Kinematic analysis of total knee prosthesis designed for Asian population

In designing a total knee replacement (TKR) prosthesis catering for the Asian population, 62 sets of femur were harvested and analyzed. The morphometrical data obtained were found to be in good agreement with dimensions typical of the Asian knee and has reaffirmed the fact that Caucasian knees are generally larger than Asian knees. Subsequently, these data when treated using a multivariate statistical technique resulted in the establishment of major design parameters for six different sizes of femoral implants. An extra-small implant size with established dimensions and geometrical shape has surfaced from the study. The differences between the Asian knees and the Caucasian knees are discussed. Employing the established femoral dimensions and motion path of the knee joint, the articulating tibia profile was generated. All the sizes of implants were modeled using a computer-aided software package. Thereupon, these models that accurately fits the local Asian knee were transported into a dynamic and kinematic analysis software package. The tibiofemoral joint was modeled successfully as a slide curve joint to study intuitively the motion of the femur when articulating on the tibia surface. An optimal tibia profile could be synthesized to mimic the natural knee path motion. Details of the analysis are presented and discussed.