Objective: Evaluate the rotational alignment of the distal femur by using axial radiographic technique.

Material and Method: Thirty-six normal volunteers (72 knees) were enrolled in the present study. Mean age was 39.47 years (range 20 to 57). Axes for rotational alignment of distal femur were outlined including posterior condylar (PC), anteroposterior (AP), anatomical epicondylar line (AEpi), and then angle between each pair of the axes were measured in the medial side including anteroposterior/posterior condylar (AP-PC) angle, anteroposterior/anatomical epicondylar (AP-AEpi) angle, and anatomical epicondylar/ posterior condylar (AEpi-PC) angle. Gender and side were compared to each other. Pearson correlation was calculated between age and all angles.

Results: Average AP-PC angle was 95.75 + 1.79 degrees. Average AEpi-PC angle was 6.77 + 1.97 degrees. Average AP-AEpi angle was 89.81 + 1.86 degrees. Results showed no statistically significant difference between side, gender, and age. Intraobserver ICC were 0.6 to 0.92 and interobserver ICC were 0.68 to 0.87.

Conclusion: The axial radiographic technique is reliable. The results of the present study are comparable with a previous study using the computerized tomography (CT) technique.

Keywords: Knee, Rotational alignment, Distal femur, Thai, Axial radiographic study, Lower extremity