2017 ISAKOS Biennial Congress ePoster #1818

 

Effect of Graft Fixation Sequence in One-Stage Anterior Cruciate Ligament and Posterior Cruciate Ligament Reconstruction on Graft In-Situ Forces

Libin Zheng, MD, Xiamen, Fujian CHINA
Soheil Sabzevari, MD, Pittsburgh, PA UNITED STATES
Brandon D. Marshall, MS, Pittsburgh, PA UNITED STATES
Junjun Zhu, BS, MS, Pittsburgh, PA UNITED STATES
Monica A. Linde, MS, RN, Pittsburgh, PA UNITED STATES
Patrick J. Smolinski, PhD, Pittsburgh, PA UNITED STATES
Freddie H. Fu, MD, Pittsburgh, PA UNITED STATES

Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, UNITED STATES

FDA Status Not Applicable

Summary

According to the results of this study, the sequence of graft fixation has a slight effect on the graft in situ forces.

Abstract

Introduction

Graft fixation during one-stage anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction may affect tibiofemoral alignment and several authors have noted the importance of preserving intact tibiofemoral alignment [1,2]. Little research has been done on graft forces in combined ACL-PCL reconstruction and this study examined the effect of ACL/PCL fixation protocol on the in situ graft forces.

Methods

Twelve fresh-frozen mature porcine hind limbs (n=12) were used. The knees were tested using a robotic testing system with a universal force-moment sensor. One-stage, combined anatomic single bundle (SB) ACL and PCL reconstructions were performed with and 8 mm grafts from bovine extensor tendon. The knee states tested were: (i) intact ACL and intact PCL, (ii) deficient ACL and deficient PCL, and (iii) one-stage ACL and PCL reconstruction. Five fixation sequences were performed in each knee in a randomized order: (1) PCL fixed 1st at 30° and ACL fixed 2nd at 30° (Recon 1), (2) PCL fixed 1st at 90° and ACL fixed 2nd at 30° (Recon 2), (3) ACL fixed 1st at 30° and PCL fixed 2nd at 30° (Recon 3), (4) ACL fixed 1st at 30° and PCL fixed 2nd at 90° (Recon 4) and (5) ACL and PCL fixed simultaneously at 30° (Recon 5). Both grafts were tensioned to 40 N. Two external loading conditions were tested: an 89 N anterior tibial and a posterior tibial load at 30° (full extension in the porcine knee), 60° and 90° of knee flexion. Data was analyzed using one-way repeated measures ANOVA, and statistical significance was set at p<0.05.

Results

Under AT load, the ACL in situ force was only restored by the fixation sequence Recon 3 at 60° of knee flexion, while the PCL in situ tissue force was restored by all reconstructions at 30°, 60° and 90° of knee flexion. Under PT load, the ACL in situ force was restored at by all reconstructions at 30°, 60° and 90° of flexion, while the PCL in situ tissue force was restored by all reconstructions at 30°, 60°, and 90° of knee flexion, except by Recon 3 and Recon 4 at 30° of knee flexion.

Conclusion

The sequence of graft fixation has a slight effect on the ACL graft in situ forces under AT loading, as well as the PCL graft in situ forces under PT loading. However, the sequence of graft fixation has no effect on the PCL graft in situ force under AT loading, as well as the ACL graft in situ force under PT loading.

References: 1. Ibrahim S.A., et al., J Bone Joint Surg, 1999. 2. Zhao J., et al., Arthroscopy, 2006.