> > It is very important to find out the mechanisms for ACL injuries
> >because if the number of incidence keeps growing, it might become a
> >possible threat to female athletic community in the near future.
> >
> > I appreciate your help.
> >
> >Satoshi Fujita

Just happened to have some info from Campbell's Othopedics;

p 1568- Selective sectioning of the anterior cruciate ligament has
shown that the anteromedial band is tight in flexion whereas the
posterolateral bulky portion of the ligament is tight in extension
(see fig. 33-82,D). It has been shown that the anteromedial band is
the primary check against the anterior translation of the tibia on
the femur when the anterior drawer test is performed in the usual
manner with the knee flexed. With the knee extended, resistance the
anterior drawer is by the posterolateral bulky portion. Marshall
has shown that it is possible to obtain an anterior drawer sign and
yet at the time of surgery palpate an "intact" anterior cruciate
ligament. When the anteromedial band of the ligament is torn, the
posterolateral bulk of the ligament may remain intact and an
anterior drawer sign will be present but the surgeon will have the
impression that the ligament is not torn. The anteromedial and
intermediate parts of the anterior cruciate ligament are in direct
contact with the intercondylar shelf in extension, and rupture
commonly occurs in this middle third of the ligament when the knee is
forced into hyperextension (fig. 33-85). The posterolateral
portion of the anterior cruciate ligament provides the principal
resistance to hyperextension of the joint. The ligament also aids
in limitation of rotation of the tibia on the femur as well as
resisting extreme varus and valgus stress.
D.W. Smith, D.C.
Santa Barbara Health Center
e-mail: dwsmith@rain.org