[A cadaveric study of relationships among rotational alignment reference axes of distal femur and tibial mechanical axis].
OBJECTIVE
To investigate the relationships among rotational alignment reference axes of distal femur and tibial mechanical axis, and determine the safest rotational alignment reference axis.


METHODS
Digital photos were taken of 30 cadaveric lower extremities with knee in extension and flexion at 90 degrees , angles were measured among tibial mechanical axis and a line perpendicular to clinical epicondylar axis, a line perpendicular to surgical epicondylar axis, Whiteside's line and femoral mechanical axis. Statistical analysis of relationships among those axes were performed.


RESULTS
The angles among the tibial mechanical axis and a line perpendicular to the clinical epicondylar axis, a line perpendicular to the surgical epicondylar axis, Whiteside's line and femoral mechanical axis were 0.6 degrees varus, 3.9 degrees varus, 0.2 degrees valgus and 3.0 degrees varus respectively. The angle between the femoral mechanical axis and the tibial mechanical axis was significantly larger than the angles among the tibial mechanical axis and a line perpendicular to the clinical epicondylar axis, the Whiteside's line (P < 0.05). There was no significant difference compared with the angle between a line perpendicular to the surgical epicondylar axis and the tibial mechanical axis. Angles of the clinical epicondylar axis, the surgical epicondylar axis and the Whiteside's line between knee extension and flexion were 2.3 degrees valgus, 0.9 degrees varus and 3.1 degrees valgus respectively.


CONCLUSIONS
The surgical epicondylar axis rather than the clinical epicondylar axis or the Whiteside's line is the safest femoral rotational alignment reference axis intraoperatively.
Zhao
Bao-hui
BH
Department of Joint Surgery, the Third Hospital of Hebei Medical University, Shijiazhuang, China.
Chen
Bai-cheng
BC
Shao
De-cheng
DC
Wang
Fei
F
Gao
Shi-jun
SJ
Lu
Bo
B
D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D005269:Femur / Q000033:anatomy & histology* / Q000601:surgery; D006801:Humans; D007720:Knee Prosthesis; D012399:Rotation; D013977:Tibia / Q000033:anatomy & histology* / Q000601:surgery