Study of Knee Angle Development in Healthy Children aged 3-16 years in Ahwaz, IRAN

Abstract

Introduction and aim: In the evaluation of genu varum-genu valgum, tibiofemoral angle (TF angle) and intercondylar (IC) and intermalleolar (IM) distance are commonly measured. This study was to performed to identify the chronological changes of the knee tibiofemoral angle(TF angle) and intercondylar(IC) and intermaleolar(IM) distances in normal healthy children in Khuzestan province. In this study also we considered the effect of epidemiologic factors such as flat foot, height, leg length, weight and delivery kind on TF angle, IC and IM.Methods and Materials: this cross-sectional study was carried out in Ahwaz in 853(M=398, F=455) males and females. The lower limb of children aged from 3-16 years were included in this study. Cases were selected randomly from kinder gardens, preschool care centers and schools of four parts of Ahwaz city. The clinical TF angle was measured with a goniometer in standing position. Superior iliac spine, the center of the patella, and the midpoint of the ankle joint were marked with a pen. After the marking the TF axis, the examiner measured the angle carefully. IC/IM distances were measured using a tape with the child standing with either knees or ankle just touching. The anterior-posterior (AP) radiography of both lower limb were taken in a standing position in some persons, randomly. Weight, height, and leg length were also measured. Information about volunteers delivery have been taken by questionnaires that completed by their families.Results: in the current study, TF angle was 6.16±1.45 (Min=3.5, Max 9.3) with range (4.46±0.5,8.45±0.41). Mean of TF angle in female 6.18 an in male=6.13. Min and Max of TF angle in female were 3.5 and 9.3 respectively. Min and Max of TF angle in male were 4 and 9 respectively. In both sexes TF angle was decreased when age increment. In boys aged 8-9 yrs and 10-11yrs, TF angle showed increment. In girls, increment in TF angle was seen in 3-4, 8-10,11-12, and 14-15 years group.Conclusion: TF angle was significantly higher in cases who born with cesarean section than normal vaginal delivery (p<0.002). Mean of TF angle was lower in cases with flat foot(P<0.035). Mean of IM was significantly higher in cases with flat foot than normal cases(P=0.03). Mean of IC in cases with normal feet was higher than cases with flat feet. Correlation coefficient between IC, IM with weight were -0.4, 0.14 respectively. the TF alignment of children living in Ahwaz is similar to Europe, North America and Turkish children but different from Chinese children. INTRODUCTION AND AIM Knowledge about changes in alignment of lower extremities during grow and its relationship to age are very important to differentiation pathologic and physiologic lower extremities condition. The bowleggedness and knock-knees are frequently encountered in pediatric orthopaedic clinics. Although benign and self-limiting in most cases, these deformities some times cause a great concern to the parents and the relatives1 . At birth, thibiofemoral angle is varus form, then at age 1-1.5 years reach near 0°. At 2-3 years of age, it is in valgus form. Maximum of valgus angle was seen in aged 3-4 years and in 6-7 years is similar to adults2 . The development of the tibiofemoral angle in children in different ages has been of extensive interest for many years3 .The purposes of the present study were to provide normal changes on the intermaleolar(IM); intercondylar(IC) distance and tibio-femoral angle(TF angle) in Khuzestan province in IRAN. METHODS AND MATERIALS This cross-sectional was carried out in Ahwaz in 853(M=398, F=455) males and females. The lower limb of children aged from 3-16 years were included in this study. Cases were selected randomly from kinder gardens, preschool care centers and schools of four parts of Ahwaz city. These case had no evidence of anomaly or joint disease. Individuals with deformity in lower limb, dysplasia of hip, cerebral palsy, neuromuscular dysfunction, and metabolic diseases affecting bone, were excluded in this study. The clinical TF angle was measured with a goniometer in Study of Knee Angle Development in Healthy Children aged 3-16 years in Ahwaz, IRAN 2 of 5 standing position. Superior iliac spine, the center of the patella, and the midpoint of the ankle joint were marked with a pen. After the marking the TF axis, the examiner measured the angle carefully. IC/IM distances were measured using a tape with the child standing with either knees or ankle just touching. TF angle, IM,IC, height, weight, and tibial length were measured for each cases by single experienced examiners. The anterior-posterior (AP) radiography of both lower limb were taken in a standing position in some persons, randomly. Weight, height, and leg length were also measured. Information about volunteers delivery have been taken by questionnaires that completed by their families.