Distal Femur Rotation Relates to Joint Obliquity in ACL-deficient Chinese

Abstract

Background The lower limb osteometry of Chinese differs from that of whites. The joint line of the knee in the coronal plane in Chinese is more medially inclined and the posterior condylar angle of the distal femur in the axial plane is larger. However, it is unclear whether there is any direct association between the coronal plane and axial plane osteometry. Questions/purposes We asked whether the joint line obliquity of the knee is related to the posterior condylar angle of the distal femur in young Chinese subjects. Methods Ninety-nine young Chinese patients with anterior cruciate ligament injuries were recruited. The lower limb alignment and joint line obliquity were measured using standing long radiographs of the whole lower limb.The rotational alignment of the distal femur was assessed in the axial cuts of the MRI. Results The distal femur rotational alignment was associated with the obliquity of the knee in Chinese. The posterior condylar angle was 5°± 2°. The knee was 5°± 3°medially inclined. Conclusions The joint line of the knee in a group of young Chinese patients was more medially inclined than that of whites. The posterior condylar angle of the distal femur was larger. The presence of an association between distal femur rotational alignment and joint line obliquity in this group of young Chinese patients suggests a possible developmental cause explaining the difference in osteometry between races.

Morphologic features of the distal femur and tibia plateau in Southeastern Chinese population

“…[ 8 – 10 , 15 – 20 ] According to the study involving 41 cadaver measurements by Yip et al, [ 8 ] the average posterior condyle angle (PCA) of Chinese men is (5.1 ± 1.9)°, which is smaller ( P < .05) than that of Chinese women (5.8 ± 1.8)°. In consistence with this study, we calculated the mean PCA of (4.5 ± 2.5)° in men and (5.1 ± 2.5)° in women, which is different from the data of the Caucasian population [ 8 , 10 , 11 , 18 , 21 , 22 ] (Table 5 ). There are several reasons that could explain the minor difference of these angles in the same ethnic group.…”

Spacer-based gap balancing is useful in total knee arthroplasty: a 3-year follow-up of a retrospective study

“…Moon et al and others have noticed that gap balancing technology leads to more external rotation than measured resection technology [ 29 , 30 ]. In addition, Yau et al [ 31 ] reported larger medially inclined (5° ± 3°) and posterior condyle angles (5° ± 2°) of the knee for Chinese patients than for Caucasians. From this, we infer that this is also one of the reasons for the increase in the femoral external rotation in the GB group.…”

Kinematics of anterior cruciate ligament-deficient knees in a Chinese population during stair ascent

“…Greater tibial varus is observed in the Asian population while external tibial rotation and a statistical difference in translation are found in the Caucasian population. Except for different protocols, these differences are attributed to the differences in the anatomy of the intercondylar notch, mechanical axis, and tibiofemoral alignment [ 33 ]. A higher quadriceps angle (Q-angle), varus alignment, and abnormal lower limb mechanical axis, including knee recurvatum, excessive navicular drop, and excessive subtalar pronation, are anatomic malalignments related to increased risk of ACL injury [ 21 ].…”

“…A higher Q-angle places the knee at risk of static and dynamic valgus stress [ 23 ]. The lower limb alignment is more varus, and the knee is medially inclined in the Chinese population when compared to the Caucasian population [ 33 ]. Our observations of greater tibial varus are compatible with these findings.…”