Laxity of knee joint in normal Chinese adults

The purpose of this study is to set up the standard data of laxity in normal Chinese knee joints via the Genucom knee analysis system. Forty male and forty female subjects without knee injury, with clinically proved stable knees were enrolled in this study. The male subjects averaged 25.3 years old (range, 17 to 38), while the female subjects had a mean of 24 years old (range, 19 to 38). The anterior-posterior drawer test at 90 degrees and 30 degrees of knee flexion and varus-valgus stress test at 10 and 25 degrees of knee flexion were performed. The tibiofemoral displacement was also measured at the same time. The tibia displaced anteriorly at a mean of 5.2±2.6 mm and 7.1±3.1 mm at 90 and 30 degrees knee flexion respectively in male subjects, while posteriorly at a mean of 2.7±1.8 mm and 3.1±2.4 mm. The female subjects revealed a mean of 6±2.5 mm and 7.1±2.4 mm anterior displacement at 90 and 30 degrees knee flexion, whereas posterior displacement at a mean of 2.8±1.9 mm and 2.8±2.2 mm. The female subjects demonstrated a 2.9±1.4 mm and 7.2±2.4 mm medial displacement at 10 and 25 degrees knee flexion, while a mean of 2.3±1.4 mm and 6.3±2.6 mm in male subjects. There is a mean of 3.4±1.7 mm and 7.8±2.24 mm lateral displacement at 10 and 25 degrees knee flexion respectively in female subject versus 2.6±1.4 mm and 7±2.7 mm in male subjects. Age did not demonstrate to be a significant factor on the ligamentous laxity of knee joint in both male and female subjects. No significant differences in anterior, posterior, medial and lateral laxity of knee joint existed in right and left limbs in both male and female groups. However, the data of the Chinese was different from those of the Caucasians.