Glenoid retroversion is the abnormal posterior angulation of the articular surface of the glenoid of the scapula and is of importance as it predisposes to posterior glenohumeral instability and tears of the posterior labrum.
The normal shoulder demonstrates neutral version, where the articular surface of the glenoid is perpendicular to the axis of the scapular body.
Causes may be developmental, such as glenoid dysplasia, or secondary to trauma or osteoarthritis, especially in throwing athletes.
Glenoid version is measured on axial CT or MR scans as the angle between the glenoid and scapular lines:
- glenoid line: at the mid-glenoid level, joins the anterior and posterior margins of the glenoid rim
- scapular line: joins the midpoint of the glenoid line to the medial tip of scapular blade
- the range of normal is 0-7°
- neutral version is 0°
- retroversion is >7°
Using this technique with CT 3D reconstructions is recommended if there is abnormal scapulothoracic position.
Treatment and prognosis
There is no standard proven surgical treatment and as such numerous surgical methods have been trialled with various success, including soft-tissue repairs, glenoplasty, and bone augmentation techniques.
The rate of success of the surgical treatment is inversely proportional to the severity of retroversion.