FEMORAL PULSE AS A GUIDE TO THE MECHANICAL AXIS IN TOTAL KNEE ARTHROPLASTY

The anatomic relationship of the center of the femoral head to the fem oral artery was studied in 140 hips in 70 patients. The coronal plane distance between the femoral artery 2.5 cm below the inguinal ligament and the center of the femoral head was measured on pelvic arteriogram s. The femoral artery was found an average of 7.7 +/- 5 mm medial (ran ge, -3-22 mm) to the center of the femoral head. The femoral artery wa s within 15 mm of the center of the femoral head in 97% of cases revie wed. A 76-cm theoretical mechanical axis was used in estimating clinic al angular changes in the axis for a given coronal plane difference. B y use of this model, the range of variability translates into a maximu m change in the mechanical axis of 1.66 degrees and up to only 1.2 deg rees in 95% of the cases reviewed. A marker placed just lateral to the palpable femoral pulse approximately 2 to 3 cm below the inguinal lig ament is suitable as a guide to locate the center of tile femoral head when determining the mechanical axis during total knee arthroplasty.