Normal Development of the Tibiofemoral Angle in Children: A Clinical Study of 590 Normal Subjects From 3 to 17 Years of Age Mehmet Arazi, M.D., Tunc ¸ C. O ¨ g ˘u ¨ n, M.D., and Recep Memik, M.D. Study conducted at Department of Orthopaedic Surgery and Traumatology, Selc ¸uk University, Konya, Turkey Summary: In evaluation of genu varum–genu valgum, tibio- femoral (TF) angle and intercondylar (IC) or intermalleolar (IM) distance are commonly measured. In this study, we de- termined mean values and normal limits for TF angle and IC/ IM distance in 590 normal Turkish children (287 girls and 303 boys) aged from 3 to 17 years using clinical methods. We noted a significantly higher degree of valgus angle than that in pre- vious reports. The maximal mean valgus angle was 9.6 degrees at 7 years for boys and 9.8 degrees at 6 years for girls. These differences were considered racial differences between Turkish children and those of other races. Turkish children, aged be- tween 3 and 17 years, exhibited 11 degrees physiologic val- gus. A measurable varus angle or a valgus higher than 11 degrees during this period should be considered abnormal. Key Words: Children—Clinical measurements—Genu valgum— Genu varum—Knee angle. Mild to moderate bowlegs in newborn and knock- knees in early childhood are well-defined and common orthopedic problems. Both pediatricians and pediatric or- thopaedic surgeons are often faced with these situations. Knowledge of normal limits of the tibiofemoral (TF) angle is important for explanation of some informative details about normal development of children to parents. Several studies have been reported and new techniques also have been described for measuring the TF angle. Radiologic, photographic, and clinical techniques have been used to assess the normal limits in TF angle (1– 4,6,9). Previously reported studies were conducted in some parts of the developmental period. There is no re- port about TF angle changes and intercondylar (IC) or intermalleolar (IM) distance in normal children from the beginning of walking age to the end of the adolescent period. We aimed to determine mean values and normal limits for TF angle and IC/IM distance in normal Turkish chil- dren aged from 3 to 17 years using clinical methods. MATERIALS AND METHODS The lower limbs of 590 Turkish children aged from 3 to 17 years were included in this study. The measure- ments were documented according to each age group (Fig. 1). There were 287 girls and 303 boys. They were selected from a daycare and preschool care center and four schools. The children with a history of musculoskel- etal system disorders were excluded from study. TF angle The clinical TF angle was measured with a goniometer in a standing position, using the method adopted by Cheng et al. (2). Superior iliac spines, the center of the patella, and the midpoint of the ankle joint were marked with a pen. After the marking of the TF axis, the exam- iner measured the angle carefully. Both lower limbs were measured (1,180 measurements) for each subject. A varus angle was expressed in positive degrees. All mea- surements were made by one author (M.A.). IC and IM distances The IC and IM distances were measured with a tape measure, as previously described (4). A measurable IM distance was expressed as negative values in centimeters. Weight and standing heights also were measured to investigate the connection of the TF angle to them. Statistical analysis Statistical analyses were conducted using SPSS ver- sion 8.0 for Windows. Mann–Whitney U test (corrected z test) was used to assess variables for differences be- tween different age groups of boys and girls. Correla- tions between the TF angle and weight and standing height measurements were studied by performing Pear- son’s correlation test. In all statistical tests, the null hy- pothesis was rejected at p < 0.05. Address correspondence and reprint requests to Dr. M. Arazi, Selc ¸uk University, Tip Fak. Ortopedi ve Travma Klin, 42080-Konya, Turkey (e-mail: marazi@selcuk.edu.tr). From the Department of Orthopaedic Surgery and Traumatology, Selc ¸uk University, Faculty of Medicine, Konya, Turkey. Journal of Pediatric Orthopaedics 21:264–267 © 2001 Lippincott Williams & Wilkins, Inc., Philadelphia 264