ISAKOS: 2019 Congress in Cancun, Mexico
ISAKOS

2019 ISAKOS Biennial Congress ePoster #795

 

Knee Lateral Extra-Articular Tenodesis Decreases In-Situ Force in the Anterior Cruciate Ligament

João V. Novaretti, MD, São Paulo, SP BRAZIL
Justin W. Arner, MD, Pittsburgh, PA UNITED STATES
Calvin K. Chan, MS, Pittsburgh, PA UNITED STATES
Sene Polamalu, BS, Pittsburgh, PA UNITED STATES
Christopher D. Harner, MD, Houston, TX UNITED STATES
Richard Debski, PhD, Pittsburgh, PA UNITED STATES
Bryson P. Lesniak, MD, Pittsburgh, PA UNITED STATES

University of Pittsburgh, Pittsburgh, PA, UNITED STATES

FDA Status Not Applicable

Summary

Lateral extra-articular tenodesis reduces in-situ forces in the ACL in the setting of ALC injury possibly providing a protective effect to the ACL. Further clinical studies are needed to evaluate the mid- and long-term outcomes of LET for rotatory knee instability, specifically its effect on ACL graft rupture and other knee structures.

Abstract

Introduction

Lateral extra-articular tenodesis (LET) combined with anterior cruciate ligament (ACL) reconstruction has been described in an attempt to address residual rotatory knee laxity. However, concern exists that this may result in over-constraint. The purpose of this study was to quantify changes in in-situ force in the ACL and knee kinematics after LET.

Methods

Nine fresh-frozen cadaveric knees (mean age=66.4) were tested using a 6-degree-of-freedom robot. Two loading conditions with 200-N compression were applied for each state at 30, 60, and 90 degrees: 134-N anterior tibial load and 7-Nm internal tibial rotation. Kinematics were recorded then replayed while a universal force moment sensor measured the change in forces with each knee state which included anterolateral capsule (ALC) deficiency and LET (semitendinosus). By the principle of superposition, in-situ forces in the ACL and ALC were calculated. An ANOVA with post-hoc Bonferroni test was performed analyze the variations of kinematics, ACL and ALC forces at full-extension, 30º, 60º and 90º of knee flexion. Significance was set at p <0.05.

Results

The in-situ force in the ACL significantly decreased after LET when compared with ALC deficiency by 43.4% and 50.0% at 60º and 90º, respectively with anterior loading (p <0.05). During internal rotation, the in-situ force in the ACL decreased after LET when compared with ALC deficiency by 54.4% at 60º (p <0.05). LET graft in-situ force was significantly higher than in the native ALC under internal rotation by 43.0%, 122.0%, and 170.8% at 30º, 60º, and 90º, respectively (p <0.05). No difference was observed in the in-situ force in the ACL between the intact and LET states. No difference in kinematics was observed between the intact and LET states.

Conclusion

LET reduces in-situ forces in the ACL in the setting of ALC injury possibly providing a protective effect to the ACL. Further clinical studies are needed to evaluate the mid- and long-term outcomes of LET for rotatory knee instability, specifically its effect on ACL graft rupture and other knee structures.