Risk Factors for Severe Proximal Humerus Fracture and Correlation Between Deltoid Tuberosity Index and Bone Mineral Density

INTRODUCTION: The aims of this study were to investigate (1) whether demographic factors would be risk factors for severe proximal humerus fracture (PHF), (2) relationship of radiological parameters with bone mineral density (BMD), deltoid tuberosity index (DTI), or severe PHF, and (3) correlation between DTI and BMD. METHODS: We conducted a cross-sectional study based on radiographs and medical records taken during admission or the visit to the orthopedic clinic. We reviewed consecutive 100 adult patients who were diagnosed with PHF in our hospital from March 2014 to December 2016. Three- and 4-part fractures were regarded as severe PHFs. Univariable and multivariable logistic regression analyses were performed to evaluate risk factors for severe PHF. Also, we investigated the correlation between BMD and DTI using the additional BMD data of the patients who underwent shoulder surgeries. RESULTS: This study included 62 nonsevere PHFs and 38 severe PHFs. There were 30 male and 70 female patients with a mean age of 66.4 ± 16.4 years. Mean T score of BMD was −2.5 ± 0.9 at the time of injury. Logistic regression analyses showed that age (odds ratio: 1.044, range: 1.011-1.079, P = .009) and sex (odds ratio of females: 3.763, range: 1.236-11.459, P = .020) were related to severe PHF. The group satisfying the radiological parameter criteria had significantly higher rates of severe PHF. The correlation coefficient (r) between DTI and T score was 0.555 (P < .001). DISCUSSION AND CONCLUSION: Older age and female were the independent risk factors for severe PHF. Conversely, BMD and other medical comorbidities were not risk factors for severe PHF. Deltoid tuberosity index showed significantly high intraclass correlation coefficient and a strong correlation with the T score of BMD. Therefore, DTI may be useful for screening osteoporosis in PHF patients. LEVEL OF EVIDENCE: Level IV, Cross-sectional study.