Volume 4, Case 12
Loren G. Yamamoto, MD, MPH
Kapiolani Medical Center For Women And Children
University of Hawaiʻi John A. Burns School of Medicine
A 16 year-old boy is brought to the Emergency Department by ambulance complaining of pain in his right shoulder. He was at a shopping center in a crowded video arcade when he turned suddenly and struck his shoulder on the edge of a door. He felt his shoulder pop out.
Exam: He is alert, cooperative, and moderately anxious in moderate pain. He is of light body build. His right upper extremity is internally rotated. The head of the humerus is noted to be protruding anteriorly, obscuring the deltopectoral groove. There is moderate tenderness on palpation of the shoulder. No crepitus is noted. His clavicle is non-tender. His mid and distal humerus are non-tender. His elbow and forearm are non-tender. His sensation and pulses are intact distally. His axillary nerve function is intact (note the method of testing this).
View axillary nerve assessment.
In addition to routinely checking distal sensation and major nerve function, the axillary nerve dermatome should be routinely tested (by lightly brushing it or testing pin prick sensation) and documented since it may be injured during a shoulder dislocation.
He is given some intravenous morphine and is sent to the imaging department for radiographs of his right shoulder.
View shoulder radiographs.
Because of this patient's discomfort, he is unable to fully cooperate with obtaining the proper radiographic views. Thus, typically, the radiographic evaluation of a dislocated shoulder involves the interpretation of less than ideal views of the shoulder. AP and lateral views should be ideally obtained. The structures are labeled in the next set of images.
View labels on radiographs.
The position of the humeral head relative to the glenoid is the most important criterion for dislocation. Note that the humeral head is medial to the glenoid and inferior to its normal position, since it should overlie the glenoid in this view. However, the humeral head is not entirely below the glenoid itself. This radiograph is dark, making the visualization of the clavicle, acromion (acr) and coracoid (co) process difficult to see. They are outlined here to show their positions. Note that the humeral head is just inferior to the coracoid, but not totally inferior to the glenoid. This "subcoracoid" type of anterior shoulder dislocation is the most common type.
This view again shows the position of the humeral head relative to the glenoid. The humeral head should be overlying the glenoid, but it is clearly medial to the glenoid and inferior to its normal position. The acromion (acr) and clavicle are dark. They are outlined to show their position. This view again demonstrates the subcoracoid dislocation.
This lateral view may be difficult to interpret at first unless you can tell how to locate the glenoid. The glenoid is located by following the lateral border of the scapula upward. This will lead to the inferior margin of the glenoid as noted in this labeled view. The humeral head should be articulating with the glenoid in this view. However, it is clearly dislocated inferiorly (relative to its expected position).
Try examining another set of shoulder radiographs to apply these landmark identifications.
View second set of shoulder radiographs.
View labels on the above radiographs.
The acromion (acr), the clavicle, the acromioclavicular joint (ac), and the coracoid (co) are better seen in this radiograph. The glenoid is outlined in black dots. The humeral head should be overlying the glenoid. However, the humeral head is medial to the glenoid and inferior to its expected position. The humeral head is below the coracoid (co) but not entirely below the glenoid. This is a another example of a subcoracoid dislocation.
On this lateral view, locate the glenoid by following the lateral margin of the scapula upward (white dots) to the inferior margin of the glenoid (oval white dots). The humeral head should be articulating with the glenoid. However, the humerus is slightly inferior to its expected location. The positions of the clavicle, acromion (acr), coracoid (co), and sternum (st) are marked.
Such anterior dislocations of the shoulder commonly present to an emergency department. Shoulder dislocations are often associated with capsular tears and, in older patients, avulsion fractures may also be seen.
The three types of anterior shoulder dislocations: subclavicular, subcoracoid (most common), and subglenoid, are diagrammed below compared to the normal shoulder anatomy.
View shoulder diagrams.
The dislocated humerus is labeled as "D" while the expected normal location of the humerus head drawn in a broken line is labeled as "N".
Both sets of radiographs displayed above show subcoracoid dislocations. Note that while the humeral head is inferior to its expected position articulating with the glenoid (subcoracoid), the humeral head is not entirely inferior to the glenoid (a subglenoid dislocation).
