Reduction of Shoulder Dislocation

Shoulder dislocation is the most common large-joint dislocation seen in the emergency department (ED). The muscular, ligamentous, and bony anatomy of the shoulder (glenohumeral joint) gives it the most extensive range of motion (ROM) of any joint in the human body. However, this anatomy also makes the glenohumeral joint the most unstable joint in the body.

Anterior dislocations (in which the humeral head is displaced anteriorly in relation to the glenoid), account for as many as 95-98% of shoulder dislocations.[1] The reason is that the muscular and ligamentous support anterior to the humeral head is much less robust than the substantial muscular and bony support afforded posteriorly by the rotator cuff and scapula. Anterior shoulder dislocations may be divided into the following four types:

• Subcoracoid (most common)
• Subglenoid
• Subclavicular (rare)
• Intrathoracic (rare)

Posterior shoulder dislocations are considerably less common, accounting for fewer than 4% of shoulder dislocations. Many posterior shoulder dislocations are initially missed by treating physicians, and diagnosis is delayed in many cases.[2] Failure to diagnose and treat posterior dislocations promptly can result in complications, including recurrent dislocations, avascular necrosis of the humeral head, degenerative disease, and chronic pain.

Inferior glenohumeral dislocation (luxatio erecta humeri) is rare, accounting for fewer than 1% of all shoulder dislocations.[3, 4] Most cases arise from forceful hyperabduction of the shoulder. This initially results in impingement of the humeral head against the acromion, and the leverage caused by this impingement ultimately drives the humeral head downward, causing it to disrupt the inferior portion of the glenohumeral capsule and dislocate. Forceful, direct axial loading of an abducted shoulder can also result in luxatio erecta.[5, 6]

Most shoulder dislocations are straightforward and can easily be reduced in the ED by using one of several techniques. However, recalcitrant cases do occur, and clinicians need to be alert for coincident injuries and complications.

Anterior dislocation

For subcoracoid and subglenoid dislocations, which account for 99% of anterior shoulder dislocations, joint reduction by the ED physician is typically indicated. Subclavicular or intrathoracic dislocations, which are caused by large forces, are not easily corrected and should be referred to an orthopedic surgeon.[7]

Posterior dislocation

For an uncomplicated posterior shoulder dislocation that is diagnosed within 3-6 weeks of injury, reduction in the ED is generally appropriate. After this amount of time, a single atraumatic attempt at relocation in the ED is not absolutely contraindicated, depending on resource availability, but is often futile. Shoulders that have been dislocated posteriorly for that extended period of time often require relocation in the operating room (OR) under general anesthesia. A small humeral head defect is not a contraindication for attempting a closed reduction in the ED. A fracture-dislocation with a nondisplaced lesser tuberosity fracture may be treated with a closed reduction.

Inferior dislocation

In a patient with an inferior glenohumeral dislocation, the presence of brachial plexus injury necessitates prompt atraumatic reduction, with the goal being smooth, uncomplicated, successful reduction on the first attempt.

Anterior dislocation

Standard closed reduction of an anterior shoulder dislocation is contraindicated if prompt surgical consultation is indicated.[7] Contraindications include the following:

• Subclavicular or intrathoracic dislocations
• Associated fractures of the humeral neck - Attempts at reduction may worsen the fracture or result in avascular necrosis

Various neurovascular injuries and common fractures do not prohibit reduction but do call for prompt and atraumatic reduction with avoidance of multiple attempts. These include the following:

• Nerve injuries - The brachial plexus, axillary nerve, or musculocutaneous nerve may be injured; neurapraxias (contusions of the nerve) usually resolve within weeks
• Suspected major arterial injury - Urgent angiography is required
• Common fractures - Hill-Sachs deformity, a compression fracture of the posterolateral aspect of the humeral head, and Bankart fracture, a detachment of the anterior aspect of the glenoid rim, may occur as the result of the dislocating force as the humeral head presses forcefully against the glenoid rim ^[7] ; avulsion fractures of the greater tuberosity of the humeral head tend to heal well but require immediate orthopedic consultation if the displacement exceeds 1 cm

Posterior dislocation

The following are contraindications for standard closed reduction of a posterior shoulder dislocation:

• Delayed (>3-6 weeks) presentation
• Large humeral head defect
• Displaced or multipart fracture-dislocations - These are treated with open reduction and internal fixation (ORIF) or with arthroplasty

Inferior dislocation

Standard closed reduction of an inferior glenohumeral dislocation is contraindicated in the setting of humeral neck or shaft fractures or in the setting of suspected major vascular injury. The presence of these associated injuries necessitates surgical intervention/open reduction.

