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INTRINSIC RISK FACTORS OF ANTERIOR CRUCIATE LIGAMENT INJURY: REVIEW
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GENDER FACTOR
The fact is that females have 3 times greater a
risk of ACL injury than males participating in
the same sport. There are multiple studies
indicating a contribution between hormonal
factors and increased ligamentous laxity during
the first half of a menstrual cycle [8].
Biomechanical explanation for the changes is
most likely related to the increased levels of
relaxin and oestrogen mediated reduction in
pro collagen. Oral contraceptive and neuro
muscular training may increase dynamic knee
stability and lessen the risk of ACL injury.
GENE FACTOR
Collagen is the most important component of
ligaments. Type 1 collagen accounts for 85% of
collagen and the rest is made up of types 3, 5,
6, 9. It has been previously demonstrated that
individuals who have a family history of ACL
tears show twice as high a risk of ACL rupture
as another. There is an association between
Col3 A1 and Col1 A1 and ACL ruptures [9].
This knowledge can help athletes with their
training.
BIOMECHANICAL FACTOR
Valgus knee:
The literature is controversial,
numerous studies have shown that a valgus
moment and valgus rotation are not associated
with ACL injury. But some training programs
for ACL injury have shown a reduction in
trauma. Also valgus knee effects the axial
compressive force on the lateral side of the
knee and may contribute to an internal
rotation [10].
Foot and Ankle:
Boden
et al.
identified a safe
and an injured position of the ankle associated
with ACL injury. This can be associated with
the lower ankle plantar flexion of athletes.
When the ankle is not in appropriate extension,
the tibia is in an unstable position and
subluxation is easier than rolling. This ankle
plantar flexion is one of the most crucial
aspects for preventing ACL injury [10].
Torso and hip:
Only 3 articles relate to torso
and hip implication in ACL injury. After video
analysis, authors concluded that patients who
had ACL rupture had significantly higher hip
flexion angles. From this data, prevention
programs worked on torso stabilisation.
NEUROMUSCULAR
Just a few articles report information on
neuromuscular risk factors of ACL injury [11].
Quadriceps:
There is a postulat that the anterior
vector of the quadriceps is the primary
contributing force of ACL injury because the
quadriceps are the biggest ones. But quadriceps
force is full in extension and compressive force
is larger than anterior force. On the MRI, bone
bruising is more associated with compressive
force than anterior translation.
Hamstring tendon:
The Hamstring tendon has
been proposed as a protective mechanism for
the ACL. As the quadriceps, the hamstring
tendon further determines a tibio-femoral joint
compression force with minor posterior
protective forces.
CONCLUSION
All these intrinsic factors must be known for
several reasons. It can help with a training plan
and prevent ACL injury. It can help also the
surgeon performing ACL surgery strategy and
revision of failedACL reconstruction. However
for the moment, the most important intrinsic
factor is probably the tibial slope and must be
known for the tibial deflexion slope osteotomy
in revision ACL procedure.
The gender factor is more interesting for
epidemiology. For the moment, evidence for