Measurement of the Axial Rotational Axis of Distal Femur Using Different Landmarks

ABSTRACT

PURPOSE: To know the discrepancy of rotational alignment using human femur. MATERIALS AND METHODS: We used 22 adult human femurs which were not able to distinguish age and sex and absent articular cartilage. In a horizontal plane, we made a cross-section perpendicularly at supra-condyle of femur to a mechanical axis and took a simple roentgenogram in coronal plane focusing on the center of transepicondylar axis. In terms of roentgenogram and gross specimen, the angle between per-pendicular to the anteroposterior axis and the posterior condylar axis, the angle between the transepi-condylar axis and the posterior condylar axis were measured by 5 observers. According to t-test in statisti-cal method, we figured out the difference between two angles and made a significance at p<0.05. RESULTS: About posterior condylar axis, the line perpendicular to anteroposterior axis was observed the average 4.8(+/-1.5)degree, 6.0(+/-1.9)degree external rotation in roentgenogram and gross specimen respectively. The transepicondylar axis was observed the average 3.5(+/-1.2)degree, 3.9(+/-1.4)degree external rotation in roentgenogram and gross specimen respectively. There was statistically significant difference between two angles. Moreover, angles measured by 5 observers were found that to have a line perpendicular to the anteroposterior axis has much more external rotation respectively and there was a statistically significant difference also. CONCLUSIONS: On determination of a rotational alignment using human femur, there is statistically sig-nificant difference between the anteroposterior axis and the transepicondylar axis in gross specimen as well as roentgenogram.