Anatomic variations between Japanese and Caucasian populations in the healthy young adult knee joint

Abstract

Our objective was to characterize variations in mechanical knee alignment, tibial torsion, tibial width, and ACL laxity measurements between Japanese and Caucasian populations in the healthy, young adult knee joint. Seventy young adult subjects participated in this study, including 23 Japanese and 47 Caucasian subjects. Coronal magnetic resonance images of the hip, knee, and ankle were acquired for analysis. Japanese subjects had a significantly higher (p ¼ 0.04) varus alignment (1.64 AE 0.438 standard error) than Caucasians (0.55 AE 0.338), while women exhibited a more valgus alignment (0.16 AE 0.528) than men (0.94 AE 0.428, p ¼ 0.04). Significant differences were found in tibial torsion and ACL laxity (p < 0.01) between ethnicities, with Japanese exhibiting lower tibial torsion (33.4 AE 10.08) and higher ACL laxity (7.5 AE 0.4 mm) measurements compared to Caucasians (38.9 AE 9.58 and 5.7 AE 0.3 mm, respectively). Significant differences between genders were found in hip-knee-ankle alignment (p ¼ 0.04), tibial width (p < 0.0001), and ACL laxity (p < 0.01) measurements. Measurements were reliable between observers and for repeated positioning. Our study provides new insight into anatomical and geometric differences in the knee joint between Japanese and Caucasians, as well as between females and males. Further consideration of these results may improve development of implants to accommodate for these differences, and understanding of characteristics leading to increased prevalence of knee OA in certain populations. The use of magnetic resonance imaging to obtain these measurements also allows soft tissue structure characterization without exposure to ionizing radiation. ß

Comparison of five patellar height measurement methods in 90° knee flexion

“…It is well known that the female knee has a different anatomy from the male knee [33,34]. Moreover, differences in the quadriceps muscle strength between right and left sides might also result in different patellar heights.…”

Posterior Displacement of the Tibia Increases in Deep Flexion of the Knee

“…Third, all subjects were Japanese in this series. The Japanese population has greater varus alignment compared with the Caucasian population [10]. However, knee alignment is considered to have little influence on knee laxity because it is determined mainly by the ligaments and soft tissues.…”

In Vivo Normal Knee Kinematics: Is Ethnicity or Gender an Influencing Factor?

“…During running or cutting maneuvers, women reveal 8°less flexion, but 11°m ore valgus position then men [35]. Women reportedly have higher ACL laxity than men (6.4 mm and 4.9 mm, respectively [27]), possibly related to anatomic variations or hormonal differences [23,39,43]. During closed kinetic chain knee extension, women experience 23.6% less knee joint surface rolling than men [26].…”