Graft-bending angle and femoral tunnel length after single-bundle anterior cruciate ligament reconstruction: comparison of the transtibial, anteromedial portal and outside-in techniques

• Published in: The bone & joint journal Vol. 96-B; no. 6; pp. 743 - 751
• Main Authors: Shin, Y S, Ro, K H, Jeon, J H, Lee, D H
• Format: Journal Article
• Language: English
• Published: England 01.06.2014
• Subjects: Adolescent; Adult; Anterior Cruciate Ligament - surgery; Anterior Cruciate Ligament Injuries; Anterior Cruciate Ligament Reconstruction - methods; Arthroscopy - methods; Cohort Studies; Female; Femur - diagnostic imaging; Femur - surgery; Follow-Up Studies; Graft Survival; Humans; Imaging, Three-Dimensional; Male; Middle Aged; Observer Variation; Prospective Studies; Tibia - diagnostic imaging; Tibia - surgery; Tomography, X-Ray Computed - methods; Treatment Outcome; Young Adult; Anteromedial portal; Anterior cruciate ligament reconstruction; 3D-CT; Transtibial; Curved planar reformation; Outside-in
• ISSN: 2049-4394; 2049-4408
• DOI: 10.1302/0301-620X.96B6.33201

We used immediate post-operative in vivo three-dimensional computed tomography to compare graft bending angles and femoral tunnel lengths in 155 patients who had undergone single-bundle reconstruction of the anterior cruciate ligament using the transtibial (n = 37), anteromedial portal (n = 72) and outside-in (n = 46) techniques. The bending angles in the sagittal and axial planes were significantly greater but the coronal-bending angle was significantly less in the transtibial group than in the anteromedial portal and outside-in groups (p < 0.001 each). The mean length of the femoral tunnel in all three planes was significantly greater in the transtibial group than the anteromedial portal and outside-in groups (p < 0.001 each), but all mean tunnel lengths in the three groups exceeded 30 mm. The only significant difference was the coronal graft- bending angle in the anteromedial portal and outside-in groups (23.5° vs 29.8°, p = 0.012). Compared with the transtibial technique, the anteromedial portal and outside-in techniques may reduce the graft-bending stress at the opening of the femoral tunnel. Despite the femoral tunnel length being shorter in the anteromedial portal and outside-in techniques than in the transtibial technique, a femoral tunnel length of more than 30 mm in the anteromedial portal and outside-in techniques may be sufficient for the graft to heal.