Though not a contraindication per se, a “buttonhole deformity” (in which the humeral head becomes trapped in a tear of the inferior capsule) often precludes successful closed reduction, necessitating open reduction.

Procedural planning

Clinical assessment determines the type of dislocation present, which guides the approach to reduction (if indicated).

Anterior dislocation

A patient with an anterior shoulder dislocation typically presents with an obvious squared-off shoulder, with the humeral head located inferior and medial to the normal anatomic location. Patients generally hold the injured arm in abduction and resist attempts to adduct or internally rotate the arm.[7] Trying to place the arm into a sling is often futile; patients usually find the position of greatest comfort.

Before any attempts at reduction, the provider should perform a neurovascular examination and assess the probability of a fracture, considering the mechanism of injury and the physical characteristics of the patient. The axillary nerve is the most commonly injured nerve in shoulder dislocations and can be evaluated by testing for sensation in the lateral upper arm and by palpating for contraction of the deltoid muscle while the patient abducts against resistance. The clinician should also look for possible damage to other branches of the brachial plexus.

Arterial injury, though rare in this setting, is also possible and can present with paresthesias, diminished pulse, paleness or coolness of the affected extremity, pain that is out of proportion to the physical findings, or paralysis.[7] Injury to the axillary artery is more common in the elderly population.[8]

Posterior dislocation

Posterior shoulder dislocations usually result from forceful contractions of the internal rotators that occur during seizures or electrical injuries. This mechanism can force the humeral head posteriorly, out of its normal alignment and behind the glenoid. Less commonly, posterior shoulder dislocations follow trauma. The mechanism may be a direct blow to the anterior shoulder or a posteriorly directed force applied through the forward-flexed arm.

A complete neurovascular examination should be performed for these dislocations as well, though the incidence of neurovascular injuries is lower with posterior dislocations than with anterior dislocations.[9] Posterior shoulder dislocations are commonly associated with posterior glenoid rim fractures and anterior compression fractures of the humeral head.

Inferior dislocation

Patients with inferior glenohumeral dislocations present with the affected arm “locked” in abduction of varying degrees.[10] Classically, the affected arm is hyperabducted, with the elbow flexed and the forearm resting on top of or behind the head (see the image below). Often, the dislocated humeral head is palpable along the lateral border of the chest wall. The patient is generally in a substantial amount of pain, particularly when attempts are made to move the injured extremity.

Classic presentation of inferior shoulder dislocation. Affected arm is hyperabducted, with elbow flexed and forearm resting on top of head.

Anterior dislocation

In some cases of anterior shoulder dislocation, standard reduction efforts will fail. If multiple attempts at closed reduction fail or signs of neurovascular injury develop, an orthopedic surgeon should be consulted to evaluate for closed or open reduction in the OR with general anesthesia.

Injuries may occur as a consequence of reduction. These may be minimized by applying the smallest effective amount of force during reduction with traction and leverage techniques so as to avoid the formation or exacerbation of existing fractures or vascular (eg, hemarthrosis) or nerve injuries (eg, neurapraxia). New fractures rarely appear on postreduction films.

Recurrence is the most common complication adverse outcome after reduction, especially in young active patients. Age at the time of dislocation is inversely related to the rate of recurrence.[11] Common fractures (eg, Hill-Sachs deformity or Bankart fracture) require prompt orthopedic follow-up because they are associated with increased joint instability and a higher risk of redislocation. After evaluation of the shoulder’s postreduction ROM, immediate immobilization with a sling and swathe or shoulder immobilizer is crucial to prevent recurrence.

Posterior dislocation

The most common complication of attempted closed reduction of a posterior shoulder dislocation is a humeral fracture, especially in older patients. Acute redislocation may also occur. Complications of the dislocation itself include the following:

• Osteonecrosis
• Posttraumatic osteoarthritis
• Joint stiffness and functional incapacity

Inferior dislocation

An estimated 50-60% of patients with luxatio erecta have associated brachial plexus injury.[12] Assessment and documentation of the presence of neurologic deficits should be carried out both before and after reduction.[13] Injury to the axillary artery, including arterial thrombosis, has also been reported.[14]

Rotator cuff tears occur very often with inferior dislocations.[15, 16] Ligamentous and connective tissue injuries include disruption of the glenohumeral ligament, the inferior glenoid capsule, or both.

