The role of the anteromedial and posterolateral bundles of the anterior cruciate ligament in anterior tibial translation and internal rotation.
BACKGROUND
A rupture of the entire fibers of the anterior cruciate ligament leads to knee instability due to increased anterior tibial translation and increased internal tibial rotation. The influence of isolated deficiency of the anteromedial or posterolateral bundle of the anterior cruciate ligament on the resulting knee kinematics have not yet been reported.


OBJECTIVE
Transection of the anteromedial bundle will lead to increased anterior tibial translation at 90 degrees. Transection of the posterolateral bundle will show an increased anterior tibial translation as well as a combined rotatory instability at 30 degrees.


METHODS
Controlled laboratory study.


METHODS
Kinematics of the intact knee were determined in response to a 134-N anterior tibial load and a combined rotatory load of 10 N.m valgus and 4 N.m internal tibial rotation using a robotic/universal force moment sensor testing system. Subsequently, the fibers of the anteromedial and posterolateral bundle were resected in an alternating order and the new translation in response to the same external loading conditions measured. Statistical analysis was performed using a 2-way ANOVA test.


RESULTS
Transection of the anteromedial bundle increased anterior tibial translation at 60 degrees and 90 degrees of knee flexion significantly. Isolated transsection of the posterolateral bundle increased anterior tibial translation in response to 134-N anterior load at 30 degrees of knee flexion significantly and resulted in a significant increase in combined rotation at 0 degrees and 30 degrees in response to a combined rotatory load compared with the intact knee and isolated resection of the anteromedial bundle.


CONCLUSIONS
The anteromedial and posterolateral bundles stabilize the knee joint in response to anterior tibial loads and combined rotatory loads in a synergistic way.


CONCLUSIONS
The results of the current study suggest that, from a biomechanical point of view, it may be beneficial to reconstruct both bundles of the anterior cruciate ligament to better restore normal anterior tibial translation and combined rotation.
Zantop
Thore
T
Department of Trauma, Hand, and Reconstructive Surgery, Westfalian Wilhelms University Münster, Münster, Germany. thore.zantop@ukmuenster.de
Herbort
Mirko
M
Raschke
Michael J
MJ
Fu
Freddie H
FH
Petersen
Wolf
W
D000368:Aged; D016118:Anterior Cruciate Ligament / Q000503:physiopathology*; D000070598:Anterior Cruciate Ligament Injuries; D002102:Cadaver; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008875:Middle Aged; D008954:Models, Biological; D009068:Movement / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D012371:Robotics; D013977:Tibia / Q000503:physiopathology*; D016474:Weight-Bearing / Q000502:physiology