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.