Associated bony injuries include fractures of the glenoid rim, greater tuberosity, acromion, clavicle, and coracoid process.[2] These injuries can be induced or exacerbated by attempted reduction; however, they more often occur as a result of the dislocation itself.

Anterior dislocation

In patients with anterior shoulder dislocations, the x-ray panel, when indicated, should include anteroposterior (AP), lateral (Y), and axillary views of the shoulder. Radiographs are generally recommended for first-time dislocations or those caused by direct trauma. Empiric reductions should be limited to those patients with clinically apparent anterior shoulder dislocation if they are neurovascularly intact and if reduction can be performed easily and rapidly.

Clinical factors that have been associated with clinically significant fractures include first episode, patient age exceeding 40 years, or involvement in selected mechanisms of injury (ie, fall from more than one flight of stairs, fight or assault, and motor vehicle collision).[17] Some argue that prereduction films are necessary only in patients who have one or more of these risk factors, especially those patients aged 40 years and older.[18]

When in doubt, bedside ultrasonography (US) can also be used to diagnose a shoulder dislocation.[19, 20, 21, 22] Images of the glenohumeral joint can be obtained by using either a high-frequency linear array or a low-frequency curvilinear transducer. In an anterior dislocation, anterior displacement of the humeral head in relation to the glenoid is observed when the joint is viewed via the posterior approach (see the images below).[23]

Ultrasound probe placement for viewing glenohumeral joint via posterior approach.

Ultrasound image of normal (right) and anteriorly dislocated shoulder (left). Arrow points to humeral head. Image courtesy of Michael A Secko, MD, RDMS.

Posterior dislocation

Posterior shoulder dislocations are often missed or diagnosed only after a significant delay; thus, prompt identification of these relatively rare dislocations is the critical element of the preprocedural evaluation. Radiography beyond AP views is important when clinical suspicion of an occult posterior dislocation is high. Because posterior dislocations may be missed on AP views alone, complete radiographs (Y view or axillary view) are essential for diagnosis.

To avoid a missed diagnosis, a thorough examination should be performed, and radiographs should be obtained that definitively show the orientation of the glenoid with respect to the humeral head. On an AP view of the shoulder, a posterior dislocation is very subtle. Several findings on AP views have been described, including the so-called trough sign, which is caused by a reverse Hill-Sachs defect, or loss of overlap of the humeral head and glenoid fossa (see the images below). However, these subtle findings frequently are missed.

Anteroposterior radiograph of left shoulder shows posterior glenohumeral dislocation. Impaction of humeral head on posterior glenoid results in reverse Hill-Sachs defect (trough sign) on anterior aspect of humeral head. Image courtesy of Dr M A Png, Singapore General Hospital.

Axial spin-echo T1-weighted magnetic resonance arthrogram of right shoulder shows tear of posterior glenoid labrum (arrow) and reverse Hill-Sachs defect (arrowhead). Patient had previous posterior dislocation.

Radiographic projections such as an axillary view or a transscapular Y view are much more reliable and should be ordered routinely when a posterior dislocation is suspected. On both of these views, the humeral head can be seen posterior to the glenoid fossa.[9]

A patient with a posterior dislocation presents with the affected arm held in adduction and internal rotation. Efforts by the examiner to abduct or externally rotate the extremity result in pain and very little movement. Additionally, a prominent acromion and coracoid are typically noted, with the humeral head palpable posteriorly. These findings may be obscured if swelling is massive swelling or if the patient is particularly large.

Inferior dislocation

Before any attempted reduction of an inferior shoulder dislocation, a focused neurovascular examination should be performed to screen for the presence of nerve or vascular injury, and the examination should be repeated after reduction to document any change.

Injuries to the brachial plexus are common in the setting of inferior glenohumeral dislocations. The sensory function of the axillary nerve can be tested by assessing pinprick sensation over the “regimental badge” area of the affected arm (see the image below). Radial nerve motor function of the affected arm can be assessed by examining the strength of wrist extension. Distal pulses and capillary refill should also be examined before and after reduction.

"Regimental badge" area. Examine pinprick sensation to this area to assess axillary nerve sensory function.

