The ACL originates from the lateral femoral condyle and inserts on the anterior tibial spine. It has two bundles and acts as the primary restraint to anterior tibial displacement when the knee is flexed at 90 degrees. ACL injuries most often occur during pivoting sports and can be accompanied by meniscal or other ligament injuries. Physical exam findings of an ACL injury include effusion, decreased range of motion, and a positive Lachman or pivot shift test. Treatment options include rehabilitation for partial tears or surgery involving reconstruction for full tears to restore stability.

2. Anatomy
• The ACL originates at
posteromedial aspect of
the lateral femoral
condyle.
• Wide tibial insertion at
the lateral aspect of the
anterior
tibial spine.
• The ACL has two fiber
bundles.
• The anteromedial.

3. Functions of ACL
• Primary restraints to anterior tibial
displacement[accounts for 85% of the
resistance to anterior drawer test,
when the knee is kept at 90 degree
of flexion.
• Secondary restraints to tibial rotation
& varus : valgus angulation at full
knee extension.
• Proprioceptive function: presence of
mechanoreceptors in the ligaments.[

4. Anterior cruciate ligament injury
ACL injury most often occurs during sports such as
football, basketball, skiing and tennis.
The injury often happens if you land on your leg and
then quickly pivot or twist your knee in the opposite
direction.
About half of people with an ACL injury also have injury
to their meniscus or another ligament in the same knee.

6. Women > men
• Several studies have shown that female athletes have a
higher incidence of ACL injury than male athletes because
of Differences in –
• Physical conditioning
• Muscular strength
• Smaller size and different shape of the intercondylar notch
• Lower extremity (leg) alignment
• The effects of estrogen on ligament properties.

7. Types of ACL Tears

8. ACL: HISTORY
• Contact vs noncontact
• Immediate effusion (first 4-12 hr)
• Unable to continue
• Mechanism = pivot, hyperextension

9. ACL: PHYSICAL EXAM
• Decreased ROM
• Effusion-hemarthrosis, immediate
• + Instability tests
• Lachman: most accurate
• Pivot shift
• Anterior drawer
• + MCL and meniscus tests

10. ACL Special Tests
• Anterior drawer
• Lachman’s test
• Pivot shift test
• Valgus stress test at
full extension for
combined MCL!

11. Anterior drawer

12. Lachman’s test

13. “Partial” ACL tear
• > 40% ACL substance
• Anterior drawer test -
• + Lachman,
• Clinically
• Most behave functionally
as full tears
• Continued shifting ↑’s risk
of meniscus damage
• Rx as full tear

14. Associated Injuries
• Injuries to the ACL rarely occur in isolation. The presence
and extent of other injuries may affect the way in which
the ACL injury is managed.
• Meniscal Lesions
• Over 50% of all ACL Ruptures have associated Meniscal
injuries. If seen in combination with a medial meniscus
tear and an MCL Injury, it is termed O’Donohue’s Triad
which has 3 components:[1]
• Anterior Cruciate Ligament (ACL) Tear
• Medial Collateral Ligament (MCL) Tear
• Meniscal Tear
• Lateral meniscus lesion are presented but with lower rate
than medial meniscus

15. Investigations

16. ACL TREATMENT
• Nonsurgical- Not physically
demanding
• modify activity
• splint & crutches, Closed chain WB to strengthen
• RICE- Rest, Ice, Compression, Elevation
• Hamstrings, gastrocnemius
• Functional bracing.
• 100% @ 9-12 months

17. ACL TREATMENT
• Surgery
• Indications
• Most active people will require surgery to
restore adequate function and decrease
instability
• Recurrent instability
• Inability to modify activity
• Associated injuries: meniscus
• Age -"you're never too old to have your ACL
reconstructed,"
• Wait three weeks due to arthrofibrosis risk
• 100% @ 6-12 months

18. Complications
 Adhesions
• If the knee with a partial ligament tear is not actively exercised, torn
fibers will stick to intact fibers and bone.
• The knee gives way with catches of pain, localized tenderness and
pain on lateral or medial rotation occur
• Confusion with a torn meniscus can be resolved by the grinding test
or arthroscopy
 Instability
• The knee continues to give way and tends to get worse predisposing
to osteoarthritis. Reconstruction before degeneration is wise.

19. Physical Exam of the Knee
• Inspection
• Palpation
• Range of Motion
• Special tests
• Neurovascular
assessment