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Management of Common Dislocations
Joint dislocations are frequently encountered in patients seen in the emergency department (ED). They can range from a simple finger joint dislocation to limb- or life-threatening consequences of high-energy trauma. Keys to clinical assessment and radiographic evaluation of these injuries are discussed along with methods of reduction. The emphasis of the chapter is on simple dislocations that should be diagnosed and initially managed in the ED ( to ). Fracture-dislocations that commonly require operative intervention and emergency orthopedic consultation are not discussed.
Preparation of the Patient
Although many authors claim that their reduction method is well tolerated without premedication, they have not usually measured the discomfort of their patients quantitatively. There are no rigid, generally accepted guidelines for the use of pharmacologic adjuncts in the management of dislocations. Each patient and each dislocation is unique, and the treating clinician must use judgment regarding whether premedication is required, which agent or agents to use, and what dose to give. In general, the authors suggest the routine judicious use of analgesia with or without sedation for the majority of reductions performed in the ED. A calm, cooperative patient may tolerate attempts at gentle reduction of a major joint such as the shoulder, but even the most stoic of patients may be quite uncomfortable with the manipulations necessary for reduction of a dislocated finger. A radial head dislocation in a child is usually easily treated without analgesia; however, reduction of a hip dislocation is unlikely to be successful without a significant amount of sedation and analgesia. Attempting any reduction technique in an extremely anxious patient without premedication will generally frustrate the operator and further upset the patient and may hinder a successful outcome. When multiple attempts are required and significant force must be exerted because of muscle spasm or an uncooperative patient, there is an additional chance of producing complications during the reduction.
Verbal techniques for alleviating anxiety and discomfort are not to be discounted because they can be of great assistance during joint reduction. In field settings, simple hypnosis techniques have been used successfully for major joint dislocations. In the ED, verbal reassurance and distracting conversation are useful adjuncts. Additionally, the use of handheld tablets has shown to aide a variety of painful procedures in the pediatric population and may be a useful adjunct.
In most circumstances, analgesia or sedation of some sort, or both, will be required; the intravenous (IV) route of drug administration is usually the method of choice because it allows rapid relief of patient discomfort and facilitates repetitive dosing for titration to the desired effect (see Chapter 33 ). Alternatives to procedural sedation and analgesia include intraarticular injection of local anesthetics, hematoma blocks, peripheral nerve blocks, and regional anesthesia (see Chapter 29, Chapter 31, Chapter 32 ).
General Principles
Clinical assessment of a patient with a dislocation must include a search for fractures or other serious injuries, especially if the mechanism involved high energy. This is most important for hip, knee, and posterior sternoclavicular dislocations. For all dislocations, perform a detailed neurovascular examination of the extremity before focusing attention on the injured joint.
Although many dislocations are clinically obvious, some may escape detection for some time as other injuries or issues dominate the clinical picture. A knee dislocation may be quite obvious in a 170-lb man who displays a deformity of the knee, but in a 400-lb patient, the knee may look deceivingly normal on first glance. The history and mechanism of injury can be quite helpful in certain circumstances. For example, a painful shoulder joint in a seizure patient should prompt assessment for a posterior shoulder dislocation, whereas a history of the knee striking the dashboard is a clue to a potential hip dislocation.
Some dislocations can be difficult to identify on plain radiographs. One should keep a high index of suspicion for dislocation when indicated. Carpal dislocations in the wrist may be subtle, but are clinically suggested by severe pain and swelling. Similarly, superior dislocation of the patella may be mistaken for high riding patella typical of patellar tendon rupture. Unlike anterior shoulder dislocations, which are often easily detected on plain films, posterior shoulder dislocations may be missed on initial radiographs.
Some dislocations will have been reduced before clinician assessment. A careful history will uncover these injuries and prompt the necessary assessment of the ligamentous integrity and the possibility of an associated vascular injury and guide proper immobilization and follow-up care. A dislocated and then spontaneously reduced knee is a severe injury that often escapes detection by even a seasoned clinician's initial evaluation. Other dislocations that are commonly first seen in a reduced state include finger dislocations, patellar dislocations, and radial head subluxations.
Although the chance that a gentle attempt at reduction will cause a fracture or neurovascular injury is extremely low, careful evaluation before and after reduction, as well as documentation of the patient's neurovascular status, is important. Frequently, the initial pain of the dislocation is distracting, and paresthesias or a weak pulse may not be readily apparent until the joint has been reduced. When the integrity of the pulse is in question, blood pressure at the wrist or foot may be compared with that in the uninjured extremity, or a pulse oximeter may be applied to the distal end of the fingers ( Fig. 49.1 ).
Pre-reduction radiographs are generally recommended. Reasons include difficulty distinguishing a fracture-dislocation by clinical examination and the potential for medicolegal problems if the fracture is not identified before attempts at reduction. More importantly, certain associated fractures predict a poor outcome with closed reduction and make orthopedic consultation a consideration before such attempts. Exceptions to this rule include suspected radial head subluxation in young children and clinical circumstances in which radiographs are not readily available (e.g., in the wilderness). Clinical conditions (i.e., vascular compromise or threatened skin penetration) may dictate the need for immediate reduction without radiographs; however, the few minutes required for initial radiographic evaluation rarely increases vascular or neurologic complications and provides very useful information to the consultant.
Some authors question the need for pre-reduction films in certain patients with obvious or recurrent anterior shoulder dislocation. Although post-reduction radiographs are traditionally obtained, the need for this in a clinically obvious successful shoulder joint relocation has been questioned. The authors suggest that post-reduction films be taken in virtually all patients who have had a dislocation reduced in the ED. Patients who have received sedatives and opioids may not remember the actual successful reduction or the immediate post-reduction period. Re-injury after release from the ED without radiographic corroboration of a successful reduction can raise questions about the adequacy of the initial procedure. Occasionally, a fracture is detected on post-reduction radiographs that was not obvious on the initial films, or a previously noted minor fracture may be found to reside in an intraarticular location. Point of care ultrasound is being used more frequently by emergency medicine physicians for musculoskeletal complaints. A growing body of research is revealing the safety and efficiency of using this modality for diagnosing dislocations and confirming successful reduction and will be discussed later in this chapter. As practitioners gain confidence and experience with ultrasound in this capacity, the need for both pre- and post-reduction radiographs may be supplanted by the performance of ultrasound.
In general, dislocations of all types are less common in children than in adults because of the relative weakness of the epiphyseal growth plate with respect to the ligamentous support of the joint. Therefore, in children the epiphysis will tend to fracture before dislocation occurs, except in the case of radial head dislocation (nursemaid's elbow). Reduction techniques for pediatric dislocations are generally similar to those used for adults.
The proper terminology for dislocations describes the relationship of the distal (or displaced) segment relative to the proximal bone or the normal anatomic structure. The terms anterior and posterior are used for most dislocations. Therefore, if the head of the humerus lies anterior to the glenoid fossa, the injury is an anterior shoulder dislocation. Similarly, if the olecranon lies behind the distal end of the humerus, the injury is a posterior elbow dislocation. In the hand, wrist, and foot, one uses the terms dorsal and volar . Palmar and plantar are sometimes used in place of volar to describe the position of the dislocated part. Dislocations can be open or closed and may have associated fractures, which require a separate description.
