Ligament injuries to the knee

Question 1

MOI for MCL injury

Answer 1

valgus stress to the knee

Question 2

Physical exam of MCL

Answer 2

Valgus stress test at both 30 degrees of flexion and at 0 degrees.
Grade 1 sprain: 5 mm
Grade 3 sprain: >10mm

Question 3

MOI for LCL injury

Answer 3

varus stress to the knee

Question 4

Physical exam of LCL

Answer 4

Varus stress test at both 30 degrees of flexion and at 0 degrees.
Grade 1 sprain: 5 mm
Grade 3 sprain: >10mm

Question 5

Tx of MCL and LCL injuries

Answer 5

Rest, ice, immobilize
Non operative care for MCL and grade 1 or 2 LCL
Refer if there is a severe injury with instability or a refractory case (don’t improve within a normal timeframe)

Question 6

MOI for ACL injury

Answer 6

Hyperextension (tibia moving forward)

Marked internal rotation

Question 7

What can be assoc. with ACL injury

Answer 7

Meniscus tear and MCL tear

Question 8

What is a big inspection finding with ACL or PCL ligament tears

Answer 8

Hemarthrosis (swelling of the knee immediately after tearing) due to the high vascularization of the cruciate ligaments

Question 9

Physical exam of ACL injury

Answer 9

Lachman’s test (Most sensitive)

Anterior Drawer test (less helpful)

Question 10

ACL tx

Answer 10

Initial: rest, ice, immobilization, crutches, qua/hamstring strengthening
Refer to ortho especially with young active pts.
Replace with autograft or allograft (patellar or hamstring tendon)

Question 11

MOI for PCL injury

Answer 11

hyperflexion of the knee (isolated PCL injury)
“Dashboard” injury (occurs in MVA)
Fall on flexed knee with plantarflexion
Hyperextension of knee, severe ACL tear

Question 12

Evaluation of PCL injury

Answer 12

Check popliteal artery and other soft tissues
Initial: Effusion and decreased ROM
Posterior Drawer Test
Posterior Sag Sign

Question 13

PCL tx

Answer 13

Conservative tx

Can have surgery if other injuries occurred or in young, active pts