MORPHOLOGY OF THE TRANSEPICONDYLAR AXIS AND ITS APPLICATION IN PRIMARY AND REVISION TOTAL KNEE ARTHROPLASTY

A morphologic anatomic study was done of the lower extremity to invest igate various relationships of the transepicondylar axis (TEA). Thirte en cadaver specimens were dissected and mounted to a metal frame with a pin passing through the TEA. The center of the knee was determined a s the depth of the anterior intercondylar groove. The ratio of the upp er leg to lower leg measured from femoral head center and ankle center to TEA was 1.02. The mean distance of the TEA to the joint line was 7 .08 cm medial and 2.53 cm lateral. The mean femoral angle comparing th e TEA to mechanical axis was 0.61 degrees varus. The mean tibial angle comparing the TEA to the mechanical axis was 0.40 varus in extension and 0.43 degrees in flexion, with no significant difference in the low er extremity angle with flexion (P < .01). The TEA is an important lan dmark that, from this study, is virtually perpendicular to the mechani cal axis of the lower extremity and parallels the knee flexion axis. F emoral component rotation and joint line positioning in total knee art hroplasty can be determined using the TEA.