Understanding the Concept of Medialization in Scapula Fractures

Abstract

To determine whether medial displacement of the glenoid with respect to the midline occurs in scapula fractures and the potential impact on fracture reduction technique. Retrospective case series. Level I trauma medical center. Seventy patients who sustained scapula fractures from 2004 to 2008 and a comparison group of 47 normal patients without scapula fractures. Computed tomography scans were analyzed from all 70 patients who sustained scapula fractures. Measurements were obtained from the most lateral aspect of the glenoid articular surface to the midline (vertebral spinous process) on both the injured and non-injured sides to assess medial or lateral displacement of the glenoid with respect to the midline. The same measurements were obtained bilaterally for the 47 patients in the comparison group. Medial or lateral displacement of the glenoid with respect to the midline. Our results showed that for all 70 patients with scapula fractures, the average distance from the glenoid articular surface to the midline was 6.0 mm ± 10.1 greater for the injured shoulder than for the non-injured side (P = 0.0017), indicating lateral displacement of the glenoid. In the comparison group, the mean right-to-left difference from midline was -0.9 mm ± 9.2 (P = 0.4399). Our analysis demonstrates that in this group of patients with scapula fractures, there was slight lateral displacement of the glenoid with respect to the midline with significant variability in the degree of medial/lateral displacement. This finding provides evidence that the glenoid fragment retains its anatomic position, and the proximal scapula body fragment may be the fracture component that lateralizes. Recognizing this pattern of displacement may enhance our understanding of scapula fractures and the techniques used during open reduction and internal fixation.