To gain a multiplanar view of the glenohumeral joint, AP and transscapular lateral or Y views of the shoulder should be obtained. These radiographs should be taken both before and after reduction. In inferior humeral head dislocations, the humeral shaft is parallel to the spine of the scapula, with the humeral head lying inferior to the glenoid (without making contact with the glenoid).[24]

The equipment required depends on the technique used (see Technique), as follows:

• The Stimson technique requires 5- to 10-lb (2.25- to 4.5-kg) weights, weight straps, and sheets or extra straps
• The traction-countertraction technique requires several sheets or wide straps
• The axial (inline) traction technique requires a lengthwise-folded or rolled-up bed sheet
• Scapular manipulation, external rotation, the Milch technique, the Spaso technique, and two-step reduction require no equipment

Anesthesia

Pain control and muscle relaxation may be necessary for reduction of a dislocated shoulder. An experienced provider may be able to perform reduction without anesthesia while causing remarkably little discomfort, but only in select cooperative patients. Various methods may be employed, depending on the patient and the nature of the dislocation.

Anterior dislocation

Pain control options for a patient with an anterior shoulder dislocation include the following:

• Intravenous (IV) procedural sedation and/or analgesia - Commonly used agents include propofol, etomidate, ketamine, fentanyl, and midazolam
• Intra-articular anesthetic (e.g. 1% lidocaine) injection
• US-guided nerve block

Procedural sedation may be necessary in patients who are anxious or uncooperative, those with a high degree of muscle spasm, or those who have undergone unsuccessful attempts at reduction without premedication.[7]

Intra-articular anesthetic injection is performed via the lateral (most common), or posterior injection techniques. The lateral technique is as follows. Under sterile conditions, insert a 35-mm needle (18-20 gauge) or spinal needle 2 cm inferior to the lateral edge of the acromion into the glenohumeral joint. After aspirating any blood present, inject 10-20 mL of 1% lidocaine, with or without epinephrine, over 30 seconds. Then, wait 15-20 minutes before performing the procedure.[7] The injection can also be performed under US guidance.

Reduction of shoulder dislocation: Stimson maneuver.

Potential advantages of intra-articular anesthetic injection include the following[25, 26, 27] :

• Reduced time to relocation and patient relief of symptoms.
• Reduction of the risks of respiratory depression and cardiac compromise
• Drainage of hemarthrosis
• Elimination of the need for IV access
• Shorter emergency department (ED) stay
• Reduced cost

A systematic review (based on five small studies) evaluating intra-articular lidocaine against IV analgesia with or without sedation using benzodiazepines and opiates reported that intra-articular lidocaine may provide comparable rates of successful anterior shoulder reduction with a lower rate of adverse events.[28]

The main potential disadvantage is the risk of infecting the joint space. However, a retrospective review of six randomized controlled trials comparing intra-articular lidocaine injection with procedural sedation found no reported cases of joint infection with the former.[29]

Anesthesiologists routinely perform brachial plexus nerve blocks for shoulder surgery with the aid of nerve stimulators or US guidance.[30, 31] The literature suggests that a US-guided interscalene nerve block of the brachial plexus can be used to provide adequate anesthesia for the reduction of shoulder dislocations.[32, 33]

A prospective randomized study by Blaivas et al found that a US-guided interscalene block not only is feasible in the ED but also can yield a significantly shorter ED stay than procedural sedation.[33]  A linear-array probe was used to identify the brachial plexus in the neck between the anterior and middle scalene muscles on the same side as the dislocated shoulder.[32, 33] The brachial plexus appeared as three anechoic circles when viewed in the short axis. A 20- or 21-gauge 1.5-cm noncutting spinal needle was used to inject 20-30 mL of 1% lidocaine with or without epinephrine or 0.25% bupivacaine. Full loss of sensory and motor function of the arm was achieved in most patients after 15-30 minutes.

Potential advantages of nerve blocks over procedural sedation in this setting include the following:

• Reduced length of ED stay
• No need for hemodynamic monitoring
• Absence of airway or cardiovascular compromise
• Reduced amount of one-on-one health care provider time needed

Potential disadvantages include the following:

• Vascular puncture (though US guidance decreases this risk substantially as a result of direct nerve and needle visualization)
• Horner syndrome
• Hoarseness or diaphragmatic symptoms due to possible involvement of the recurrent laryngeal nerve or the phrenic nerve

Posterior dislocation

Procedural sedation and analgesia are required if there is significant pain or muscle spasm. An experienced practitioner may be able to perform reduction without analgesia or sedation in a cooperative, calm patient when there is minimal muscle spasm.

