Chapter 122 - Ligamentous Injuries of the Knee

Question 1

what tunnel malposition does transtibial femoral tunnel preparation lead to in ACL reconstruction?

Answer 1

vertical tunnel placement

Question 2

what does drilling the femoral tunnel NOT in hyperflexion put you at risk of?

Answer 2

posterior cortical blowout

Question 3

when performing a double bundle reconstruction of the ACL what knee position should you fix each bundle in?

Answer 3

anteromedial bundle should be fixed in 30-40 degrees of FLEXION

posterolateral bundle should be fixed in full extension

Question 4

what is the re-rupture rate for ACL reconstruction in the literature?

Answer 4

1-20%

Question 5

what is the rate of contralateral ACL tear?

Answer 5

3-6%

Question 6

who should NOT get an allograft acl?

Answer 6

young people who participate in cutting sports

Question 7

clinical outcomes of double bundle ACL reconstruction?

Answer 7

no difference in clinical outcomes, double bundle = higher cost, longer surgical times

Question 8

what is more common in BTB autografts than other types?

Answer 8

1. more kneeling pain
2. higher rate of return to elite level athletics than other autografts

Question 9

when an ACL does get infected, what is the most common bacterial pathogen?

Answer 9

staph epi

Question 10

what is the biggest risk factor for DVT following ACL?

Answer 10

previous blood clot
oral contraceptives
family history

Question 11

chronic PCL injury leads to arthritis in what compartments?

Answer 11

patellofemoral and medial compartment

Question 12

what indicates a positive quadriceps active test for PCL injury?

Answer 12

when the tibia translates anteriorly at 90 degrees of flexion with resisted knee extension (indicates the tibia is subluxated posteriorly at rest)

Question 13

non-operative rehab for PCL injuries includes what?

Answer 13

isolated quadriceps strengthening
quadriceps/hamstring isometric co-contractions

**Isolated hamstring contraction, especially in flexion should be avoided

Question 14

what is the most common ligament injured in the knee

Answer 14

MCL

Question 15

most common injury associated with MCL injury?

Answer 15

ACL (95% of concomitant in jury)
meniscal injury

Question 16

MCL resists what loads

Answer 16

valgus (especially at 30deg)
external rotation (especially in extension)

Question 17

proximal MCL injuries

Answer 17

• more reliably heal non-operatively
• may have difficulty achieving full ROM

Question 18

distal MCL injuries

Answer 18

• less likely to heal without surgery
• result in residual laxity

Question 19

most common outcome of non-op management of grade II or III MCL injuries?

Answer 19

asymptomatic residual laxity

Question 20

in concurrent ACL/MCL injury - timing of surgery

Answer 20

delay proportionally to grade of MCL injury to allow MCL to heal in
G1: 2-4 weeks
G2: 4-6 weeks
G3: 6-8 weeks
(also this is the return to sport time for isolated non-op MCL)

Question 21

what degree of knee flexion should the graft be fixed for MCL recon, or should the repair occur in MCL repair?

Answer 21

30degrees flexion

Question 22

popliteus restricts what?

Answer 22

anterior tibial translation, varus, and EXTERNAL rotation

Question 23

combined ACL/LCL is more common than what?

Answer 23

isolated LCL/PLC injury

Question 24

timing of lateral injuries - LCL, PLC, etc

Answer 24

acute - within 2-3 weeks
after 3 weeks, lateral/posterolateral structures are retracted and scarred