It is generally accepted that the sooner a dislocation is reduced, the better. This alleviates the patient's discomfort and corrects distortion of the surrounding soft tissues. In some studies the success rate of reduction is higher when attempted closer to the time of injury. However, there is no reason to forego an attempt at closed reduction of an “old injury” in the vast majority of dislocations. Although chronic dislocations persisting several days, weeks, or longer are often difficult to reduce in a closed manner, such cases are infrequent and should not deter the physician from attempting closed reduction.
A certain percentage of all types of dislocations are not amenable to closed reduction. Inability to complete a closed reduction is generally the result of interposition of soft tissue structures or fracture fragments and not necessarily due to improper technique. If sedation and analgesia are adequate to permit relaxation of the patient's muscle tone, reduction should be relatively straightforward. When reduction under adequate sedation and analgesia is unsuccessful after several attempts, further attempts at closed reduction are inappropriate. Generally, orthopedic consultation should be obtained after two or three failed attempts.
Once an attempt at reduction is completed, recheck the neurovascular status that was documented before the reduction was performed. For the elbow, hand, and forefoot joints, perform passive range of motion to assess the stability of the reduction and to ensure a smoothly gliding joint that is free of intraarticular obstruction. For the shoulder, one must be cautious after reduction as full passive range of motion may cause repeated dislocation. Testing the ability to place the palm of the ipsilateral hand on the contralateral shoulder can safely assess successful range of motion and confirmation of reduction. In addition to close monitoring of the medicated patient, proper aftercare involves adequate immobilization of the injured joint for comfort and to prevent repeated dislocation. Recommendations for follow-up care depend on the injury and its severity.
Timing of Reduction
Questions often arise concerning the necessity of immediate versus delayed reduction, with the clinician fearing disastrous neurovascular consequences if a dislocation is not manipulated immediately on arrival at the ED. In reality, there is rarely an instance in which pre-reduction radiographs, even portable films, cannot be obtained before treatment. Even if the pulse is weak or the fingers are numb, a few minutes' delay is usually acceptable to gain important radiographic information on the type of dislocation and the presence of an associated fracture and to provide documentation for follow-up clinicians. Important clinical information may be difficult to obtain, or the specific initial injury may be impossible to reconstruct once the joint has been reduced ( Fig. 49.2 ). Of equal importance, a dislocation with concomitant neurovascular injury should be reduced with the least amount of trauma possible, which often requires a few minutes for induction of analgesia and sedation, a time during which radiographs can be obtained. If a vascular or neurologic abnormality is documented before reduction, the joint should be reduced by the timeliest and least traumatic procedure available. Each case should be handled individually by taking the specific injury, available resources, and the clinician's experience into account. Although multiple unsuccessful or forceful attempts at reduction in the ED should be avoided with all dislocations, this is especially important in patients with vascular or neurologic compromise. Occasionally, the more prudent course is reduction under general anesthesia, but this decision must take into consideration the availability of consultation and other resources.
The remainder of this chapter covers dislocations of the various joints with the exception of carpal (wrist) dislocations, which are complex and require orthopedic consultation, and temporomandibular joint dislocations, which are discussed in Chapter 63 .
Shoulder Dislocations
The human shoulder joint is remarkable for its degrees of motion. The glenohumeral joint has the greatest range of motion of any joint in the body, largely because of the loose joint capsule and the shallow nature of the glenoid fossa. However, these anatomic features that allow for great mobility contribute to its instability, making it the most frequently encountered large joint dislocation. Posterior dislocation is uncommon, mainly because of the anatomic support of the scapula and the thick muscular support in this area. Anterior support is less pronounced, with the inferior glenohumeral ligament serving as the primary restraint to anterior dislocation. The depth of the glenoid fossa is somewhat increased by the fibrocartilaginous glenoid labrum, which forms the rim of this structure.
Most shoulder dislocations are anterior (i.e., the humeral head becomes situated in front of the glenoid fossa). Posterior dislocations are the next most common, but they generally account for less than 4% of shoulder dislocations. Less common variations include inferior (luxatio erecta), superior, and intrathoracic dislocations.
Anterior Shoulder Dislocations
As stated earlier, shoulder dislocations are the most common major joint dislocation encountered and reduced in the ED, with anterior dislocations comprising the vast majority. The usual mechanism of injury is indirect and consists of a combination of abduction, extension, and external rotation. Only rarely is the mechanism a direct blow to the posterior aspect of the shoulder. Occasionally, especially with recurrent dislocations, the mechanism is surprisingly minor and can be puzzling to the clinician. An anterior dislocation can be induced by mere external rotation of the shoulder while rolling over in bed or reaching behind oneself for the seat belt. When the first dislocation occurs at a younger age, the recurrence rate is higher. If the first dislocation occurs before 20 years of age, there is an 80% to 92% rate of recurrence. If the first dislocation takes place after 40 years of age, the rate of recurrence is 10% to 15%. Rotator cuff injuries, however, occur more frequently in older patients with anterior shoulder dislocations.
The four types of anterior dislocations are classified according to where the humeral head comes to rest. Subcoracoid dislocations account for more than 75% of anterior dislocations. The other anterior shoulder dislocations include subglenoid dislocation and the uncommon subclavicular and intrathoracic dislocations ( Fig. 49.3 ).
Clinical Assessment
The presence of an anterior shoulder dislocation is usually obvious ( Fig. 49.4 ). A posterior dislocation is more subtle in terms of both clinical and radiographic findings. It can be misdiagnosed as a severe contusion ( Table 49.1 ). A patient with an anterior shoulder dislocation supports the injured extremity and leans toward the injured side while holding the arm in abduction and slight external rotation. The patient cannot adduct or internally rotate the shoulder. Visual inspection reveals loss of the rounded appearance of the shoulder because of absence of the humeral head beneath the deltoid region. The acromion is prominent and an abrupt drop-off below the acromion can be seen or palpated. An anterior fullness in the subclavicular region is visible in thinner individuals and is easily palpable in most others. Comparison with the uninjured side is a useful aid for both visual examination and palpation. Any attempt at internal rotation is quite painful and resisted by the patient. An inability to place the palm from the injured extremity on the uninjured shoulder is consistent with an anterior shoulder dislocation; after reduction, this maneuver should be possible.