Inferior dislocation

Adequate analgesia and amelioration of muscle spasm are the keys to successful reduction of an inferior shoulder dislocation. Intra-articular anesthetic injection, which is useful for most humeral head dislocations, can be difficult, if not impossible, in the setting of inferior dislocation, where hyperabduction of the arm alters the position of landmarks used to target needle placement. The use of systemic analgesics, muscle relaxants, or procedural sedation is often necessary to facilitate reduction of inferior dislocations.

The degree of anesthesia should be determined on a case-by-case basis, with the following patient-related factors taken into account:

• Age
• level of anxiety and cooperation
• Time since injury
• History of previous shoulder dislocations
• History of adverse reactions to systemic analgesics, muscle relaxants, or sedatives

In general, younger and more anxious patients, those with no previous history of shoulder dislocations, and those whose injury occurred a significant amount of time before presentation are more likely to require higher levels of analgesia, muscle relaxation, or procedural sedation.

The following non-patient-related factors should also be taken into consideration in the choice of an anesthesia method:

• Operator comfort and experience with the reduction technique
• Resource availability
• Time
• Ancillary support

Reduction techniques can vary in terms of required force, time, equipment, and staff.[7] No single reduction method is successful in every instance; therefore, the clinician should be familiar with several reduction techniques.

Techniques commonly used to reduce anterior shoulder dislocations include the following[34, 35, 36, 37, 38, 39] :

• Stimson maneuver
• Scapular manipulation
• External rotation
• Milch technique
• Spaso technique
• Davos technique
• Traction-countertraction

Posterior shoulder dislocations are typically reduced by means of traction-countertraction.

Techniques commonly used to reduce inferior shoulder dislocations include the following:

• Axial (inline) traction
• Two-step reduction

Adequate pain control and muscle relaxation, in conjunction with smooth atraumatic technique, are the keys to a successful reduction. Slow, consistent movements by the operator prevent pain and associated muscle spasm; quick pulling or release of tension is sure to cause resistance and pain. Most techniques are facilitated by the following two maneuvers:

• Flexion of the elbow 90° to relax the biceps tendon
• External rotation of the humerus, which releases the superior glenohumeral ligament and presents the favorable side of the humeral head to the glenoid fossa

Signs of a successful reduction include the following:

• Palpable or audible clunk
• Return of rounded shoulder contour
• Relief of pain
• Increase in range of motion (eg, the patient can touch the opposite shoulder with the palm of the affected arm)

Before any attempts at reduction, it is essential to explain the procedure, benefits, risks, and complications to the patient or the patient’s representative and to obtain informed consent.

Most neurovascular injuries are caused by the dislocation itself, but they can be induced or exacerbated by attempted reduction. A conscientious neurovascular examination, both before and after reduction, is important for documenting the presence and alteration of these injuries.

For complex dislocations and failed initial attempts, orthopedic consultation in the emergency department (ED) is recommended.

The patient is placed in the prone position on an elevated stretcher. The affected shoulder should be off the edge of the stretcher, hanging downward in 90° of forward flexion. The stretcher should be high enough to allow the patient’s arm to dangle without touching the floor.

To prevent the patient from sliding off the stretcher, he or she is tightly strapped down with a sheet, and 5-10 lb (2.25-4.5 kg) of weight is securely fastened to the wrist of the affected arm to provide continuous traction. If weights are unavailable, two to four 1-L containers of normal saline and a stockinette can be used (see the image below). The patient is instructed to maintain this position for at least 15-20 minutes or until reduction is accomplished.

Reduction of shoulder dislocation: Stimson maneuver.

To facilitate reduction, the physician may apply gentle external rotation of the extended arm, flexion of the elbow 90°, or scapular manipulation (see below).[7, 40]

The advantages of the Stimson maneuver are as follows:

• No assistance is required
• The shoulder is reduced with minimal force (gravity and weights)
• Success rates are high - Scapular manipulation, with proper analgesia, has a success rate of 96% ^[41]

The disadvantages are as follows:

• The patient may slip off the elevated stretcher (a belt or wrap may be placed around the bed to prevent this)
• The patient must be monitored at all times
• Equipment is necessary
• Sufficient premedication may be necessary
• The time required for reduction is relatively long

With the patient prone or seated and the back exposed, the affected arm is placed in 90° of forward flexion at the shoulder, and slight traction is applied.

If the patient is prone, weights are used (as in the Stimson technique; see above), or manual downward traction is applied by an assistant. If the patient is seated, an assistant should stand, facing the patient, and use one arm to firmly grasp the wrist of the dislocated arm. The assistant should then apply steady forward traction parallel to the floor while applying countertraction with the other arm, which is outstretched and resting on the patient’s clavicle (see the image below).

