Glenoid hypoplasia

Abstract

Glenoid hypoplasia, also known as glenoid dysplasia and dysplasia of the scapular neck, is a failure of ossification of the posteroinferior two-thirds of the glenoid. Once thought to be a rare condition, more recent studies have shown that the incidence of glenoid hypoplasia ranges from 18% to 35%. This case report and literature review highlights the typical clinical presentation, the radiologic findings, and the management options for patients with glenoid hypoplasia.

Keywords: Glenoid dysplasia; Glenoid hypoplasia; Glenoid retroversion.

Fig. 1

MRI of glenoid hypoplasia in a 43-year-old man. (A) Axial fast spin echo (FSE) proton density (PD) fat-suppressed (FS) image shows hypoplasia of the posterior glenoid (arrowheads), retroversion of the glenohumeral joint, and mild posterior humeral head subluxation. Note the concomitant posterior labral tear, detachment (arrow), and enlargement. (B) Normal shoulder in 40-year-old man. Axial FSE PD fat-suppressed image through the midglenohumeral joint shows the normal glenoid version, posterior labrum (arrowhead), and glenohumeral relationship (g = glenoid, h = humeral head). (C) Retroversion is assessed by obtaining the angle (α) between the glenoid articular surface (dotted line) and a line extending through the long axis of the scapula on axial view. Humeral head subluxation is assessed by calculating (ab/ac) × 100%. The conventional method of assessing glenoid version on cross-sectional imaging was described by Friedman et al . Glenoid version is the angle between the glenoid line (the axis along the anterior and posterior glenoid rim) and the line perpendicular to the scapular axis (along the root of the scapular spine and center of the glenoid line). (D) Sagittal FSE T2 FS image shows the deficient portion of the posterior glenoid with complex joint fluid (arrow) extending between the glenoid (g) and imaged portion of the posterior labrum (arrowhead). c = coracoid, a = acromion.

Fig. 2

Glenoid retroversion and normal version demonstrated on chest radiographs. (A) Coned down frontal view chest radiograph in this patient demonstrates the hypoplastic left glenoid (arrows) and visualization of the glenohumeral joint in profile. The glenoid and humeral head should normally overlap on a chest radiograph since the glenohumeral joint is obliquely oriented to the X-ray beam. (B) Coned down image from a 22-year-old woman shows the normally formed glenoid (arrowhead) and the normal overlapping (asterisk) of the glenoid and humeral head.