TABLE 49.1
Comparison of Anterior and Posterior Shoulder Dislocations: Classified According to Displacement of the Humeral Head
| TYPE OF DISLOCATION | FEATURES | OTHER CLINICAL CLUES | RADIOGRAPHS |
|---|---|---|---|
| Anterior 99% subcoracoid and subglenoid Humeral head anterior to the glenoid |
Arm held in abduction and slight external rotation (abduction more prominent with subglenoid dislocation) The patient cannot adduct or internally rotate the shoulder |
Seen from the front, the shoulder appears “squared off” Distal acromion prominent on a side view |
On AP view : obvious dislocation On lateral or “Y” view : humeral head appears anterior to the glenoid fossa |
| Posterior 95% subacromial 5% subglenoid and subspinous Humeral head posterior to the glenoid |
Arm held in the sling position with adduction and internal rotation Attempts at abduction and external rotation cause extreme pain |
Coracoid process prominent, glenoid fossa empty anteriorly, and humeral head bulging posteriorly | On AP view : vacant glenoid sign, 6-mm sign, light bulb sign On lateral or “Y” view : humeral head appears posterior to the glenoid fossa |
AP, Anteroposterior.
Careful assessment of the neurovascular status of the affected extremity is essential ( Figs. 49.5 and 49.6 ). Injury to the axillary artery is rare. It usually occurs in the elderly and can be quickly assessed by a decreased or absent radial pulse or by the appearance of an expanding hematoma. It is important to evaluate the status of the axillary nerve because this is the most common nerve injury resulting from anterior dislocations. Assess the sensory component of the axillary nerve by testing for sensation over the lateral aspect of the upper part of the arm in the “regimental badge” area over the deltoid muscle. Testing the motor component of the axillary nerve is a difficult undertaking in a patient with a dislocated shoulder, as it requires activation of the deltoid muscle. Less commonly, the brachial plexus may be injured by a stretch injury and produce variable nerve deficits. Perform a complete assessment of all the major nerves to the arm because other nerve injuries may occur, such as injuries to the ulnar and radial nerves. A neurologic deficit does not preclude closed reduction, but in patients with a nerve injury, avoid multiple forceful attempts at reduction.
Brachial plexus injuries require an especially atraumatic reduction. If generous sedation and analgesia do not permit easy reduction in the ED, reduction of a dislocation with a nerve injury may be more prudently performed in the operating room with the patient under general anesthesia. Nerve injuries in this setting generally have a good prognosis, but the patient should be informed of the findings and the need for follow-up. The symptoms may require many months to resolve.
Vascular injuries, such as axillary artery disruption, are rare but usually quite obvious because of dysaesthesias and coolness of the involved arm. An expanding axillary hematoma, pulse deficit, peripheral cyanosis, and pallor can be seen. Collateral circulation may produce a faint pulse in the extremity, so comparison with blood pressure on the uninjured side may be helpful. Specific lesions include complete disruption, linear tears, and thrombosis. Axillary artery injuries can occur at all ages, but they are more common in the elderly. The artery is particularly at risk with anterior dislocations, and dislocation with spontaneous reduction can produce the injury. Arteriography with surgical repair of the artery is required, occasionally with fasciotomy of the forearm if the ischemia is long-standing.
In many shoulder dislocations, some portion of the rotator cuff will be injured. Rotator cuff tears are easier to evaluate after reduction, when the pain and swelling have subsided.
Radiologic Examination
Associated fractures are detected in 15% to 35% of anterior shoulder dislocations, with fractures of the greater tuberosity being the most common. The presence of a fracture of the greater tuberosity does not change the initial management of anterior shoulder dislocations, and these fractures usually heal well after closed reduction in routine fashion. The Hill-Sachs deformity, a sign of repeated dislocations, produces a groove in the posterolateral aspect of the humeral head and may be seen on pre-reduction or post-reduction films ( Fig. 49.7 ). The Hill-Sachs deformity is caused by impaction of the humeral head against the glenoid rim after dislocation. It rarely has any clinical significance but may result in a loose body within the joint. Impaction of the humeral head against the glenoid during dislocation may also cause disruption of the anteroinferior portion of the cartilaginous labrum of the glenoid or the inferior aspect of the bony glenoid, an injury known as a Bankart lesion . It has been implicated as one source of recurrent dislocations but does not affect immediate ED management.
Fractures of the humeral neck are frequently displaced with attempts at closed reduction, which can lead to avascular necrosis of the humeral head. The fact that humeral neck fractures are a known complication of shoulder relocation supports the value of pre-reduction radiographs of anterior shoulder dislocations. However, some argue that clinically obvious recurrent dislocations and first-time anterior dislocations without a blunt traumatic mechanism (information usually offered by the patient) can be reduced without prior radiographs because fracture is quite unlikely in these situations. Hendey and coworkers performed a prospective validation study of an algorithm for selective radiography that incorporated the mechanism of injury, previous dislocations, and the clinician's certainty of joint position. In this study, 24 patients with recurrent atraumatic anterior shoulder dislocations who received neither pre-reduction nor post-reduction radiographs had no clinically significant fractures found on follow-up. These patients had much shorter ED lengths of stay than did patients who received only pre-reduction or post-reduction films, or both.
One retrospective case-control study found that the presence of any of three risk factors (age >40 years, first episode of dislocation, traumatic mechanism of injury defined as a fall greater than one flight of stairs, a fight or assault, or a motor vehicle collision) predicted clinically important fractures with a sensitivity of 97.7%. However, in a prospective study by Atef and colleagues, associated injuries were found in 60% of patients with anterior shoulder dislocation, a much higher frequency than previously thought; most commonly noted was a rotator cuff tear but the injuries ranged from axillary nerve injury to greater tuberosity fracture.
Anterior dislocations are not subtle on routine anteroposterior (AP) radiographs, and this view detects the most important fracture to identify, that of the humeral neck ( Fig. 49.8 ). An adequate AP view, when combined with the typical clinical examination, allows successful detection of most anterior shoulder dislocations. A true AP view of the shoulder is taken at a right angle to the scapula and requires rotation of the patient to 30 to 45 degrees.
The typical lateral views obtained include a scapular Y view (see Fig. 49.8 ), a transthoracic view, and an axillary view. These views rarely add to the AP film in patients with an obvious anterior dislocation, but they are of value in posterior dislocations ( Fig. 49.9 ). The usefulness of additional views for anterior shoulder dislocations is primarily to detect fractures, and the previously mentioned lateral views (especially the transthoracic view) are quite limited in this respect. The apical oblique view has been found to be more valuable than the oblique scapular projection for acute shoulder trauma. This view is obtained by angling the beam 45 degrees caudad with the patient in a 45-degree oblique position ( Fig. 49.10 ).
Post-reduction radiographs are obtained to document the success of the reduction. Occasionally, they will reveal a fracture not detected on pre-reduction radiographs. In one series, 8% of patients with anterior shoulder dislocations had Hill-Sachs deformities noted only on post-reduction films. A more recent prospective observational study (2007) found 37.5% of detected fractures associated with anterior shoulder dislocation were only seen on post-reduction radiographs; none however changed clinical management.
Recent advances in the use of point-of-care ultrasound by emergency physicians have resulted in its growing use for diagnosis and confirmation of successful reduction of shoulder dislocations and for administration of local anesthetic to facilitate closed reduction. A study by Abbasi and colleagues found that ultrasound had identical results as plain radiographs for both the detection of shoulder dislocation as well as complete reduction, with a sensitivity of 100%. Whereas further validation studies, as well as studies to determine the ability of ultrasound to recognize associated fractures, still need to be performed, we expect ultrasound to continue to become an ever-increasingly useful tool in the treatment of shoulder dislocations. One disadvantage of using only ultrasound diagnosis is difficulty in maintaining a permanent record of a successful reduction.
