Three dimensional morphometry of the knee to design the total knee arthroplasty for Chinese population.

Anthropometric data on the proximal tibia and distal femur of 172 normal knees (94 male knees, 78 female knees) were obtained using three dimensional computer tomographic measurements. We measured the tibial mediolateral (tML) and tibial anteroposterior (tAP) dimension in resected proximal tibia surface, femoral mediolateral (fML) and femoral anteroposterior (fAP) dimension in resected distal femur surface. The measurements were compared with the similar dimensions of five total knee prostheses conventionally used in China. We found that in the smaller sized prostheses the tibial mediolateral dimension was undersized, while in the larger size prostheses the tibial mediolateral dimension was overhang. For all sizes of prostheses the femoral mediolateral dimension was overhang. We found a progressively decreased in the aspect ratio (ML/AP %) with an increasing anteroposterior dimension both in the tibia and femur, as compared to the constant aspect ratio shown by the conventional total prostheses. Male had larger values in mediolateral dimension and aspect ratio than female under a given anteroposterior dimension both in the tibia and femur. There were strong correlations between measurements of the tibia and femur. The results of this study may provide guidelines for designing suitable total knee prosthesis for the Chinese population, especially for design of gender-specific prostheses.