Don’t assume that every shoulder dislocation is the same.
A 49-year-old, right-hand- dominant male presents to the emergency department with right shoulder pain. The patient was playing volleyball and immediately after spiking the ball felt severe pain to the right shoulder. He was unable to lower the arm, and states that he feels numb over the arm and fingers. There is no reported trauma, and he has no history of similar events. Physical exam is limited by pain but demonstrates an abducted right arm with inability to range the shoulder to neutral position. There is diffuse tenderness to palpation over the shoulder, decreased sensation to light touch over entire hand though he is able to move all fingers and 2+ radial/ulnar pulses.
The shoulder is the most frequently dislocated joint in the body, affecting 1-2% of the population. Dislocations are most often secondary to trauma and associated with weakened epiphyseal growth plates. They are more commonly seen in children. Shoulder dislocations are less commonly associated with fractures than with decreased joint stability – which is more common in elderly patients due to weakened capsule and ligaments with higher incidence of concomitant fracture.
Approximately 95% of dislocations are anterior, presenting with an abducted and externally rotated arm following activities involving external rotation, abduction, extension, or falls on outstretched arms. Posterior dislocations occur in 3-4% of patients, and present with adducted and internally rotated arms. Posterior dislocations are secondary to forceful adduction and internal rotation – an action most commonly seen in seizures or rarely due to falls on outstretched arms.
The residual <1% are inferior dislocations: Luxatio Erecta. Luxare means “to dislocate” and erecta simply means “erect.” These patients present with an abducted shoulder that is often bent at the elbow or with the arm fixed above and behind the head. Inferior dislocations are usually the result of axial pressure on a fully abducted shoulder or forceful abduction as is seen in a motorcycle collision. These mechanisms force the superior aspect of the humeral head below the inferior rim of the fossa of the glenoid, disrupting and/or rupturing the inferior glenohumeral ligaments. Luxatio Erecta often has associated fractures or soft tissue injury with tears of the labrum or fracture of the humeral tuberosity occurring in up to 80%, and have the highest incidence of axillary nerve injury (60%), vascular compromise (3%) of all shoulder dislocations.
Diagnosis is usually made by history of the injury, clinical presentation and radiologic studies. There is a substantial rate of misdiagnosis as an anterior and sub-glenoid dislocation occurs due to similarities in radiographic features. Anterior posterior films should demonstrate the superior articular surface of the humeral head beneath the glenoid fossa with the humeral shaft parallel to the scapular spine. This is in contrast to anterior dislocations where the humeral shaft should be parallel to the chest wall. Additionally, the stereotypic patient position with inability to lower and adduct the arm can lead to the correct diagnosis.
Due to the higher incidence of complications with neurovascular, fracture or soft tissue injuries, early reduction with appropriate analgesia is encouraged. Patients often require significant pain control and intravenous procedural sedation to achieve adequate reduction. Most case reports advocate use of ketamine, propofol, or other medications depending on other associated traumatic injuries and patient stability. Local anesthesia injected into the glenohumeral joint without sedation has also been described. Closed reduction in the emergency department should be attempted unless contra-indicated by the presence of humeral neck or shaft fractures or concern for significant vascular injury at which time emergent orthopedic consultation and operative open reduction is indicated. If there is concern for vascular injury, immediate arteriogram and emergent orthopedic or vascular surgery consultation should be obtained. A thorough pre- and post-reduction neurovascular exam should be documented with attention to the high incidence of axillary nerve or brachial plexus injuries.
There are multiple reduction techniques available, the most common being the “opposite traction” technique. This involves the physician standing at the head of the bed directly inline with the dislocated humerus. The physician begins applying traction inline with the direction of the humerus while counter traction is applied in the opposite direction (180 degrees). An alternate technique involves the physician first converting the luxatio erecta into a more commonly seen anterior dislocation by placing one hand on the humeral shaft and the other hand on the medial epicondyle. The shaft hand applies gentle anterior force, reducing the humeral head from an inferior to anterior position, from which the humerus can be adducted to the torso. Then the anterior dislocation is reduced by operator preference with scapular manipulation, external rotation, etc… Once successfully able to range the shoulder, a sling should be applied and the EP should conduct a post-reduction neurovascular exam and radiographs to ensure successful reduction and evaluate for iatrogenic neurovascular injury or fracture. Consider monitoring the patient overnight to ensure adequate post-reduction perfusion with regular neurovascular exams.
Initial successful closed reduction can be achieved in more than 75% of cases. Most common causes of failure include entrapment of the humeral head in the torn inferior joint capsule, fracture involving more than 25% of the glenoid, persistent displacement of the greater tubercle, or persistent or recurrent joint instability. Open reduction with immediate or delayed capsule reconstruction for persistent joint instability is indicated for unsuccessful closed reductions. The Emergency physician should consult with orthopedic specialists to ensure close follow-up for continued neurovascular and joint stability evaluation, as well as coordination of physical therapy to present frozen shoulder complications. Multiple case reports have shown good to excellent outcomes and even return of brachial plexus function despite initial injury with emergency department closed reduction.
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References
- Imerci, A, et.al., “Inferior glenohumeral dislocation (luxatio erecta humeri): report of six cases and review of the literature,” Ulus Trauma Acil Cerrahi Derg 2013 Jan; 19(1):41-4.
- Mallon W, et.al., “Luxatio erecta: the inferior glenohumeral dislocation,” J Orthop Trauma 1990; 4(1):19-24.
- Nho SJ, et.al. “The two-step maneuver for closed reduction of inferior glenohumeral dislocation (luxation erecta to anterior dislocation reduction,” J Orthop Trauma 2006 May; 20(5):354-7.
- Rosen, Peter, John A. Marx, Robert S. Hockberger, Ron M. Walls, and James Adams. “Shoulder: Inferior Glneohumeral Dislocation.” Rosen’s Emergency Medicine: Concepts and Clinical Practice. Philadelphia, PA: Mosby Elsevier, 2006. 692-93. Print.
- Wilson, Sharon R. “Shoulder Dislocation in Emergency Medicine .” Shoulder Dislocation in Emergency Medicine. Medscape, 07 Oct. 2011. Web. 15 May 2013.
- Yamamoto T, at.al., “Luxatio erecta (inferior dislocation of the shoulder): a report of five cases and a review of the literature,” Am J Orthopedics 2003 Dec; 32(12):601-3.
- Yanturali S, et.al., “Luxatio erecta: Clinical presentation and management in the emergency department,” Journal of Emergency Medicine 2005 Jul; 29(1):85-9.