In vivo kinematic analysis of normal knees in chinese adults / 中华骨科杂志

ABSTRACT

Objective To provide an essential features of the knee for the prothesis design more suitable in Chinese. Methods 240 knees of 120 healthy Chinese adults were selected on trial, with an average age of 30.6 years (range, 21 to 40 years) and an average height of 1.68 m ranging from 1.60 m to 1.75 m. Each individual was asked to do deep flexion activities. Fluoroscopy were used to determine accurately the weightbearing kinematics in vivo of 240 knees at different position. The anterior articular surface of the femoral condyle was designated as the "extension facet"(EF), while the posterior surface as the "flexion facet"(FF). Their centers are labelled as EFC and FFC respectively. The distances between the ipsilateral posterior tibial cortex and the center of the posterior femoral condylar circles at different position were measured by drawing a line through the most protruding points in the medial and lateral tibial subchondral bony landmark. A second line was drawn perpendicular to the first and tangent to the posterior tibial cortex. The distance d1 and d2 were measured perpendicularly from FFC and EFC to the second line respectively. The change of d1 and d2 in different positions denoted the relative movement between the tibia and femur. The data were used by ANOVA analysis containing two factors with SAS software. Results The difference of sex and side had no influence on the relative movements between the tibia and femur. In normal adults, the range of relative motion at the medial and lateral condyle during deep flexion was (1.4?0.3) mm and (15.9?4.7) mm respectively. Conclusion The lateral condyle undergoes posterior translation including sliding and rolling significantly during the deep flexion that leads to the relative axial rotation of the tibia to the femur.