Specogna Adrian V, Birmingham Trevor B, Hunt Michael A, Jones Ian C, Jenkyn Thomas R, Fowler Peter J, Giffin J Robert
Wolf Orthopaedic Biomechanics Laboratory, Fowler Kennedy Sport Medicine Clinic, Univerwity of Western Ontario, London, Canada.
Am J Sports Med. 2007 Jan;35(1):65-70. doi: 10.1177/0363546506293024. Epub 2006 Sep 22.
Radiographic measures of lower limb malalignment are used to indicate abnormal loading of the knee and to plan corrective procedures.
Weightbearing status during hip-to-ankle radiographs will significantly affect malalignment measures; malalignment in single-limb standing will be most highly correlated to the external knee adduction moment during gait, a proposed dynamic measure of functional knee joint load.
Controlled laboratory study.
Mechanical axis angle was measured in 40 patients with varus gonarthrosis from hip-to-ankle radiographs taken with patients in single-limb standing, double-limb standing, and supine positions. Kinematic and kinetic data were collected during walking and used to calculate the peak adduction moment about the knee.
Repeated-measures analysis of variance and Scheffé post hoc tests indicated that mechanical axis angle measured on single-limb standing radiographs (-8.7 degrees +/- 4.0 degrees) was significantly greater than on double-limb standing radiographs (-7.1 degrees +/- 3.8 degrees), which was significantly greater than on supine radiographs (-5.5 degrees +/- 2.8 degrees). The peak knee adduction moment (2.8 +/- 0.8 percentage body weight x height) was only moderately correlated with mechanical axis angle on single-limb standing (r = -0.46), double-limb standing (r = -0.45), and supine (r = -0.43) radiographs.
Patient position significantly affects frontal plane knee alignment. However, the peak knee adduction moment is only moderately correlated to mechanical axis angle, regardless of weightbearing status.
These findings are inconsistent with the hypothesis that mechanical axis angle measured in single-limb standing is more representative of dynamic joint load and further highlight the differences between static and dynamic measures. Results also underscore the importance of reporting patient position during radiographs and keeping positions consistent when evaluating patients over time.
下肢力线排列的影像学测量用于指示膝关节的异常负荷并规划矫正程序。
髋至踝关节X线片拍摄期间的负重状态将显著影响力线排列测量结果；单腿站立时的力线排列与步态期间的膝关节外展力矩相关性最高，膝关节外展力矩是一种提议的功能性膝关节负荷动态测量指标。
对照实验室研究。
对40例膝内翻患者在单腿站立、双腿站立和仰卧位时拍摄髋至踝关节X线片，测量机械轴角。在步行过程中收集运动学和动力学数据，并用于计算膝关节的峰值内收力矩。
重复测量方差分析和谢费尔事后检验表明，单腿站立X线片上测量的机械轴角（-8.7度±4.0度）显著大于双腿站立X线片上的测量值（-7.1度±3.8度），而双腿站立X线片上的测量值又显著大于仰卧位X线片上的测量值（-5.5度±2.8度）。膝关节峰值内收力矩（2.8±0.8体重百分比×身高）与单腿站立（r=-0.46）、双腿站立（r=-0.45）和仰卧位（r=-0.43）X线片上的机械轴角仅呈中度相关。
患者体位显著影响额状面膝关节力线排列。然而，无论负重状态如何，膝关节峰值内收力矩与机械轴角仅呈中度相关。
这些发现与单腿站立时测量的机械轴角更能代表动态关节负荷这一假设不一致，并进一步突出了静态和动态测量之间的差异。结果还强调了在X线片拍摄期间报告患者体位以及在长期评估患者时保持体位一致的重要性。
