Arthroscopically blind anatomical anterior cruciate ligament reconstruction using only navigation guidance: a cadaveric study

Background: To develop a preoperative planning and navigation system for anatomic anterior cruciate ligament (ACL) reconstruction and to evaluate the accuracy and the efficacy of anatomical ACL reconstruction using only navigation guidance.

Methods: A three-dimensional (3D) preoperative planning and navigation system was developed from open source libraries. Twenty knees from 10 fresh-frozen human cadavers underwent navigation-only guided double-bundle ACL reconstruction using the transportal technique. A computed tomography (CT) scan was performed after ACL reconstruction to create a 3D surface model of the distal femur. We evaluated the tunnel position by Bernard's quadrant method, the tunnel orientation by measuring the tunnel angle in three projected planes, and the incidence of posterior cortical damage. Then, we compared preoperative planning with the postoperative results.

Results: The difference in tunnel position between preoperative planning and the postoperative results was a mean of 2.50±1.75mm (range, 0.77 to 5.85mm) in the anteromedial (AM) tunnel and a mean of 3.53±2.20mm (range, 0.39 to 7.92mm) in the posterolateral (PL) tunnel. The difference in tunnel orientation was a mean of 6.74±6.70° (range, 0.35 to 25.6°) in the AM tunnel and a mean of 5.73±3.51° (range, 1.58 to 15.04°) in the PL tunnel. No statically significant difference was observed. Posterior cortical damage developed in seven cases (35%).

Conclusions: Our navigation-only guided ACL reconstruction produced consistent femoral tunnel position and orientation results. The accuracy and consistency of femoral tunneling were improved by using the preoperative planning and navigation system.