ACR Codes: 4.9
Patient with glenoid hypoplasia may present with shoulder pain and limited range of motion. Asymptomatic patients are discovered incidentally on chest radiographs. Rockwood et al. report that the incidence is not known. The anomaly is seen in men and women equally. There is unilateral or bilaterally symmetric dysplasia of the scapular neck with an irregular glenoid surface. There may be associated hypoplasia of the humeral head and varus deformity of the proximal humerus as well as enlargement and bowing of the acromion and /or clavicle. Hasson et al. speculate that glenoid hypoplasia is a maldevelopment of the inferior secondary growth center. They report that the defect may be sporotic or inherited in an autosomal denominate fashion. It is analogous to hip dysplasia.
Unilateral glenoid dysplasia may be a manifestation of brachial plexus injury if associated neuropathies exist. In the setting of acute or remote trauma, avascular necrosis may also create similar radiographic features that are isolated to the shoulder.
Bilateral glenoid dysplasias may be associated with other anomalies that include congenital defects in the hips, ribs, and spine. These findings suggest underlying entities such as epiphyeal dysplasia, scurvy, or rickets.
Treatment is dictated by the degree of disability and pain. Asymptomatic patients are advised to avoid vigorous manual labor and very symptomatic patients may require total joint replacement after conservative measures of physical therapy have failed or if significant shoulder instability exists.
Reference(s): Resnick and Kransdorf, Bone and Joint Imaging. 3rd ED