Rotational Alignment of the Distal Femur in Korean Female Patients with Osteoarthritis Using a Computer Image Program / 대한정형외과학회잡지

ABSTRACT

PURPOSE: The purpose of this study was to propose a method to measurement of the exact anatomical alignment from the femur using a reference axis on computed tomography (CT) images and compare the difference of alignment axis between healthy young females and female patients with osteoarthritis of knee. MATERIALS AND METHODS: A total of 218 female patients with osteoarthritis of the knee joint (OA group), who underwent total knee arthroplasty, between January 2013 and December 2014, were enrolled in this study. The control group included 50 female patients with healthy knee joint. Each study subjects took a CT scan of their knee, and a series of axial CT images of the distal femur were overlapped using the image program. Angles were measured among the anteroposterior (AP) axis, posterior condylar axis (PCA), anatomical transepicondylar axis (aTEA), and surgical transepicondylar axis (sTEA). The differences of rotation angle between the normal and osteoarthritic knee were evaluated. RESULTS: The mean AP-PCA angle in the OA group was 92.9°±1.70°, whereas that in the control group was 96.3°±1.87° (p<0.01). The mean AP-aTEA angle was 84.5°±2.59°, and 90.8°±1.12° respectively (p<0.01). The mean AP-sTEA angle in the OA group was 88.7°±1.98°, whereas that in the control group was 95.1°±1.27° (p<0.01). The mean aTEA-PCA angle in the OA group was 8.4°±2.84°, while control group was 5.5°±2.00° (p<0.01). The mean sTEA-PCA angle in the OA group was 4.3°±1.17°, whereas that in the control group was 1.2°±2.10° (p=0.917). CONCLUSION: We measured the exact relationship between the rotational axes of the distal femur by overlapping the axial images of a CT scan. The OA group revealed a more internally rotated AP axis compared with aTEA and an increased angle of aTEA-PCA than control group.