BASICS
DESCRIPTION
- Subluxation (partial dislocation) or dislocation occurs when the humeral head is displaced from the glenoid fossa of the shoulder
- Shoulder is prone to subluxation/dislocation because of its inherent instability, particularly anteriorly (90% of subluxations/dislocations occur anteriorly)
RISK FACTORS
- Prior shoulder subluxation or dislocation
- Contact sports in adolescents
PATHOPHYSIOLOGY/ETIOLOGY
- Anterior dislocation usually occurs when a force is applied to an arm in an abducted, extended, and externally rotated position or an anteriorly directed force to the back of the shoulder
- Posterior dislocations may be due to a direct blow to the anterior aspect of the shoulder, an indirect force with the arm in flexion, adduction, and internal rotation, or a massive muscle contraction, as occurs with an electrical shock or seizure.
- Some children can voluntarily dislocate their shoulder due to increased joint laxity. They will often not be in severe pain and reduction can be achieved without much or any analgesia.
COMMONLY ASSOCIATED CONDITIONS
- Up to 35% of first-time anterior dislocations are associated with axillary nerve neuropraxia manifesting as decreased sensation over the deltoid.
DIAGNOSIS
HISTORY
- Plausible mechanism (above)
- Complaint of acute pain, made worse with any attempt at movement
PHYSICAL EXAM
- Obvious deformity with a prominent acromion and flattening of the contour of the lateral upper arm
- For anterior dislocation the arm is typically held in slight abduction and external rotation, and the humeral head is palpable anteriorly, with a defect inferior to the acromion
- In posterior dislocation the arm is usually held in adduction and internal rotation. There is limited, painful external rotation and abduction and the shoulder will be flattened anteriorly with a prominent coracoid process and posterior appearance
DIAGNOSTIC TESTS & INTERPRETATION
Pathological Findings
- Visualization of displaced humeral head
Imaging
- AP, lateral and axillary view radiographs
- Delaying reduction to acquire imaging if not readily available is not recommended if diagnosis can be determined from history and exam
DIFFERENTIAL DIAGNOSIS
- Humeral head fracture
- Ligamentous sprain
TREATMENT
MEDICATION
First Line
- Pain control with morphine, 0.1mg/kg IV, max 4mg
Second Line
- Consider procedural sedation in younger patients if facility is capable, consider ketamine, 1-2mg/kg IV, max 100mg
- Older adolescents may tolerate pain medication and intra-articular lidocaine
SURGERY / OTHER PROCEDURES
- Fast and atraumatic reduction is the key treatment, there are many methods (see additional reading)
- Apply gentle, longitudinal traction through the forearm with the arm abducted and elbow flexed, the arm can be gently internally and externally rotated to help disengage the humeral head. This technique may be applied for 15 to 20 minutes to overcome muscle forces.
- Perform a complete neurovascular exam after reduction
- Place affected arm in a sling for comfort, instruct to wear for 2-3 weeks
DISPOSITION
Admission Criteria
- Surgical management of fracture, all intra-articular fractures require orthopedic evaluation, and most require operative management
Discharge Criteria
- Normal neurovascular exam
- Pain controlled
Issues For Referral
- Unable to reduce
- Need for procedural sedation
- Associated fracture
FOLLOW UP
FOLLOW-UP RECOMMENDATIONS
- Discharge instructions and medications
- Pain control with ibuprofen (10m/kg, max 600mg)
- Pain should acutely improve after reduction, persistent pain warrants re-evaluation
- Activity
- As tolerated with arm in sling for 2-3 weeks
Patient Monitoring
- Follow-up with pediatrician or sports medicine specialist in 1-2 weeks
- Consider orthopedic and/or physical therapy referral
PROGNOSIS
- Recurrence after traumatic dislocation is reported to be as frequent as 70-100%
COMPLICATIONS
- Most common is recurrent shoulder instability
- Axillary nerve injury with anterior dislocation
- Fracture
- Osteonecrosis of humeral head
REFERENCES
- Herring, JA. Tachdjian’s Pediatric Orthopaedics. Fifth Edition. Elsevier Saunders, 2014
- Rockwood, CA. Rockwood and Wilkins’ Fractures in Children. 7th ed. Wolters Kluwer/Lippincott, Williams & Wilkins, 2010.
ADDITIONAL READING
- Cochrane Review of Conservative Management: Hanchard NC et al. Conservative Management Following Closed Reduction of Traumatic Anterior Dislocation of the Shoulder. Cochrane Database System Review. April 2014.
See Also (Topic, Algorithm, Electronic Media Element)
- www.shoulderdislocation.net for videos of reduction techniques
PEARLS AND PITFALLS
- There are multiple reduction methods, review a few and gain a level of comfort with them
- Give anticipatory guidance about high risk of recurrence