Special Feature

Anterior Shoulder Dislocation: Uncommon Reduction Techniques for a Common Injury

By Jacob W. Ufberg, MD

Introduction

The shoulder has the greatest range of motion of any of the body’s joints, and thus is prone to dislocation. Fifty percent of all joint dislocations involve the shoulder, with anterior dislocations making up 90-96% of shoulder dislocations.1 The most common mechanism of injury is extreme abduction, external rotation, extension, and a posteriorly directed force against the humerus. Forceful abduction or external rotation alone also can cause dislocation, as can direct blows to the posterior humerus, forced elevation and external rotation, or a fall on the outstretched hand.2 Among patients with recurrent dislocations, the mechanism may be surprisingly minor, such as external rotation of the shoulder while rolling over in bed.3

Most emergency physicians are familiar with several methods of reduction of anterior shoulder dislocations, such as traction-countertraction, scapular manipulation, external rotation, the Milch technique, and the Stimson technique of hanging weights. No technique is 100% effective, and approximately 5-10% of anterior shoulder dislocations will prove irreducible in the emergency department (ED).4 There are multiple factors to consider when deciding which technique to use, including the availability of assistants, whether or not sedation/analgesia is necessary, and the treating clinician’s experience with the various techniques. This article will discuss the diagnosis of anterior shoulder dislocation, the need for diagnostic imaging, and the management of anterior shoulder dislocations using three less commonly known alternative techniques.

Diagnosis

Clinical. Many shoulder dislocations are clinically apparent. The injured patient frequently supports the affected extremity with the other arm, and leans toward the side of injury. The arm often is held in slight abduction and external rotation. The shoulder loses its normal, rounded appearance, and the acromion process may appear prominent. An anterior fullness may be palpable, and a defect may be seen and felt in the area where the humeral head normally resides.

It is imperative to perform a complete neurovascular examination of the affected arm. The axillary nerve is the most commonly injured nerve,5 and its sensory component can be tested by checking for sensation over the lateral aspect of the upper arm in the regimental badge area. Motor testing of this nerve is extremely difficult, due to the injury. The neurologic exam also should include a complete assessment of the other major nerves to the affected arm, as other injuries may occur infrequently.5 Vascular injury to the axillary artery is rare, and may be assessed by checking for an expanding hematoma and by comparing the radial artery pulses between the affected and unaffected extremity.

Diagnostic Imaging. Anterior dislocation of the shoulder easily can be diagnosed by plain radiography using the standard anteroposterior (AP) view. Additionally, the scapular Y view and the axillary view often are performed. These views are useful in diagnosing posterior dislocation, but rarely add to the AP view in obvious anterior dislocation.

Fractures may be detected in up to 35% of anterior shoulder dislocations. The most common of these fractures is that of the greater tuberosity.6 The Hill-Sachs deformity (a notch in the posterolateral area of the humeral head) and the Bankart lesion (a disruption of the inferior aspect of the glenoid rim) also are commonly seen on pre- or post-reduction radiographs. While these fractures may affect the long-term outcome of patients with anterior shoulder dislocations, they rarely affect immediate ED management.

This lack of immediate consequences of most radiographic findings has led some to question the need for pre- or post-reduction radiographs in all cases. Several authors suggest that minimally traumatic, recurrent, clinically obvious dislocations may be reduced without the need for prior radiographs.7,8 Some argue that pre-reduction films are necessary to document any possible proximal humerus fracture, but that post-reduction films are of little value.7,9 However, many authorities continue to recommend both pre- and post-reduction radiographs, as humeral neck fractures are a known complication of the reduction of anterior shoulder dislocations.6

Management

Premedication. The obvious benefits of reduction without premedication include reduced ED length of stay, reduced staff requirements, and avoidance of complications associated with sedation and analgesia. However, most patients who are anxious, uncooperative, have muscle spasm, or who are in a great amount of pain will require premedication. In general, if reduction is attempted without pharmacologic assistance, only one attempt should be made before resorting to some type of premedication. This decision should be made on a case-by-case basis by the treating clinician. One alternative is the administration of intra-articular lidocaine to patients in whom there is a reason to avoid sedation and analgesia.

Studies by Kosnik and Orlinsky demonstrate significant pain relief during reduction using intra-articular lidocaine.10,11 However, both studies indicated increased patient satisfaction with sedation and analgesia, and Orlinsky’s study indicated increased physician-perceived muscle relaxation with sedation and analgesia. It is reasonable to conclude that intra-articular lidocaine is a viable alternative among patients who decline, or who have a contraindication to, intravenous sedation and analgesia.

New/Uncommonly Used Reduction Techniques

Spaso Technique. This technique is performed with the patient lying flat in the supine position. The clinician holds the affected extremity around the wrist or distal forearm and gently lifts the arm vertically until the arm is pointed directly up toward the ceiling. While maintaining gentle vertical traction on the arm, the clinician slowly rotates the arm externally at the wrist. Reduction, which may require several minutes of traction, generally will be noted by the familiar "clunk." However, reduction may be subtle.

This technique has a reported success rate of 87.5%,12 although little literature has appeared since this technique was first reported in 1998.13 This technique is useful, as it requires little force, is simple to perform, and does not require any assistants.

