Inferior displacement sign in fracture of humeral greater tuberosity / 中华创伤骨科杂志

ABSTRACT

Objective To explore the clinical significance of the inferior displacement sign on the initial anterioposterior (AP) view X-ray for fractures of humeral greater tuberosity.Methods This study retrospectively analyzed the imaging and clinical data of 24 patients with isolated fracture of humeral greater tuberosity who had sought medical treatment during the period from January 2008 to June 2015.They were 10 males and 14 females,with an average age of 54 years (from 19 to 68 years).Laterality8 left sides and 16 right sides.The AP view X-ray films of the 24 patients present the inferior displacement sign defined as the inferior cortical margin of the greater tuberosity overlapping the proximal humeral shaft on the initial AP view.The patients received further CT examination to determine the displacement direction and whether the humeral neck fracture was complicated.Results A slight displacement of humeral anatomic neck fracture was shown on the initial AP view X-ray in 10 patients.Further CT examination revealed that humeral anatomic neck fracture was confirmed in 23 patients,the greater tuberosity was displaced posteriorly in 22 patients and posteroinferiorly in 2 patients.Radiographic measurements showedthe mean posterior displacement was 10.5 ±4.5 mm;the displacement between the humeral head and the humeral shaft was 2.5 ± 1.5 mm;the neck shaft angle was 147.2° ± 9.2°;the distance between the humeral head and greater tuberosity was 10.8 ± 3.4 mm;the overlap between the inferior edge of greater tuberosity and the upper edge of lateral humeral shaft was 12.5±5.9 mm.Pearson correlation analysis showed no correlation between the overlap and the head-tuberosity distance (P ＞ 0.05),but a significant correlation between the overlap and the neck-shaft angle (P ＜ 0.05).Conclusions The inferior displacement sign on the initial AP view X-ray is actually the overlap of posterior displaced greater tuberosity fracture shown on the X-ray.The posterior displaced greater tuberosity fracture complicated with slight displaced anatomic neck fracture is a presentation of the valgus impacted fracture of the proximal humerus.The inferior displacement sign in the fracture of humeral greater tuberosity can highly suggest the presence of occult or slight displacement of the humeral anatomic neck fracture.