Gender differences of proximal tibia morphology in a Chinese population:comparison with sizing of tibial implants

Background The aim of this study was to determine the differences in morphology at the surface of the resected proximal tibia in Chinese males and females and compare the anthropometric values with the dimensions of available tibial components currently used in China. Methods The anthropometric characteristics of the proximal tibias in 241 Chinese individuals (121 males, 120 females) were assessed via computed tomography imaging. We measured the mediolateral (ML), anteroposterior (AP), medial and lateral anteroposterior dimensions and the ML/AP aspect ratio of the resected proximal tibial surface. The ML/AP aspect ratios were classified into 3 groups on the basis of the AP dimensions (< 48 mm, 48–51 mm, > 51 mm) to compare gender differences. All the morphological data were compared with the dimensions of the six tibial components currently used. Results The tibias ML and AP dimensions of females were significantly smaller than that of males (69.5 ± 3.4 mm, 46.7 ± 2.3 mm vs 78.4 ± 3.2 mm, 52.6 ± 2.9 mm ). There was no significant gender difference in the ML/AP aspect ratio ( 149.4 ± 6.9 vs 149.1 ± 6.1). After adjusting for AP dimensions, females had a smaller ML/AP aspect ratio than males did in the subgroups (< 48 mm P  = 0.009; 48–51 mm P  < 0.001; >51 mm P =  0.043). Compared with component sizes, there was a mismatch between tibial morphology and the dimensions of all the implants. Tibial components with smaller AP measurements were undersized in the ML dimension, and those with larger AP measurements were oversized in the ML dimension in males and females. Conclusion In the Chinese population, females have smaller dimensions and ML/AP aspect ratios than their male counterparts do. The commonly used tibial components may not provide an appropriate fit and coverage for the Chinese population. These data can serve as guidelines for designing optimal tibial components with different ML/AP aspect ratios for Chinese males and females.