Week 1 Flashcards
What type of joint is the tibiofemoral joint?
double condyloid (ovoid articular curface +condyle)
The tibiofemoral joint prevents motion in the _ plane.
frontal
How many degrees of freedom does the tibiofemoral joint allow? Describe them.
2 degrees of freedom
F/E in sagittal plane, IR/ER in transverse plane
Which of the following is indicative of the femoral articular surface?
A. large AP convexity
B. Small curvature posteriorly
C. The Lateral condyle is longer then the medial
d. The lateral condyle extends further distally for angled femur
b is true
a - small AP convexity
c - medial > lateral
d - medial extends further distally
Describe the medial and lateral tibial plateaus in terms of shape and differences.
They are concave and slope posteroinferiorly
Medial plateau is 50% larger (oval and long) and its articular cartilage is 3x thicker
Lateral: more circular
What structure(s) function to increase stability of the knee by deepening the tibial plateau?
menisci
Which of the following is not true for the menisci?
a. increases friction by 20%
b. increases contact area by 70%
c. attenuates forces
d. enhances proprioception via mechanoreceptors
a - decreases friction by that much
Debate the differences between the medial and lateral menisci.
medial: c-shaped, firm attachment to MCL, thick posteriorly
lateral: o-shaped, loose attachment to lateral capsule, uniform thickness
Both are thicker on periphery, thinner along inner margin
Menisci transmit _% of imposed load at the knee.
50-60%
How much is shock absorption capability reduced by following menisectomy?
20%
Which of the following is not true for the MCL?
a. prevents abduction (valgus stress)
b. attaches 7-10cm below joint line
c. assists in prevention of anterior tibial translation w/ ACL
d. doesn’t attach to joint capsule and medial meniscus
d - it does attach
The anterior fibers of the MCL are taut in _.
The posterior fibers of the MCL are taut in _.
midrange, full flexion
Which of the following is true for the LCL?
a. prevents abduction
b. attachment to capsule or menisci
c. assists with translational restraint
d. Less laxity than MCL
e. has pencil-like band of tissue
e is true
a - prevents adduction (varus stress)
b - no attachment there
c - assists with IR/ER restraint
d - greater laxity than MCL
LCL fibers are tight in knee _ and loosen as knee _.
extension, flexes
What are the functions of the ACL?
prevent anterior tibial translation/posterior femoral; check hyperextension; work with MCL to stabilize knee against valgus
True/False: The PCL is one of the strongest ligaments.
true
Which of the following is not true regarding the PCL?
a. prevents posterior translation of tibia on femur
b. minor restraint to varus/valgus
c. shorter and less oblique than ACL
d. injured easiest
d - rarely injured
What term is associated with an increased Tibiofemoral angle above 180 deg and increased medial compressive forces?
genu varum (knock-knee)
What term is associated with a decreased TF angle below 165deg and increased lateral compressive forces?
genu valgum
What is the Q angle?
angle formed by line drawn from ASIS to mid-patella to tibial tuberosity
What gender has a higher Q angle?
females
How much flexion is normal at the knee?
130-140deg
How much extension is normal at the knee?
5-10deg
Hyperextension can be normal (excessive >10deg = genu recurvatum)
Decreased DF = decreased knee _.
flexion
Decreased PF = decreased knee _.
extension
Match the Flexion ROM needed for the activity:
60-70, 75, 70-80, 90, 115 (one is repeated)
Gait, advanced function, sit/rise chair, in/out bath, on/off toilet, stair climbing
gait = 60-70
Advanced = 115
sit/rise chair = 90
in/out bath = 90
on/off toilet = 75
stair climbing = 70-80
ROM in knee IR/ER is influenced by amount of knee _.
flexion
Full extension = _ rotation.
