Knee

Question 1

What mechanisms of injury can lead to PCL tears?

Answer 1

direct blow to anterior aspect of flexed knee- ex fall, femur fracture

Question 2

MCL resists ____ and LCL resists ____

Answer 2

MCL resists valgus

LCL resists varus

Question 3

What mechanism of injury can cause ACL damage?

Answer 3

bones of leg twist in opposite direction under full weight

Question 4

The meniscus contains predominantly type ___ collagen

Answer 4

1

Question 5

What is the key function of the meniscus

Answer 5

bearing weight

minimal contribution to stability, shock attenuation in the normal knee

Question 6

What is the key function of the meniscus

Answer 6

bearing weight

minimal contribution to stability, shock attenuation in the normal knee

Question 7

What is the Q angle?

Answer 7

angle between the shaft of the tibia and the patellar tendon, up to 15 degrees
patella is pulled laterally when the quadriceps contracts

Question 8

Patellas tend to dislocate _______

Answer 8

laterally

Question 9

What factors make patellar dislocation more likely

Answer 9

shallow femoral groove, increased Q angle, weak muscles, damaged patellofemoral ligament

Question 10

Describe the classic load deformation curve of ligaments

Answer 10

ligaments have low stiffness at low loads, but high stiffness and resistance to deformity as load increases

Question 11

How is the integrity of the ACL tested?

Answer 11

anterior drawer test

Lachmans test

Question 12

ACL and PCL have a ________ location and heal poorly after injury

Answer 12

intra-articular

Question 13

MCL and LCL are _____, and thus a blood clot forms when they tear and they heal well

Answer 13

extra-articular

Question 14

When the patella dislocates, the _________ ligament is always torn

Answer 14

medial patellofemoral ligament

Question 15

Describe the phases of ligament healing after injury

Answer 15

1. inflammatory phase, including blood clot formation
2. proliferative phase- increased fibroblasts, production of disorganized collagen matrix
3. remodeling- decreased cellularity, organization of collagen

*** this pattern is classically seen in MCL which heals well, not seen in ACL which heals poorly

Question 16

Describe radiographic findings in osteoarthritis of the knee

Answer 16

joint space narrowing, slcerosis, marginal osteophytes, subchondral cysts

Question 17

What patterns of pain are common in knee osteoarthritis?

Answer 17

activity related pain, stiffness improves with activity, feels better early in the day and worse after heavy labor

can have joint effusions but not hot joints as in inflammatory arthritis

Question 18

Describe the etiology of knee OA

Answer 18

genetics
intra-articular fracture or bone bruise
overloading
obesity
knee alignment- deformities that are self reinforcing

Question 19

At the knee, varus causes loads to be concentrated ________, and valgus causes loads to be concentrated _______.

Answer 19

varus= medial
valgus= lateral

self-reinforcing deformity

Question 20

Describe the etiology of knee OA

Answer 20

genetics
intra-articular fracture or bone bruise
overloading
obesity
loss of meniscus
knee alignment- deformities that are self reinforcing

Question 21

At the knee, varus causes loads to be concentrated ________, and valgus causes loads to be concentrated _______.

Answer 21

varus= medial
valgus= lateral

self-reinforcing deformity

Question 22

_______ increases peak loads in the knee compartments by as much as 300%

Answer 22

meniscectomy

Question 23

It seems that ACL tear predisposes to DJD only if there is concurrent ___________

Answer 23

meniscus tear

Question 24

Describe treatment of knee osteoarthritis

Answer 24

• decrease loads: activity modification, weight loss, braces
• improve range of motion
• improve strength and balance
• surgical: joint replacement (arthroscopy for meniscus tear only is controversial)

Question 25

What is patellofemoral pain?

Answer 25

diffuse aching of anterior knee that is increased with activities that load the patellofemoral joint may have articular cartilage damage

Question 26

What is the treatment for patellofemoral pain syndrome?

Answer 26

activity modification, orthotics, PT no surgery

Question 27

Joint line pain and tenderness are the hallmarks of a _______

Answer 27

meniscus tear

Question 28

Meniscus repair is only possible for what types of meniscus tears?

Answer 28

Tears that involve only the vascular peripheral 1/3 of the meniscus- area where healing can occur

Question 29

A tense ______ develops within a few hours of ACL tear, and is helpful in diagnosis

Answer 29

hemarthrosis- a tense effusion

Question 30

What patients are good candidates for surgical repair of ACL tears, vs conservative therapy?

Answer 30

sedentary individuals with managable symptoms: non-operative treatment young active athletes: more likely to have instability and develop new meniscal tears, so better surgical candidates

Question 31

How is the ACL repaired?

Answer 31

a new ACL is made out of native tissue from other sites

Question 32

Describe the surgical approach to ACL tears

Answer 32

Surgical reconstruction: a new ACL is made out of native tissue from other sites - ACL repair is ineffective combined with meniscus REPAIR whenever possible