Reduction of shoulder dislocation: scapular manipulation. Sitting position.

The treating physician then stands lateral to the affected shoulder and stabilizes the scapula by placing the palm of one hand on the lateral aspect of the shoulder with the thumb securely on the superior lateral border, then placing the other palm over the inferior tip of the scapula and positioning the thumb on the inferior lateral border of the scapula (see the image below).

Reduction of shoulder dislocation: scapular manipulation. Hand placement.

The physician then uses both hands to rotate the inferior tip of the scapula medially and the superior aspect laterally with slight dorsal displacement. The goal is to move the glenoid fossa back into the correct anatomic position.[7, 40] To facilitate reduction, the assistant may apply, along with traction, slight external rotation of the humerus, elbow flexion in 90°, or both.

The advantages of scapular manipulation are as follows:

• This reduction is tolerated well by patients
• Reduction can be performed without premedication
• Minimal force is required
• Success rates are high - Pishbin et al obtained success rates of 87.5% without medication; this figure rose to 97.3% with the addition of intravenous (IV) midazolam ^[42]

The disadvantages are as follows:

• The borders of the scapula are difficult to locate in obese patients
• Assistance is needed for traction if the patient is prone and weights are unavailable or if the patient is seated

The patient is placed supine on a stretcher. The treating physician adducts the affected arm tightly to the patient’s side with one hand, then, with the other hand, grasps the patient’s wrist, bends the elbow to 90° of flexion, and gently rotates the upper arm externally, using the forearm as a lever, without force or traction (see the video below).

If the patient experiences pain, a short pause should be taken to allow the muscles of the upper arm to relax. After the pain has subsided, rotation continues until the forearm is in the coronal plane. Reduction typically takes place between 70° and 110° of external rotation; sometimes, it takes place during return on internal rotation.[7, 40]

The advantages of external rotation are as follows:

• This reduction is tolerated well by patients ^[43]
• The procedure can be performed by a single operator
• Premedication is not necessary
• The reduction can be done quickly and easily
• No force or traction is necessary

The main disadvantage is a success rate that may be lower than those obtained with other methods. Previously documented success rates were approximately 80%; however, some reports cited first-attempt success rates of 89-90%, mostly without the use of sedation.[43, 44]

The patient may be supine or prone, with the shoulder close to the edge of the stretcher. The affected arm is placed in full abduction overhead, or the patient is instructed to raise the arm laterally and behind the head. The operator may assist abduction gently.

With the patient’s arm in full abduction, the physician gently applies longitudinal traction and external rotation with one arm (see the video below). If reduction is not completed, the physician uses the thumb or fingers to push the humeral head up into the glenoid fossa, with gradual adduction of the extended arm still held in traction.[7, 40]

The advantages of the Milch technique are as follows:

• This reduction is tolerated well by patients
• Procedural sedation is not necessary
• The reduction can be performed by a single operator
• Minimal force is required
• Success rates are in the range of 70-90% ^{[40, 45]}

This technique has no significant disadvantages.

With the patient supine on a stretcher, the physician grasps the affected arm around the wrist or distal forearm and lifts it vertically to the ceiling, applying upward traction and gentle external rotation (see the video below). If the patient experiences pain, the physician should stop and wait until the muscles relax; this may take several minutes. Once the muscles have relaxed, the physician may continue gently. If an audible or palpable clunk is not heard, direct pressure should be applied to the humeral head with the other hand.[7, 40, 46]

An alternative to the standard Spaso technique is the Waldron variation. In this approach, while the elbow is maintained in a flexed position, the physician firmly holds the epicondyles and applies vertical traction on the humerus while moving the forearm through an arc extending from 10° of external rotation to 10° of internal rotation.

The advantages of the Spaso technique are as follows:

• This reduction can be performed by a single operator
• Minimal force is required.
• Published success rates range from 67.6% to 87.5% - Yuen et al demonstrated a success rate of 87.5% with premedication, whereas another study reported a 75% success rate without anesthesia or assistance and no complications ^{[47, 46, 48]}

This technique has no significant disadvantages.

The Davos (Boss-Holzach-Matter) technique, described in 1993 at Davos hospital in Switzerland,[39]  allows for self-reduction in appropriately selected patients, with a high success rate and without the need for sedation. Analgesia is recommended.

