Evaluation of the relationship between scapula morphology and anterior shoulder dislocation accompanying greater tuberosity fracture

Introduction: It is estimated that 5-30% of traumatic anterior shoulder dislocations are accompanied by greater tuberosity fracture (GTF), and the pathomechanism of these fractures is not yet clear. Our hypothesis is to examine the relationship between the scapula morphology and anterior shoulder dislocation (ASD) accompanying GTF. Materials and methods: The patients were divided into two groups according to the accompanying GTF. 40 patients with isolated traumatic ASD and 31 patients with accompanying GTF were included in the study. Critical shoulder angle (CSA), glenoid inclination (GI), acromial index (AI) and greater tuberosity angle (GTA) values were measured in two sessions by two independent observers in the standard antero-posterior radiographs of the patients in both groups. Results: The mean CSA was 40.82 degrees +/- 3.19 degrees and 35.49 degrees +/- 2.19 degrees in accompanying GTF group and the isolated ASD group, respectively. The mean CSA was significantly higher in accompanying GTF group than isolated ASD group (P<0.001). The GI was significantly higher in the isolated ASD than in accompanying GTF group (P = 0.001). The mean GI was 18.7 degrees +/- 6.85 degrees and 10.45 degrees +/- 4.87 degrees in accompanying GTF group and the isolated ASD, respectively. Cut-off value of CSA and GI was 38 degrees (88.2% sensitivity,88.9% specificity) and 14.5 degrees (70.6% sensitivity and 72.2% specificity), respectively. There was no significant difference regarding the mean GTA and AI values between GTF group and the isolated ASD group (P = 0.98, P = 0.63). Conclusions: Increased CSA and GI values are associated with traumatic anterior shoulder dislocation accom-panied by greater tuberosity fracture.