2015 ISAKOS Biennial Congress ePoster #1342

In Vivo Relationship Between Graft Isometricity and Tunnel Positions in Single Bundle ACL Reconstruction

Sung-Hwan Kim, MD, Seoul KOREA, REPUBLIC OF
Min Jung, MD, PhD, Seoul KOREA, REPUBLIC OF
Yong-Min Chun, MD, PhD, Assoc. Prof., Seoul KOREA, REPUBLIC OF
Inje Cho, MD, Seoul KOREA, REPUBLIC OF
Seong Min Kim, MD, Seoul KOREA, REPUBLIC OF
Sang-Woo Jeon, MD, Seoul KOREA, REPUBLIC OF
Ji-Young Yoon, MD, Seoul KOREA, REPUBLIC OF
Chong-Hyuk Choi, MD, PhD, Seoul KOREA, REPUBLIC OF
Sung-Jae Kim, MD, PhD, Seoul KOREA, REPUBLIC OF

Yonsei University College of Medicine, Seoul, KOREA

FDA Status Not Applicable

Summary: Following anatomical single bundle ACL reconstruction the intra-articular graft length change during knee flexion showed non-isometric behavior during early knee flexion below 60°.

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Abstract:

Introduction

The relationship between length change of grafted tendon during different flexion angles and different tibial and femoral tunnel positions was investigated for anatomical single bundle ACL reconstruction.

Methods

The tibial and femoral tunnel position was examined using postoperative 3 dimensional CT images of 77 cases that received anatomic single bundle ACL reconstruction using the anteromedial transportal technique. The femoral tunnel position was confirmed by the depth and height ratio using the Bernard-Hertel method and the tibial tunnel position was confirmed using the anteroposterior (tAP) ratio and medial to lateral (tML) ratio. The patients were divided into group A (52 cases) with less than 3mm total graft length change (TGLC), and group B (25 cases) with over 3mm TGLC. The relationship between each tibial and femoral tunnel position and graft length change (GLC) was analyzed.

Results

During knee flexion from 0 to 120° the average TGLC was 2.3 ± 1.0 mm, average femoral depth and height ratio was 26.8 ± 3.7 % and 32.5 ± 7.2 %, average tAP ratio and tML ratio was 43.5 ± 5.9 % and 41.9 ± 2.2 %, respectively. Multiple linear regression analysis showed that only tAP ratio had a significant positive correlation with TGLC (ß = .325, p = .012). Univariate analyses between group A and B showed that femoral depth ratio (26.0 ± 3.4%, 28.8 ± 4.4%, p = .006) and tAP ratio (42.1 ± 4.5%, 48.4 ± 5.5 %, p = .001) were significantly increased in group B. However multiple logistic regression analysis revealed that only tAP ratio to have significant correlation (p = .018). Comparison between different knee flexion angle ranges showed significant GLC between 0 to 60° knee flexion range (p < .001), with the largest significant value observed between 15 to 30° of knee flexion range (0.9 ± 0.5 mm in GLC, 46.2 ± 20.4 % in proportional GLC).

Conclusion

Following anatomical single bundle ACL reconstruction the intra-articular graft length change during knee flexion was an average of 2.4 mm and showed non-isometric behavior during early knee flexion below 60°. These changes were more prominent with a more posterior tibial tunnel location.