The patient is seated with the ipsilateral knee and hip in maximal flexion. The patient clasps his or her fingers below the flexed knee, or, commonly, a wrap such as an elastic bandage is placed around the wrists, also below the flexed knee. The patient's foot can be stabilized by the physician or assistant if available. The patient relaxes the shoulder, scapular, and arm muscles while leaning back and extending the neck slightly, pulling the shoulder into reduction.

The patient is supine on a securely locked stretcher, with the bed elevated to the height of the operator’s ischial tuberosities; this positioning is critical for ensuring smooth application of force. One sheet or strap is placed over the patient’s upper chest, under the axilla of the affected shoulder and underneath the back, so that the two ends of the sheet are of equal length and open to the unaffected side.

Standing on the unaffected side, the assistant takes a firm hold of each end of the sheet with each hand or securely ties the sheet around his or her own waist at the level of the ischial tuberosities. When instructed to start, the assistant leans back to provide countertraction with body weight.[9]

While maintaining the affected arm in 90° of flexion at the elbow, with both hands around the forearm, the physician applies traction by leaning backward with fully extended arms. It is important to use body weight, not upper arm muscles (eg, biceps), to provide traction along the axis of dislocation while the assistant applies countertraction.

Alternatively, to facilitate traction and reduce fatigue, the clinician can wrap another sheet around his or her proximal forearm and tie it around the back, letting the continuous loop sit at the level of the ischial tuberosities (see the images below). The affected extremity is flexed at the elbow and is placed inside the loop. With the elbow maintained in flexion, the clinician steps back to make the sheet taut and then leans back—again, using body weight to apply traction. The operator’s hands thus are free to guide and stabilize the extremity.[9]

Reduction of shoulder dislocation: traction and countertraction.

Reduction of shoulder dislocation: traction and countertraction.

Traction should be applied in a gentle, smooth, firm manner for several minutes, until reduction is attained. Patience is rewarded; yanking, placing the operator’s foot in the patient’s axilla, or other impatient maneuvers will only increase the likelihood of complications. At reduction, the affected arm is usually lengthened and relaxed, with an audible clunk. Slight external rotation may ease reduction.[7]

In a patient with a posterior dislocation, an assistant may apply additional gentle pressure to the humeral head in the posterior[7, 9]  and lateral[9, 49] directions to disengage it from the posterior glenoid. When the head of the humerus disengages, the arm may be externally rotated. However, the operator must exercise extreme caution here because external rotation can cause a fracture of the humerus if the head is not disengaged from the glenoid.[50]

If the joint is stable, the patient may be placed in a sling and swathe; if it is unstable, the patient may be splinted in slight abduction and neutral rotation.[49, 7]

The advantages of the traction-countertraction technique are as follows:

• This traditional method is familiar to most clinicians
• The success rate is high; thus, the procedure is useful in patients with severe muscle spasm or pain and in those who cannot relax

The disadvantages are as follows:

• Procedural sedation is typically required; accordingly, this method usually is not the initial method of choice
• More than one operator is required
• This reduction requires prolonged force and endurance
• Equipment is needed

The patient is placed supine on a sturdy immobile surface (eg, a wheel-locked gurney). The physician, standing on the affected side at the patient’s head,[7]  applies axial traction in line with the abducted arm. To facilitate the procedure, an assistant can apply parallel countertraction by using a sheet wrapped diagonally over the affected shoulder. During the application of axial traction, increasing the degree of abduction (if possible) and applying cephalad pressure to the displaced humeral head can aid in reduction (see the image below).

Reduction of shoulder dislocation: axial traction and countertraction. Axial traction is applied to arm, and parallel countertraction is applied with sheet wrapped over shoulder. Increasing degree of abduction (if possible) and applying cephalad pressure to displaced humeral head (star) can aid in reduction.

After successful reduction of the humeral head, the arm should be fully adducted against the chest wall and supinated and immobilized in that position (see the image below).

Reduction of shoulder dislocation: axial traction and countertraction. After inferior dislocation is reduced, arm is adducted, supinated, and immobilized for postreduction radiography.

In 2006, Nho et al described a two-step method for the reduction of inferior shoulder dislocation (ie, luxatio erecta humeri).[51] In this technique, the inferior dislocation is converted to an anterior dislocation (step 1), which is subsequently reduced (step 2).

The patient is placed supine on a sturdy immobile surface (eg, a wheel-locked gurney). The clinician, standing on the affected side near the patient’s head, places one hand (the hand nearer the patient) on the lateral aspect of the midhumerus and places the other hand on the medial condyle.