Reduction Techniques
Hippocrates (450 bc ) is generally credited with the first detailed description of reduction techniques, and it is believed that a drawing in the tomb of Upuy (1200 bc ) is the earliest depiction of such a method. The Hippocratic technique involves placement of the operator's foot in the axilla to allow countertraction. This technique is problematic and not recommended by some authors. Likewise, the Kocher method, which involves forceful leverage of the humerus, is associated with an increased rate of complications and is generally discouraged in favor of other techniques.
This section discusses several methods of reduction that are well studied, proven to be safe, and easy to master. Regardless of the reduction technique used, gradual, gentle application of the technique is essential. Although all the techniques discussed are generally acceptable and many authors state that their techniques are quite painless, few studies have quantified the actual pain reported by patients. As noted previously, intraarticular lidocaine may also be used to reduce the pain accompanying reduction ( Fig. 49.11 ). In studies by Matthews and Roberts and Kosnick and colleagues, intraarticular injection of lidocaine was found to offer significant relief of pain during reduction of anterior shoulder dislocations. In addition, a 2014 meta-analysis showed that intraarticular lidocaine had similar success rates as procedural sedation and led to decreased length of stay and complication rates, thus making it a useful alternative to procedural sedation and analgesia. A previous prospective study and Cochrane review reported similar results. Ultrasound may be used to assist intraarticular lidocaine injection in both adults and pediatric patients. When using intraarticular lidocaine, any blood present should be aspirated from the glenohumeral joint before injecting the anesthetic. Note that 10 to 20 mL of 1% lidocaine has been used with the intraarticular technique and that it may take as long as 15 to 20 minutes for adequate analgesia.
The use of regional nerve blocks (suprascapular and scalene) under ultrasound guidance have also been used to provide analgesia for closed reduction of anterior shoulder dislocations. Studies have demonstrated similar analgesia and reduction success rates when compared to procedural sedation, but with significantly less one-on-one practitioner time and a lower ED length of stay (see Chapter 31 ).
It is important to note that neither local nor regional anesthesia produces muscle relaxation, but they may obviate the need for IV access and prolonged observation. Operator judgment is an important part of the decision as to whether reduction should be attempted without premedication. Advantages of such an approach include avoidance of potential complications from drug therapy, reduced staff requirements, and theoretically, more rapid patient disposition. Certainly, a patient who is markedly intoxicated may require little, if any supplemental sedative therapy. However, all patients who are reluctant or too anxious to cooperate with an attempt at reduction without medication and those with a high degree of muscle spasm should receive premedication. Generally, only one attempt is made; if unsuccessful, further attempts at reduction are made after the IV administration of sedatives. When in doubt, it is best to use pharmacologic adjuncts (see Chapter 33 ).
Several factors will help in deciding which reduction technique is best in each clinical situation. Do not use forceful techniques such as traction-countertraction in patients who are not being sedated. The clinician's comfort level with a given technique is always a factor as the greatest success rates will probably result from techniques with which the clinician is most familiar. The time and resources available to the clinician must also be considered because methods such as the Stimson maneuver require more time and the availability of weights and straps. In addition, certain reduction techniques can be performed without assistance, whereas others require an additional person to apply countertraction or to help with manipulation of the scapula or humeral head. Ideally, the emergency clinician should become familiar with a number of different techniques for reducing anterior shoulder dislocations because no single method has a 100% success rate nor is any technique ideal in every situation.
Stimson Maneuver ( Fig. 49.12A )
The Stimson maneuver is a classic technique that offers the advantage of not requiring an assistant. Place the patient prone on an elevated stretcher and suspend approximately 2.5 to 5.0 kg (5 to 10 lb) of weight from the wrist. The weights can be strapped to the wrist, or a commercially available Velcro wrist splint can be placed and the weights hung from the strap with a hook. The slow, steady traction produced with this method often permits reduction, but 20 to 30 minutes may be required. If needed, facilitate reduction by externally rotating the extended arm.
Variations of this method include the recommendation for flexion of the elbow to further relax the biceps tendon and the application of manual traction instead of weights. Rollinson allowed the arm to hang under its own weight after a supraclavicular block and reported a 91% success rate with usually no more than a gentle pull on the arm after 20 minutes in this position. Each variation of the Stimson method can be used in combination with the scapular manipulation technique described later. Indeed, a success rate of 96% has been reported with the combined prone position, hanging weights, IV analgesia and sedation, and scapular manipulation.
Disadvantages of the Stimson method include the time required to achieve reduction and possible dangers to the patient associated with the positioning required for this technique. There is a potential danger of patients slipping off the elevated bed. A “seat belt” strap or bedsheet may be placed around the patient and stretcher to avoid movement of the patient off the stretcher. Airway access to a patient in the prone position may be more difficult in the setting of an overly intoxicated patient or one who becomes overly sedated. Logistically, the Stimson method may be difficult. One must have a bed that elevates to a suitable height for length of the patient's arm and a convenient method to hang the weights. Sometimes locating the weights themselves can be challenging in a busy ED.
Scapular Manipulation Technique (See Fig. 49.12B )
This method is popular because of its ease of performance, reported safety, and acceptability to patients. To date, no complications from the scapular manipulation technique have been reported in the literature. Shoulder reduction via this method focuses on repositioning the glenoid fossa rather than the humeral head, and less force is required than with many other methods. Its success rate is high, generally greater than 90% in experienced hands. Some studies report higher success rates in patients who have had repeated dislocations and lower rates in patients with an associated greater tuberosity fracture. The initial maneuver for scapular manipulation is traction on the arm as it is held in 90 degrees of forward flexion. This may be performed with the patient prone and the arm hanging down, as described for the Stimson method, with or without flexion of the elbow to 90 degrees. Alternatively, this traction may be applied by placing an outstretched arm over the seated patient's midclavicular region while pulling the injured extremity with the other arm. Regardless of the means of arm traction, slight external rotation of the humerus may facilitate reduction by releasing the superior glenohumeral ligament and presenting a favorable profile of the humeral head to the glenoid fossa.
The prone patient position is recommended for those not familiar with the technique because it facilitates identification of the scapula for manipulation (medial rotation of the tip). Nonetheless, the technique can be performed with the patient supine given that the patient's shoulder is flexed to 90 degrees and the scapula is exposed during gentle upward traction on the humerus. Although seated scapular manipulation offers the advantage of not requiring the patient to go through the awkward and potentially uncomfortable assumption of the prone position, it is a technically more difficult variation of scapular manipulation, especially if sedation is going to be necessary. When using the prone position, place the injured shoulder over the edge of the bed to allow the arm to hang perpendicular for the application of traction (see Fig. 49.12 A ) .
