The Knee Flashcards
What is the knee joint?
hinge joint with rotational component
designed for stability with weight bearing/mobility.
What is the function of menisci?
improve joint congruity/stability
increase contact between femur and tibia for better load transmission across knee
disperses forces across entire knee
assists in lubrication and nutrition of joint.
How many zones of the meniscus and what are they?
3 zones
red-red: highly vascular
red-white: less vascular
white-white: least vascular, least likely to heal
What kind of joint is the knee?
synovial
What ligaments stabilize the tibiofemoral joint?
anterior cruciate ligament
posterior cruciate ligament
What 2 ligaments stabilize the medial and lateral sides of the knee?
medial collateral ligament (MCL)
lateral collateral ligament (LCL)
What muscles make up the quadriceps femoris?
vastus medialis, vastus lateralis, vastus intermedius, and rectus femoris
What muscles make up the hamstring group?
biceps femoris-long and short head, semitendinosus, semimembranosus.
What is the functional anatomy of the knee?
required to do flexion, extension, rotation and arthrokinematic motions of rolling/gliding.
What is the PCL’s purpose?
Limits anterior translation when tibia is fixed and posterior translation is non-weight bearing.
What is the purpose of the ACL?
stop excessive internal rotation, stabilize the knee in full extension and prevents hyperextension.
limits posterior translation when tibia is fixed and anterior translation non-weight bearing.
How does a medial collateral ligament sprain occur and how many grades are there?
severe blow from valgus force(lateral side).
3 grades.
What are signs and symptoms for a grade 1 MCL sprain?
little fiber tearing/stretching, stable valgus test, little to no joint effusion some joint stiffness/point tenderness on lateral aspect relatively normal ROM
Management for grade 1 MCL sprain:
RICE 24 hrs
crutches if necessary
follow-up care will include cryokinetics w exercise
return to play when areas returned to normal
~ weeks to recover
Signs and symptoms of grade 2 MCL sprain:
complete tear of deep capsular ligament + partial tear of superficial layer of MCL
no gross instability; laxity at 5-15degrees of flexion
slight swelling
moderate-severe joint tightness w decreased ROM
pain along medial aspect of knee.
Management of grade 2 MCL sprain:
RICE 48-72 hrs; crutch use until acute phase resolved
possible brace/casting prior to initiation of ROM activities
modalities 2-3x daily for pain
gradual progression from isometric to isokinetic exercises; functional progression activities
What are signs and symptoms of grade 3 MCL sprain?
complete tear of supporting ligaments complete loss of medial stability minimal-moderate swelling immediate pain followed by ache loss of motion due to effusion/ hamstring guarding positive valgus stress test
Management of MCL sprain grade 3:
RICE,
conservative non-operative versus surgical approach
- limited immobilization; progressive weight bearing & increased ROM over 4-6 weeks
rehab similar to grade 1/2 injuries.
What is the cause of Lateral collateral ligament sprains?
varus force; generally w tibia internally rotated.
if severe enough, damage can occur to cruciate ligaments, ITB, meniscus and produce bony fragments.
Signs and symptoms of LCL sprain:
pain & tenderness
swelling & effusion
joint laxity with varus testing
may cause irritation to peroneal nerve.
Management of MCL injuries:
RICE
possible bracing
progression of exercises from isometric to isokinetic depending on severity.
What is the etiology of the anterior cruciate ligament (ACL) sprain?
MOI- tibia internally rotated and valgus force at knee
linked to inability to decelerate valgus and rotational stresses- landing strategies
male versus female
impact to femoral notch, ACL size/laxity, Q-angle & faulty biomechanics
extrinsic factors: conditioning, skill acquisition, playing style, equipment
damage to other structures including meniscus, capsule and MCL
Signs and symptoms of ACL sprain:
experience pop with severe pain and disability
positive anterior drawer and lachman’s or other ACL tests
rapid swelling at joint line
Management for ACL sprain:
RICE; crutches
w/o surgery, joint degeneration may occur
age/activity may factor into surgical option
surgery may involve joint reconstruction w grafts
- bracing, 4-6 months rehab
What is the etiology of Posterior Cruciate Ligament (PCL) sprain?
at risk during 90 degrees flexion
fall on bent knee
damaged due to rotational force
What are signs and symptoms of PCL sprain?
feeling pop in back of knee
tenderness and relatively little swelling in popliteal fossa
laxity w posterior sag test
Management for PCL sprains:
RICE
non-operative rehab of grade 1/2 injuries should focus on quad strength
What are some causes for meniscal lesions?
similar to causes of ligament injury
combination of joint compression, valgus or varus loading, internal/external rotation.
tears are longitudinal, oblique or transverse
What are signs and symptoms of meniscal lesions?
effusion developing over 48-72 hrs joint line pain & loss of motion intermittent locking/giving way pain with squatting chronic shows recurrent swelling or muscle atrophy
What are management techniques for meniscal lesions?
non-locked knee with indication of tear recommend diagnostic testing
locking occurs- anesthesia to unlock joint w arthroscopic surgery
w surgery all efforts made to preserve meniscus
rehab allows partial weight bearing,
immobilization and gradual return to activity over 12 weeks.
What are the special tests for knee assessment?
posterior sag sign
ballotable or patellar tap
brush or swipe test
what occurs in a positive posterior sag sign test?
tibia drops back or sacks back on the femur
result is PCL sprain
What occurs if the ballotable or patellar tap is positive?
downward movement of patella followed by a rebound (patella appears to float)
suggests moderate to severe joint effusion. (40-50mL)
What occurs in a positive brush or swipe test?
fluid passes medially and bulges just below medial, distal border of patella.
suggests minimal joint effusion (4-8ml)
What structures do you need to palpate during a knee assessment?
patella, tibial tuberosity, tibial plateau, medial collateral ligament, lateral collateral ligament, head of fibula.
What is the purpose of the quadriceps femoris group?
extension of the knee.
What quadricep muscle crosses two joints?
rectus femoris
What is the “screw home mechanism”?
as knee extends, it externally rotates because medial femoral condyle is larger than lateral.
“locks” knee in terminal extension and allows rigid lever arm for gait.
popliteus “unlocks” screw home mechanism by slightly internally rotating tibia.
