Lower Extremity Orthopedics Jaynstein (Exam 2)

Question 1

What 4 ligaments stabilize the knee?

Answer 1

MCL, LCL, ACL, PCL

Question 2

Describe varus vs valgus

Answer 2

Varus is bowed legs (Rum bottle between knees)

Valgus is knock knees (gum sticks the knees together)

Question 3

Where do the ACL and PCL insert?

What motion does each prevent?

Answer 3

All in relation to the tibia

ACL insert anteriorly into tibia. ACL keeps tibia from moving anteriorly
PCL inserts posteriorly into tibia, keeps tibia from moving posteriorly

Question 4

Describe a typical ACL MOI (mech. Of injury)

Answer 4

Non-contact deceleration producing valgus twisting. Occur when bones of the leg twist in opposite directions under full body weight

Question 5

Sxs of ACL tear?

Answer 5

“Pop”
Marked, immediate effusion (hemarthrosis; very vascular)
Difficulty/inability to weight bear
Knee feels unstable

Question 6

Exams to perform if ACL tear suspected?

Answer 6

Lachman
Anterior Drawer
Lever

Question 7

Dx of ACL tear?

Answer 7

Xray shows large effusion
Can demonstrate a Segond fx: avulsion of lateral tibial plateau, present in 75% of ACL ruptures
TOC is MRI w/o

Question 8

PCL is the strongest ligament in the knee. Sprains or partial tears are more common than complete tear, which usually occurs in major trauma. Over 70% of PCL tears have assoc injuries, such as ACL and MCL tears, but also one more that is much more life/limb threatening. What is it?

Answer 8

Knee dislocation, popliteal artery tear

Question 9

What is the MOI for most PCL tears?

Answer 9

Blow to the knee while it’s flexed
Striking knee against dashboard during auto accident
Falling on knee while flexed