2015 ISAKOS Biennial Congress ePoster #1127

Effects of Anterolateral Capsular Injury and Extra-Articular Tenodesis on Knee Kinematics

Fabio V. Arilla, MD, Estancia Velha, RS BRAZIL
Amir Ata Rahnemai Azar, MD, Pittsburgh, PA UNITED STATES
Daniel Guenther, MD, PD, Cologne GERMANY
Carlos H. Yacuzzi, MD, Buenos Aires, BA ARGENTINA
Ben Engel
Freddie H. Fu, MD, Pittsburgh, PA UNITED STATES
Richard E Debski, PhD, Pittsburgh, PA UNITED STATES
Volker Musahl, MD, Prof., Pittsburgh, Pennsylvania UNITED STATES
University of Pittsburgh, Pittsburgh, PA, USA

FDA Status Not Applicable

Summary: This study evaluated the effect of anterolateral capsule injury and extra-articular tenodesis on the anterior tibial translation relative to the femur during physical examination.

Abstract:

Background

Recent studies suggest that procedures such as extra articular tenodesis may help to restore rotational stability of the knee (Duthon et al., 2013). However, the contribution of the anterolateral capsule combined with reconstructive procedures to knee stability are poorly understood.

Purpose

To determine the effect of anterolateral capsule injury and extra-articular tenodesis on the anterior tibial translation (ATT) relative to the femur during physical examination.

Methods

Seven knees from whole lower extremity fresh-frozen human cadavers were utilized. A single surgeon performed pivot shift tests (ATT was evaluated); maximal ATT and maximal rotatory tests (internal and external rotations) at 0°, 30°, 60° and 90° of flexion. Three trials of each examination were recorded in seven knee states (1-intact, 2-ACL deficient, 3-ACL reconstructed, 4-ACL reconstruction combined to extra articular tenodesis; and the states 2, 3 and 4 added to lateral capsule injury). Extra articular tenodesis was performed by a modified Lemaire procedure. An electromagnetic tracking system with accuracy of 0.5 mm and 0.5 degrees (Nest of Birds, Ascension Technology) was used to measure knee kinematics.
Multiple univariate repeated measures ANOVAs and post-hoc analysis were used to investigate differences in ATT during the pivot shift test and to investigate differences of ATT and internal-external rotation during the manual tests. Statistical significance: P< 0.05.

Results

Pivot shift test: The ACL deficient knee showed higher ATT compared to the ACL reconstructed knee or the intact knee (p<0.05), however no significant difference was observed between intact, ACL reconstructed and ACL reconstructed + extra articular tenodesis knees. Injuring the anterolateral capsule significantly increased the ATT of ACL-deficient knee (increase of 25%, p<0.05). A significant decrease in ATT was observed after ACL-reconstruction (54%, p<0.05) and an additional extra articular tenodesis did not result in a significant decrease in anterior tibial translation.
Manual tests: Creating an injury to the anterolateral capsule in an ACL deficient knee, a significant difference in anterior tibial translation was found at 0° and 30° of flexion (p<0.05). When extra articular tenodesis followed an ACL reconstruction, no significance difference was found (p>0.05).

Discussion

The most important finding of this study is that benefit from adding an extra articular tenodesis to an ACL-reconstruction could not be proved. Our findings partially agree with Monaco et al. (2012) who found a significant difference at all degrees of flexion for anterior tibial translation after injuring the lateral capsule, and only at 30° for internal rotation. It could be explained by the capsular injury model utilized in both studies (horizontal 2 cm tear at the joint line), what may not represent the in vivo pattern. In the future, an injury model to properly simulate capsular stretching will be developed to properly assess the role of this injury.
From the findings of this study, extra articular tenodesis is not necessary in isolated ACL injury; furthermore the potential to over-constrain the lateral compartment of the knee could exist with this procedure.