Ligamentous injuries of knee

Question 1

Ligaments are

Answer 1

type 1 collagen
designed to resist tension
and provides stability

strength of ligament depends on the size and thickness and what is the age and general health of the individual

Question 2

Scar develops in the form of type

Answer 2

Type three collagen
not as strong

Question 3

make up of early healing ligament

Answer 3

less organized Fiber alignment
altered proteoglycan content
fewer Collagen cross-links
increased vascularity
Decreased innervation

weaker
Decreased proprioception

Question 4

Immobilization and ligament recovery

Answer 4

do not immobilize for more than a week or two

protected movement is important to initiate healing
However, immobilization can be harmful

ligament can start to atrophy - decrease tensile strength

Question 5

Insertion into the bone recovers…

Answer 5

first, within weeks
While the ligament takes longer, within months

Question 6

MCL resists

Answer 6

valgus stress
External rotation

Question 7

in the MCL, which layer is more commonly injured

Answer 7

Superficial layer

Question 8

MCL deep fibers tend to attach to the

Answer 8

Medial meniscus and medial joint capsule

Question 9

when are the MCL fibers more taut

Answer 9

Posterior fibers are taut than anterior fibers with the knee extended

Anterior fibers are more taut in slight knee flexion

Question 10

mechanism of injury of MCL

Answer 10

Valgus trauma
often With planted foot

Local pain, swelling, difficulty walking, instability with activities

Question 11

valgus stress test

Answer 11

Push knee medially while using your body and elbow to increase valgus stress by creating a counter force

30° flexion first then if positive test in full extension

A positive positive finding is pain reproduction in the area you are testing, as well as increased movement or a lack of a firm end feel

Question 12

LCL resist

Answer 12

varus stress

ER

Question 13

LCL is separated from the capsule by

Answer 13

popliteus tendon

LCL is not attached to the meniscus

Question 14

mechanism of injury of LCL

Answer 14

varus trauma
Often with planted foot

Local pain, swelling, difficulty walking instability with activities

Question 15

varus stress test

Answer 15

push me laterally while using your body and elbow to increase the varus stress by creating a counter force

Test 30° function first then positive test in full extension

Positive finding is pain reproduction in the area you are testing, as well as increased movement or lack of end feel

unreliable assessment

Question 16

grading ligament sprains

Answer 16

Grade 1- pain with stress testing no instability

Grade 2 - pain with stress testing positive instability, but with firm end feel

Grade 3 - complete tear, positive instability, no firm end feel, may have less pain due to complete ligament rupture

Question 17

ACL resists

Answer 17

Anterior translation of the tibia on the femur

Hyper extension of knee
Internal rotation of tibia on femur

Question 18

Anteromedial bundle of the ACL

Answer 18

maintains tension throughout the knee range of motion, especially 45 to 60° flexion

Question 19

Posterolateral bundle of ACL

Answer 19

taut in extension
Slack once knee flexes

Question 20

once the knee flexes to 90°, what happens to ACL

Answer 20

Anteromedial and posterolateral bundles cross over each other

Question 21

MOI ACL

Answer 21

80% noncontact- cutting pivot on fixed foot, rotational, valgus, hyper extension

20% contact- posterior directed force on distal femur or medial directed force on lateral knee when foot is planted

Significant knee pain, swelling, popping, episodes of knee giving away, quads inhibition, loss of range of motion

Question 22

Lachmans test

Answer 22

ACL
knee tested at about 20 to 30° flexion

Attempt to glide the tibia anteriorly

Positive test is mushy or soft end feel

Question 23

anterior drawer test

Answer 23

ACL
Knee in 90° flexion

Slightly abduct externally rotate hip to improve hamstring relaxation

Draw tibia anteriorly

Positive test is greater than 5 mm of movement

Assess position tibia to avoid false positive or negative

Question 24

lever test

Answer 24

ACL
full knee extension

rest fist under proximal third of the calf

other hand will apply anterior to posterior force on the distal third of the quadriceps

Positive test is no elevation of the heel

Question 25

PCL resists

Answer 25

Posterior translation of tibia on femur
Rotation of tibia on femur

Provides posteriolateral stability of knee joint

Question 26

What other structures help provide stability of the posteriolateral corner

Answer 26

lateral head of gastrocnemius
Popliteus
poplitealfibular Ligament
LCL
arcuate ligament

Question 27

PCL in comparison to the ACL

Answer 27

PCL is 50% thicker and twice the tensile strength compared to the ACL

Question 28

what are the bundles of the PCL

Answer 28

Anterolateral
Posteromedial

Question 29

PCL is more taut in

Answer 29

Knee flexion

Question 30

MOI PCL

Answer 30

high impact posterior directed force on the tibia

MVA with shin to dashboard

acute onset of posterior knee pain , swelling, instability

Question 31

posterior drawer test

Answer 31

knee in 90 flexion

hold proximal tibia with hands so that thumbs are on anterior joint line and fingers can palpate hamstring tendons

Push tibia posteriorly

positive test is excessive movement of the tibia compared to the other side or a lack of end feel

Question 32

posterior sag sign

Answer 32

Patient supine with knees flexed 90°

Observe the position of the tibial, tuberosities and plateau

Positive test is posterior displacement of involved tibia

Patient contract hamstrings to see if that further displaces involved tibia posterior