It is important to have a sufficient femoral tunnel length for the graft fix strength and the maturation in the anterior cruciate ligament reconstruction. The high resolution MRI is used on the knees of 6 young healthy volunteers. Based on the reconstructed MRI 3D models. two main observations are made:for the I.D.E.A.L. point as the fixed femoral tunnel location, the higher the tunnel outlet point, or the larger the femoral runnel angle, the longer tunnel would be achieved; and the outlet curves with the tunnel length of 30mm, 35mm, 40mm arranged from lower to upper in an ascending order on the lateral cortex of the lateral femoral condyle, with the mean maximum femoral runnel angle of 17.2°±8.6°, 31.6°±9.1° and 41.4°±8.8°. Therefore, beside the anatomy characteristics such as the sizes of the femur and the intercondylar notch, the length of the femoral tunnel in the trans-portal reconstruction is related with the anterior-medial portal position. For a fixed tunnel location, to get a longer tunnel length, the relative position of the skin portal to the tunnel location should be even lower, and using the accessory for the anterior-medial portal or increasing knee flexing angle, a longer femoral tunnel would be obtained.

femoral tunnel length  /  anterior-medial portal  /  anterior cruciate ligament reconstruction