After the application of traction, manipulate the scapula to complete the reduction. Anderson and associates recommended manipulation of the scapula after the patient's arm is relaxed; however, success is possible with no delay in performing this second step. Manipulate the scapula by stabilizing the superior aspect of the scapula with one hand and pushing the inferior tip of the scapula medially toward the spine. Place the thumb of the hand stabilizing the superior aspect of the scapula along the lateral border of the scapula to assist the pressure applied by the thumb of the other hand. A small degree of dorsal displacement of the scapular tip is recommended as it is being pushed as far as possible in the medial direction.
When the patient is properly positioned with the affected arm hanging perpendicularly, the lateral border of the scapula may be difficult to find in larger patients. This border is generally located quite laterally with the patient in this position, and it must be properly located before any attempt at reduction. The reduction itself is occasionally so subtle that it may be missed by both the patient and operator. A minor shift of the arm may be the only clue that reduction has been successful. Careful palpation of the subclavicular area to locate the position of the humeral head before repositioning the patient may be used to determine the success of the reduction.
Best of Both (BOB) Technique (See Fig. 49.12C )
A variation of the seated scapular manipulation technique is the “best of both” (BOB) maneuver. To perform the BOB maneuver, position the patient seated sideways on the stretcher with the unaffected shoulder and hip against the fully elevated head of the stretcher. Stand on the foot end of the gurney at the patient's affected side and use one hand to apply downward force on the proximal end of the patient's bent forearm. Use the other hand to grasp the patient's hand and gently rotate the arm internally or externally as needed. Once downward force is being applied, ask an assistant to perform the scapular manipulation maneuver described earlier.
External Rotation Method (See Fig. 49.12D )
This method offers the advantage of requiring only one person and no special equipment. The technique needs no strength or endurance on the part of the operator and is well tolerated by patients. The actual pain experienced by patients with this technique has not been quantified, but Plummer and Clinton stated that it can be performed with “little, if any sedation.” In this technique, the basic maneuver is slow, gentle external rotation of the fully adducted arm. In 1957, Parvin described a self-reduction external rotation technique in which the patient sits on a swivel-type chair and grasps a fixed post positioned waist high and slowly turns the body to enact external rotation. Parvin reported that the reduction usually takes place at 70 to 110 degrees of external rotation.
Since Parvin's initial study, this method has been described with the patient supine and the affected arm adducted tightly to the patient's side. Flex the elbow to 90 degrees and hold it in the adducted position with the operator's hand closest to the patient. Use the other hand to hold the patient's wrist and guide the arm into slow and gentle external rotation. The procedure may require several minutes because each time the patient experiences pain, the procedure is halted momentarily. Although the report of Mirick and coworkers mentioned using the forearm as “a lever,” a later description clearly recommends allowing the forearm to “fall” under its own weight. No additional force should be applied to the forearm, and no traction is exerted on the arm.
The end point of the reduction may be difficult to identify because reduction is frequently very subtle. It is therefore recommended that external rotation be continued until the forearm is near the coronal plane (lying on the bed, perpendicular to the body), a process that usually takes 5 to 10 minutes. If the patient's dislocation persists after full external rotation, apply steady gentle traction at the elbow. Reduction may occasionally be noted when the arm is rotated back internally. The success rate of this technique in three series performed by emergency clinicians was approximately 80%.
Milch Technique (See Fig. 49.12E )
Proponents of this method praise its gentle nature, high success rate, lack of complications, and tolerance by patients. It can be described as “reaching up to pull an apple from a tree.” The basic steps of this technique are abduction, external rotation, and gentle traction of the affected arm. Finally, if needed, the humeral head can be pushed into the glenoid fossa with the thumb or fingers.
In describing this technique, Milch wrote that the fully abducted arm was in a natural position in which there was little tension on the muscles of the shoulder girdle. He postulated that this was related to our ancestral “arboreal brachiation” (swinging from trees). The primary step in this technique is to abduct the affected arm to an overhead position. Russell and colleagues had their patients raise their arm and put their hand behind their head as a first step. Although this seems odd, patients can usually do this quite readily with little assistance and be quite comfortable in this position. Alternatively, abduct the arm by grasping the patient's elbow or the wrist. Lacey and Crawford found that the prone position, with the patient's shoulder close to the end of the bed, facilitated this step.
Once the arm is fully abducted, apply gentle longitudinal traction with slight external rotation. If reduction does not occur quickly, push the humeral head upward into the glenoid fossa with the thumb or fingers of the other hand. Beattie and associates reported a success rate of 70% with the Milch technique, but others have achieved success rates of 90% or greater. In a comparison study of external rotation and the Milch technique for reduction of anterior shoulder dislocations without sedation, success rates were equivalent but external rotation was noted to be easier and less painful for the patient.
Traction-Countertraction (See Fig. 49.12F )
This method is commonly used in the ED, largely because of tradition, clinician comfort, and a high success rate. Clinician familiarity is an advantage of this technique, but it requires more than one operator, some degree of force, and occasionally, endurance. This technique is usually quite uncomfortable for the patient, and premedication is recommended before any attempt. In a 2014 comparison study of traction-countertraction versus modified scapular manipulation, modified scapular manipulation was better tolerated by patients and had a better success rate on first attempt; traction-countertraction was more successful on second attempt.
With the patient supine, wrap a sheet or strap around the upper part of the patient's chest and under the axilla of the affected shoulder. Ask an assistant to hold the sheet, preferably by wrapping it around the assistant's waist to take advantage of body weight rather than arm strength to apply the countertraction. Traction may then be applied onto the extended arm by the clinician, but this generally results in operator fatigue, especially if the operator relies on biceps strength to provide continuous traction. Instead, flex the elbow of the affected side to 90 degrees and wrap a sheet or strap around the proximal part of the forearm and then around the operator's waist. Elevate the bed to the point at which the sheet can sit at the level of the operator's ischial tuberosities. This allows the operator to comfortably lean back and use body weight to supply the force of traction, thereby reducing the possibility of operator fatigue. The portion of the sheet that is positioned on the patient's forearm has a tendency to ride up; flexion of the elbow beyond 90 degrees will minimize this problem. Alternatively, the operator merely leans backward with the arms fully extended, again using the continuous weight of the body rather than the strength of the biceps to provide constant traction.
Once traction has been applied, the operator must be patient because the procedure may take a number of minutes to be successful. The premedication is probably inadequate if the patient resists the procedure or is notably uncomfortable during attempts at reduction. Do not hesitate to order supplementary medications. Gentle, limited external rotation is sometimes useful to complete the reduction. Applying traction to an arm that is slightly abducted from the patient's body is often successful, but some operators prefer to slowly bring the arm medial to the patient's midline while maintaining traction or to have an assistant apply a gentle lateral force to the midhumerus to direct the humeral head laterally. Successful reduction is usually presaged by slight lengthening of the arm as relaxation occurs, and a noticeable “clunk” may occur at the point of reduction. A brief wave of fasciculations in the deltoid may also be seen at the time of reduction.
