The 45-Degree Arthroscope Improves Visualization of the Femoral Attachment of the Anterior Cruciate Ligament

Background: Exposure of the insertion site of the anterior cruciate ligament (ACL) is important for appropriate tunnel placement in ACL reconstruction surgery. However, observing the femoral ACL insertion site via the standard anterolateral portal is sometimes difficult. In this study, we compared views of the femoral ACL insertion site between 30-degree and the 45-degree arthroscopes. Methods: We first inserted the 30-degree and the 45-degree arthroscope into the anterolateral portal of a knee simulator in which we had drawn a lattice pattern on the lateral intercondylar notch based on the quadrant method. Next, we compared the arthroscopic views provided by the 30-degree and 45-degree arthroscopes during ACL reconstruction surgery by measuring the area of the lateral intercondylar notch visible through each of the arthroscopes. Results: In the knee simulator, the 45-degree arthroscope showed the entire area of the lateral intercondylar notch, whereas the 30-degree arthroscope had to be introduced more deeply to show the most superior and posterior quadrant, where the attachment of the anteromedial bundle of ACL is located. During the ACL reconstruction, the area of the lateral intercondylar notch in the field of view was larger through the 45-degree arthroscope than through the 30-degree arthroscope. Conclusion: The 45-degree arthroscope provides a better view of the femoral ACL insertion site via the anterolateral portal, which may be helpful during ACL reconstruction.