Axial alignment of the lower extremity in Chinese adults.
BACKGROUND
The restoration of normal axial alignment of the lower extremity is important to surgeons who perform reconstructive surgery of the knee. However, data on the normal alignment of the lower extremity in Chinese adults are not available.


METHODS
The axial alignment of the lower extremity in twenty-five adult male and twenty-five adult female volunteers of southern Chinese origin was measured on weight-bearing radiographs of the entire lower limb. The mean age was twenty-four years for the male volunteers and twenty-three years for the female volunteers. The results were compared with those of two similar studies of white volunteers in the United States.


RESULTS
The medial inclination of the tibial plateau in the Chinese subjects (mean and standard deviation, 5.4 +/- 2.5 degrees for women and 4.9 +/- 2.3 degrees for men) was greater than the commonly reported 3 degrees. The extremities of the Chinese women were found to have a mean of 2.2 +/- 2.5 degrees of varus alignment, and those of the Chinese men had a mean of 2.2 +/- 2.7 degrees of varus alignment.


CONCLUSIONS
Compared with the white subjects described in the studies by Moreland et al. and Hsu et al., the Chinese subjects had significantly larger medial inclination of the knee joint (knee-joint obliquity) (p < 0.005) and the female Chinese subjects had significantly more varus alignment of the lower extremity (p < 0.025).


CONCLUSIONS
Five degrees of external rotation of the femoral component, instead of the commonly reported 3 degrees, may be required to obtain a rectangular flexion gap in total knee arthroplasty in Chinese patients. The racial difference in the knee-joint obliquity may contribute to the racial difference in the ratio of knee osteoarthritis to hip osteoarthritis. Additional studies are necessary to confirm this relationship.
Tang
W M
WM
Department of Orthopaedic Surgery, Queen Mary Hospital, Pokfulam, Hong Kong, China. wmtanga@hkucc.hku.hk
Zhu
Y H
YH
Chiu
K Y
KY
D000328:Adult; D019645:Arthroplasty, Replacement, Knee; D044466:Asian People; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D007866:Leg / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008297:Male; D020370:Osteoarthritis, Knee / Q000208:ethnology / Q000601:surgery; D011859:Radiography; D012016:Reference Values; D044465:White People