Spaso Technique (See Fig. 49.12G )
This technique was first reported by Spaso Miljesic as a simple, single-operator technique requiring minimal force. One published series reported an 87.5% success rate in premedicated patients when performed by junior house officers. A 2015 study comparing the Spaso technique to external rotation found both to be equally efficacious, however the Spaso technique was faster, more efficient, and more easily performed. Place the patient in the supine position and grasp the affected arm around the wrist or distal end of the forearm. Gently lift the affected arm vertically toward the ceiling and apply gentle vertical traction. While maintaining traction continuously, externally rotate the arm. Reduction may be subtle but is generally signaled by hearing or feeling a “clunk.” Completion of this technique may require several minutes of gentle traction to allow the muscles of the patient's shoulder to relax.
Other Methods
Poulsen reported a method termed the Eskimo technique that may be performed in field settings (see Fig. 49.12 H ). In this technique the patient lies on the unaffected side and is lifted a short distance off the ground by grasping the abducted arm on the injured side. The patient's body weight acts to effect the reduction. Poulsen's success rate was 74% in a series of 23 patients, all of whom were premedicated. However, the author also postulated that this technique could place undue stress on the brachial plexus or axillary vessels. Use of this technique, when other options are available, should probably be reserved until more data are obtained.
Noordeen and coworkers reported a simple method in which the patient sits sideways in a chair with the affected arm draped over the backrest. The operator holds the arm with the wrist supinated, and the patient is instructed to stand up. The success rate was 72% in 32 patients treated in this manner. A variation of the chair technique, which was successful in 97% of 188 anterior shoulder dislocations, involves operator-applied traction on the patient's flexed elbow by means of a cloth loop or stockinette. Standing beside the patient, the operator holds the involved elbow in 90 degrees of flexion while stepping down on the cloth loop. The patient sits in the chair, and an assistant may help support the patient by applying countertraction under the involved arm.
Post-reduction Care
After an attempt at reduction, the neurovascular status of the affected extremity should be rechecked and the results documented in the patient's medical record. Indirect evidence that the reduction has been successful includes an immediate decrease in pain, restoration of the round shoulder contour, and increased passive mobility of the shoulder. No harm is done by putting the joint through a limited range of motion. If the patient can tolerate placement of the palm from the injured arm on the opposite shoulder, it is quite likely that the shoulder reduction was successful ( Fig. 49.13 A ). For patients with possible axillary nerve injury, close to 90% will recover with expectant management. Nevertheless, it is prudent to refer these patients for early orthopedic follow-up.
Post-reduction radiographs are often recommended to make a careful search for new fractures. Although most greater tuberosity fractures do not alter patient management, patients with greater tuberosity fractures displaced more than 1 cm after closed reduction almost always have an associated rotator cuff tear and should receive prompt orthopedic consultation because they may require operative repair.
Traditional post-reduction treatment focuses on the importance of preventing the shoulder from dislocating again after the patient is discharged. This is best accomplished by immobilizing the joint with a commercially available shoulder immobilizer or a sling and swath to limit external rotation and abduction (see Chapter 50 ). Orthopedic follow-up is recommended for all anterior shoulder dislocations because the incidence of rotator cuff injury is as high as 38% and it might complicate restoration of normal function. As a general rule, the older the patient, the shorter the recommended time of immobilization. Those older than 60 years should have early follow-up (e.g., 5 to 7 days) to allow early mobilization and avoid persistent shoulder joint stiffness or adhesive capsulitis. Younger patients are usually immobilized for approximately 3 weeks and can be instructed to follow up within 1 or 2 weeks of the event. As mentioned earlier, young age confers risk of recurrent dislocation, but it is not clear if prolonged immobilization decreases recurrence rates. A 2010 meta-analysis found that immobilization for more than 1 week did not reduce recurrence rates.
Since the early 2000s, the wisdom of immobilization in internal rotation has been questioned. Several studies have shown that placing the arm in internal rotation actually increases labral detachment from the glenoid rim, whereas some degree of external rotation maximizes contact between the detached labrum and the glenoid rim. In one study, cadavers were used to measure the force of contact between the labrum and the glenoid rim in different arm positions. The authors of this study found that maximum contact force was actually generated in 45 degrees of external rotation, whereas no contact force was generated with the arm in internal rotation. Unfortunately, the question of which position (e.g., internal versus external rotation) is superior for post-reduction immobilization remains unanswered. Clinical studies thus far have shown conflicting results. Nevertheless, in the most recent systemic review and meta-analysis comparing recurrence rates and patient-based quality of life assessments between external and internal rotation immobilization (2014), Liu and colleagues found that immobilization in external rotation did not reduce recurrence rates or improve quality of life. As a result, it is not unreasonable to immobilize the extremity in a manner consistent with the recommendations of the orthopedic surgeons at one's institution until further evidence is presented. When in doubt, a simple sling or the traditional shoulder immobilizer will certainly suffice pending 5- to 7-day follow-up (see Fig. 49.13 B ).
Discharge the patient with oral analgesics (either nonsteroidal antiinflammatory drugs or narcotics) to minimize discomfort and instruct them to return if the clinical condition worsens. Periodically, one may encounter a return visit from a successfully treated patient who is in severe pain from hemarthrosis. In one series of patients older than 60 years, Trimmings reported excellent pain relief by aspirating the hemarthrosis 24 to 48 hours after shoulder reduction. This can be accomplished by using the technique of arthrocentesis described in Chapter 53 . In addition, intraarticular instillation of 10 to 20 mL of 1% lidocaine (or a longer-acting local anesthetic) may be helpful for further pain relief.
Posterior Shoulder Dislocations
Posterior shoulder dislocations account for less than 4% of all shoulder dislocations. Because they are so uncommon, posterior dislocations have the potential to be missed. In fact, delays in diagnosis for weeks to months have been reported. This may lead to increased rates of dislocation arthropathy and chronic pain. The mechanism of injury is almost always indirect and consists of a combination of internal rotation, adduction, and flexion. Classic precipitating events include seizure, electrical shock, and falls. Some patients may not be seen until at a point well past the original event. In addition, patients with seizures may not complain of pain or a limited range of motion in the immediate postictal period because of their altered mental status.
Clinical Assessment
Though clinically less obvious than anterior dislocations, posterior shoulder dislocations do occur in a typical, recognizable manner. Mistakes may be made if the clinician is overly reliant on AP radiographs, which are potentially misleading and may result in misdiagnosing the injury as a soft tissue contusion or acromioclavicular (AC) strain. The principal sign of a posterior dislocation is an arm that is somewhat fixed in adduction and internal rotation ( Fig. 49.14 ). Abduction and external rotation are limited, and attempts to perform these movements generally elicit pain. Inspection and palpation reveal loss of the normal anterior contour of the shoulder, as well as a prominent coracoid and acromion. The shoulder is flattened anteriorly and rounded posteriorly, and the humeral head may be palpable.
Comparison with the opposite shoulder should be undertaken with caution because this injury may occasionally occur bilaterally. Perform a neurovascular assessment in the standard manner, but such complications are unusual with posterior dislocations.
