Abstract
High-definition cross-sectional images were acquired and reconstructed by CT of the lower extremity, and knee rotation and tibial torsion were measured. In particular, a new method is established and obtained knee rotation was 9.20±2.40 and tibial torsion was 28.3±6.21. CT measurements made in 20 normal legs by the tibial posterior tangent method and by a method that uses the medial margin of the patellar ligament as described by Kudo (the Kudo method) were compared and assessed. The results showed that the tibial rotation values decreased in 6 steps when measured by the Showa University method, the tibial posterior tangent method, and the Kudo method. Increases in tibial torsion values by 6 were obtained in the same order. We subsequently measured 20 more limbs, and using the 40 limbs as a control group, compared the data obtained with measurements of knee rotation and tibial torsion in 76 limbs of patients with osteoarthritis of the knee (OA group) . Knee rotation was 10.14±3.29 in the control group and 8.29±4.59 in the OA group, and although it was slightly smaller in the OA group, the difference was not significant. Tibial torsion was 23.4±8.43 in the control group and lower, 17.6±6.94, in the OA group, but the difference was not significant. When the coefficient for the correlation between age and tibial torsion was calculated, a strong correlation was found in the control group, but hardly any correlation was observed between age and tibial torsion in the OA group. Because of these findings it could be concluded that tibial torsion decreases with age in healthy persons, but that OA of the knee patients often have highly altered values. A strong correlation was found between the degree of progression of OA and knee rotation ( FTA) . No other correlations were found, i.e., among knee rotation, tibial torsion, age, FTA, and age bracket.
