Acute Injuries of the Knee Flashcards
(42 cards)
Who is most at risk of ACL tears?
- 15-45yrs
- Active individuals - 70% occur in sporting activities
- Females>Males
What are the functions of the ACL?
Prevents
- Posterior displacement of the femur
- Hyperextension of the knee joint.
- Minimises tibial rotation
- Resists valgus/varus stress
Where does the ACL arise from and attach to?
Arises from anterior intercondylar area of the tibia, and attaches to the posteromedial aspect of the intercondylar notch of the femur

How do ACL tears occur?
As a result of an acute non-contact deceleration injury, forceful hyperextension, or excessive rotational forces about the knee.

Tearing what ligament can also result in an ACL tear?
MCL
Is the ACL intracapsular or extracapsular?
Intracapsular
What are the symptoms of an ACL tear?
- Mechanism of injury - twisting motion
- Popping sound
- Swelling
- Inability to return to play
What are the clinical signs of ACL tear?
- Effusion
- Haemarthrosis? - immediate swelling?
- Anterior Draw sign - positive
- Lachman’s test - positive
- Decreased ROM - esp. flexion

How would you investigate a suspected ACL tear?
Clinical diagnosis!!
Imaging
- MRI Scan (INITIAL TEST) - For clinical confirmation
How would you manage someone with a ruptured ACL?
- RICE
- Analgesia
- Protected weight-bearing - with crutches +/- knee immobiliser
- Physiotherapy
- Surgical reconstruction - autograft - iin the young/increased knee instability
What groups of individuals are more likley to suffer collateral ligament ruptures?
- Adults
- 20-35 yrs
- Most common in American footbal, skiing, rugby
Where are the attachment points for the MCL?
- Medial epicondyle of the femur
- Medial condyle of the tibia

Which collateral ligament attaches to its respective meniscus?
Medial collateral ligament
What is the function of the MCL?
- Resist valgus
- Resist external rotation forces
What are the attachement points for the LCL?
- Lateral epicondyle of femur
- Lateral surface of the head of the fibula

Does the LCL attach to the lateral meniscus?
No
What tendon passes deep to the LCL?
Tendon of popliteus
What is the mechanism of injury in a MCL tear?
- Valgus stress - blows to lateral aspect of the knee while foot is fixed
- External rotation load placed on the knee
- Overuse - Breast stroke whip kick, gymnastics
What are the symptoms of a collateral tear?
- Sudden sharp pain - medial or lateral side
- Feeling a crack
- Mechanism of injury - varus/valgus stress
What are the signs of a collateral ligament tear?
- Effusion - haemarthrosis if immediate
- Tenderness - over affected ligament
- Bruising? - over one side of the knee
-
Positive medial/collateral assessment
- Laxity on valgus stress - MCL damage
- Laxity on varus stress - LCL damage

How would you investigate someone with a suspected collateral ligament tear?
- MRI scan - clinical confirmation
- X-ray - fracture/loose body, avulsion
- US - tendon rupture, meniscal tears
How would you manage someone with a collateral ligament tear?
- RICE
- Analgesia
- Protected weight-bearing - with crutches +/- knee immobiliser
- Physiotherapy
- Surgical Reconstruction - rarely needed in MCL; LCL often more severe and can involve cruciates, therefore more likely to need surgery
What are menisci made of?
- Fibrocartilage - Fibro and chondroblasts in matrix of type 1 collagen
- Collagen fibres arranged in radial and circumferential orientation

What is an important thing to remember about the vascular supply of the menisci?
Vascular supply to menisci diminishes as you move more towards the centre of the meniscus - important when considering how to manage tear in relation to where it is


