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Figure. Anteroposterior radiograph of the right shoulder.
A 64-year-old woman presents to the emergency department with severe right shoulder pain after a fall. She tripped on her sidewalk and fell with her arm extended. She is now unable to move the arm because of severe pain. On physical examination, she has a small area of ecchymosis over the deltoid muscle but otherwise no deformity. A radiograph of the right should is taken (Figure 1).
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Proximal humerus fractures are one of the most common fracture types in adults. Proximal humerus fractures represent 20% of all fragility fractures (fall from a standing height in patients with osteoporotic bone).1 Radiographs are the initial imaging modality and understanding fracture patterns is critical in guiding treatment.
Inferior subluxation of the humeral head in relation to the glenoid cavity is a common finding in proximal humerus fractures but can be misdiagnosed as a fracture dislocation. Recognizing this fracture pattern prevents unnecessary closed reduction attempts of the shoulder. Inferior subluxation is seen in less than 20% of proximal humerus fractures and is best seen on the anteroposterior view of a shoulder radiograph.1 Risk factors include advanced age, female gender, osteoporotic bone, and obesity.1 The cause of the inferior subluxation of the humeral head may be deltoid atony often from an axillary nerve injury. The inferior subluxation resolves spontaneously within 6 weeks in 90% of patients and is rarely seen beyond 1 year regardless of conservative vs surgical intervention.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopedics for Physician Assistants.
References
1. Cirino CM, Kantrowitz DE, Cautela FS, Gao M, Cagle PJ, Parsons BO. Incidence and risk factors for pseudosubluxation of the humeral head following proximal humerus fracture. JSES Int. 2022;6(3):338-342. doi:10.1016/j.jseint.2022.01.013
2. Mighell MA, Kolm GP, Collinge CA, Frankle MA. Outcomes of hemiarthroplasty for fractures of the proximal humerus. J Shoulder Elbow Surg. 2003;12(6):569-577. doi:10.1016/s1058-2746(03)00213-1
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