Comparison of 3-Dimensional Notch Volume Between Subjects With and Subjects Without Anterior Cruciate Ligament Rupture

Purpose: The aim of this study was to determine whether individuals with anterior cruciate ligament (ACL) injuries have smaller notch volumes than uninjured subjects. A secondary aim was to determine the correlation between intraoperative 2-dimensional (2D) notch measurements, patient demographic factors, and notch volume. Methods: Manual digital tracings of the femoral intercondylar notch perimeter were performed on axial magnetic resonance images to calculate 3-dimensional (3D) notch volume. Notch volume was compared between 50 patients with ACL injury and 50 patients without ACL injury (control subjects). From the 50 patients with ACL injury, intraoperative 2D measurements of the notch were taken. These 2D measurements and patient demographic factors were correlated to 3D notch volume, by use of the Pearson correlation coefficient. In addition, notch size was compared between men and women. All group comparisons were performed by use of unpaired t tests. Results: The notch volume was larger (6.5 +/- 1.7 cm(3) [mean +/- SD]) for the group with ACL injury compared with control subjects (5.9 +/- 1.4 cm(3)); this difference approached statistical significance (P = .054). There were no significant correlations between the 2D dimensions and the 3D notch volume. Larger notch volumes were significantly correlated with increased subject height (r = 0.636, P < .001) and weight (r = 0.364, P < .001) but not body mass index (P = .269). Male patients had significantly larger notch volumes than female patients (P < .001). Conclusions: Contrary to our hypothesis, there was a trend toward larger notch volumes in patients with ACL injury compared with patients without ACL injury. Intraoperative notch measurements did not correlate with 3D notch volume. Notch volume was related to patient height, weight, and gender but not body mass index. Level of Evidence: Level III, case-control study.