Cruciate Ligaments Flashcards
What is the function of the posterior cruciate ligament? Where does it attach??
Attaches at the posterior intercondylar region of the tibia and ascends anteriorly to attach to the anteromedial femoral condyle.
It prevents posterior dislocation of the tibia onto the femur from an anterior force and hyeprflexion
What is the function of the anterior cruciate ligament? Where does it attach?
Attaches at the anterior intervondylar region o the tibia where it bless with the medial meniscus.. Ascends posteriorly to attach to the femur in the intercondylar fossa.
Prevents anterior dislocation of the tibia on the femur and hyper extension o the knee
Contributes to internal knee rotational stability
How can the ACL be damaged?
hyperextension of the knee or large force to the back of the knee with the joint partly flexed
Twisting injuries - twisting force applied to bent knee
How can the PCL be damaged?
Large force applied to the shins when the knee is flexed - dashboard injury - pushing tibia posteriorly
Hyperflexion of the knee joint with plantar flexed foot
How can ACL damage be tested for? PCL?
Anterior draw test - attempt to pull tibia forwards - if it moves, ACL is torn.
Posterior draw test - hold knee flexed and push tibia posteriorly - if there is movement, PCL is torn.
How does a torn PCL present? On examination? God standard for diagnosis?
Immediate posterior knee pain\Instability of the joint
Postive posterior draw test with a posterior sag.
MRI scan for diagnosis
How are PCL tears treated?
Conservative - knee brace and physiotherapy
Surgical - insertion of graft if symptoms continue and recurrent instability
When does ACL tear typically occur?
Athlete with history or twisting knee while weight bearing
Majority occur without contact and result from landing form a jump
How does ACL tear present?
Rapid joint swelling and significant pain
Instability may also be evident - leg giving way
Why does the knee swell in ACL injury?
Ligament is highly vascular and so damage results in haemarthrosis
What are the clinical tests to identify ACL damage
Lachman test
Place knee in 30 degrees flexion and with one hand stabilising the femur, pull the tibia forward to assess the amount of anterior movement of the tibia compared to the femur. Other knee for comparison.
Anterior draw test
Flex knee to 90, place thumbs on the joint line and index fingers on hamstring tendons posteriorly.
Force applied anteriorly to demonstrate any tibial excursion. Compare sides.
What investigations in ACL injury?
XR of knee (AP and lateral) to exclude any bony injury, joint effusion or lipohaemarthrosis
MRI scan of knee is gold standard for ACL injury, also showing meniscal tear.
What does ACL tear commonly present with?
Lateral meniscal tear
How is ACL tear managed immediately?
RICE - rest, ice , compression, elevate
What is the specific management for ACL rupture?
Conservative - rehabilitation, using strength training of the quadriceps to stabilise the knee, canvas knee splint for comfort
Surgical - use of tendon or artificial graft following period of rehabilitation with physiotherapy prior to surgery
