knee Flashcards
knee ROM
flexion 0-140
ext 0-15
when knee flexed:
med rot 20-30
lat rot 30-40
knee muscles and actions
flexion = hamstrings, sartorius, gracilis, popliteus, grastroc
extension = quads
internal rot = gracilis, semimemb/tend
ext rot = biceps femoris, sartorius
meniscus
semi-lunar fibrocartilagenous discs, located on tibial plateau and held down by coronary ligaments
avascular except peripheral, which has inc healing
functions
- limit shear
- lubricate and nourish
- shock absorption
- distribute axial load
- joint congruency: inc stability of femorotibial jt
ligamentous conditions
classified acc to:
- functional disruption
- amt laxity
- direction of laxity
typically ID specific MOI and sensations at time of injury, esp 3rd deg
MCL/LCL more superficial, pinpoint pain
ACL/PCL w/in jt, diffuse pain
types of instabilities
straight anterior
anteromedial
anterolateral
straight posterior
posteromedial
posterolateral
straight medial
straight lateral
anterior instability
unidirectional, rare
MOI = deceleration, landing, cutting mvmnt w/o leg rot
injured = ACL
- anterior drawer (potential false neg/pos)
- false neg bcs hamstrings spasm prevents mvnt
knee must be at 90deg flexion, challenging if jt effusion
lachman’s test: 20-30deg flex, better bcs dec hamstrings spasm and works around effusion
anteromedial instability
more common than just ant
MOI = pulled foot and twist, deceleration w tibial ext rotation
injured = ACL, MCL, medial meniscus
lachman’s test
valgus stress
mcmurray’s test
slocum drawer test = tibia ext rotated, then ant translation
anterolateral instability
MOI = deceleration, cutting, foot planted and tibial INTERNAL rot
injured = ACL, IT band, lateral capsular ligs
lachman test
slocum test = this time tibia is int rot, then ant translate
jerk test = knee and hip flexed, int rot tibia and foot…pull leg into extension
lateral pivot shift test = tibia int rot, hand applies valgus force while knee moves
- pos = clunk
straight posterior instability
MOI = hyperextension, fall on flexed knee
injured = PCL, arcuate complex, oblique popliteal lig
posterior drawer
sag sign = if tibial tubercle is depressed
reverse lachman’s test
medial instability
MOI = valgus force
injured = MCL, medial meniscus, PCL, posteromedial capsule
valgus stress test
- 0deg for superficial fibres
- 30deg for deep fibres/intracapsular
mcmurray test
posterior drawer
lateral instability
MOI = varus force
injured = LCL, lateral capsule, PCL
varus stress
posterior drawer
posteromedial instability
SIGNIFICANT injury
MOI = hyperextension plus valgus force, tibia shifts posterior and opens up on medial side
injured = MCL, ACL, PCL, posteromedial jt capsule, oblique popliteal lig
postero-medial drawer
posterior medial pivot shift test
posterolateral instability
MOI = hyperextension plus varus force
injured = PCL, LCL, arcuate complex, posterolateral capsule
varus stress
postero-lateral drawer
external rotation recurvatum = lift both feet and look for sag
- pos = lateral side sags more, appears bowlegged
- IDs PCL injury
ACL reconstruction
key sign of ACL tear = rapid jt effusion
post-op bruising, limb swelling
wound dehiscence = opening of surgical wound, surgical sequelae
- forceful flexion plus effusion can inc pressure, cause wound to open
anterior knee pain causes
patellar articulating surface-related pain
segments: another injured part of limb causes pain
- proximal segments
- distal segments
tracking problem: patella doesn’t glide well
patella has medial and lateral retinaculum attaching to it
patella articulating surface-related ant knee pain
medial and lateral facets on articulating side
- also odd facet, active extreme ROM
hyop-pressure = too little pressure
hyperpressure = too much pressure
- usually lateral side has too much tension
cause biomechanical issues
chrondomalacia
medial and lateral facet syndrome
chondromalacia
changes to articular cartilage, degeneration
- bcs of hyper/hypopressure b/w femur and patella
- cartilage goes thru cycles of compression and release to allow nutrients
MOI = abnormal compressive forces
stage 1 = cartilage softens, age
2 = fissures
3 = fissures –> fibrillation/projections
4 = exposed subchondral bone as fibrillations break off…painful contact w periosteum
clarke’s test