90 deg flexion = _ rotation.
full extension = restricted rotation by interlocking of condyles
90 deg flexion = 0-45 ER and 0-30 IR
Concave or convex?
distal femur
proximal tibia
distal femur - convex
proximal tibia - concave
Tibial-on-femoral extension occurs in what direction?
same
Femoral-on-tibial extension occurs in what direction?
opposite
What is the screw home mechanism?
lateral rotation of tibia on femur during the last 5 deg of extension - augmented by tension on ACL and lateral pull of quads
According to the screw home mechanism, flexion requires unlocking so the femur must _ rotate on tibia (CKC) and tibia must _ rotate (OKC).
laterally, medially
What functions to unlock the knee by moving the knee in IR/ER?
popliteus
What type of cartilage is on the posterior surface of the patellofemoral joint?
thick hyaline
The patella slides within what structure?
trochlear groove
Match the facet of the patella to the description:
Medial, lateral, odd
medial angle, longer than medial, flat to slightly convex
medial - flat to slightly convex
lateral - longer than medial
odd - medial angle
True/False: The patella is free-floating in full extension.
true
The first PF contact is between what degrees of flexion?
10-20
By 90 degrees of flexion, what facets have contact?
medial and lateral
At 135 degrees of flexion, what facets have contact?
odd and lateral
True/False: As the angle of flexion increases, so does the compressive forces.
true
greatest compression force at 90 deg
At knee flexion of 10-15 degrees, how much force is applied to PF?
50%
At 60 degrees of flexion, how much force is applied to PF?
3.3x body weight
At 130 degrees of flexion, how much force is applied to the PF?
7.8x body weight
Which facet will bear the most weight?
medial facet
What are the transverse stabilizers of the PFJ?
med/lat retinaculum, VMO/VL, MPFL
What are the longitudinal stabilizers of the PFJ?
quad tendon, patellar tendon
What two other structures provide PFJ stability?
ITB and lateral wall of femoral groove
What type of meniscal lesion is most common and typical of the third decade?
longitudinal
True/False: A complete longitudinal lesion can become a bucket-handle lesion, most frequent in medial meniscus.
true
Where do oblique tears to the meniscus generally occur?
region between 1/3 back and 1/3 medium of meniscus
Complex lesions to the meniscus are typically produced by what mechanism of injury?
repeated knee trauma
Radial lesions to the meniscus typically originate from where?
free side of periphery
What are degenerative meniscal lesions involving the intramural portion?
horizontal tears
A superficial articular cartilage lesion with soft indentation and/or superficial fissures and cracks generally classifies as a grade _.
1
What grade generally is given to an articular cartilage lesion extending down to less than 50% of cartilage depth?
2
What grade is given to a severely abnormal articular cartilage lesion that extends down above 50% of depth as well as down into the calcified layer but not down to the subchondral bone?
grade 3
What grade is given to a severely abnormal articular cartilage lesion that does reach the subchondral bone?
grade 4
Which surgical procedure(s) is indicated for an articular cartilage lesion <2.5 cm2 with low demand?
debridement or microfracture
Which surgical procedure(s) is indicated for an articular cartilage lesion <2.5 cm2 with high demand?
microfracture, ADT, maybe AMIM?
Which surgical procedure(s) is indicated for an articular cartilage lesion 2.5-4.0 cm2 with low demand?
microfracture, ADT, ACT, AMIM?
Which surgical procedure(s) is indicated for an articular cartilage lesion 2.5-4.0 cm2 with high demand?
ADT, ACI, OAT, MACI?
Which surgical procedure(s) is indicated for an articular cartilage lesion > 4 cm2?
ACI, OAT, MACI?
