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INTRODUCTION
The articular surfaces of the tibiofemoral joint
in combination with the primary ligaments
play an important role in controlling the
biomechanical behavior of the joint. In
particular, the geometry of the tibial plateau
has a direct influence on the biomechanics of
the joint in terms of translation, the location of
instantaneous center of rotation, the screw-
home mechanism, and the strain biomechanics
of the knee ligaments such as the anterior
cruciate ligament (ACL) [1].
It is probable that the cruciate, collateral
ligaments and the menisci are functional
members that act in concert to align the
opposing knee joint surfaces to afford
congruent contact and normal kinematic
articulating motion [2].
ACL injury occurs predominantly via
noncontact mechanisms. Because of a high
incidence of long-term sequelae to ACL injury
including pain, instability, and early
development of osteoarthritis, identification of
risk factors for ACL injury is an important step
in the development of injury prevention [3].
Recently in the literature, there has been a great
focus on anatomic risk factors [4].
Posterior Tibial slope (PTS) is commonly
defined as the angle between a line fit to the
posterior-inferior surface of the tibial plateau
and a tibial anatomic reference line [5, 6, 7, 8,
9, 10, 11].
Biomechanically, a higher tibial slope in the
presence of a compressive load will generate a
higher anterior shear component of the tibio-
femoral reaction force, resulting in increased
anterior motion of the tibia relative to the
femur. Because theACL is the primary restraint
against this type of motion in the knee, it
logically follows that an increase in posterior
tibial slope will generate an increased load in
the ACL. This hypothesis was first by Butler
et al.
in the year 1980 [3].
Reliable clinical measurements of posterior
tibial slope are important for understanding
ACL injury mechanisms. It’s widely mentioned
in the literature that ACL-injured individuals
have a greater posterior tibial slope than
healthy controls [12].
It remains unclear whether the risk of
noncontact ACL injury could be increased in
those with increased slope in one or both
compartments and individual analysis of the
compartments separately could be essential to
understand the functional consequences of
tibial slope [13].
TIBIAL SLOPE AND ACL RUPTURE:
MRI ASSESSMENT
S. LUSTIG, A. ELMANSORI, T. LORDING,
E. SERVIEN, P. NEYRET