waldron test
patella compression test
medial and lateral facet syndrome
tension on patella bcs of shape, biomechanical factors
medial facet syndrome = younger pop, hypo-pressure
lateral = older, hyper-pressure, males
S/S = crepitus, effusion, pain and tender
ant knee pain from prox/distal segments
prox segment
- back i.e. lordosis, lateral pelvic tilt
- hips and thighs i.e. tight flexors, quad/hamstring imbalance
distal seg
- tibia i.e. genu valgus or varum
- foot/ankle i.e. tight achilles, cavus foot
patellar-tracking related ant knee pain
lateral tracking is usually the problem bcs tension of structures…IT band, retinaculum, weak vastus medialis oblique
causes
- patella shape, position
- collagenous structures
- musc weak
patella alta = sits higher, can be bcs inc Q angle or genetics
- leads to sublux or chondromalacia
patella baja = lower, can be bcs of post-op immobilization
bipartite patella = bone hasn’t fulled fused
patella plica syndrome
plica = fold of synovial lining that wraps posterior to quad tendon
- can be asymptom until trauma
S/S = gradual ant knee pain, effusion, PAIN W LONG SITTING, PSEUDOLOCKING, sharp pain first 8-10 steps, creptisu
manage by treat symptoms and modify activities
osgood-schlatter disease
apophysitis
inflammation of tibia apophysis (site of attachment for tendon onto bone)
MOI = fraction forces
teens involved in kick/jump/jump, engaging quads
- growth spurt bone > musc
S/S = pt tender tibial tubercle, pain allev w rest, prainful extreme ROM and forced flexion
sinding-larsen-johanssen disease
apophysitis of inferior pole of patella
MOI = traction forces, quad growth spurt
S/S = grad onset, painful palp of inferior patellar pole, painful extreme ROM
knee bursitis
MOI = trauma i.e. fall on flexed knee, overuse kneeling
pre-patellar = right over knee cap
infrapatellar = below kneecap
if lateral/medial to tendon –> fat pad impingement
medial knee pain
pes anserine musc attach here
- bursitis
- strain
- tendonitis
MCL tear
meniscus conditions
medial meniscus inc tear bcs less mobile, attached to MCL and synovial lining
MOI = compression, tear, shear
- degenerative or acute
S/S = delayed swelling post-activity, joint line pain, click/lock, buckling
- vague initial symptoms bcs no nerve
mcmurray test = full flex knee, compress tibia and circular motion like scour
apley’s compression = distraction and compression
bounce home = passive flexion and drop leg into passive extension
- for end feel/locks
osteochondritis dissecans
bone frag caused by avascular necrosis
- attached or loose body
MOI = in/direct trauma, lig laxity, skel abnormalities
S/S = aching/diffuse pain, swell w activity, knee lock/buckle
lateral knee pain
ITB syndrome
later meniscus tear
LCL sprain
biceps femoris strain
biceps femoris strain
AROM = painful knee flex/hip ext, painful hip flex and ext
PROM = painful knee ext and hip flex
resisted = knee flex and hip ext
IT band friction syndrome
MOI = excessive copression and friction, biomechanics, dec flexibility
S/S = pt tenderness, prox to lateral jt line over epicondyle
- gradual
- sharp pain at lateral knee that can stop exercise
- non-restrictive to restricting ADLs
noble compression test = press ITB above jt line, patients flexes and extends leg
ober test = move ITB over greater trochanter by hip extension…if leg lifts/stays in air bcs of tension
posterolateral complex of knee injury
popliteus = int rot tibia, helps initiate KNEE FLEX
issues i.e. abulsion of fibula from biceps fem
MOI = hyperextension plus varus force or ext rot
baker’s cyst
MOI = secondary condition to smth else i.e. mensicus, osteoarthritis
S/S = swelling post knee, aggro by knee flex/tend
herniation of synovial fluid from jt
can be drained, but must address origin of cyst
waldron test
patellofemoral jt pathology
- flexed knee, add compressive force on patella while forcing knee to flex more
- positive: crepitus, pain
- then ask them to squat while adding compressive force to knee
- TWO PHASE TEST
clarke’s test
for chondromalacia
- compressive force to the patella
- put webbed part of thumb around superior border of affected patella, then ask patient to contract quads as if extending knee….apply downward and inferior pressure
- positive = pain, cannot complete test
