Transtibial versus anteromedial portal of the femoral tunnel in ACL reconstruction: a cadaveric study.

The aim of this cadaveric study was to compare the transtibial versus the anteromedial portal with respect to the anatomic femoral positioning of the ACL attachment. Ten fresh frozen cadaveric knees were included in our study. A standard arthroscopy was performed and the normal ACL was partially cut through with arthroscopic scissors leaving a small footprint of 2 mm at the anatomical insertion area on the lateral femoral condyle. The femoral tunnel was drilled through the tibial tunnel and subsequently through the anteromedial portal. Using a probe with standard magnification, we measured the distances of the two femoral tunnels from the margin of ACL footprint arthroscopically. The femurs were then dissected and we measured the distances of the two tunnels from the posterior part of the lateral femoral condyle. The median arthroscopically measured distance of the centers of transtibial femoral tunnel and of the femoral tunnel through the anteromedial portal from the margin of the femoral ACL footprint were 6.20 mm and 2.80 mm respectively. The difference was statistically significant. After femoral dissection the median distance of the centers of the transtibial femoral tunnel and the femoral tunnel performed through the anteromedial portal from the border of the articular surface at the lateral femoral condyle was 6.10 mm and 5.25 mm respectively (p<0.001). Both measurements showed that ACL reconstruction technique through the anteromedial portal is more accurate compared to the transtibial technique.