Use of a Fluoroscopic Overlay to Assist Arthroscopic Anterior Cruciate Ligament Reconstruction

Abstract

Background: A growing body of evidence supports the importance of anatomic tunnel positioning in the success of anterior cruciate ligament (ACL) reconstruction, which stimulates the need for technologies to aid surgeons in achieving accurate anatomic tunnel placement. Intraoperative fluoroscopy is potentially one such technology, while its efficacy and usability have yet to be established. Purpose: To investigate the performance of an intraoperative fluoroscopic overlay in guiding tunnel placement during ACL reconstruction. Study Design: Controlled laboratory study. Methods: Twenty cadaveric knees underwent computed tomography (CT) scans and arthroscopic digitization of ACL insertion sites. The outlines of the digitized insertion sites were mapped to the corresponding CT-acquired bone models through a co-registration procedure. Twenty orthopaedic surgeons performed simulated ACL reconstructions, each on a randomly assigned cadaveric knee, first without and then with the aid of a fluoroscopic overlay system. The overlay system displayed on a lateral fluoroscopic image targets points representing the locations of the ACL insertion sites estimated from the literature data. Surgeons were allowed to adjust their tunnel positions under the guidance of the fluoroscopic image. Their initial, intermediate, and final positions were documented and compared with the target points as well as the native insertion sites. Results: Surgeons demonstrated significant ( P < .01) improvements in femoral and tibial tunnel placements relative to the target points from an average distance of 3.9 mm to 1.6 mm on the femur and 2.1 mm to 0.9 mm on the tibia. The improvements toward the knee-specific actual insertion sites were significant on the tibial side but not on the femoral side. Conclusion: Surgeons can be successfully guided with fluoroscopy to create more consistent femoral and tibial tunnels during ACL reconstruction. More research is warranted to develop better population representations of the locations of natural insertion sites. Clinical Relevance: Intraoperative fluoroscopy can be an effective, easy, and safe method for improving tunnel positioning during ACL reconstruction.