German Sport University Cologne, Institute of Biomechanics and Orthopaedics, Germany.
J Biomech. 2011 Feb 24;44(4):706-11. doi: 10.1016/j.jbiomech.2010.10.040. Epub 2010 Nov 13.
The aim of the study was to examine the external knee adduction moments in a group of older and younger adults while descending stairs and thus the possibility of an increased risk of knee osteoarthritis due to altered knee joint loading in the elderly. Twenty-seven older and 16 younger adults descended a purpose-built staircase. A motion capture system and a force plate were used to determine the subjects' 3D kinematics and ground reaction forces (GRF) during locomotion. Calculation of the leg kinematics and kinetics was done by means of a rigid, three-segment, 3D leg model. In the initial portion of the support phase, older adults showed a more medio-posterior GRF vector relative to the ankle joint, leading to lower ankle joint moments (P<0.05). At the knee, the older adults demonstrated a more medio-posterior directed GRF vector, increasing in knee flexion and adduction in the second part of the single support phase (P<0.05). Further, GRF magnitude was lower in the initial and higher in the mid-portions of the support phase for the elderly (P<0.05). The results show that older adults descend stairs by using the trailing leg before the initiation of the double support phase more compared to the younger ones. The consequence of this altered control strategy while stepping down is a more medially directed GRF vector increasing the magnitude of external knee adduction moment in the elderly. The observed changes between leading and trailing leg in the elderly may cause a redistribution of the mechanical load at the tibiofemoral joint, affecting the initiation and progression of knee osteoarthritis in the elderly.
本研究旨在观察老年人和年轻人在上下楼梯时膝关节外展力矩的差异，从而探讨老年人因膝关节负荷改变而导致膝关节骨关节炎风险增加的可能性。27 名老年人和 16 名年轻人使用定制的楼梯进行测试。运动捕捉系统和力板用于确定受试者在运动过程中的三维运动学和地面反作用力（GRF）。通过刚性的、三段式的 3D 腿部模型来计算腿部运动学和动力学。在支撑阶段的初始部分，老年人踝关节处的 GRF 向量更偏向中后部，导致踝关节力矩降低（P<0.05）。在膝关节处，老年人在单支撑阶段的第二部分显示出更偏向中后部的 GRF 向量，随着膝关节的弯曲和内收而增加（P<0.05）。此外，老年人在支撑阶段的初始和中部分的 GRF 幅度较低（P<0.05）。研究结果表明，与年轻人相比，老年人在双支撑阶段开始前更多地使用后腿来下楼梯。这种改变控制策略的结果是，GRF 向量更偏向内侧，增加了老年人膝关节外展力矩的大小。老年人在主导腿和跟随腿之间的观察到的变化可能导致胫骨股骨关节机械负荷的重新分布，从而影响老年人膝关节骨关节炎的发生和进展。
