Intraoperative 3-dimensional imaging-based navigation-assisted anatomic double-bundle anterior cruciate ligament...

In anatomic double-bundle anterior cruciate ligament (ACL) reconstruction, it is more technically demanding, even for experienced surgeons, to place 2 femoral tunnels within the ACL attachment than to place 2 tibial tunnels. We describe a technique using a three-dimensional (3-D) fluoroscopy-based navigation system to place 2 femoral tunnels accurately. After a reference frame is rigidly attached to the femur, an intraoperative image of the distal femur is obtained. The image is transferred to a navigation system and reconstructed into a 3-D image. During the placement of guidewires for the femoral tunnels through an accessory medial portal, a femoral guide with a tracker feeds back to the surgeons the direction of the guidewire on the 3-D femur bone surface image in real-time. The femoral guide is placed at the center of the footprint with the aid of visual guidance of the navigation and an arthroscopic view. The flexion angle of the knee is then adjusted to prevent posterior blowout on the computer screen during insertion of the guidewire. The length of the femoral tunnel can also be estimated before overdrilling the guidewire. This technology allows surgeons to place 2 femoral tunnels precisely without any complication during anatomic double-bundle ACL reconstruction.