2015 ISAKOS Biennial Congress ePoster #1005

Evaluation of the Anterolateral Ligament Length and Isometric Pattern with Serial Computer Tomography

Camilo P. Helito, MD, PhD, São Paulo, SP BRAZIL
Marco K. Demange, MD, PhD, São Paulo, SP BRAZIL
Marcelo B. Bonadio, MD, São Paulo, SP BRAZIL
Roberto Freire da Mota e Albuquerque, MD, PhD, São Paulo, SP BRAZIL
José R. Pécora, Prof., São Paulo, SP BRAZIL
Riccardo Gomes Gobbi, MD, PhD, São Paulo, SP BRAZIL
Luís Eduardo P. Tírico, MD, São Paulo, SP BRAZIL
Paulo Helito, MD, São Paulo, SP BRAZIL
Fabio J. Angelini, MD, Sao Paulo, SP BRAZIL
Gilberto L. Camanho, MD, São Paulo, SP BRAZIL

Institute of Orthopedics and Traumatology, Faculty of Medicine, University of São Paulo, São Paulo, São Paulo, BRAZIL

FDA Status Not Applicable

Summary: The ALL has no isometric behavior during the range of motion of the knee. The ALL increases in length by 16.7%, on average, from full extension to 90 degrees flexion. The increase in length is greater from 60 to 90 degrees than from 0 to 30 degrees and from 30 to 60 degrees. The increase in length at higher degrees of flexion suggests greater tension with increasing flexion.

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Abstract:

Background

Recent anatomical studies have identified the knee anterolateral ligament (ALL). Injury of this structure may lead to the presence of residual pivot-shift in some reconstructions of the anterior cruciate ligament. The behavior of the length of this structure and its tension during range of motion has not been established and its essential when planning reconstruction.

Purpose

To establish the differences in the ALL length during the range of knee motion.
Study Design: Descriptive Laboratory Study

Methods

Ten unpaired cadaver were dissected. The attachments of the ALL were isolated. Its origin and insertion were marked with a 2-mm diameter metallic sphere. Computed tomography scans were performed on the dissected parts under extension, 30°, 60° and 90° flexion; measurements of the distance between the two markers were taken at all mentioned degrees of flexion. The distances between the points were compared.

Results

The mean ALL length increased with knee flexion. Its mean length at full extension and at 30°, 60° and 90° of flexion was 3.79cm, 3.93cm, 4.09cm and 4.41cm, respectively. The mean increase in length from 0°-30° was 3.99%, from 30°-60° was 4.20%, and from 60°-90° was 7.45%. From full extension to 90° flexion, the ligament length increased on average 16.7%. From 60° to 90° flexion, there was a significantly higher increase in the mean distance between the points compared with the flexion from 0° to 30° and from 30° to 60°.

Conclusion

The anterior lateral ligament shows no isometric behavior during the range of motion of the knee. The ALL increases in length from full extension to 90° flexion by 16.7%, on average. The increase in length was greater from 60° to 90° than from 0° to 30° and from 30° to 60°. The increase in length at higher degrees of flexion suggests greater tension with increasing flexion.
Clinical Relevance: The present study is important because knowledge of the ALL behavior during the range of motion of the knee will allow for fixation (during its reconstruction) to be performed with a higher or lower tension, depending on the chosen degree of flexion.