R. Belayneh1,2, J. Haglin1, A. Lott1, S. Konda1, K. A. Egol1 1New York University School Of Medicine,New York, NY, USA 2Howard University College Of Medicine,Washington, DC, USA
Introduction: The prevalence of obesity in adults has increased significantly in the United States and worldwide. It has been extensively reported in the literature to cause not only medical problems, but musculoskeletal issues as well. In addition to being associated with high rates of osteoarthritis as compared to normal weight populations, obese patients have a 48% increased risk of trauma, including minor injuries and fractures. Obesity is also associated with an increased risk of injury to the upper limbs resulting from falls from an individual’s own height, including proximal humerus fractures, which account for 4-6% of all fractures. The purpose of this study is to evaluate if there is a relationship between obesity and proximal humerus fracture characteristics.
Methods: : Proximal humerus fractures at one academic medical center were prospectively followed. Fractures were classified according to the international AO-Müller/Orthopedic Trauma Association (AO/OTA) classification in order to determine their severity. All Type OTA 11-A proximal humerus fractures were categorized as less severe and type OTA 11-B or 11-C were categorized as more severe. Patients’ Body Mass Indexes (BMI) were calculated and used to identify two groups, BMI ≥ 30 kg/cm (obese) and < 30 kg/cm (non-obese). Variables such as age, gender, height, weight, Charlson Comorbity Index (CCI), AO classification; number of complications, latest follow-up shoulder range of motion (ROM), latest follow-up Disabilities of the Arm, Shoulder, and Hand (DASH) survey scores were also recorded. Independent t-tests were used for statistical analysis of continuous variables and χ2 tests for categorical variables. Regression analysis was performed to determine if BMI was a predictor of severity of fractures as determined by the AO classification. Statistical significance was considered as p<0.05.
Results: Overall, 190 patients who sustained proximal humerus fractures were available for analysis where the average age at time of injury was 59.6±13.9 years. There were 56 OTA 11-A, 67 OTA 11-B, and 67 OTA 11-C fracture types. 58 patients (30.5%) were obese, while 132 patients (69.5%) were non-obese. No significant differences were seen between groups in regards to age, gender, height, CCI, complication rates, or functional and clinical outcomes as determined by follow-up DASH scores and shoulder ROM, respectively. Statistical analysis also demonstrated that obese patients had greater fracture severity per the AO classification (P=0.025).
Conclusion: Based on the results of this study, obesity is associated with more severe fractures of the proximal humerus as determined by the AO/OTA classification. However, there are no differences outcomes or complication rates between obese patients and non-obese patients. With increasing rates of obesity, this relationship may have important epidemiological implications in the future, including predicting proximal humerus fracture burden and severity in society. Additionally, orthopaedic surgeons should be reassured that performing proximal humerus fixation in obese patients yields similar outcomes and complication rates to non-obese patients.