lecture 7- knee Flashcards
bones of the knee
femur
tibia
patella
2 articulations of the knee
Tibiofemoral
- femur and tibia
Patellofemoral
- patella and femur
what 5 things help with stability of the knee?
capsule, ligaments, menisci, muscles, tendons
Capsule of the knee
the joint capsule on the back is tight
the joint capsule on the back is extensive and redundant (allows joint flexion)
resists hyperextension
provides rotational stability
Extracapsular ligaments of the knee
MCL (medial collateral)
LCL
what movement do the collateral ligaments prevent?
side to side movements of the knee
Intracapsular ligaments of the knee
ACL
- prevents anterior displacement of tibia on fixed femur, hyperextension
PCL
-prevents posterior displacement of tibia on fixed femur
what does the posterior cruciate ligament prevent?
prevents tibia from moving forwards, prevents femur from moving backwards
is the medial or lateral meniscus longer?
medial (c shaped)= longer!!!
lateral is o shaped= smaller!!!
Menisci
- fibrocartilage
-medial and lateral
-attached to tibial plateau
-attached to capusle by coronary lligaments
-provides cushioning and stability
-increases synovial fluid, circulation
what does the quadriceps femoris do?
extends the leg at the knee, helps w PCL to prevent tibia from moving backwards
what does the rectus femoris do?
helps w hip flexion
Hamstrings: 3
semimembranosis
semitendinosis
biceps femoris
=flex lower leg on thigh at knee,
extend thigh on trunk at hip
what does the hamstring do?
helps the ACL to prevent tibia moving forwards
the last bit of knee locking comes from
tibia externally rotating, femur internally rotating
–> able to do this bc of length difference between medial and lateral tibial plateau
(medial condyle is larger than lateral)
tensor fascia latae function
helps flex and abduct thigh on trunk at hip
adds lateral stability to knee
gracilis help with
knee flexion
(same origin and insertion as semimembranosis, semitendinosis)
3 types of bursae
prepatellar
suprapatellar (and fat pad)
infrapatellar (and fat pad)
how does knee flexion and extension work?
gliding of condyles on plateau and menisci
Knee Ax
pain, tenderness
snap or pop
observation:
limp, instability
swelling= intercapsular injury
ROM:
compare sides
thigh circumference
palpation
knee alignment deviations
patellar malalignment
Q-angle= line between ASIS through patella and then a line between the patella through the tubercle
Genu valgum, genu varum, genu recurvatum, genu antecurvatum
knee contusion (injury)
direct blow, worse if muscles relaxed
- no heat, no deep tissue massages (can increase bleeding)
Weight bearing functional assessment
- Gait
- Squat
- Single leg squat
- Thessaly
- Duck walk
- 2 legged hop
- Single leg hop
bursitis (injury)
direct blow or kneeling, overuse
-inflammation, tenderness
-heat, physio, rehab, police, padding, NSAIDs
bursitis– knee extension is painful if it is
infrapatellar or suprapatellar
knee sprains Hx
direct blow (usually medial into valgus position)
3 degrees of knee sprains
1st degree= mild pain, mild swelling
2nd degree= snap or pop, increased laxity, firm endpoint
3rd degree= snap or pop, swelling, soft endpoint
meniscal tears
caused by torsion, hyperextension
- acute= no surgery
- free floating fragment of meniscus= arthroscopy
capsular tears
caused by torsion, hyperextension
- only seen on MRI
- similar to meniscus tear
SSx: pain, swelling, tenderness, rotary instability
Tx: rest, physio, rehab, surgery
patellofemoral pain syndrome
= paint around patellofemoral joint
- overpronation, genu valgum, large Q angle contributes to abnormal patellar tracking
chondromalacia patellae
= softening and deterioration of cartilage on the back of the patella
tx: conservative!!! (police, decrease activity, activity modification, orthotics, strengthening)
Patellofemoral Stress Syndrome
= Lateral tracking of patellae in femoral groove
-tight musculature, weak hip abductors/stabilizers
SSx: pain lateral patellae, crepitis with patellar compression
Tx: POLICE, avoid aggravating activities, McConnell taping (keep patella in its groove)
name the 3 acute traumatic knee injuries
- patellar subluxation/dislocation
- unhappy triad
- osteochondritis dissecans
what is the unhappy triad?
ACL tear, MCL tear, meniscal tear, capsular tear
Tx: reconstructive surgery, brace, physio, rehab
- more common in females
what if you have effusion (collection of fluid) in an unhappy triad?
hospital asap!!!!
osteochondritis dissecans
= damage to the cartilage and subchondral bone
- cartilage is free floating
- they drill into the bone which causes bleeding, can increase chondrocytes but also increases risk of osteoarthritis
what do do for ACL (post surgical rehab)?
- quad/hamstring activation
- ROM focusing on full extension
- caution 3-4 months post-surgery
- closed kinetic chain before open kinetic chain
- strengthening (quads and hamstrings balanced)
- 6 months: increase loads, jogging/running
- neuromuscular training
- RTP- technique, education
- RTP- functional testing
- brace? depends on athlete
how to screen for risk of knee injury?
drop vertical jump test
- are knees in line w toes as they land?
if yes, good
“knees kissing”= weak abductors, increased risk of ACL tear
Ottawa knee rules
X ray for knee surgery if:
- age 55+
OR - isolated patella tenderness
OR - head of fibula tenderness
OR - inability to flex 90 degrees
OR - inability to weight bear for 4 steps (limping doesn’t count)
