Effect of body mass index on quadriceps angle and tibial torsion in school-aged children

Abstract Background The prevalence of excessive body mass (BMI) is increasing in pediatric population. Accordingly, the number of musculoskeletal problems in this population is also likely to increase. The quadriceps angle (Q-angle) is a clinical measure used to measure knee alignment in relation to the hip, femur, and tibia, as well as evaluating alignment of the patella. Tibial torsion (T.T) is an important morphological feature of human tibia. The aim of that study was to study the relationship between the Q-angle and TT in children 8 to 12 years old, the effect of BMI on Q-angle and T.T, and the difference in Q-angle and TT between dominant and non-dominant side. Results “Seventy-five children from primary schools” were enrolled in the study and allocated into 3 groups (25 subjects in each group), according to BMI: group I (normal weight = 25), group II (overweight = 25), and group III (obese = 25). The mean value of age of groups I, II, and III was 10.35 ± 1, 10.74 ± 1.2, and 10.17 ± 1.18 years respectively; the mean value of weight was 29.88 ± 3.94, 43.68 ± 6.55, and 50.06 ± 10.44 kg respectively; the mean value of height was 135.28 ± 7.63, 143.2 ± 8.85, and 140.72 ± 9.3 cm respectively; and the mean value of BMI was 16.22 ± 1, 21.18 ± 1.4, and 25.17 ± 2.67 kg/m 2 . The number (%) of boys in groups I, II, and III was 15 (60%), 18 (72%), and 17 (68%) respectively and of girls was 10 (40%), 7 (28%), and 8 (32%) respectively. The significant values were Q-angle and TT. Data were expressed as mean ± SD. ANOVA was used to compare between subjects’ characteristics of the groups. Kolmogorov-Smirnov test was used for testing normality of data distribution. One-way MANOVA was used to compare parametric variables (Q-angle and TT) between the two groups. Compared with normal weight children, there was statistically significant increase in Q-angle and TT angle in overweight and obese children. Conclusion Any change in BMI would eventually lead to change in both Q-angle and TT angle. The greater the BMI values, the greater the values of Q-angle and TT angle.