Inferior displacement of greater tuberosity fracture suggests an occult humeral neck fracture: a retrospective single-centre study.

PURPOSE: To radiographically characterize the relationship between inferior displacement of great tuberosity (GT) fracture and associated occult or minor displaced humeral neck fracture.

METHODS: Thirty patients with inferior displacement of the GT on the initial anterior-posterior (AP) view X-ray were included in this study. Twenty-four patients received further computed tomography (CT) scans. One patient with negative CT scans underwent MRI. Radiographic indexes included the cervico-diaphyseal angle, the distance of the inferior displacement of the GT fracture, the apex-tuberosity distance, and the direction of the GT shift on the 3D-CT scan. The measurement reliability was analyzed by calculating intra-class correlation (ICC) coefficients. The relationships between the parameters were revealed using Pearson correlation analysis.

RESULTS: In the 30 cases, humeral neck fractures were detected by AP view X-ray (6 cases), CT (23 cases), and MRI (1 case). The mean cervico-diaphyseal angle was 146.7° ± 8.9°. The mean inferior displacement of the GT fracture was 13.4 ± 5.9 mm. The mean apex-tuberosity distance was 11.8 ± 2.8 mm. Posterior/inferior displacement of the GT fractures was observed in 24 patients via CT scan. All the evaluated parameters presented correlations among methods, indicating intra-rater and inter-rater reliability. The Pearson correlation analysis revealed that inferior displacement of GT fracture was correlated with the cervico-diaphyseal angle (P < 0.05).

CONCLUSION: The inferior displacement of GT fracture on AP view X-ray is a useful diagnostic clue for the early recognition of occult humeral neck fracture and may indicate the need for further CT/MRI examination.