临床上,前交叉韧带重建(ACLr)后的步态正常化定义为没有可观察到的偏差。然而,生物力学研究报告在负荷反应(LR)期间改变了膝关节力学;双肢支撑和四肢之间的重量转移时间。可以想象,全身力学的微妙调整,包括质心(COM)速度和地面反作用力(GRF)峰值和时间,是存在的。
目的是比较ACLr术后手术和非手术肢体步态LR期间的肢体和全身力学。
初始接触时的前和垂直COM速度;膝关节屈曲运动范围,膝关节伸肌力矩峰值,峰值垂直和后GRF,在ACLr后112±17天,确定了20名个体在LR期间的最小垂直COM位置以及最大前和垂直COM速度,而没有可观察到的步态缺陷。要评估COM变量时序的差异,计算耦合角(矢量编码),用于垂直和前后COM速度和GRF的多方向协调,并归类为同相,反相,垂直相位,或前后相协调。配对t检验比较了四肢之间的峰值;非参数Wilcoxon符号秩检验比较了协调模式频率。
膝部运动范围较小(5.6°),膝关节伸肌力矩减小30%,后GRF小11%,与非手术肢体相比,在手术中观察到初始接触时的前COM速度(2%)和LR期间的峰值(1.3%;所有p<0.05)。对于COM速度协调,在手术肢体中观察到较少的反相位(7.38%)和较大的同相位协调(2.88%).对于GRF协调,在手术肢体中观察到较少的同相协调(1.94%)。
协调模式的差异,建议ACLr后的个体对全身力学的时间进行细微调整;特别是在步态期间的COM速度。这些调整与手术膝盖中的矢状平面载荷减少是一致的。
Clinically, normalization of gait following anterior cruciate ligament reconstruction (ACLr) is defined as the absence of observable deviations. However, biomechanical studies report altered knee mechanics during loading response (LR); a time of double limb support and weight transfer between limbs. It is conceivable that subtle adjustments in whole body mechanics, including center of mass (COM) velocity and ground reaction force (GRF) peaks and timing, are present.
The purpose was to compare limb and whole body mechanics during LR of gait in the surgical and non-surgical limbs post-ACLr.
Anterior and vertical COM velocity at initial contact; knee flexion range of motion, peak knee extensor moment, peak vertical and posterior GRF, minimum vertical COM position and maximum anterior and vertical COM velocity during LR were identified for twenty individuals 112 ± 17 days post-ACLr without observable gait deficits. To assess differences in timing of COM variables, coupling angles (vector coding) were calculated for multidirectional coordination of vertical and anteroposterior COM velocities and GRFs and categorized as in-phase, anti-phase, vertical phase, or anteroposterior phase coordination. Paired t-tests compared peaks between limbs; non-parametric Wilcoxon signed-rank tests compared coordination pattern frequency.
Less knee range of motion (5.6 °), 30% smaller knee extensor moment, 11% smaller posterior GRF, and slower anterior COM velocity at initial contact (2%) and peak during LR (1.3%; all p < 0.05) were observed in the surgical compared to the non-surgical limb. For COM velocity coordination, lesser anti-phase (7.38%) and greater in-phase coordination (2.88%) were observed in the surgical limb. For GRF coordination, less in-phase coordination (1.94%) was observed in the surgical limb.
Differences in coordination patterns, suggest that individuals post-ACLr make subtle adjustments in timing of whole body mechanics; particularly in COM velocity during gait. These adjustments are consistent with reduced sagittal plane loading in the surgical knee.