The Effect of Obesity on Pediatric Tibia Fractures.

Background: Childhood obesity affects nearly one fifth of all children in the United States. Understanding the unique injury characteristics and treatment of tibia fractures in this population has become increasingly important. This study aims to explore the different injury characteristics between tibia fractures in obese and non-obese children. Methods: 215 skeletally immature children aged 2-18 who sustained tibia fractures between 2007.2019 were retrospectively reviewed. Patients were analyzed by weight group: underweight, normal weight, overweight, and obese as defined by body mass index (BMI) percentile based upon age. Analyses were performed on dichotomized groups: underweight and normal weight versus overweight and obese. Chi-square or Fisher's exact test was used to compare differences in categorical outcome between the 2-category BMI class variables; Wilcoxon test was used to compare continuous outcomes. A multivariate logistic regression model was used to evaluate BMI associations while controlling for age, sex, race, and mechanism of injury. Results: Distribution of BMI in the cohort included 6.5% underweight, 45.6% normal weight, 16.7% overweight and 31.2% obese. Overweight and obese children sustained fractures from low energy mechanisms at more than double the rate of normal and underweight children (20.5% versus 9.7%, p=0.028). Overweight and obese children sustained physeal fractures at a rate of 54.4% in comparison with 28.6% in their normal and underweight peers (p<0.0001, OR 2.50 (95% CI, 1.26-4.95)). Overweight and obese children sustained distal 1/3 tibia fractures at a higher rate of 56.9% compared to under and normal weight children at 33.9% (p=0.003, OR 2.24 (95% CI, 1.17-4.30)). Overweight and obese children underwent unplanned changes in treatment at a lower rate than normal and underweight children at 1% versus 8% rates of treatment change, respectively (p=0.013, OR 0.076 (95%CI, 0.009-0.655)). No significant differences were found in the rates of operative treatment, repeat reduction, post treatment complications, or physical therapy. Conclusion: Overweight children sustain tibia fractures from low energy mechanisms at higher rates than their peers. Similarly, obese and overweight patients have higher rates of physeal injuries and higher rates of distal 1/3 tibia fractures. Complication rates are similar between obese and non-obese children undergoing treatment for tibia fractures.