The purpose of this study was to measure the three-dimensional movements of the femur, tibia and patella in healthy young people during activities of daily living. A mobile biplane X-ray imaging system was used to obtain simultaneous measurements of six-degree-of-freedom (6-DOF) tibiofemoral and patellofemoral kinematics and femoral condylar motion in ten participants during standing, level walking, downhill walking, stair ascent, stair descent and open-chain (non-weightbearing) knee flexion. Seven of the eleven secondary motions at the knee—three translations at the tibiofemoral joint, three translations at the patellofemoral joint, and patellar flexion—were coupled to the tibiofemoral flexion angle (r² ≥ 0.71). Tibial internal–external rotation, tibial abduction–adduction, patellar rotation, and patellar tilt were each weakly related to the tibiofemoral flexion angle (r² ≤ 0.45). The displacements of the femoral condyles were also coupled to the tibiofemoral flexion angle (r² ≥ 0.70), with the lateral condyle translating further on the tibial plateau than the medial condyle. The center of rotation of the tibiofemoral joint in the transverse plane was located on the medial side in all activities. These findings expand our understanding of the kinematic function of the healthy knee and may be relevant to a range of applications in biomechanics, including the design of prosthetic knee implants and the development of knee models for use in full-body simulations of movement.

本研究的目的是测量健康年轻人在日常生活活动中股骨、胫骨和髌骨的三维运动。移动双平面 X 射线成像系统用于同时测量 10 名参与者在站立、水平行走、下坡行走、楼梯上升、楼梯下降和开链（非负重）膝关节屈曲。膝关节的 11 个次要运动中有 7 个——胫股关节的 3 个平移、髌股关节的 3 个平移和髌骨屈曲——与胫股屈曲角相关 ( r ² ≥ 0.71)。胫骨内-外旋、胫骨外展-内收、髌骨旋转和髌骨倾斜均与胫股屈曲角微弱相关（r ²  ≤ 0.45）。股骨髁的位移也与胫股屈曲角相关（r ² ≥ 0.70)，外侧髁比内侧髁在胫骨平台上平移得更远。在所有活动中，胫股关节在横断面上的旋转中心位于内侧。这些发现扩展了我们对健康膝关节运动学功能的理解，并且可能与生物力学中的一系列应用有关，包括假肢膝关节植入物的设计和用于全身运动模拟的膝关节模型的开发。