ISPUB.COM The Internet Journal of Orthopedic Surgery Volume 21 Number 1 1 of 6 Influence Of Body Positions On Tibio-Femoral Angle Measurement In Children A O Akinpelu, B A Tella, O O Oyewole, A C Odole Citation A O Akinpelu, B A Tella, O O Oyewole, A C Odole. Influence Of Body Positions On Tibio-Femoral Angle Measurement In Children. The Internet Journal of Orthopedic Surgery. 2013 Volume 21 Number 1. Abstract Purpose: Tibio-Femoral Angle (TFA) may be clinically measured in supine or standing positions, but the influence of these positions on TFA measurement has not been extensively investigated. This study was therefore conducted to determine the influence of body positions on TFA measurement in children. Methods: A cross sectional survey was carried out to assess the knee angle of children, ages 1-10 years. The TFA of 1903 children was measured using clinical methods. Results: The mean valgus angle rose steeply from -10.3±9.30 (supine) and -10.1±8.80 (standing) at one year to -15.0±5.50(supine) and -14.7±5.30 (standing) at 3 years, then fell steeply to -10.1±4.70 and -9.6±4.60 at 6 years after which it rose to -10.6±3.00 (supine) and -10.3±3.10 (standing). Measurement of intercondylar/intermalleoli distances showed a similar trend from minimum valgus at one year (-0.1±0.4cm) to a maximum valgus (-2.2±0.1cm) at age 3 years, then falling steeply to -0.7 cm at age 6 years with little change thereafter. Values of TFA measured in standing were significantly lower than those measured in supine (t = 16.5; p = 0.00) but no gender difference. Conclusion: our sample showed a valgus knee angle with minimum values at age 1 year, peak at age 3 years and decreases thereafter. The TFA measurement in standing gives lower values than in supine. Body positions should be considered in interpreting TFA values reported by different studies. INTRODUCTION The development of the knee angle from varus alignment in the infant to valgus alignment in early childhood as a part of normal and physiological development is well documented [1-6]. This physiological variation in knee angle often causes apprehension among the parents [5, 6]. Knowledge of normal variations is useful in alleviating the apprehension of these parents. Such normal ranges have been reported in studies from various regions, some of which suggest that there is regional variation [1-4, 7-9]. The knee angles are often assessed by radiologic, photographic, and clinical techniques [such as Tibiofemoral Angle (TFA), intercondylar distance (ICD) or intermalleoli distance (IMD)] [3-6, 9, 10]. These techniques have been used to assess the normal limits of the TFA in the previous studies. It is important to have a thorough understanding of normal lower limb development and lower extremity examination so that referrals of true pathologic variants to the specialist may be optimized. Five studies have reported patterns of TFA development in Nigerian children and adolescents [4, 9, 11-13]. In most of these studies, TFA was measured using clinical methods to establish normal values, but participants were placed in different positions, such as supine, long sitting and standing. The different positions might be one of the reasons for the different values reported for the same age by these studies. This study was undertaken to determine the influence of two positions (supine and standing) on TFA measurement in Nigerian children age 1-10 years. We hypothesized that body positions would not have any influence on TFA in Nigerian children age 1-10 years. We also assessed pattern of development and the gender variations. METHODS This cross-section survey was approved by the University of Ibadan and University College Hospital Research Ethics Committee. Nine schools (5 private and 4 public) were selected using a table of randomized numbers from the list of 47schools in Ojo Local Education District of Lagos state. The 5 private schools also day care and play group classes from where children ages 1-4 were sourced. Participants were 1903 children between ages 1 and 10 who had no