CT Evaluation of Extra-articular Glenoid Neck Fractures

Does the Glenoid Medialize or Does the Scapula Lateralize?

Abstract

Objectives: 

Medial translation of the glenoid is frequently described as the main mode of displacement after glenoid neck fracture. Indeed, plain radiographs typically show the glenoid medialized relative to the scapular body. However, whether this truly represents medialization of the glenoid relative to the axial skeleton or lateralization of the scapular body remains unclear. The goal of this investigation was to assess the relationship between the glenoid, the scapular body, and the axial skeleton in patients with glenoid neck fractures using computed tomographic data analysis with the contralateral shoulder serving as an internal control.

Design: 

Retrospective radiographic review.

Setting: 

Two Level I trauma centers.

Participants: 

Eighteen patients (5 women and 13 men; average age, 38.7 years; range, 17–75 years) admitted between January 2000 and March 2006 with isolated extra-articular glenoid neck fractures (OTA 14C1 fractures) and chest computed tomographic scans that included both shoulders.

Main Outcome Measurements: 

Glenoid to midline distance and scapular width.

Results: 

The injured glenoid was lateralized an average of 9.8 mm (range, 8 mm medialized to 23 mm lateralized) (P < 0.001). Relative to the uninjured side, glenoid medialization infrequently occurred (4 of 18 patients) and when present was less than 1 cm (range, 2–8 mm). Lateralization occurred more frequently (14 of 18 patients), with an average displacement of 13.7 mm (range, 1–23 mm). The injured scapula was shortened by an average of 3.3 mm (range, 18 mm shorter to 20 mm longer) (P = 0.09). In 15 of 18 patients, the scapular width was shortened by an average of 5.9 mm (range, 1–18 mm), whereas in only 3 of 18 patients was the injured scapular width longer, an average of 9 mm (range, 1–20 mm).

Conclusions: 

In patients with glenoid neck fractures, pure medial translation of the glenoid relative to the axial skeleton rarely occurs. Instead, there is typically a component of shortening of the scapula width combined with lateralization of the scapular body.