Biomechanical evaluation of a newly devised model for the elongation-type anterior cruciate ligament injury with partial laceration and permanent elongation.
OBJECTIVE
To biomechanically evaluate a newly devised model for the elongation-type anterior cruciate ligament injury with partial laceration and permanent elongation.


METHODS
Thirty-six rabbits were randomly divided into 4 groups of 9 animals each, after a quantitative injury was given to the right anterior cruciate ligament. The 4 groups were sacrificed at 0, 6, 12, and 24 weeks after surgery, respectively. Biomechanical and histological evaluations were performed at each period.


BACKGROUND
No adequate animal models have been established for the elongation-type anterior cruciate ligament injury in which the mid-substance is permanently elongated with partial laceration.


METHODS
The anteromedial and posterolateral half of the anterior cruciate ligament was transected at the proximal and distal one-third levels, respectively. Then, the anterior cruciate ligament was stretched by applying an anterior drawer force to the tibia at 90 degrees of knee flexion.


RESULTS
The treatment significantly increased the anterior translation of the knee into approximately 150-250% at each period after surgery. The maximum load and the stiffness of the femur-anterior cruciate ligament-tibia complex significantly decreased to 30% or less immediately after surgery, and then gradually increased to 50% at 12 weeks.


CONCLUSIONS
In this model, this quantitative treatment created serious injuries with partial laceration and permanent elongation in the anterior cruciate ligament to similar degrees. Also, incomplete tissue healing occurred in the anterior cruciate ligament to similar degrees after the treatment.


CONCLUSIONS
This model will be useful to study new therapeutic methods for the elongation-type anterior cruciate ligament injury.
Department of Medical Bioengineering and Sports Medicine, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo 060-8638, Japan.
Eiji
E
Kondo
Kazunori
K
Yasuda
Masanori
M
Yamanaka
Akio
A
Minami
Harukazu
H
Tohyama
D000818:Animals; D016118:Anterior Cruciate Ligament / Q000473:pathology / Q000503:physiopathology*; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D005260:Female; D022125:Lacerations / Q000473:pathology / Q000503:physiopathology*; D011817:Rabbits; D013718:Tensile Strength