Effects of maturation on the mechanical properties of regenerated and residual tissues in the rabbit patellar tendon after resection of its central one-third

Maeda, Eijiro; Tohyama, Harukazu; Noguchi, Hitoshi; Yasuda, Kazunori; Hayashi, Kozaburo

doi:10.1016/j.clinbiomech.2010.07.001

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Volume 25, Issue 9 , Pages 953-958, November 2010

Effects of maturation on the mechanical properties of regenerated and residual tissues in the rabbit patellar tendon after resection of its central one-third

Eijiro Maeda
- Biomechanics Laboratory, Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
- Corresponding author. Division of Human Mechanical Systems and Design, Graduate School of Engineering, Hokkaido University, N13 W8, Sapporo, 060-8628, Japan.
- Present, Division of Human Mechanical Systems and Design, Graduate School of Engineering, Hokkaido University, Sapporo, Japan.
Harukazu Tohyama
- Department of Sports Medicine and Joint Reconstruction Surgery, Hokkaido University School of Medicine, Sapporo, Japan
Hitoshi Noguchi
- Biomechanics Laboratory, Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
- Present, Denso Corporation, Nagoya, Japan.
Kazunori Yasuda
- Department of Sports Medicine and Joint Reconstruction Surgery, Hokkaido University School of Medicine, Sapporo, Japan
Kozaburo Hayashi
- Biomechanics Laboratory, Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
- Present, Department of Biomedical Engineering, School of Engineering, Okayama University of Science, Okayama, Japan.

Received 2 November 2009; accepted 1 July 2010. published online 02 August 2010.

Abstract

Background

The central one-third portion of the patellar tendon is commonly used as a graft for the reconstruction of the anterior cruciate ligament. Although several studies have been carried out on mechanical properties of healing tendons in mature animals, there have been no studies on regenerated and residual tissues in the immature patellar tendon after the removal of its central portion.

Methods

An entire one-third defect was made in the patellar tendon of 2-, 3- and 6-month-old rabbits. After 3 weeks, the tissue regenerated in the defect and the residual tissue were biomechanically and histologically evaluated.

Findings

The length of patellar tendons in 6-month-old animals after the resection of its central one-third was significantly longer than that in age-matched controls. The cross-sectional area of all operated tendons was significantly larger compared to age-matched controls. There were no significant effects of maturation on the mechanical properties of regenerated and residual tissues in operated tendons, although tensile strength and tangent modulus of normal tendons were significantly greater in 6-month rabbits than in immature ones. The histology of each of regenerated and residual tissues was similar in the three groups.

Interpretation

There were no remarkable effects of maturation on regenerated and residual tissues after the removal of the central one-third tendon. However, the strength and the modulus of normal tendons are significantly lower in immature patients than in mature ones. Therefore, surgeons should take account of the inferior mechanical properties of the tendon in skeletally immature patients at the time of surgeries for the reconstruction of the anterior cruciate ligament.

Keywords: Patellar tendon, Healing, Regenerated tissue, Residual tissue, Mechanical properties, Regenerative medicine