Shoulder dislocations represent 50% of all major joint dislocations, with anterior dislocation being most common. The shoulder is an unstable joint due to a shallow glenoid that only articulates with a small part of the humeral head.
The shoulder joint is the most regularly dislocated joint in the body. The shoulder can dislocate forward, backward, or downward, and completely or partially, though most occur anteriorly. Fibrous tissue that joins the bones can be stretched or torn, complicating a dislocation. It takes a strong force, such as a blow to the shoulder to pull the bones out of place. Extreme rotation can pop the shoulder out of its socket. Contact sports injuries often cause a dislocated shoulder. Trauma from motor vehicle accidents and falls are also a common source of dislocation.
The shoulder is the most regularly dislocated joint in the body; the dislocation may anteriorly, posteriorly, inferiorly, or anterior-superiorly. Anterior locations are the most common. Patients with prior shoulder dislocation are more prone to redislocation. Reoccurance occurs because the tissue does not heal properly or it becomes lax. Younger patients have a much higher frequency of redislocation; most like due to higher activity level. Patients who tear their rotator cuffs or fracture the glenoid also have a higher incidence of redislocation.
Types of Dislocation
Anterior dislocation is the most common, accounting for up to 97% of all shoulder dislocations.
Posterior dislocations account for 2% to 4% of shoulder dislocations.
Inferior dislocations (also known as luxatio erecta) are the most uncommon type (less than 1%).
Patients may report:
Remember to ask about any previous dislocations. When the shoulder dislocates, the nerves can get stretched out. Some patients report stinging and numbness in the arm at the time of the dislocation.
The physical examination should confirm a suspected dislocation.
Performing a detailed neurovascular examination before reduction is imperative. Injury to the axillary nerve during shoulder dislocation is as high as 40%. Practitioners should record the neuromuscular examination before and after any dislocated shoulder.
Diagnosis and Management
Carefully examine the patient for neurovascular compromise. Axillary nerve injury is most common. The axillary nerve innervates deltoid and teres minor and provides sensation to lateral shoulder. Axillary nerve compromise presents in over 40% of dislocations, but usually, resolves with reduction. Although dislocation is often obvious, pre-reduction imaging for associated fractures can be useful and should be done when trauma is known. Clinically important fractures occur in about 25% of dislocations.
Reduction of the Dislocated Shoulder
Often conscious sedation with fentanyl, midazolam, ketamine, etomidate, or propofol used. This is done with continuous monitoring with capnography. If conscious sedation not needed, an intraarticular injection of 10 cc of local lidocaine or similar anesthetic may be helpful.
Contraindications to reduction in ED
Reduction techniques for anterior shoulder dislocation
Scapular Manipulation (80% to 100% successful)
External Rotation Technique
The external rotation technique reduces anterior glenohumeral dislocation by overcoming spasm of the internal rotators of the humerus, unwinding the joint capsule, and enabling the external rotators of the rotator cuff to pull the humerus posteriorly.
Milch Technique (add Milch technique if external rotation unsuccessful)
Kocher’s and Hippocratic Techniqueoot placed in patient’s axilla before traction) no longer recommended due to higher risk of complications
Posterior Shoulder Reduction
Disposition After Shoulder Reduction