Radiologic Examination
The key point regarding radiographs for posterior shoulder dislocations is the subtle nature of this dislocation on a single AP film ( Figs. 49.15 A and 49.16 A ) and the diagnostic importance of the scapular Y view (see Fig. 49.15 B ) or the axillary view (see Fig. 49.16 B ). Diagnosis of posterior shoulder dislocation is quite easy with the axillary view, whereas the routine AP and lateral views are difficult to interpret in approximately half the cases. The axillary view is generally available in the radiology department and can be obtained with as little as 20 to 30 degrees of abduction and the plate placed on the shoulder. In addition to easy visualization of the posteriorly situated humeral head, the axillary view often reveals an impression fracture of the humeral head (see Fig. 49.16 B ). The scapular Y view is produced by superimposing the head of the humerus over the coracoid, acromion, and body of the scapula, which form a Y shape. In the event of a posterior shoulder dislocation, the head of the humerus will lie posterior to the glenoid (away from the chest wall) (see Figs. 49.9 B and 49.15 B ).
Even though axillary and scapular Y views are diagnostic, clues to posterior dislocation do exist on AP films. The internally rotated humeral head appears symmetric on an AP film and is in the shape of a light bulb, as opposed to the normal club-shaped appearance created by the greater tuberosity ( Fig. 49.17 ). With posterior dislocation, the space between the articular surface of the humeral head and the anterior glenoid rim is widened, and there is a decrease in the half-moon–shaped overlap of the head and the fossa. There may also be a compression fracture on the medial aspect of the humeral head, as indicated by a dense line. This is known as the trough sign. A fracture of the lesser tuberosity should always prompt a search for the presence of a posterior shoulder dislocation.
As mentioned earlier in this section, ultrasound is being used increasingly for the diagnosis of shoulder dislocations, including posterior shoulder dislocations and may be useful as an adjunct to the physical exam when dislocation is clinically suspected but not radiographically apparent.
Reduction Technique ( Fig. 49.18A )
Reduce an acute posterior dislocation by applying traction on the internally rotated and adducted arm combined with anteriorly directed pressure on the posterior aspect of the humeral head. Generous premedication is usually indicated, and countertraction may be applied with a sheet looped in the affected axilla, similar to the procedure described for anterior dislocations. Kwon and Zuckerman recommended applying lateral traction on the upper part of the humerus if the humeral head is locked on the posterior glenoid. Hawkins and colleagues suggested that posterior dislocations with an impression defect of the humeral head greater than 20% of the articular surface require open reduction. Posterior dislocations that have been diagnosed late are difficult to reduce in a closed manner, but an attempt with adequate premedication is generally indicated.
Post-reduction Care
As with anterior dislocations, neurovascular examination and radiographs should be repeated after attempts at reduction. Successful reduction is suggested by a patient's ability to place the palm of the injured arm on the opposite shoulder. Given the rarity of these injuries, orthopedic consultation is often sought early in the care of these patients. In a training environment, involvement of orthopedic residents is of benefit to their education and should be considered early. An analysis and review of the literature of posterior dislocations suggests the majority (65%) of posterior shoulder dislocations will have an associated injury (fracture, reverse Hill-Sachs injury, or rotation cuff tear) underscoring the importance of orthopedic consultation.
Unusual Shoulder Dislocations
Luxatio Erecta
Inferior dislocations of the shoulder, known as luxatio erecta , are quite rare but also quite obvious. The patient has the arm locked in marked abduction with the flexed forearm lying on or behind the head ( Fig. 49.19 ). Occasionally, the humerus may have less abduction, thus potentially obscuring the diagnosis. The humeral head can be palpated along the lateral chest wall. With this injury, the inferior capsule is almost always torn. Associated injuries include fractures of the greater tuberosity, acromion, clavicle, coracoid process, and glenoid rim. Neurovascular compression may be present, but this is usually reversed once reduction is accomplished. Long-term complications include adhesive capsulitis and recurrent dislocations.
To reduce an inferior shoulder dislocation, apply overhead traction (generally with the arm in full abduction) in the longitudinal direction of the arm, and exert cephalad pressure over the humeral head much as with the Milch technique (see Fig. 49.18 B ) . If needed, apply countertraction toward the patient's feet by using a sheet placed over the injured shoulder. After reduction, bring the abducted arm into adduction against the body and supinate the forearm.
Alternatively, use the “two-step” maneuver described by Nho and associates, in which the luxatio erecta is first converted to an anterior dislocation. To perform this maneuver, place one hand on the medial condyle of the elbow and the other hand around the shaft of the humerus. Push anteriorly on the shaft of the humerus while stabilizing the medial condyle of the elbow, and rotate the humeral head from an inferior to an anterior position. The authors then describe using the external rotation method to reduce what is now a typical anterior dislocation.
Scapular dislocation or “locked scapula” is a rare condition characterized by obvious protrusion of the lateral border of the scapula and significant swelling of the medial border because of tearing of the musculature. To reduce the scapula, apply traction on the abducted arm and apply medial pressure on the scapula.
AC Joint Subluxation and Dislocation
The AC joint is a true diarthrodial joint that consists of a synovial cavity surrounded by a relatively lax capsule and the weak AC ligament. This structure allows the gliding motion necessary for shoulder movement. The major stability of the AC joint comes from two ligaments. The AC ligament is primarily responsible for joint stability in the AP direction. The coracoclavicular ligament, which has posterior (conoid) and anterior (trapezoid) components, anchors the distal end of the clavicle to the coracoid process of the scapula and therefore supports the joint in a superior-inferior direction. In general, AC injuries arise from a direct force such as a fall on the point of the shoulder with the arm adducted. AC joint injuries are categorized according to the Rockwood classification (types I to VI) ( Fig. 49.20 ).
First Degree (Type I)
This injury consists of a minor tear in the AC ligament. The coracoclavicular ligament is intact. The clinical findings are limited to tenderness in the area of the AC joint. Radiographs show little, if any change in position of the clavicle in relation to the acromion. Management of this condition consists of a sling for comfort, ice, and mild analgesics. Generally, the symptoms subside with 7 to 10 days of rest. Orthopedic referral is not usually necessary unless return to normal function is delayed beyond 2 weeks.
Second Degree (Type II)
In addition to a complete tear of the AC ligament, the coracoclavicular ligament is stretched or incompletely torn. The patient generally supports the injured arm and has slight swelling and definite tenderness over the AC joint. Radiographs demonstrate a definite change in the relationship of the distal end of the clavicle to the acromion. However, in type II injuries the inferior edge of the clavicle should not be separated from the acromion by more than half its diameter, and the coracoclavicular distance is the same as that on the uninjured side. This injury can be treated in closed fashion with a sling. Orthopedic referral is recommended, and some still recommend a sling-strap device that elevates the arm and depresses the clavicle for these injuries.
