Glenohumeral Dislocation, Anterior

Ovid: 5-Minute Sports Medicine Consult, The

Glenohumeral Dislocation, Anterior
Jason Glowney
Sourav K. Poddar
  • Humeral head is displaced anteriorly beyond the glenoid fossa due to external rotation while arm is in abduction.
  • Sometimes (less commonly) caused by direct contact to the posterior aspect of the shoulder.
  • Most commonly dislocated diarthrodial joint; 45% of all dislocations are of the shoulder.
  • Bimodal incidence with peaks in the 2nd and 6th decades of life
  • 2% lifetime incidence between 18 and 70 yrs of age
  • 96% of glenohumeral dislocations are anterior.
Risk Factors
  • History of previous dislocation
  • Generalized ligamentous laxity
  • Sports such as wrestling, football, rugby, skiing, and skateboarding
Commonly Associated Conditions
  • Bankart lesions: Detachment of inferior glenohumeral ligament-labral complex from anterior glenoid rim. Very common in younger patients. Strongly associated with dislocation recurrence.
  • Rotator cuff tears: Between 14 and 63% of anterior dislocations are associated with rotator cuff tears, with increasing frequency in older individuals. Often the subscapularis muscle with anterior dislocation.
  • Fractures: Humeral head and neck (significant displacement may be a contraindication to closed reduction), glenoid rim, and greater tuberosity avulsions. Seen especially with traumatic etiology.
  • Hill-Sachs lesion: Depression fracture of posterolateral humeral head. More than 50% of anterior dislocations in patients younger than 40 yrs old are associated with this type of lesion. Presence of a Hills-Sachs lesion associated with recurrent dislocation.
  • Neurologic injury: Common complication with 10% suffering injury to the axillary nerve. Less frequently injured are the brachial plexus or musculocutaneous nerve.
  • Vascular injury: Infrequent complication (1–2%), axillary artery most frequently injured in anterior dislocation, higher incidence in older individuals given the loss of arterial elasticity secondary to atherosclerosis.
  • Recurrent dislocation: Rate varies inversely with age, with up to 95% recurrence in athletic patients, with initial dislocation at younger than 20 yrs old without surgical intervention.
  • West Point view (reverse axillary lateral) helps in showing bony Bankart lesions.
  • Styker notch (anteroposterior internal rotation of humerus) good to demonstrate Hill-Sachs deformity
  • Often occurs after a fall on the outstretched arm or with reaching (making a tackle) and having arm forcibly abducted
  • 1st time event vs recurrence (may affect ease of reduction and long-term treatment plan)
  • Amount of trauma involved (traumatic vs atraumatic) can give clues as to whether there is a component of ligamentous instability.
  • Duration shoulder has been dislocated (helps in decision concerning analgesia)
Physical Exam
  • Anterior fullness of the shoulder
  • Forearm of affected arm often cradled with shoulder in externally rotated, partially abducted position
  • Patient usually guarding and very uncomfortable
  • Sulcus sign (depression in the skin below the acromion)
  • Perform neurovascular exam, both before and after reduction, to check for previously mentioned nerve injuries.
  • Check deltoid muscle strength and lateral shoulder sensation to assess axillary nerve function (former not always practical prior to reduction of dislocated shoulder).
  • Check proximal and distal muscle function and range of motion before and after relocation.
  • No crepitus should be felt or heard during relocation.
Diagnostic Tests & Interpretation
  • At least 2 views orthogonal to each other are required.
  • Normally acute traumatic shoulder dislocations are evaluated with a trauma series that includes an axillary view, a trans-scapular (Y) lateral view, and a true shoulder anterior-posterior view
  • Standard anteroposterior: Head of humerus displaced medially on glenoid; difficult to distinguish anterior from posterior dislocations
  • True lateral (trans-scapular, Y) view: Humeral head displaced toward coracoid process
  • Axillary view: Allows easier visualization of associated injuries, but requires movement of an already uncomfortable patient
Diagnostic Procedures/Surgery
May utilize advanced imaging, such as CT scan, MRI, or musculoskeletal US, to assess if associated injuries suspected
Differential Diagnosis
  • Acute subluxation
  • Acromioclavicular joint separation
  • Fractures of humeral head, coracoid, acromion, proximal humerus, clavicle, rib
  • Rotator cuff injury
  • Posterior dislocation
Ongoing Care
  • Little data exist as to when it is safe for an athlete to return to play after sustaining a dislocation.
  • Most experts would recommend waiting until athlete has full range of motion and strength before their return (4)[C].
  • Athletes returning to play with history of instability are at risk for recurrence, with 1 study showing 37% incidence of repeat dislocation during the ongoing season (4)[B].
Follow-Up Recommendations
  • Growing consensus for early arthroscopic stabilization after primary anterior shoulder dislocation in young athletic patients unwilling to modify their risk factors, as numerous studies have shown a high rate of recurrence in nonoperative treated subjects in this group. When surgically stabilized, athletes show significant decreased rates or dislocation recurrence (2)[A].
  • Recurrent instability patients likely to benefit from orthopedic referral for arthroscopic or open surgical repair as warranted
  • Patients with multidirectional instability should be treated with traditional methods, although surgical repair is often necessary with recurrences.
  • Early orthopedic referral indicated for all except uncomplicated, recurrent anterior dislocations.
  • Orthopedic referral with humeral head or neck fractures and irreducible dislocations
1. Cox CL, Kuhn JE. Operative versus nonoperative treatment of acute shoulder dislocation in the athlete. Curr Sports Med Rep. 2008;7:263–268.
2. Dodson CC, Cordasco FA. Anterior glenohumeral joint dislocations. Orthop Clin North Am. 2008;39:507–518, vii.
3. Kuhn JE. Treating the initial anterior shoulder dislocation—an evidence-based medicine approach. Sports Med Arthrosc. 2006;14:192–198.
4. Cutts S, Prempeh M, Drew S. Anterior shoulder dislocation. Ann R Coll Surg Engl. 2009;91:2–7.
Additional Reading
Arciero RA, St Pierre P. Acute shoulder dislocation. Indications and techniques for operative management. Clin Sports Med. 1995;14:937–953.
Wen DY. Current concepts in the treatment of anterior shoulder dislocations. Am J Emerg Med. 1999;17:401–407.
831.01 Closed anterior dislocation of humerus

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