Impact of body mass index on fracture severity, clinical, radiological and functional outcome in distal radius fractures: a retrospective observational study after surgical treatment

Distal radius fracture (DRF) is one of the three most common fractures of the human body with increasing incidences in all groups of age. Known causes of increasing incidence, such as ageing of the population or increased obesity, have been described and discussed. So far, literature reports ambivalent effects of body mass index (BMI) on bone physiology. It is worthwhile to examine the influence of BMI on the outcome of fractures more detailed. This study aims to investigate the influence of an abnormal BMI on fracture severity and treatment, as well as clinical, radiological, and functional outcome to improve clinical decision making. A retrospective observational study was conducted on data obtained from patients, who underwent open reduction and internal fixation (ORIF) of a DRF at a local Level 1 Trauma Center between May 2018 and October 2021. Follow-up examinations were performed approximately 1 year after surgical fracture treatment, during which various questionnaires and functional measurements (CMS, DASH, NRS, ROM) were applied. In addition, postoperative complications were recorded and radiological examinations of the affected hand were performed. After excluding incomplete data sets and applying set exclusion criteria, the complete data of 105 patients were analyzed. 74 patients were female and 31 male with significant difference in mean BMI [p = 0.002; female: 23.8 (SD ± 3.3), men: 26.2 (SD ± 3.9)]. Patients with higher BMI had significantly more severe fractures (p = 0.042). However, there was no significant difference in surgery time for fracture management. At follow-up, patients with lower BMI showed a smaller difference in hand strength between the fractured and the other hand (p = 0.017). The BMI had no significant effect on the clinical and radiological outcome. Despite the ambivalent effects of BMI on the skeletal system, our findings indicate that a higher BMI is associated with more severe DRF. Thereby BMI does not correlate with surgery time for fracture treatment. Furthermore, no evidence of an influence on the clinical and radiological outcome could be detected.