The presentation is distinctive
Patients with this type of dislocation present with their arm elevated, elbow flexed, and hand behind their head. Due to mechanical entrapment of the humeral head, patients can’t move their arm. The abducted position of the arm may hinder further assessment with computed tomography (CT) for life-threatening injuries, as was the case with our patient.
While an immobile, abducted arm is virtually pathognomonic, radiographs are useful for confirming the diagnosis and assessing for associated fractures. It is essential to obtain anteroposterior, axillary, and Y views.5 Radiographs typically show the shaft of the humerus directed superiorly and parallel to the scapular spine, with the humeral head below the coracoid process or glenoid fossa.3,5
Rotator cuff tears are a common complication
There are a number of complications associated with luxatio erecta. Eighty percent of patients with this injury have either an associated rotator cuff tear or a fracture of the greater tuberosity (which we’ll get to in a bit).3 Magnetic resonance imaging studies have shown rotator cuff injuries to involve the supraspinatus, infraspinatus, and, less frequently, the subscapularis tendon.6 It’s believed that rotator cuff tears may be even more prevalent than reported in the literature since they are often underrecognized at the time of presentation with the dislocation.6
Other complications. Sixty percent of patients report some degree of neurologic dysfunction after the dislocation.5 The most common nerve affected is the axillary, followed by the radial, ulnar, and median nerves.3 These injuries are more likely to occur with associated fractures of the greater tuberosity or axillary artery injuries.7 Symptoms generally resolve after reduction, although there have been cases that have taken up to 6 weeks to resolve.8
Vascular compromise, most commonly occurring as a result of axillary artery injury, has been reported in 3.3% of cases.5 This injury is most common in elderly patients, with 75% of cases occurring in patients older than 60 years.7 It’s been hypothesized that this is due to the loss of arterial elasticity as an individual ages. The most common presenting signs and symptoms include absent radial and/or brachial pulses, severe pain, axillary swelling, axillary masses due to hematoma formation, and neurologic deficits.7 Complications are minimal if diagnosed and treated early.