Abstract：
BACKGROUND: Many patients report more difficulty when descending stairs compared to level walking after total knee arthroplasty (TKA). Different implant designs can affect knee biomechanics and muscle activity during gait, but their effect during stair descent is unclear. The purpose of this study was to evaluate knee biomechanics and muscle activations of quadriceps, hamstrings, and gastrocnemius muscles during a stair descent task in patients who underwent TKA with either a posterior stabilized (PS) or medial ball-and-socket (MBS) implant and to compare them to a group of healthy controls.
METHODS: There were 28 TKA patients who were randomized to either an MBS (n = 14) or PS (n = 14) implant and were compared with 14 controls. Patients visited the biomechanics lab approximately 12 months after TKA, where knee biomechanics and muscle activity were measured as they descended a three-step staircase.
RESULTS: Compared to the MBS and control groups, the PS group descended the stairs with a reduced knee flexion angle and greater hamstring muscle activation throughout single limb support. Knee joint moments and power were similar between the MBS and PS groups, but neither reached the level of the control group.
CONCLUSIONS: Lower knee flexion angles and increased hamstring muscle activity indicated that the PS group descended the stairs with a stiffer knee gait pattern than the MBS group. The MBS implant design may provide additional stability as patients require less muscle activity than the PS group.
METHODS: There were 28 TKA patients who were randomized to either an MBS (n = 14) or PS (n = 14) implant and were compared with 14 controls. Patients visited the biomechanics lab approximately 12 months after TKA, where knee biomechanics and muscle activity were measured as they descended a three-step staircase.
RESULTS: Compared to the MBS and control groups, the PS group descended the stairs with a reduced knee flexion angle and greater hamstring muscle activation throughout single limb support. Knee joint moments and power were similar between the MBS and PS groups, but neither reached the level of the control group.
CONCLUSIONS: Lower knee flexion angles and increased hamstring muscle activity indicated that the PS group descended the stairs with a stiffer knee gait pattern than the MBS group. The MBS implant design may provide additional stability as patients require less muscle activity than the PS group.
摘要：
背景：与全膝关节置换术（TKA）后的水平行走相比，许多患者报告下楼梯时更困难。不同的植入物设计会影响步态过程中的膝关节生物力学和肌肉活动，但它们在楼梯下降过程中的作用尚不清楚。这项研究的目的是评估膝关节生物力学和股四头肌的肌肉活动，腿筋,在接受TKA并进行后稳定型（PS）或内侧球窝（MBS）植入物的患者的楼梯下降任务期间，腓肠肌和腓肠肌，并将其与一组健康对照进行比较。
方法：有28名TKA患者随机接受MBS（n=14）或PS（n=14）植入，并与14名对照组进行比较。患者在TKA后约12个月访问了生物力学实验室，当他们下楼梯时，测量了膝盖的生物力学和肌肉活动。
结果：与MBS组和对照组相比，PS组下楼梯时，膝盖屈曲角度减小，并且在整个单肢支撑中的腿筋肌肉激活更大。MBS组和PS组的膝关节力矩和力量相似，但均未达到对照组的水平。
结论：较低的膝关节屈曲角度和增加的腿筋肌肉活动表明，PS组比MBS组以更硬的膝关节步态模式下楼梯。MBS植入物设计可以提供额外的稳定性,因为患者比PS组需要更少的肌肉活动。
方法：有28名TKA患者随机接受MBS（n=14）或PS（n=14）植入，并与14名对照组进行比较。患者在TKA后约12个月访问了生物力学实验室，当他们下楼梯时，测量了膝盖的生物力学和肌肉活动。
结果：与MBS组和对照组相比，PS组下楼梯时，膝盖屈曲角度减小，并且在整个单肢支撑中的腿筋肌肉激活更大。MBS组和PS组的膝关节力矩和力量相似，但均未达到对照组的水平。
结论：较低的膝关节屈曲角度和增加的腿筋肌肉活动表明，PS组比MBS组以更硬的膝关节步态模式下楼梯。MBS植入物设计可以提供额外的稳定性,因为患者比PS组需要更少的肌肉活动。
