![Shoulder dislocation while carrying a frail elder](https://upload.wikimedia.org/wikipedia/commons/b/bf/Shoulder_dislocation_while_carrying_a_frail_elder.jpg)
A dislocated shoulder is a condition in which the head of the
humerus
The humerus (; ) 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 and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...
is detached from the
shoulder joint
The shoulder joint (or glenohumeral joint from Greek ''glene'', eyeball, + -''oid'', 'form of', + Latin ''humerus'', shoulder) is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint. ...
.
Symptoms include shoulder pain and instability.
[ Complications may include a ]Bankart lesion
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 th ...
, Hill-Sachs lesion, rotator cuff tear
A rotator cuff tear is an injury where one or more of the tendons or muscles of the rotator cuff of the shoulder get torn. Symptoms may include shoulder pain, which is often worse with movement, limited range of motion, or weakness. This may limi ...
, or injury 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. Th ...
.[
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, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 Picometre, picometers to 10 Nanometre, nanometers, corresponding to frequency, ...
.[ They are classified as anterior, posterior, inferior, and superior with most being anterior.][
Treatment is by ]shoulder reduction
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 ...
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 one of the allied health professions. It is provided by physical therapists who promote, maintain, or restore health through physical examination, diagnosis, management, prognosis, patient ...
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 care of pati ...
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 stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...
, 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 mak ...
.
* 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 stimuli. In everyday speech this is generally referred to as num ...
of the arm.
* Visibly displaced shoulder. Some dislocations result in the shoulder appearing unusually square.
* No palpable bone
A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
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 form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves ...
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 mak ...
dislocations, the humerus is displaced anteriorly. 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
The glenoid fossa of the scapula or the glenoid cavity is a bone part of the shoulder. The word ''glenoid'' is pronounced or (both are common) and is from el, gléne, "socket", reflecting the shoulder joint's ball-and-socket form. It is a sha ...
, subclavicular
The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the rig ...
, 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 a ...
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 their ...
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 lesion
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 th ...
s 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. Th ...
(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
The suprascapular nerve is a nerve that branches from the upper trunk of the brachial plexus. It is responsible for the innervation of two of the muscles that originate from the scapula, namely the supraspinatus and infraspinatus muscles.
Structur ...
(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 osteofascial comp ...
(22%). Axillary nerve damage results in a weakened or paralyzed deltoid muscle
The deltoid muscle is the muscle forming the rounded contour of the human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle appears to be 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 (plural ''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 ...
initiates abduction from a fully adducted
Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative ...
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
Electrical injury is a physiological reaction caused by electric current passing through the body. The injury depends on the density of the current, tissue resistance and duration of contact. Very small currents may be imperceptible or produce ...
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 refers to ages nearing or surpassing the life expectancy of human beings, and is thus the end of the human life cycle. Terms and euphemisms for people at this age include old people, the elderly (worldwide usage), OAPs (British usage ...
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 the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the:
* Peritoneal li ...
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 th ...
and torso
The torso or trunk is an anatomical term for the central part, or the core, of the body of many animals (including humans), from which the head, neck, limbs, tail and other appendages extend. The tetrapod torso — including that of a human ...
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
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 ...
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
Procedural sedation and analgesia (PSA) is a technique in which a sedating/dissociative medication is given, usually along with an analgesic medication, in order to perform non-surgical procedures on a patient. The overall goal is to induce a decr ...
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. When used for local anaesthesia or in nerve blocks, lidoca ...
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
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.
Dislocated shoulder
A d ...
may be considered. Arthroscopic surgery
Arthroscopy (also called arthroscopic or keyhole surgery) is a minimally invasive surgical procedure on a joint in which an examination and sometimes treatment of damage is performed using an arthroscope, an endoscope that is inserted into the ...
techniques may be used to repair the glenoidal labrum
The glenoid labrum (glenoid ligament) is a fibrocartilaginous structure (not a fibrocartilage as previously thought) rim attached around the margin of the glenoid cavity in the shoulder blade. The shoulder joint is considered a ball and socket j ...
, capsular ligaments, biceps
The biceps or biceps brachii ( la, musculus 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 ...
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.
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
{{DEFAULTSORT:Dislocated Shoulder
Injuries of shoulder and upper arm
Shoulder
Dislocations, sprains and strains
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