Knee conditions

Question 1

What are some of the possible complications of a distal femur fracture?

Answer 1

Separation of condyles

Haemorrhage from popliteal artery

Question 2

What is a consequence of seperation of femoral condyles?

Answer 2

Malalignment of articular surfaces of knee joint

Question 3

What is a consequence of haemorrhage from popliteal artery?

Answer 3

Compromises blood supply to leg

Question 4

How does the tibia break in a proximal tibia fracture?

Answer 4

Condyles are broken up

Question 5

What is a complication of a proximal tibia fracture?

Answer 5

Injury to ligaments of knee joint

Question 6

What is meant by a patellar dislocation?

Answer 6

Patella displaces out of the intercondylar fossa of the femur

Question 7

What direction does the patella dislocate in?

Answer 7

Laterally

Question 8

What causes a patella dislocation?

Answer 8

Force to patella

Twisting of knee

Question 9

What normally prevents patella dislocation?

Answer 9

Medial pull by horizontal fibres of vastus medialis

Lateral femoral condyle projects more anteriorly

Question 10

What causes a patellar fracture?

Answer 10

Direct blow to bone

Sudden powerful contraction of quadriceps femoris

Question 11

What type of fracture do patella fractures usually involve?

Answer 11

Transverse fracture

Question 12

How do the bony fragments of a transverse patella fracture displace? Why?

Answer 12

Proximal fragment displaces superiorly by pull of quadriceps tendon

Distal fragment displaces inferiorly by pull of patellar ligament

Question 13

What is the mechanism of a collateral ligament injury?

Answer 13

Foot is placed on ground

Force applied against one side of knee

Stretches and tears collateral ligament on opposite side of impact

Question 14

What is a complication of a medial collateral ligament injury?

Answer 14

Tearing of medial meniscus

Question 15

Why does a medial collateral ligament injury often result in tearing of medial meniscus?

Answer 15

Because the medial collateral ligament is attached to the medial meniscus

Question 16

What causes a tear of the anterior cruciate ligament?

Answer 16

Hyperextension of knee joint

Application of force to back of knee joint

Question 17

How does the tibia displace in an anterior cruciate ligament tear? Why?

Answer 17

Slides anteriorly over femur

because no longer held back by anterior cruciate ligament

Question 18

How do you test for a tear of the anterior cruciate ligament?

Answer 18

Anterior drawer test

Question 19

What is the anterior drawer test? How are the results interpreted?

Answer 19

Attempt to move tibia forwards

If it does so, means anterior cruciate ligament has been torn

Question 20

How is the posterior cruciate ligament torn?

Answer 20

Knee is flexed
large force applied to shin
pushing tibia posteriorly

Hyperextension of knee joint

Question 21

How does the tibia displace in a posteiror cruciate ligament tear? Why?

Answer 21

Tibia slides posteriorly over femur

because no longer held forward by posterior cruciate ligament

Question 22

How do you test for a posterior cruciate ligament tear?

Answer 22

Posterior drawer test

Question 23

What is the posterior drawer test? How are the results interpreted?

Answer 23

Attempt to push tibia posteriorly

If it does so, means posterior cruciate ligament is torn

Question 24

Which meniscus is more commonly injured?

Answer 24

Medial meniscus

Question 25

Do meniscal injuries heal well or not? Why?

Answer 25

Yes | because of good blood supply to knee joint via genicular arteries

Question 26

What are the complications of a meniscal injury?

Answer 26

Torn meniscus lodges in knee | causes locking of knee joint

Question 27

What is the unhappy triad?

Answer 27

Injury of the following three all at once - medial collateral ligament - medial meniscus - anterior cruciate ligament

Question 28

How do you test for injury to medial collateral ligament?

Answer 28

Pain on medial rotation of leg | means injury of medial collateral ligament

Question 29

How do you test for injury to lateral collateral ligament?

Answer 29

Pain on lateral rotation of leg | means injury to lateral collateral ligament

Question 30

What is prepatellar bursitis?

Answer 30

Inflammation of the prepatellar bursa of the knee | between the skin and the patella

Question 31

What causes prepatellar burstis?

Answer 31

Friction between skin and patella - prepatellar bursa lies between the two Compressive forces to anterior knee joint

Question 32

What is prepatellar bursitis also known as?

Answer 32

Housemaid's knee

Question 33

What is superficial infrapatellar bursitis?

Answer 33

Inflammation of superficial infrapatellar bursa of knee | between patella ligament and skin

Question 34

What causes superficial infrapatellar bursitis?

Answer 34

Excessive friction between skin and patella ligament - superficial infrapatellar bursa lies between the two

Question 35

Division of femoral nerve at level of inguinal ligament - would sensation over lateral thigh be preserved or not? Why?

Answer 35

Yes it would Innervated by lateral cutaneous nerve of thigh branches off lumbar plexus directly doesn't travel under inguinal ligament

Question 36

What does prepatellar bursitis look like?

Answer 36

Swelling in anterior knee