According to Kellgren and Lawrence, what is a grade 0 radiograph for OA?
no findings
According to Kellgren and Lawrence, what is a grade 1 radiograph for OA?
minute osteophytes of doubtful clinical significance
According to Kellgren and Lawrence, what is a grade 2 radiograph for OA?
definite osteophytes with unimpaired joint space
According to Kellgren and Lawrence, what is a grade 3 radiograph for OA?
definite osteophytes with moderate joint space narrowing
According to Kellgren and Lawrence, what is a grade
4 radiograph for OA?
definite osteophytes with severe joint space narrowing and subchondral sclerosis
What are the limitations of radiographic exam for OA?
can have normal image even though there are early signs of cartilage degeneration (MRI can pic up early cartilage loss better), standard MRI may appear normal even though there are degenerative changes within cartilage
True/False: cartilage is not innervated, therefore, unlikely is the source of pain in OA.
true
What are the possible sources of pain in knee OA?
synovium, bone, nerves
Describe synovitis and why it may causing to OA pain.
is from inflammatory cell infiltration, cartilage, and bone debris
infrapatellar fat pad irritation may trigger synovitis
Describe why bone may be causing OA pain.
subchondral bone: thinning of cartilage and vascular congestion may result in intraosseous pressure, bone angina, bone attrition
periostitis from osteophyte formation
bone marrow lesion
Describe why nerve may be causing OA pain.
damage to joint tissues may also result in alterations of nerve structure in them
may result in neuropathic pain
nerves become hypersensitive
What factors may influence OA outcome?
obesity, joint mobility, lower limb alignment, knee instability, psycho-social factors
Briefly describe how obesity influences OA.
increased probability of development and/or progression of knee OA
obese individuals with knee OA have greater disability than those with knee OA who are not obese
Briefly describe how knee mobility influences OA.
reduced F/E excursion associated with lower function score
reduced max knee flexion associated with lower function on WOMAC
Briefly discuss how Knee alignment influences OA.
Greater pain relief in neutral aligned group compared to mal-aligned group
If you improved your self-reported knee instability rating by one level you were _ likely to be a responder to treatment. (For knee OA)
more
Adherence to home exercise and physical activity recommendations were associated with what results according to Pisters’ Arthritis Care and Research?
reduced pain (WOMAC), better function (WOMAC)
How do we encourage adherence?
periodic communication, periodic face-to-face rechecks, use of exercise diaries, use of booster sessions, engaged family
According to the study by Heuts, what were the findings on fear of physical activity and functional deadline?
people with higher levels of pain-related fear will be less likely to participate in a physically active lifestyle
if you decreased (improved) FABQ by 2.5-3.0 point, you were more likely to be a responder to tx.
Briefly compare the method in the 70s vs now in TKA.
70s - admitted 1-2 days before surgery, bed rest 2-3 days post op, ambulation with knee splint begun POD3, Knee ROM began POD7, no d/c until flex knee to 90 degrees
now - admitted morning of surgery, mobilize day of surgery or POD1, usually WBAT, LOS less than 5 days
Describe the NMES Treatment protocols presented in lecture for TKA.
started POD2
electrodes over distal VM and proximal VL
intensity set to max tolerance
parameters: biphasic, 50Hz, 250s, 15:45, 15 reps (2x/day) for 3 weeks then move down to once a day for three weeks
What are the red flags to monitor for after TKA?
DVT, PE, infection
What are the s/s of infection?
persistent fever, shaking chills, increasing redness/tenderness/swelling of knee wound, drainage from knee wound, increasing knee pain with activity AND rest
Describe the Canadian Probability Model for DVT.
Criteria:
Active cancer, paralysis/paresis/recent plaster immobilization LE, surgery <4weeks/bedridden > 3 days, thigh + calf swelling, tenderness along deep venous system, affected calf > 3 cm larger than other calf, pitting edema, collateral superficial veins
High probability = 3 or more points (each worth 1 pt each)
Describe Well’s CPR for PE.
Clinical s/sx of DVT (3 pts), alt dx less likely than PE (3 pts), HR greater than 100 bpm(1.5 pts), immobilization or surgery in previous 4 weeks(1.5 pts), previous DVT/PE(1.5 pts), Hemoptysis(1pt), Malignancy(1pt)
2-6 pts - mod risk; high - 6 or more
