2015 ISAKOS Biennial Congress ePoster #1357

An In Vivo 3D-CT Analysis of Femoral Tunnel Geometry and Aperture Morphology Between Rigid and Flexible Systems in Double Bundle Anterior Cruciate Ligament Reconstruction Using the Transportal Technique

Jae Gyoon Kim, MD, PhD, Prof., Ansan, Gyeonggi KOREA, REPUBLIC OF
Hong Chul Lim, MD, Seoul KOREA, REPUBLIC OF
Jihoon Bae, MD, PhD, Seoul KOREA, REPUBLIC OF
Jin-Hwan Ahn, MD, Seoul KOREA, REPUBLIC OF
Jun-Ho Kim, MD, Seoul KOREA, REPUBLIC OF
Keon Woo Kim, MD, Seoul KOREA, REPUBLIC OF
Yoon Kwang Bae, MD, Ansan-Si KOREA, REPUBLIC OF
Joon Ho Wang, MD, PhD, Seoul KOREA, REPUBLIC OF
Korea University College of Medicine, Ansan Hospital, Ansan-si, KOREA

FDA Status Not Applicable

Summary: The AM femoral tunnel length and the AM/PL femoral graft-bending angle of the flexible system were longer and less acute than those of the rigid system, however, the aperture morphology of the AM/PL femoral tunnel and the aperture axis angle of the PL femoral tunnel in the rigid system were more elliptical and closer to parallel to the femoral shaft axis than those of the flexible system.

Abstract:

Purpose

To compare the femoral tunnel length, femoral graft-bending angle, posterior wall breakage, and femoral aperture morphology between the rigid and the flexible system after double bundle (DB) ACL reconstruction using the TP technique.

Methods

We retrospectively evaluated postoperative 3D-CT results for 54 patients who underwent DB ACL reconstruction using the TP technique with either a flexible system (Clancy Anatomic Cruciate Guide System; Smith & Nephew, London, UK) (n=27) or a rigid system (Bullseye® Femoral Footprint Guide; ConMed Linvatec, NY, USA) (n=27). Inclusion criteria were primary anatomic DB ACL reconstruction with or without meniscus tear. Exclusion criteria for rigid group were multiple ligament injury and revision ACL reconstruction. CT scans were performed on all knees at three days after ACL reconstruction. The femoral tunnel length, femoral graft bending angle, posterior wall breakage, femoral tunnel aperture height/width ratio (H/W ratio), aperture axis angle and femoral tunnel position were assessed using the OsiriX® and Geomagic® Qualify 2012 program after extracting the Digital Imaging and Communications in Medicine (DICOM) data from the Picture Archiving and Communication System (PACS) software. Two orthopedic surgeons developed all measurement methods together.

Results

The mean AM femoral tunnel length for the flexible group (35.8 ± 6.4 mm) was significantly longer than that of the rigid group (31.4 ± 3.1 mm, P = .009). In the rigid group, the number of cases with a femoral tunnel length <30 mm was 7 (25.9%) for the AM and 6 (22.2%) for the PL; in the flexible group; there was only one case for both AM and PL (3.7%) with a length <30 mm. The mean AM femoral graft-bending angle in the rigid group (108.4 ± 7.4º) was significantly more acute than that of the flexible group (115.5 ± 5.5º, P< .001), and the mean PL femoral graft bending angle in the rigid group (109.3 ± 9.2º) was also significantly more acute than that of the flexible group (117.3 ± 9.7º, P= .003). There were 4 cases of posterior wall breakage (AM femoral tunnel) in both the rigid and flexible group (P=1.00). The mean H/W ratios in the rigid group were significantly larger (more elliptical) than those of the flexible group (AM, P< .001; PL, P= .006). The mean aperture axis angle of the PL femoral tunnel in the flexible group (30.3 ± 19.0°) was more perpendicular to the femoral shaft axis and had a more variable range than the rigid group (8.09 ± 7.70°, P < .001). There were no significant differences in femoral tunnel position between the two groups (P>0.05).

Conclusion

The AM femoral tunnel length and the AM/PL femoral graft-bending angle of the flexible system were significantly longer and less acute than those of the rigid system. However, the aperture morphology of the AM/PL femoral tunnel and the aperture axis angle of the PL femoral tunnel in the rigid system were significantly more elliptical and closer to parallel to the femoral shaft axis than those of the flexible system.
Level of evidence: Level III, comparative study