Sabharwal Sanjeev, Zhao Caixia
Department of Orthopedics, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, 90 Bergen Street, Doctor's Office Center, Suite 7300, Newark, NJ 07103, USA.
J Bone Joint Surg Am. 2009 Oct;91(10):2461-8. doi: 10.2106/JBJS.I.00015.
It is well recognized that the alignment of the lower limb changes during early childhood. The hip-knee-ankle angle is often referred to as the mechanical femoral-tibial angle and is measured on a full-length radiograph of the lower extremity. While several authors have independently reported consistent reference values for the hip-knee-ankle angle in adults, such values have not been well documented for children. The purpose of our study was to establish reference values for the hip-knee-ankle angle and assess the relationship between it and the anatomic femoral-tibial angle in children.
A database at a single institution was searched for patients who were between one and less than eighteen years old at the time that a standing full-length radiograph of the lower extremities was made. Radiographs of the uninvolved extremity (the limb without any radiographic abnormalities or documented clinical concerns) were analyzed. The angle between a line connecting the center of the ossified femoral head and the center of the distal femoral epiphysis and another line connecting the center of the distal femoral epiphysis and the center of the talar dome was measured. Simple regression analyses were performed to determine the relationship between this angle and the anatomic femoral-tibial angle.
A total of 354 unaffected lower extremities of 253 children were analyzed. The mean hip-knee-ankle angle was +3.6 degrees (varus) in children between one and two years old and -2.5 degrees (valgus) in those between two and three years old. After the age of seven years, the mean value was +0.3 degrees (varus), which was within 1 degrees of the reference values available for the adult population (mean, +1.2 degrees [varus]). There was a linear relationship between the hip-knee-ankle and anatomic femoral-tibial angles in the children (r = 0.87, p < 0.0001). Despite varying hip-knee-ankle angles at different ages, the mean absolute difference between that angle and the anatomic femoral-tibial angle remained relatively constant (mean, 6.7 degrees ) and was not associated with changing age (r = -0.09).
In our study sample, reference values for the hip-knee-ankle angle in children older than seven years of age approached those reported for adults in North America. Although this angle and the anatomic femoral-tibial angle in children younger than seven were distinct from those reported for the adult population, the difference between the two angular measurements remained essentially unaffected. The use of age-specific reference values for both the hip-knee-ankle and the anatomic femoral-tibial angle is recommended for children younger than seven years old.
人们普遍认识到，幼儿期下肢的对线会发生变化。髋-膝-踝角通常被称为机械性股胫角，通过下肢全长X线片进行测量。虽然有几位作者独立报告了成人髋-膝-踝角的一致参考值，但儿童的此类值尚未得到充分记录。我们研究的目的是建立儿童髋-膝-踝角的参考值，并评估其与解剖学股胫角之间的关系。
在一家单一机构的数据库中搜索在拍摄下肢站立全长X线片时年龄在1岁至未满18岁之间的患者。分析未受累肢体（无任何X线异常或记录在案的临床问题的肢体）的X线片。测量连接股骨头骨骺中心与股骨远端骨骺中心的线与连接股骨远端骨骺中心与距骨穹窿中心的另一条线之间的角度。进行简单回归分析以确定该角度与解剖学股胫角之间的关系。
共分析了253名儿童中354条未受影响的下肢。1至2岁儿童的平均髋-膝-踝角为+3.6度（内翻），2至3岁儿童为-2.5度（外翻）。7岁以后，平均值为+0.3度（内翻），在成人参考值（平均值，+1.2度[内翻]）的1度范围内。儿童的髋-膝-踝角与解剖学股胫角之间存在线性关系（r = 0.87，p < 0.0001）。尽管不同年龄的髋-膝-踝角有所不同，但该角度与解剖学股胫角之间的平均绝对差值保持相对恒定（平均值，6.7度），且与年龄变化无关（r = -0.09）。
在我们的研究样本中，7岁以上儿童的髋-膝-踝角参考值接近北美报道的成人参考值。虽然7岁以下儿童的这个角度和解剖学股胫角与成人报道的不同，但两个角度测量值之间的差异基本不受影响。对于7岁以下儿童，建议使用针对年龄的髋-膝-踝角和解剖学股胫角参考值。
