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