Chair Technique. Nordeen and Westin have reported different variations on this simple and effective technique.14,15 In Nordeen’s technique, the patient is seated sideways in a chair with the dislocated extremity draped over the backrest of the chair. While the clinician holds the wrist in the supinated position, the patient is instructed to stand up slowly, pausing when it is too painful to continue, until reduction is accomplished. The reported success rate in Nordeen’s study was 72%.14

Westin reported a technique in which the patient is seated in a chair. The affected arm is flexed 90º at the elbow, and a cloth loop is made from stockinette and placed around the proximal forearm. The clinician places one hand on the humeral head to exert pressure, while the other hand is used to maintain flexion at the elbow. Then the clinician places one foot in the loop and provides firm, gradual downward traction while an assistant stabilizes the patient’s torso. Westin reported a 97% success rate and performed 93% of reductions without sedation or opioid analgesia.15

While both these techniques are simple and may be effective in many patients, they may prove difficult among patients requiring sedation, analgesia, and monitoring. The Nordeen technique requires the patient to cooperate and stand up, while the Westin technique requires maintaining seated position, both of which may be difficult in the sedated patient.

Self-Reduction Technique. Aronen reported this simple technique, in which the patient performs his or her own reduction. Because the patient applies the force necessary to reduce the dislocation, the patient can control the amount of force being used to maintain tolerable levels of pain. In this technique, the patient is seated on a stretcher in the upright position. The patient is positioned with the ipsilateral knee flexed to approximately 90° and the foot flat on the stretcher. The patient is instructed to clasp the hands around the ipsilateral knee with the fingers interlocked. The patient then leans back slowly until the elbows are straight. Then, the patient applies steady, gradual pressure by leaning back and extending at the hip and knee. This created both a traction and a countertraction force for reduction, which may take several minutes.16 The advantages of this technique lie in its simplicity. No equipment, or even a stretcher, is necessary. The self-reduction technique may be attempted on sports fields or wherever the injury may have occurred, as reduction generally becomes more difficult as time passes. The patient can control the amount of pain by pausing during the reduction to allow muscle spasm to resolve before applying further pressure.

Post-reduction Care

After reduction, limited passive range of motion may be checked to ensure reduction clinically. Restoration of the normal contour of the shoulder and dramatic decrease in pain also may be clues to a successful reduction. The need for post-reduction radiographs is discussed in the section on diagnostic imaging.

Immobilization of the affected shoulder should be adequate to prevent external rotation or abduction of the shoulder. This can be accomplished with a sling and swath or a commercially available shoulder immobilizer. The duration of immobilization differs among different patient groups. Younger patients should be instructed to follow up within 1-2 weeks, and immobilization generally is maintained for approximately 3-4 weeks. Older patients will be immobilized for a considerably shorter period of time, and should be instructed to follow up within 5-7 days to allow for early mobilization.6

Orthopedic follow-up for all patients with anterior shoulder dislocation should be ensured, as the incidence of concurrent rotator cuff injury is significant, especially among older patients with anterior shoulder dislocations.17 Many patients will re-dislocate at some future point. Patients with a first shoulder dislocation prior to age 20 will have a recurrence rate of 80-92%, as opposed to a recurrence rate of 10-15% among patients who first dislocate after age 40.6

Dr. Ufberg, Assistant Professor of Emergency Medicine, Assistant Residency Director, Department of Emergency Medicine, Temple University School of Medicine, Philadelphia, PA, is on the Editorial Board of Emergency Medicine Alert.

References

1. DePalma AF, et al. Acute anterior dislocation of the shoulder. Am J Sports Med 1973;1:6-15.

2. Welsh S, et al. Shoulder dislocations. www.emedicine.com. (Accessed 12/01/2003.)

3. Rowe CR. Prognosis in dislocations of the shoulder. J Bone Joint Surg Am 1956;38:957.

4. Riebel GD, et al. Anterior shoulder dislocation: A review of reduction techniques. Am J Emerg Med 1991; 9:180-189.

5. de Laat EA, et al. Nerve lesions in primary shoulder dislocations and humeral neck fractures: A prospective clinical and EMG study. J Bone Joint Surg Br 1994; 76:381-383.

6. Rockwood CA, et al. Subluxations and Dislocations about the Glenohumeral Joint. In: Rockwood CA, et al, eds. Rockwood and Green’s Fractures in Adults, 4th ed., Vol. 2. Philadelphia: Lippincott-Raven; 1996:1193-1339.

7. Hendey GW, et al. Clinically significant abnormalities in postreduction radiographs after anterior shoulder dislocation. Ann Emerg Med 1996;28:399-402.

8. Shuster M, et al. Prereduction radiographs in clinically evident anterior shoulder dislocation. Am J Emerg Med 1999;17:653-658.

9. Harvey RA, et al. Are postreduction anteroposterior and scapular Y views useful in anterior shoulder dislocations? Am J Emerg Med 1992;10:149-151.

10. Kosnik J, et al. Anesthetic methods for reduction of acute shoulder dislocations: A prospective randomized study comparing intraarticular lidocaine with intravenous analgesia and sedation. Am J Emerg Med 1999; 17:566-570.

11. Orlinsky M, et al. Comparative study of intra-articular lidocaine and intravenous meperidine/diazepam for shoulder dislocations. J Emerg Med 2002;22:241-245.

12. Yuen MC, et al. An easy method to reduce anterior shoulder dislocation: The Spaso technique. Emerg Med J 2001;18:370-372.

13. Miljesic S, et al. Reduction of anterior dislocations of the shoulder: The Spaso technique. Emerg Med 1998; 10:173-175.

14. Noordeen MHH, et al. Anterior dislocation of the shoulder: A simple method of reduction. Br J Accident Surg 1992;23:479-480.

15. Westin CD, et al. Anterior shoulder dislocation: A simple and rapid method for reduction. Am J Sports Med 1995;23:369-371.

16. Aronen JG, et al. Anterior shoulder dislocations: Easing reduction by using linear traction techniques. Phys Sports Med 1995;23:65-69.

17. Beeson MS. Complications of shoulder dislocation. Am J Emerg Med 1999;17:288-295.