Abstract
Purpose of study The purpose of this study was to present the anterior femoral cortical line (AFCL) as a new anatomical landmark to aid the assessment of intra-operative femoral component rotation. The AFCL was compared with an established axis (the anteroposterior (AP) axis or Whiteside’s line) in both a cadaveric and clinical study.
Methods Two points indicating the AP axis were identified and marked on 50 normal cadaveric femora. The AFCL was identified and marked with a rigid wire secured on the surface and the distal femur was photographed. A perpendicular to the AP axis was drawn on each image and the angle between this line and the AFCL was measured.
68 consecutive patients undergoing total knee arthroplasty for osteoarthritis of the knee were included in the clinical part of the study. After a routine exposure the AP axis was marked on each distal femur. The AFCL was identified and the anterior cortical cut was made parallel to this line. The angle between this cortical cut and the perpendicular to the AP axis was measured with a sterile goniometer.
Results In the cadaveric study the AFCL was a mean 7.0 degrees internally rotated to the AP axis (SD = 5.1 degrees). In the clinical study in 8 patients it was impossible to draw the AP axis because of dysplasia or destruction of the trochlea by osteoarthrosis. In the remainder the mean difference between the anterior femoral cortical line and the AP axis was 1.5 degrees internally rotated (SD = 1.9 degrees) .
Conclusion The anterior femoral cortical line has been shown in this study to be a useful clinical axis for assessing rotation of the femoral component and is without some of the disadvantages associated with other landmarks.
The abstracts were prepared by Mr Roger Smith. Correspondence should be addressed to him at the British Association for Surgery of the Knee, c/o BOA, Royal College of Surgeons of England, 35–43 Lincoln’s Inn Fields, London WC2A 3PN.
