Abstract
Introduction: Normal axial alignment of the lower extremity is important to surgeons who perform reconstruction surgery of the knee. The data are, however, not available for Chinese adults.
Methods: The axial alignment of the lower extremity of twenty-five adult males and twenty-five adult females of southern Chinese origin was measured by using weight-bearing radiographs of the entire lower limb. The mean age of the male and female volunteers was twenty-four years and twenty-three years respectively. The axial alignment of the lower extremity was measured and the results were compared with two similar studies conducted in the United States.
Results: The medial inclination of the tibial plateau in the Chinese volunteers was greater than the commonly cited 3 degrees (with a mean of 5.4 ± 2.5 degrees for females and 4.9 ± 2.3 degrees for males). The extremities in Chinese volunteers were found to have a mean of 2.2 ± 2.5 degrees varus (females) and 2.2 ± 2.7 degrees varus (males).
Conclusions and Discussion: The medial inclination (knee joint obliquity) of the Chinese knee joint was significantly larger than Caucasian subjects. The higher knee joint obliquity exposes the cartilage of the Chinese knee to a higher shearing force and subsequently result in osteoarthritis. This may explain the racial difference in the ratio of knee to hip osteoarthritis. When performing total knee arthroplasty, a 5-degree, instead of the commonly cited 3-degree, external rotation of the femoral component may be required to obtain a rectangular flexion gap in total knee arthroplasty in Chinese patients.
The abstracts were prepared by Professor Jegan Krishnan. Correspondence should be addressed to him at the Flinders Medical Centre, Bedford Park 5047, Australia.
