Knee Injuries Flashcards
ACL injury mechanism
Valgus twisting e.g. forcefully landing on leg when attempting to rapidly change direction
Generally non contact
Typical ACL injury presentation
Popping sound at the time of injury
Fall to the ground, unable to finish playing sports, need to be helped from the field.
Knee swells quickly. Unable to weight-bear.
If no fracture acute knee swelling indicates…
ACL injury
Mechanism of PCL injury
Direct blow to flexed knee
Typical presentation of PCL injury
Posterior knee pain, a subtle limp, a modest effusion, and reduced end-of-range knee flexion.
Mechanism of MCL/LCL injury
Significant varus or valgus strain. Normally requires contact injury.
Direct blow pushing knee sideways
Typical presentation of MCL/LCL injury
Medial or lateral pain. Feeling of instability.
No significant swelling (as it is extra-articular)
Is MCL or LCL injury more common?
MCL
Mechanism of meniscal injury
Loaded knee is twisted
Typical presentation of meniscal injury
Locking, blocking or catching
Mild effusion can develop
What type of knee injury is caused by ACL type injuries / hyperextension and is commonly seen in children?
Tibial eminence #
What type of knee injury is caused by jumping activities e.g. basketball, gymnastics, football and is commonly seen in adolescents?
Tibial tuberosity #
Mechanism patella #
Direct blow to knee or forceful contraction of quad against semi-flexed knee
Mechanism of tibial plateau #
Axial loading with varus or valgus stress
Falling onto an extended leg
Typical presentation of tibial plateau #
Tenderness over medial or lateral margins of proximal tibia
Often unable to weight-bear
May be associated with knee ligament injuries
Mechanism of patella dislocation
Twisting or direct blow on partially flexed knee
Typical presentation of patella dislocation
Very painful knee in flexed position with laterally displaced patella. May have large effusion.
Patella dislocations are more common in what age group
Adolescents
Mechanism of knee dislocation
High energy trauma
How common is knee dislocation?
Rare
Why worry about knee dislocation?
Potentially limb-threatening
Neurovascular compromise needs to be ruled out
Special tests on exam for ACL injury
Lachman and pivot shift tests