Many textbooks will recommend that radiographs of the shoulder be obtained for all dislocations. In older adults, associated fractures are not uncommon. Fractures are less common in teenagers. A typical history and a cooperative teenager would generally indicate that no fracture is present. Loss of the normal delto-pectoral groove is indicative of an anterior dislocation since the humeral head commonly protrudes anteriorly into this space.
View delto-pectoral groove.
This model shows a normal delto-pectoral groove (arrows). This groove is normally not visible in an anterior shoulder dislocation. The non-affected side can be compared clinically.
In younger children with shoulder deformities, radiographs are mandatory since a dislocated shoulder is uncommon (fractures are more common). Thus, are radiographs necessary in a teenager with a typical anterior shoulder dislocation? It would seem that such a patient is at low risk for fracture. Obtaining radiographs may be an unnecessary delay that would prolong the discomfort for such patients. Since poor radiographs are often obtained initially, perhaps it would be better to obtain radiographs following closed reduction if clinical factors suggest this to be beneficial. Higher quality radiographs would be obtained, the patient would not suffer as long, and any complications can be identified more definitively (because of better radiographs) to receive appropriate care. Decisions on when to obtain radiographs are not without controversy. Understanding the pros and cons of obtaining radiographs can assist you in deciding on whether to obtain radiographs pre-reduction, post-reduction, both pre- and post-reduction, or not at all.
Following closed reduction, the axillary nerve should be reassessed. The joint should be palpated for any signs of fracture. Range of motion should be documented. The patient should feel as though their shoulder is "back to normal". The patient should be placed in a shoulder immobilizer. Follow-up with their primary care physician or an orthopedic surgeon should be arranged. Recurrent dislocations are common, and these should be referred to an orthopedic surgeon to consider corrective surgery (for ligament laxity).
Complications of an anterior shoulder dislocation include: rotator cuff tears, avulsion of the greater tuberosity, brachial plexus injury, axillary nerve injury, humeral head fracture, glenoid rim fracture, etc. Most of these complications are more common in older patients (adults). Occasionally, soft tissue (rotator cuff, capsule, muscle, or tendon) will be interposed in the joint, making closed reduction difficult or impossible. Orthopedic surgery is indicated for these patients.
Posterior shoulder dislocations are less common and beyond the scope of this discussion. Posterior dislocations should generally be referred to an orthopedic surgeon.
We will review four popular methods of closed reduction of an anterior shoulder dislocation; 1) external rotation, 2) Stimson (dangling weights) technique, 3) traction-countertraction, and 4) scapular manipulation.
External rotation method:
This method is highly effective and is conceptually the simplest since it does not require diagrams to understand. This is the preferred reduction method of one text (1) and my favorite as well.
View external rotation method.
With the patient's back (both shoulders) against the gurney in the supine position, the affected upper extremity is adducted against the torso. The elbow is flexed to 90 degrees so that the long axis of the forearm points to the ceiling (as noted in the photo). The upper arm is externally rotated slowly and gently, using the forearm as an external rotation lever. No traction (pulling) is required. The rotation is halted as pain is produced, then continued as muscle spasm and pain subside. Reduction occurs spontaneously as the forearm is rotated externally from the sagittal plane (vertical in the supine patient) to the coronal plane (horizontal in the supine patient). This maneuver can also be performed with the patient sitting up or at 45 degrees.
While this method is almost always successful, one text recommends that if reduction does not occur spontaneously after external rotation, the arm should be slowly elevated and the humeral head should be lifted into the socket.
Stimson (dangling weights) technique:
This technique involves the use of weights attached to the wrist/forearm.
View Stimson technique.
The patient is positioned prone. 5 to 10 kg (10 to 20 pounds) of weight are strapped to the wrist or forearm of the affected upper extremity. A special velcro wrist brace can be used to attached the weights to the wrist, or a soft restraint can also be used. The weighted arm dangles, placing constant traction on the shoulder, which gradually overcomes muscle spasm, and reduction occurs spontaneously after about 20 to 30 minutes. Analgesia and/or muscle relaxation is recommended. If reduction does not occur spontaneously, reduction may be achieved by gently rotating the humerus externally and then internally with mild force.