Step 1 of the reduction may be divided into two parts. In part 1, the clinician pushes anteriorly with the hand on the midhumerus and pulls posteriorly with the hand on the medial condyle (see the first image below). This motion brings the humeral head to a position anterior to the glenoid (ie, the humeral head is now anteriorly rather than inferiorly dislocated). In part 2, the clinician adducts the arm and moves the hand on the medial condyle to grasp the wrist (see the second image below).

Reduction of shoulder dislocation: two-step reduction. Step 1, part 1. Push anteroinferiorly on midhumerus with hand A while pulling posteriorly on medial condyle with hand B.

Reduction of shoulder dislocation: two-step reduction. Step 1, part 2. After conversion of inferior dislocation to anterior dislocation, adduct arm and grasp patient's wrist.

In step 2 of the two-step reduction, the clinician, while holding the arm in adduction against the chest wall, externally rotates the shoulder by pulling on the wrist (see the image below).

Reduction of shoulder dislocation: two-step reduction. Step 2. Hand A holds patient's arm in adduction while hand B externally rotates arm to reduce now anteriorly dislocated humeral head.

The goals of pharmacotherapy are to reduce morbidity and prevent complications.

Class Summary

Administration of temazepam immediately before a procedure can decrease the risk of tachycardia and hypertension resulting from anxiety regarding the operation. In the operating room, intravenous (IV) administration of a small dose of midazolam before arterial line insertion can also reduce anxiety, tachycardia, and hypertension.

Midazolam

Midazolam is a short-acting benzodiazepine with a rapid onset of action.

Class Summary

Local anesthetics block the initiation and conduction of nerve impulses. Anesthetics used for the procedure include lidocaine.

Lidocaine and epinephrine (Xylocaine MPF with Epinephrine)

Lidocaine is an amide local anesthetic used in 1% concentration. It inhibits depolarization of type C sensory neurons by blocking sodium channels.

Epinephrine prolongs its effect and enhances hemostasis (maximum epinephrine dose, 4.5-7 mg/kg).

Lidocaine anesthetic (Xylocaine, Zingo)

Class Summary

After standard monitoring equipment is attached and peripheral venous access achieved but before the arterial line is inserted, the midazolam dose is administered. Before placement of the arterial line, it should be ensured that a radial artery graft will not be used for coronary artery bypass grafting.

Propofol (Diprivan)

Propofol is a phenolic compound unrelated to other types of anticonvulsants. It has general anesthetic properties when administered intravenously. Intravenous propofol produces rapid hypnosis, usually within 40 seconds. The effects are reversed within 30 minutes following the discontinuation of infusion. Propofol has also been shown to have anticonvulsant properties.

Etomidate (Amidate)

Amidate is a nonbarbiturate imidazole compound with sedative properties. It is short acting and has a rapid onset of action; the duration of action is dose dependent (15-30 min). Its most useful feature as an induction agent is that it produces deep sedation while causing minimal cardiovascular effects.

The major application of etomidate is induction for endotracheal intubation, particularly in patients with, or at risk for, hemodynamic compromise. Etomidate has been shown to depress adrenal cortical function; however, this effect is not significant clinically during short-term administration. Since the drug is mixed in propylene glycol, continuous infusion is not recommended.

Class Summary

Analgesics ensure patient comfort, promote pulmonary toilet, and have sedating properties that are beneficial for patients who experience pain.

Fentanyl citrate (Duragesic, Abstral, Actiq, Fentora, Onsolis)

Fentanyl citrate is a synthetic opioid that has 75-200 times more potency and a much shorter half-life than morphine sulfate. It has fewer hypotensive effects than morphine and is safer in patients with hyperactive airway disease because of minimal or no associated histamine release. By itself, fentanyl citrate causes little cardiovascular compromise, although the addition of benzodiazepines or other sedatives may result in decreased cardiac output and blood pressure.

Fentanyl citrate is highly lipophilic and protein-bound. Prolonged exposure to it leads to accumulation of the drug in fat and delays the weaning process.

Morphine sulfate (Duramorph, Astramorph, MS Contin, Avinza, Kadian)

Morphine sulfate has reliable and predictable effects, safety profile, and ease of reversibility with naloxone.

Various intravenous doses are used; it is commonly titrated until the desired effect is obtained.

Hydromorphone (Dilaudid, Dilaudid-HP, Exalgo)

Ketamine (Ketalar)