2015 ISAKOS Biennial Congress ePoster #1314

A Comparative Study of the Femoral Footprint of Anterior Cruciate Ligament Between Arthroscopic Viewing Position Using Three-Dimensional Computed Tomography Model

Tomohiko Shirata, MD, PhD, Tokyo JAPAN
Yuki Kato, MD, PhD, Tokyo JAPAN
Takashi Horaguchi, MD, PhD, Tokyo JAPAN
Yu Nagai, MD, Tokyo JAPAN
Bunsei Goto, MD, PhD, Tokyo JAPAN
Yusuke Morimoto, MD, Tokyo JAPAN
Katsuaki Taira, Tokyo JAPAN
Yasuaki Tokuhashi, MD, PhD, Tokyo JAPAN
Department of Orthopaedic Surgery, Nihon University., TOKYO, JAPAN

FDA Status Not Applicable

Summary: Difference in Vision of the Femoral Footprint of Anterior Cruciate Ligament depending on the Viewing Position. A Knee Arthroscopy Simulation Study using Three-Dimensional Computed Tomography.

Abstract:

Background

Tunnel placement is one of the most important factors for successful result in anterior cruciate ligament (ACL) reconstruction. Especially femoral tunnel placement has evolved from isometric point to anatomic area. It is, however, difficult to create anatomic femoral tunnel. Therefore, we have to check tunnel placement using 3D-CT after the surgery. Femoral tunnel placement is usually represented by the image in a direction perpendicular to medial wall of the lateral femoral condyle according to Bernard’s Quadrant method. The view according to the Quadrant method is different from arthroscopic views during ACL reconstruction. Basically arthroscopic views of ACL footprint is oblique perspective views. It must be crucial for arthroscopic surgeons to discriminate between the Quadrant view (90 degree view) and the arthroscopic view (oblique perspective view). Purpose: The purpose of this study is to show the difference between the Quadrant view and the oblique perspective view assumed in arthroscopic surgery, creating views of 3D-CT model.

Method

Twelve-paired cadaveric knees were dissected. The femoral ACL footprint was divided into 2 functional bundles, anteromedial bundle (AMB) and posterolateral bundle (PLB). These two bundle’s outline was marked using copper metallic thread. A 3D-CT model of cadaveric knee, showing anatomical ACL femoral foot print, was created to compare the simulated arthroscopic views and the Quadrant view. The two simulated arthroscopic views (30 degree view and 45 degree view) were assumed to observe the ACL femoral foot print at 30 and 45 degrees to the medial wall of the lateral femoral condyle. The Quadrant view (90 degree view) was assumed to observe the ACL femoral footprint at 90 degrees to the medial wall of the lateral femoral condyle. The grid is aligned with the Blumensaat’s line, which is a projection of the femoral notch roof on the radiograph. A zero point was established on the point of intersection of the Blumensaat’s line and the outline of the posterior wall of the lateral femoral condyle. An X-axis is established to be parallel to the Blumensaat’s line. A Y-axis is established to be perpendicular to the X axis. The grid was drawn, and measurements were performed as previously described by Bernard et al. The center position of each bundle was shown by the below expression, (X, Y) (%).

Results

The center positions of AMB were (9.1, 34.9) (%) at 30 degree view, (14.5, 32.9) (%) at 45 degree view, and (16.2, 35.5) (%) at 90 degree view. X-value at 30 degree view was significantly deeper than 90 degree view (P=0.008). There was not a significant difference among Y-values at three views. The center positions of PLB were (21.2, 66.2) (%) at 30 degree view, (31.2, 70.9) (%) at 45 degree view, and (31.6, 67.0) (%) at 90 degree view. X-value at 30 degree view had a tendency to be deeper than that at 90 degree view without any significant difference. There was not a significant difference among Y-values at three views.

Conclusion

This study showed femoral tunnel creation in arthroscopic ACL reconstruction surgery might have a tendency to create a shallower AMB femoral tunnel than anatomic position.