Sat., 10/20/07 Upper Extremity, Paper #55, 10:42 am OTA-2007
CT Evaluation of Extra-Articular Glenoid Neck Fractures: Does the Glenoid Medialize or Does the Scapula Lateralize?
J. Megan M. Patterson, MD1 (n); Leesa Galatz, MD1 (n); Jared Toman, MD2 (n);
Paul Tornetta, III, MD2 (a,c,e-Smith+Nephew),
William M. Ricci, MD1 (a,c,e-Smith+Nephew; a-Synthes, AONA);
1Washington University School of Medicine, St. Louis, Missouri, USA;
2Boston Medical Center, Boston, Massachusetts, USA
Purpose: Medial translation of the glenoid is a commonly cited indication for operative management of glenoid neck fractures. Indeed, plain radiographs typically show the glenoid medialized relative to the scapula. However, whether this truly represents medialization of the glenoid or lateralization of the scapula remains unclear. The purpose of this study was to assess the relationship between the glenoid, the scapular body, and the axial skeleton using CT data analysis with the contralateral shoulder acting as an internal control.
Methods: Patients admitted to two Level I trauma centers between January 2000 and March 2006 with isolated extra-articular glenoid neck fractures (OTA 09A2.3 fractures) and complete shoulder radiographs and chest CT scans were included (n = 18; 5 females, 13 males; average age 38.7 years, range 17-75 years) and identified retrospectively. Injury chest CT scans that included both the injured and uninjured scapulae were used to evaluate the glenoid to midline distance (defined as the distance from the lateral aspect of the base of the coracoid to the midline of the body) and scapular width (defined as the distance from center of glenoid to the medial border of scapula). Injury AP radiographs of the shoulder were used to determine the glenopolar angle (defined as the angle between the vertical line tangent to the margins of the glenoid and the line connecting the most cranial point of the glenoid with the most caudal point of the scapular body).
Results: The glenoid to midline distance showed that the fractured glenoid was most commonly lateralized (14/18 patients) an average of 13.7 mm (range, 1-23 mm). Medialization was seen in only four patients (average 3.7 mm; range, 2-8 mm). The average glenopolar angle was 25.7° (range, 9.7°-43.0°). In 15 of 18 patients, the scapular width was shortened an average of 5.9 mm (range, 1-18 mm). In only 3 of 18 patients was the injured scapular width longer, average of 6 mm (range, 1-10 mm).
Conclusions and Significance: In patients with glenoid neck fractures, pure medial translation of the glenoid does not occur. Instead, there is a component of shortening of the scapula combined with either lateralization of the scapular body or rotation of the glenoid. Therefore, treatment algorithms for glenoid neck fractures should not rely on perceived medial glenoid translation as measured on AP radiographs.
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