Malunion following displaced fractures of clavicle most commonly occurs with shortening and anterior rotation of the distal fragment. This results in scapular malalignment, which has been documented clinically as scapular winging. However, to our knowledge, this scapular malalignment has never been quantified radiographically. The purpose of our study was to quantify the radiographic parameters in patients with symptomatic midshaft clavicle malunions demonstrating scapular winging.

Fourteen patients with symptomatic midshaft clavicle malunions demonstrating scapular winging of the affected shoulder were identified. Each patient underwent CT scanning of both clavicles and scapulae. A standardised CT protocol was used for each patient. Multiple measurements were used to document the clavicle malunion and scapular malalignment including clavicular length, the distance from the tip of the scapula to the chest wall and to the nearest adjacent spinous process, and the relative height of each scapula on the chest wall. Statistical analysis using the Student t-test was performed.

The mean time from fracture was twenty-nine months. There were eleven males and three females with a mean age of 33.1 years. The mean clavicular shortening was 17mm (P> 0.001). The mean anterior-rotation through the malunion was nine degrees, and showed a trend toward significance (P=0.1). The distal fragment was anteriorly translated 13.5mm (P> 0.001) relative to the opposite normal shoulder. The scapula was displaced laterally 10.3mm (P> 0.001) from the nearest spinous process, superiorly 16.3mm and 12.2mm (P> 0.001) off the chest wall on average compared to the opposite normal shoulder.

Patients with symptomatic clavicle malunions often complain of periscapular pain, and winging of the scapula has been noted in such individuals. Ours is the first study to document and quantify scapular malalignment in this clinical setting. Since most shoulder musculature is scapular based, identification and quantification of scapular malalignment may have important ramifications in decision-making regarding treatment of clavicle fractures and malunions.