the thoracic wall (rib cage and associated skin, muscle, and fascia). The central compartment of the thoracic cavity is the mediastinum. There ...
or retroperitoneal
The retroperitoneal space (retroperitoneum) is the anatomical space (sometimes a potential space) behind (''retro'') the peritoneum. It has no specific delineating anatomical structures. Organs are retroperitoneal if they have peritoneum on thei ...
dislocations may also occur.
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.
A Hill–Sachs lesion is an impaction of the head of the humerus left by the glenoid rim during dislocation. 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. Bankart lesions are disruptions of the glenoid labrum with or without an avulsion of bone fragment.
Damage to the axillary artery
In human anatomy, the axillary artery is a large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla (armpit) and the upper limb. Its origin is at the lateral margin of the first rib, before which it is c ...
and axillary nerve
The axillary nerve or the circumflex nerve is a nerve of the human body, that originates from the brachial plexus ( upper trunk, posterior division, posterior cord) at the level of the axilla (armpit) and carries nerve fibers from C5 and C6. ...
(C5, C6) may result. The axillary nerve is injured in 37% making it the most commonly injured structure with this type of injury. Other common, associated, nerve injuries include injury to the suprascapular nerve (29%) and the radial nerve
The radial nerve is a nerve in the human body that supplies the posterior portion of the upper limb. It innervates the medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the Posterior compartment of the ...
(22%). Axillary nerve damage results in a weakened or paralyzed deltoid muscle
The deltoid muscle is the muscle forming the rounded contour of the shoulder, human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle is made up o ...
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
The supraspinatus (: supraspinati) is a relatively small muscle of the upper back that runs from the supraspinous fossa superior portion of the scapula (shoulder blade) to the greater tubercle of the humerus. It is one of the four rotator cuff mus ...
initiates abduction from a fully adducted position.
File:Luxation epaule.PNG, An anterior dislocation of the shoulder
File:AnterDisAPMark.png, Anterior dislocation of the right shoulder. AP X ray
File:AnterDisMark.png, Anterior dislocation of the right shoulder. Y view X ray.
Posterior (backward)
Posterior dislocations are uncommon, and are typically due to the muscle contraction from electric shock
An electrical injury (electric injury) or electrical shock (electric shock) is damage sustained to the skin or internal organs on direct contact with an electric current.
The injury depends on the Current density, density of the current, tissu ...
or seizure. 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.
Posterior dislocations may go unrecognized, especially in an elderly
Old age is the range of ages for people nearing and surpassing life expectancy. People who are of old age are also referred to as: old people, elderly, elders, senior citizens, seniors or older adults. Old age is not a definite biological sta ...
person and in people who are in the state of unconscious trauma. An average interval of 1 year was noted between injury and diagnosis in a series of 40 people.
Inferior (downward)
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. It is caused by a hyper abduction of the arm that forces the humeral head against the acromion. Such injuries have a high complication rate as many vascular, neurological, tendon, and ligament
A ligament is a type of fibrous connective tissue in the body that connects bones to other bones. It also connects flight feathers to bones, in dinosaurs and birds. All 30,000 species of amniotes (land animals with internal bones) have liga ...
injuries are likely to occur from this mechanism of injury.
Treatment
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
In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between ...
and torso
The torso or trunk is an anatomical terminology, anatomical term for the central part, or the core (anatomy), core, of the body (biology), body of many animals (including human beings), from which the head, neck, limb (anatomy), limbs, tail an ...
may provide support and increase comfort. Strong analgesics are needed to allay the pain of a dislocation and the distress associated with it.
Reduction
Shoulder reduction may be accomplished with a number of techniques including traction-countertraction, external rotation, scapular manipulation, Stimson technique, Cunningham technique, or Milch technique.[ Pain can be managed during the procedures either by procedural sedation and analgesia or injected ]lidocaine
Lidocaine, also known as lignocaine and sold under the brand name Xylocaine among others, is a local anesthetic of the amino amide type. It is also used to treat ventricular tachycardia and ventricular fibrillation. When used for local anae ...
into the shoulder joint. Injecting lidocaine into the joint may be less expensive and faster. If a shoulder cannot be relocated in the emergency room, relocation in the operating room may be required.[ This situation occurs in about 7% of cases.][
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.
]
Post-reduction
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. A 2008 study of 300 people for almost six years found that conventional shoulder immobilisation in a sling offered no benefit.
Surgery
In young adults engaged in highly demanding activities shoulder surgery may be considered. Arthroscopic surgery
Arthroscopy (also called arthroscopic or keyhole surgery) is a minimally invasive surgery, surgical procedure on a joint in which an examination and sometimes treatment of damage is performed using an arthroscope, an endoscope that is inserted in ...
techniques may be used to repair the glenoidal labrum, capsular ligaments, biceps
The biceps or biceps brachii (, "two-headed muscle of the arm") is a large muscle that lies on the front of the upper arm between the shoulder and the elbow. Both heads of the muscle arise on the scapula and join to form a single muscle bel ...
long head anchor or SLAP lesion or to tighten the shoulder capsule.
Arthroscopic stabilization surgery has evolved from the Bankart repair, a time-honored surgical treatment for recurrent anterior instability of the shoulder. However, the failure rate following Bankart repair has been shown to increase markedly in people with significant bone loss from the glenoid (socket). In such cases, improved results have been reported with some form of bone augmentation of the glenoid such as the Latarjet operation.
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. Damaged ligaments, including labral tears, occurring as a result of posterior dislocations may be treated arthroscopically.
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. More recently, the procedure has been carried out as an arthroscopic procedure, rather than open surgery, again with comparable results.[ Most recently, the procedure has been carried out using radio frequency technology to shrink the redundant shoulder capsule (thermal capsular shrinkage); 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.]
Physiotherapy
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.
Prognosis
After an anterior shoulder dislocation, the risk of a future dislocation is about 20%. This risk is greater in males than females.
See also
* Shoulder problems
References
External links
{{Dislocations, sprains and strains
Injuries of shoulder and upper arm
Shoulder
shoulder Dislocated
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