Accuracy of 3 reference axes for femoral rotation in total knee arthroplasty: a comparative study of 124 cases

Abstract

Objective To compare the accuracy of rotation of the femoral component using 3 reference axes in total knee arthroplasty (TKA), namely, the Whiteside line, surgical transepicondylar axis (sTEA), and sulcus line of the trochlear groove. Methods A retrospective analysis was performed on 124 patients (25 males and 99 females, at a median age of 66.0 years; including 133 knees, 70 left and 63 right knees) with knee osteoarthritis or rheumatoid arthritis who met the inclusion criteria in our center from August 2016 to June 2018. Based on the three-dimensional model established by knees CT scan data, the rotational alignment of femoral component was simulated with reference to the Whiteside line, sTEA and sulcus line, respectively. The difference was compared between the simulated rotation angle of femoral component and the actual angle of femoral rotation. The deviation and its outlier were calculated. Results The deviation between the actual angle of femoral rotation and the simulated rotation angle of femoral component obtained by referring to the Whiteside line, sTEA and sulcus line was (-2.61±2.76)°, (0.79±2.09)°, and (-0.65±1.64)°, respectively, and the differences between each pair were statistically significant (P 3° was 48.12%, 11.28% and 8.27%, respectively. Conclusion Compared with the Whiteside line and sTEA, the femoral rotation with the sulcus line as the reference axis is more accurate during TKA.

Keywords

• total knee arthroplasty
• femoral osteotomy
• rotational alignment
• sulcus line
• whiteside line
• transepicondylar axis