Knee

Question 1

Which guidelines are best for evaluating radiographs for acute knee injuries?

Answer 1

Ottawa and Pittsburgh

Question 2

What makes Ottawa and Pittsburgh “the best?”

Answer 2

Excellent sensitivity for identifying fractures by applying simple predictive parameters

Question 3

When should radiographs be ordered after a trauma to the knee?

Answer 3

• Joint effusion after direct blow or fall
• Inability to walk without limping
• Palpable tenderness over patella or fibular head
• Inability to flex knee to 90

Question 4

When shouldn’t radiographs be ordered?

Answer 4

If patient had a twisting injury but is able to walk and no effusion present

Question 5

What do meniscal tears present with?

Answer 5

Intermittent clicking and eventually chronic blocking or loading of knee joint motion
Effusion
Pain

Question 6

What is the standard modality for evaluating meniscal tears?

Answer 6

MRI, menisci seen as LOW signal intensity (dark) with HIGH signal intensity (bright) tear that extends to the surface

Question 7

In what direction are meniscal tears most common?

Answer 7

Vertically

Question 8

What are longitudinal extensions from vertical tears called?

Answer 8

Bucket handle tears

Question 9

What direction of meniscal tears is most common in older individuals?

Answer 9

horizontal

Question 10

How does a patient present who injured a collateral ligament?

Answer 10

After an acute episode with pain, joint effusion, instability upon examination with ligamentous stress testing

Question 11

Which collateral ligament is more commonly injured?

Answer 11

Medial, often associated with tears of joint capsule and medial meniscus

Question 12

Which structures are injured in O’Donoghue’s terrible triad?

Answer 12

MCL, MM, ACL

Question 13

Which imaging technique is best for looking at collateral ligamentous injuries?

Answer 13

MRI T2-weighted, discontinuity of low-signal intensity ligament best seen on coronal image

Question 14

How many ACL injuries occur per year?

Answer 14

200,000

Question 15

How much more are women prone to ACL injuries than men?

Answer 15

8 times more

Question 16

What is the MOI for PCL injuries?

Answer 16

external forces that strike anterior aspect of knee, as in dashboard injuries

Question 17

What is the MOI for ACL injuries?

Answer 17

non-contact forces that place great valgus and rotary stresses on the knee, as when athlete suddenly decelerates, turns and hears “pop” of rupture

Question 18

What is dynamic lower extremity valgus force?

Answer 18

Combination of motions and rotations at all 3 LE joints

Ex: hip ADD/IR, knee ABD, tibial ER/anterior translation, ankle eversion

Question 19

What imaging should be used to view cruciate ligament injuries?

Answer 19

Radiographs required to evaluate an avulsion fracture

Sagittal MRI best to demonstrate cruciates

Question 20

What are the routine radiographs for the knee?

Answer 20

AP, lateral, PA axial (tunnel) and tangenital view of patellofemoral joint (sunrise)

Question 21

When are CT used?

Answer 21

degree of fragmentation or depression of articular surfaces, pre-op planning

Question 22

When are MRIs used?

Answer 22

injuries to articular cartilage, menisci, cruciate and collateral ligaments, soft tissue

Question 23

What are bone scans used?

Answer 23

Occult or subtle fractures, stress fractures, injury to articular cartilage (great sensitivity, inexact location)

Question 24

Which portion of proximal tibia is most involved in a fracture?

Answer 24

Tibial plateau, usually lateral

Question 25

What are the 2 types of injuries patella is vulnerable to?

Answer 25

Fracture from direct blow

Avulsion fracture from forceful contraction of quads

Question 26

DJD at knee hallmarks

Answer 26

Decreased joint space
Sclerotic subchondral bone
Osteophyte formation at joint margins
Subchondral cyst formation
Varus or valgus deformities

Question 27

Genu varum, valgum, recurvatum

Answer 27

varum = bowleges
valgum = knock knees
recurvatum = hyperextended