Acute Knee Trauma

Question 1

Injuries and mechanisms:

*****Inward (from lateral side) blow - what structures will be damaged? - 3

Outward (from the medial side) blow - what structures will be damaged? - 2

Answer 1

Medial collateral ligament first
Then the ACL
Medial meniscus

The medial meniscus is more commonly injured because it is firmly attached to the medial collateral ligament and joint capsule.

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Lateral collateral
ACL

Question 2

Why is the ACL more commonly damaged?

Answer 2

PCL is stronger

Question 3

Injuries and mechanisms:

Anterior/posterior blow - what is damaged?

What will be damaged if you plant foot and rotate knee?

Answer 3

Both cruciate ligaments

Meniscus

Question 4

What is the typical triad of damage that occurs when an inward blow occurs?

What is this triad called?

Answer 4

ACL + Medial Collateral ligament + Medial meniscus

O’Donoghue

Question 5

Patella fracture - what kind of trauma causes this? - 2

Answer 5

A direct blow to a flexed knee (e.e. dashboard/fall)

Question 6

Presentation

Main symptoms - 2

What is heard when an ACL tears?

What symptoms suggest meniscal injury?

Answer 6

Pain and tenderness

A popping sound at the time of injury - followed by instability and swelling

Locking and giving way

Question 7

Investigations:

Examination:

• What test on examination is used to determine if there is a torn cruciate ligament?
• What test on examination is used to determine if there is a torn collateral ligament?

XR:

Ottawa Knee Rules are used to assess if there is fracture after acute trauma. What are some of the rules?

Answer 7

Anterior/posterior draw test

Flexing knee
One hand on the opposite side of joint you are testing
Other hand applies force to the tibia

Age >55 
Isolated patella tenderness
Fibular head tenderness 
Unable to flex to 90 degrees 
Unable to bear the weight

Question 8

Management - Soft tissue (ligaments):

RICE is the general initial Rx + analgesia - what does RICE stand for?

What is done if the joint is unstable?

Surgery needed if there is no response to Rx!

Answer 8

Rest
Ice
Compression
Elevation

Unstable and physiotherapy

Question 9

Management - Fracture:

What is done for a minimally displaced patella fracture?

What is done for a displaced fracture?

Answer 9

Brace in extension - Grace

Fixation