Objectives: A cross sectional study was conducted to assess the knee joint alignment in overweight and obese children, compare their findings with normal weight children and to determine the relationship between body mass index and deformities of the knee joint in the 3 groups. Methods: 220 children from both sexes with age ranged from 8 to 12 years were participated in this study. They were classified according to body mass index into normal, overweight and obese children. The tibiofemoral and knee hyperextension angles were measured by using a computer aided design (Auto CAD) program and the intermalleolar and intercondylar distances were assessed for all children. Results: Statistically significant differences in tibiofemoral angle, intermalleolar distance and knee hyperextension angle were found among the 3 groups with greater values in obese children. There were significant correlations between body mass index and intermalleolar distance as well as knee hyperextension angle in overweight and obese children. Significant differences were also observed between boys and girls in tibiofemoral angle in the 3 groups. Conclusion: It was concluded that increased body mass index in children may lead to adverse effects on the knee joint in the form of genu valgus and recurvatum which may progress to sever deformities later in life if body mass indexis not controlled.