Third Degree (Type III)
In this injury, the distal end of the clavicle is essentially free floating because both the AC and coracoclavicular ligaments are completely disrupted. The arm is supported by an uncomfortable-appearing patient, and the distal end of the clavicle is usually seen to be riding high above the acromion. The diagnosis is generally obvious, and radiographs are used mainly to rule out an associated fracture. Radiographic criteria for this degree of injury include the inferior border of the clavicle raised above the acromion or a discrepancy in the coracoclavicular distance between the normal and affected sides ( Fig. 49.21 ). These injuries require orthopedic referral, and a fair bit of controversy exists regarding their subsequent management. Larsen and coworkers conducted a prospective, randomized trial of conservative versus operative management of significant AC separations and concluded that conservative management was generally better, with possible exceptions made for patients with significant cosmetic deformity and for those who frequently keep their arm at 90 degrees of abduction. Even though optimal therapy is still unclear, a logical approach includes ED treatment with a sling and early orthopedic referral.
Fourth, Fifth, and Sixth Degrees (Types IV to VI)
In type IV injury, the distal end of the clavicle is free floating and posteriorly displaced into or through the trapezius muscle. Type V injury is characterized by inferior displacement of the scapula with a marked increase (two to three times normal) in the coracoclavicular interspace. Type IV and V dislocations generally require surgery, and orthopedic referral is necessary. Type VI injury involves dislocation of the distal end of the clavicle inferiorly. Because this is usually the result of major trauma, other fractures are often present and should be sought.
Radiographic Examination
The diagnosis of AC dislocation is usually made clinically by noting pain and local tenderness at the AC joint in the absence of other findings. Radiographs are generally indicated to rule out associated fractures and to aid in assessing the degree of injury. A single radiograph of the injured shoulder often suffices, but some clinicians prefer to obtain views of the opposite shoulder for comparison. Although their efficacy has never been proved, it has traditionally been recommended that “weighted” films be obtained for suspected type I or II injuries. Weighted films are generally performed after routine “unweighted” radiographs and are obtained by strapping approximately 4.5 to 7.0 kg (10 to 15 lb) of weight to the patient's wrists and repeating the radiographs. Weighted films are of questionable value in mild injuries and superfluous in obvious type III to VI injuries. In a prospective study of 70 type I or II injuries, the use of weights was associated with less evident separation in 7 cases, essentially producing a false-negative study in comparison to plain unweighted films. Only three injuries were re-categorized as type III after the performance of weighted films. The authors of this study recommend abandoning the use of weighted films in patients with AC dislocation.
Sternoclavicular Dislocations
Despite the fact that the sternoclavicular joint is the least stable joint in the body, sternoclavicular dislocations are rare. The primary supports of this joint are the sternoclavicular and costoclavicular ligaments. Anterior dislocations are much more common and usually the result of an indirect mechanism involving a blow thrusting the shoulder forward, or they may be atraumatic, caused by ligamentous laxity in teens and young adults. Posterior dislocations also usually result from a blow to the shoulder but can also be caused by a direct superior sternal or medial clavicular blow. Athletic injuries and those resulting from motor vehicle accidents account for the vast majority of sternoclavicular dislocations. Posterior sternoclavicular dislocation (also known as retrosternal dislocation because the medial end of the clavicle dislocates both posteriorly and medially) is potentially life-threatening because injury to the great vessels or compression of the airway might occur. Patients may complain of dyspnea, choking, or hoarseness with tracheal compression; dysphagia with esophageal compression; ipsilateral upper extremity pain and swelling with subclavian vessel occlusion; or paresthesias if the brachial plexus is compromised. Any suggestion of these complications should prompt immediate surgical consultation.
The clinical manifestation of these injuries is usually straightforward and consists of pain, swelling, tenderness, and deformity of the joint. Patients may complain of pain that is worse with arm movement and when they are supine. Plain radiographs of this joint are difficult to interpret and generally include an apical lordotic-type view with the radiographic tube angled 45 degrees cephalad. Confirmation of the diagnosis is best made with a thoracic computed tomography (CT) scan, which may also identify high rib fractures, pulmonary contusion, or pneumothorax ( Fig. 49.22 ). CT angiography should be obtained to identify associated vascular injury when indicated. Children may have epiphyseal disruption with retrosternal displacement of the medial aspect of the clavicle.
To reduce both types of sternoclavicular dislocation, place a rolled blanket or a sandbag between the scapula and spine to separate the medial aspect of the clavicle from the manubrium. Apply traction on the 90-degree abducted, 10-degree extended arm in line with the clavicle and then push (anterior dislocation) or lift (posterior dislocation) the clavicle back into position. Posterior dislocations may be difficult to reduce and to maintain via closed reduction. Therefore some authors recommend reduction in an operating suite unless complications necessitate immediate reduction. Given the rarity of this injury and the potential for major underlying complications, early consultation is recommended for suspected posterior sternoclavicular dislocations. Once reduced, a clavicle strap may be used to immobilize both anterior and posterior dislocations for up to 6 weeks.
Elbow Dislocations
The elbow is second only to the shoulder as a site of major joint dislocations in adults; it is the most commonly dislocated joint in children. Anatomically, the principal articulation of the humerus and ulna is a stable hinge joint with the intercondylar groove of the distal end of the humerus nestled in the olecranon fossa. Because of the stability of the elbow, any dislocation is expected to be accompanied by considerable soft tissue damage. Associated fractures of the radial head and coronoid process of the ulna are common. Elbow dislocations are usually simply divided into posterior and anterior dislocations ( Fig. 49.23 ). However, there are actually several additional types of elbow dislocations, including lateral, divergent, and isolated dislocations of the radius. In the rare divergent dislocations, the radius and ulna are dislocated in opposite directions, either anterior and posterior or medial and lateral.
Studies have shown that many patients report long-term problems including residual pain and joint stiffness after elbow dislocation. However, the most serious complication of elbow dislocation is injury to the brachial artery. This injury is possible with any type of elbow dislocation and is a frequent occurrence with open dislocations. Vascular compromise can be delayed in onset and result from either unsuspected arterial injury or progressive soft tissue swelling. The circulatory status of the arm must be carefully monitored even after successful reduction. In most cases, orthopedic consultation should be sought before disposition. Patients with any variety of elbow dislocation who have significant or immediate soft tissue swelling or hematoma formation or those who have questionable vascular integrity or neurologic findings are often admitted to the hospital or ED observation unit.
Injury to the median and ulnar nerves may be the result of stretch, severance, or entrapment. It is difficult to clinically distinguish these causes; therefore management of nerve injuries is frequently expectant. It is imperative to conduct a careful neurologic examination before and after reduction because any increase in findings may indicate entrapment and the need for surgical intervention. Myositis ossificans is also a potential complication of elbow dislocations secondary to hemarthrosis, which underscores the advisability of orthopedic consultation early in the course of care.
Posterior Dislocations
Posterior dislocations make up the vast majority of elbow dislocations. The usual mechanism is a fall on an outstretched hand with the elbow in extension. Findings on clinical examination are usually diagnostic unless severe soft tissue swelling is present. The patient has a shortened forearm that is held in flexion, and the olecranon is prominent posteriorly. The normally tight triangular relationship of the olecranon and the epicondyles of the distal end of the humerus is disturbed in a posterior dislocation. A defect may also be palpated above the prominence of the olecranon.
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