A Study of Factors Associated With Carrying Angle of the Human Elbow in Pediatric Age Group

Purpose This prospective cohort study aims to determine the factors that are associated with the carrying angle of the human elbow in the pediatric age group. Methods One hundred forty children up to 15 years of age were assessed for age, sex, forearm lengths of both sides, arm length of both sides, trans-trochanteric diameter, height, BMI, the inter-epicondylar distance of both sides, Baumann's angle of both sides, presence or absence of secondary sexual characteristics, clinical carrying angle (CCA) of both sides, and radiological carrying angle (RCA) of both sides. Unpaired t-test was used to compare the means of carrying angle in the unrelated groups, namely gender and secondary sexual characteristics. The strength and direction of the relationship between carrying angle and continuous variables were tested by calculating Pearson's correlation. Variables found to be associated with carrying angle at significance level >0.25 on bi-variable analysis were used to design a linear regression model to identify factors associated with carrying angle. Results The mean age was 5.84±4.76 years. Ninety-eight (70%) were males, and forty-two (30%) were females. The mean CCA on the right side was 8.55±2.01. The mean CCA on the left side was 8.77±2.03. The mean RCA on the right side was 8.85±2.09. The mean RCA on the left side was 9.07±2.13. On bi-variable analysis, the CCA was found to be associated with age, secondary sexual characteristics, weight, height, arm length, forearm length, inter-epicondylar distance, trans-trochanteric distance, and Baumann's angle. CCA was found to be significantly negatively correlated with BMI. On multivariate linear regression, the CCA was found to be associated with age and inter-epicondylar distance. Conclusion Age and inter-epicondylar distance are the true associations of carrying angle.