QuestionSBA
QuestionChoice
The cruciate ligaments of the knee help stabilise the movements of the knee - particularly whilst it is rotating.

The anterior cruciate ligament specifically prevents the tibia from sliding in front of the femur - preventing excessive anterior translation.

Tests that would help confirm a diagnosis of an ACL tear include a positive Lachmann's, Anterior Drawer or Pivot Shift tests. It is worth searching for a video of these on Youtube to have an idea of what they look like.
10001792
a
Excessive anterior translation of the knee
QuestionChoice
The ACL is a soft-tissue structure in the knee, being a ligament. Therefore, you would not expect to see any change to the bony structures to the knee - if there are changes, you would then be expecting to be making another diagnosis on top of the ACL tear!
10001796
e
MRI changes to the patellar bone
QuestionChoice
This would be a sign seen in an Achilles (calcaneal) tendon rupture. The Achilles tendon connects the calf muscles to the foot and allows for plantarflexion of the foot (i.e. pointing your feet).

Therefore, you would expect someone with an Achilles tendon rupture to be unable to do a heel raise (this is the same movement as pointing their feet). This would **not** be found in an ACL injury.
10001794
c
Inability to perform heel raises
QuestionChoice
This is also what you would find in an Achilles tendon rupture, not an ACL tear.

The Achilles tendon allows the foot to perform plantarflexion - essentially allowing someone to point their feet. Without an Achilles tendon, the tendons responsible for dorsiflexion (the opposite of plantarflexion) take over, keeping the affected foot held in dorsiflexion.
10001795
d
Left foot held in dorsiflexion
QuestionChoice
The cruciate ligaments of the knee also help stabilise the backwards movement of the knee - whilst the ACL prevents excessive **anterior** movement of the tibia over the femur, the posterior cruciate ligament (PCL) prevents excessive movement of the tibia under the femur.

An injury in the **posterior** cruciate ligament would result in excessive posterior subluxation, but this would not be found in an ACL injury.
10001793
b
Excessive posterior subluxation of the knee
Concept
Chapter
2693
3873
Cruciate ligament injuries
Topic
145
Orthopaedics
12905
A 26-year-old man presents to the Emergency Department after he fell during a game of football, twisting his knee in the process.

An MRI scan confirms a left anterior cruciate ligament (ACL) tear - which of the following signs and symptoms would you expect to find in this patient?
a