Effects of measurement methods for tibial rotation axis on the morphometry in Korean populations by gender.

Background: There have been arguments for methodology in tibial rotation axis measurement, which accordingly determines the morphometry of the proximal tibia in total knee arthroplasty. The morphometry of the proximal tibia for the Korean population is determined by gender, based on the anatomical tibial axis and reliable rotational orientation in knee replacements, to evaluate the size suitability of the currently available prostheses in Korea.

Methods: This study reconstructed the MRI images in three-dimensions for identification and measurement of the mediolateral (ML) and anteroposterior (AP) lengths of the proximal tibia and the tibial aspect ratio (ML/AP) using proximal tibial anthropometric data for 700 osteoarthritic knees (587 females and 113 males). The ML and AP lengths were measured using tibial rotation axis techniques based on the medial one-third tibial tubercle and Cobb's method.

Results: Significant differences (P<0.05) in ML, medial anteroposterior (MAP), lateral anteroposterior (LAP) lengths, and aspect ratio (ML/LAP) were observed for males and females with respect to different measurement techniques for the tibial rotation axis. However, the measured aspect ratio (ML/MAP) of tibiae for the Korean population did not show significance. The measured aspect ratio (ML/AP) ratio of tibiae for the Korean population was higher than that of currently available tibial components.

Conclusions: Results from this study can guide development of gender-specific tibial prosthesis designs with different ML and AP aspect ratios based on the tibial anatomical rotation axis for the Korean population.