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Flashcards in Knee Deck (32):
1

What mechanisms of injury can lead to PCL tears?

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

2

MCL resists ____ and LCL resists ____

MCL resists valgus
LCL resists varus

3

What mechanism of injury can cause ACL damage?

bones of leg twist in opposite direction under full weight

4

The meniscus contains predominantly type ___ collagen

1

5

What is the key function of the meniscus

bearing weight

minimal contribution to stability, shock attenuation in the normal knee

6

What is the key function of the meniscus

bearing weight

minimal contribution to stability, shock attenuation in the normal knee

7

What is the Q angle?

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

8

Patellas tend to dislocate _______

laterally

9

What factors make patellar dislocation more likely

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

10

Describe the classic load deformation curve of ligaments

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

11

How is the integrity of the ACL tested?

anterior drawer test
Lachmans test

12

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

intra-articular

13

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

extra-articular

14

When the patella dislocates, the _________ ligament is always torn

medial patellofemoral ligament

15

Describe the phases of ligament healing after injury

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

16

Describe radiographic findings in osteoarthritis of the knee

joint space narrowing, slcerosis, marginal osteophytes, subchondral cysts

17

What patterns of pain are common in knee osteoarthritis?

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

18

Describe the etiology of knee OA

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

19

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

varus= medial
valgus= lateral

self-reinforcing deformity

20

Describe the etiology of knee OA

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

21

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

varus= medial
valgus= lateral

self-reinforcing deformity

22

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

meniscectomy

23

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

meniscus tear

24

Describe treatment of knee osteoarthritis

- 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)

25

What is patellofemoral pain?

diffuse aching of anterior knee that is increased with activities that load the patellofemoral joint

may have articular cartilage damage

26

What is the treatment for patellofemoral pain syndrome?

activity modification, orthotics, PT

no surgery

27

Joint line pain and tenderness are the hallmarks of a _______

meniscus tear

28

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

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

29

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

hemarthrosis- a tense effusion

30

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

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

31

How is the ACL repaired?

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

32

Describe the surgical approach to ACL tears

Surgical reconstruction: a new ACL is made out of native tissue from other sites
- ACL repair is ineffective

combined with meniscus REPAIR whenever possible