Blumentritt S, Schmalz T, Jarasch R
Otto Bock Health Care GmbH, Forschung, Max-Näder-Strasse 15, 37115 Duderstadt.
Orthopade. 2001 Mar;30(3):161-8. doi: 10.1007/s001320050590.
The influence of three alignment parameters of a transtibial prosthesis (sagittal foot position, plantar flexion, mediolateral foot position) on the load and motion of the lower extremity joints was investigated in 13 unilateral transtibial amputees. The aim was to determine whether a correlation exists between static prosthetic alignment and gait pattern that would allow an optimal biomechanical prosthetic alignment. The gait pattern was measured using kinematic, kinetic, and electromyographic methods. Statics was defined using the alignment apparatus L.A.S.A.R. Posture. The electromyogram of the m. vastus lateralis and m. biceps femoris was recorded on both sides. The motion of joints is described by joint angles. External joint moments define the mechanical loads. Alignment has almost no influence on muscle activity and joint mechanics of the contralateral leg. In contrast, prosthetic alignment affects clearly and systematically the load and motion of the knee joint during the stance phase on the ipsilateral side. The sagittal foot position influences the maximal flexion angle in the stance phase. The plantar flexion of the foot affects the temporal structure of knee motion. The mediolateral foot position causes correspondingly different varus and valgus moments acting on the knee. Swing phase motion does not depend on prosthetic alignment. The iEMG of the m. vastus lateralis is reduced. Innervation characteristics of the m. biceps femoris on the prosthetically fitted leg has completely changed. The ischiocrural muscles take over the neuromuscular action of the m. gastrocnemius to compensate for the external knee extension moment during the second part of the stance phase. Prosthetic statics determines if the knee joint is physiologically stressed in a standing posture and during walking. Statics will be correct if the anatomical knee axis of the standing amputee is located about 15 mm posterior to the load line in the sagittal plane. In the frontal plane, the load line touches the lateral patella border and strikes the middle of the foot about 5 cm anterior to the adapter. During walking, attention should be paid to performance of knee flexion in the stance phase.
在13名单侧经胫骨截肢者中，研究了经胫骨假体的三个对线参数（矢状面足部位置、跖屈、内外侧足部位置）对下肢关节负荷和运动的影响。目的是确定静态假体对线与步态模式之间是否存在相关性，从而实现最佳的生物力学假体对线。使用运动学、动力学和肌电图方法测量步态模式。使用L.A.S.A.R. Posture对线装置定义静态状态。记录双侧股外侧肌和股二头肌的肌电图。关节运动通过关节角度来描述。外部关节力矩定义机械负荷。对线对健侧腿的肌肉活动和关节力学几乎没有影响。相比之下，假体对线在同侧站立期对膝关节的负荷和运动有明显且系统性的影响。矢状面足部位置影响站立期的最大屈曲角度。足部的跖屈影响膝关节运动的时间结构。内外侧足部位置会相应地在膝关节上产生不同的内翻和外翻力矩。摆动期运动不依赖于假体对线。股外侧肌的表面肌电图降低。假肢侧股二头肌的神经支配特征完全改变。坐骨神经支配的肌肉在站立期第二部分接管了腓肠肌的神经肌肉作用，以补偿外部膝关节伸展力矩。假体静态状态决定了膝关节在站立姿势和行走过程中是否受到生理应力。如果站立截肢者的解剖学膝关节轴线在矢状面内位于负荷线后方约15毫米处，则静态状态是正确的。在额状面内，负荷线接触髌骨外侧边缘，并在适配器前方约5厘米处撞击足部中部。在行走过程中，应注意站立期膝关节屈曲的表现。