There are three things that I don't like about the Stimson technique. 1) It is slow. 2) Most teenagers are tall and our gurneys cannot be raised high enough to prevent the dangling weights from touching the floor. Note this in the photo. Additionally, patients tend to roll toward their affected shoulder lowering the weights further. 3) Since these patients are usually sedated, and reduction occurs after some delay, a nurse must watch the patient continuously to prevent the patient from falling asleep and rolling off the gurney.
Traction-countertraction methods:
There are several variations on this method. All of them involve inferior and/or lateral traction of the upper extremity.
View traction method #1.
In this traction-countertraction method (#1), two persons are required. One person pulls downward on the affected arm (traction). The other person provides counter traction in the opposite direction by pulling on a sheet wrapped around the upper chest under the axilla of the affected shoulder.
View traction method #2.
This method #2 is similar to traction method #1, except that upward lateral traction is added by a third person using another sheet as shown. This method is not routinely recommended.
View traction method #3.
This method #3 was recently described in the American Journal of Sports Medicine by sports medicine clinics serving skiers in Utah. This report refers to it as the Snowbird reduction technique. With the patient sitting upright on a fixed chair (without wheels), a one-meter loop of 10 cm (4-inch) cast stockinette is hung from the patient's elbow of the affected arm. The elbow is flexed. Downward traction is provided by gradually applying downward tension on the loop using your foot. The operator should assist the patient in maintaining this elbow flexion to prevent the loop from slipping. Countertraction is provided by the chair, however, an assistant can be helpful by clasping his hands around the chest in the axilla of the affected shoulder to prevent the patient from tilting toward the downward traction. The operator providing downward foot traction can use his/her hands to apply rotation if necessary.
View traction method #4.
This method #4 is known as the Hippocratic method. While many clinicians use this method, several textbooks indicated that this method should NOT be used. There are more effective methods than this one.
Scapular manipulation method:
This method is intriguing and is reported to be highly effective. Forward traction is provided by pulling on the forearm with countertraction over the clavicle as noted in the photograph.
View scapular manipulation method.
As one operator provides the forward traction, a second operator from the patient's back manipulates the scapula by pivoting it clockwise for a right shoulder and counter clockwise for a left shoulder. This is done by pushing the inferior tip medially (adducting it) with both thumbs as shown, while supporting the top of the scapula.
An alternative way of doing this is to have the patient prone with forward traction provided by weights attached to the affected arm as in the Stimson technique. The scapula is then manipulated in the same fashion.
Which method is the best to try first?
Only four methods would qualify to be considered here. The external rotation method, the Stimson technique, the Snowbird technique (traction method #3), and scapular manipulation. I have only tried the external rotation method and the Stimson technique myself. Of these two, I find the external rotation method to be preferable. The problems with the Stimson technique limit its use. The best traction-countertraction method seems to be the Snowbird technique (traction method #3). However, it is not as "elegant" as the external rotation method or the scapular manipulation method. The external rotation method is the simplest. The Snowbird technique requires a somewhat elaborate set-up. The scapular manipulation method has been shown to be less successful when performed by inexperienced operators. Thus, it is not the simplest method here. However, all of these methods have been reported to be highly effective overall.
Which method is the least painful?
The two recently described techniques in the literature, the Snowbird technique and scapular manipulation, were reported to be less painful compared to other methods. This was concluded because only a small fraction of the patients required narcotic analgesics and/or benzodiazepines. While most texts recommend narcotic analgesics and/or benzodiazepines routinely, this often is not done. I generally recommend IV narcotic analgesics and/or benzodiazepines to patients prior to reduction. However, in my experience, more than half the teenagers decline this (when the patient is empowered to make this decision) because it will delay reduction which is what they really want. In these instances where IV medications are declined, reduction using the external rotation is achieved quickly and patients tolerate it well. However, it is intriguing that the scapular manipulation method is reported to be the least painful in an uncontrolled study. Because of this, it should be considered after identifying the anatomic landmarks and practicing the technique on a colleague (without a dislocated shoulder of course).
References