Purpose: The aim of this paper was to determine whether the change in the position of the patient's leg as well as the use of flexible reamers may help in obtaining a longer femoral tunnel with minimal risk of perforating the posterior cortex.
Methods: One hundred and twenty-five patients who had undergone anatomic ACL reconstruction between 2010 and 2013 were included in this prospective cohort study. The first group was composed of patients whose femoral tunnel had been drilled with rigid reamers, while the leg being operated on was positioned on an arthroscopic leg holder (82 patients). In the second group of patients, the femoral tunnel was also drilled with rigid reamers, but the leg was positioned on the table (25 patients), while the third group was composed of patients whose femoral tunnel was drilled with flexible reamers, and the leg was positioned on a leg holder (18 patients). The length of the femoral tunnel was measured intraoperationally, while the site of femoral insertion and the position of the tunnel were read from native radiographic images.
Results: When the femoral tunnel was drilled on the medial aspect of the lateral condyle, the centre of the tunnel was located at 31.4 % from the most proximal point of the femoral condyle and 34.7 % from the Blumensaat line. The length of the tunnel drilled with rigid reamers on the operating table (36.1 mm) was statistically significantly greater (p < 0.05) than the length of the tunnel drilled with the same reamers, but with the leg positioned on the leg holder (32.5 mm). The length of the tunnel drilled with flexible reamers with the leg positioned on the leg holder (42.5 mm) was highly statistically significantly greater than the length of the tunnel drilled with rigid reamers (p < 0.01), and it was statistically significantly greater than the length of the tunnel drilled with rigid reamers with the leg placed on the operating table (p < 0.05).
Conclusion: The drilling of the femoral tunnel during anatomic ACL reconstruction with the use of flexible reamers provides a longer femoral tunnel than when it is drilled with rigid reamers, without any danger of perforation of the posterior cortex.
Level of evidence: III.
Keywords: Anatomic reconstruction; Anterior cruciate ligament; Femoral tunnel; Posterior femoral cortex.