Knee pathology: muscle, ligament, meniscus Flashcards
which muscles are commonly injured in the lower extremity?
hamstring and quadriceps, incidence increases with age
what is the MOI for muscle injuries in the knee?
eccentric contraction. most likely to occur at musculotendinous junction
what are some locations of injury in the knee?
origin, musculotendinous junction, muscle belly, and insertion of the muscle
what are the classification of muscle knee strains?
first, second and third degree
what is a first degree muscle strain at the knee?
result of stretching of the musculotendinous unit and involves tearing of only a few muscle fibers
what is a second degree muscle strain at the knee?
more severe tear without complete disruption of the musculotendinous unit
what is a third degree muscle strain at the knee?
complete tear of the musculotendinous unit
what are some risk factors to muscle strains at the knee?
inadequate flexibility
inadequate strength or endurance
muscle fatigue
insufficient warm up time
poor running technique
premature return to sport
what is the clinical picture we see with muscle strains in the knee?
pain in posterior or anterior thigh
tenderness over the injury site
ecchymosis
palpable mass
pain with movement and resistance
how do we diagnosis muscle strains at the knee?
if it fits the clinical picture
may require x-rays if avulsion injury is suspected
what is a differential diagnosis for knee strains?
lumbar radiculopathy
how do we medically manage knee strains?
PT, NSAIDs, surgical intervention maybe necessary
what is a quadriceps avulsion?
a rupture of the quadriceps musculature from extreme force
what is the clinical picture we see for a quadriceps avulsion?
retracted muscles mass/muscle belly
gapping/dimple near patella
do quadricep avulsions need surgery?
yes to reattach the quads to the extensor aponeurosis
when do myositis ossificans of the knee typically occur?
after trauma. common in young adults, large muscles of the extremities
what is the clinical picture we see for myositis ossificans of the knee?
pain, tenderness to palpation, enlarging mass
how can we diagnose myositis ossificans at the knee?
x-ray, MRI, CT
how do we treat myositis ossificans at the knee?
NSAIDs, physical therapy exercise and modalities, surgical excision
With who do we see IT band syndrome most commonly?
distance runners, cyclists, soccer and hockey athletes. equally males to females usually in ages of 15-50, repetitive use, misalignments
what is the pathophysiology for IT band syndrome?
irritation of the iliotibial band as it crosses over the lateral femoral condyle. increased tension leads to increased irritation/inflammation
what is the MOI for IT band syndrome?
repetitive use, misalignment, weakness/poor endurance of hip abductors, over pronation of foot
what are some symptoms of IT band syndrome?
burning pain at lateral aspect of knee near lateral femoral condyle- may radiate into lateral thigh or calf
what are some functional complaints of IT band syndrome?
worsens with activity- particularly activity where knee flexes/extends. may report popping noise during walking or running
what are the functions of the IT band?
flex, abduct, and rotate the hip. lateral knee stabilizer. crosses the lateral femoral condyle-30º knee flexion
what is the clinical picture we see for IT band syndrome?
complaints of pain at lateral aspect of knee can include hip, pain worsens with physical activity, may report audible popping noise in knee with walking or running
what is the second most common injury in the knee?
meniscus
what is the menisci function?
transmission of forces, distribution of load, amount of contact force, pressure distribution patterns
with who do we see meniscal tears?
males 20% > risk of tear
medial tear > lateral tear
risk of tear increases with age
often associated with ACL tear
we see ICF diagnosis of joint pain and mobility impairments when the patients present with?
twisting injury
tearing sensation at time of injury
delayed effusion (6-24 hours postinjury)
history of “catching” or “locking”
pain with forced hyperextension
pain with maximum flexion
pain or audible click with McMurray’s maneuver
joint line tenderness
discomfort or a sense of locking or catching in the knee over either the medial or lateral joint line during the Thessaly test when performed at 5º or 20º of knee flexion
what are the 6 common types of meniscus tears?
intrasubstance/incomplete tear
radial tear
horizontal tear
bucket-handle tear
complex tear
flap tear
what are the grades of ligament sprains?
1: few fibers torn
2: approx 1/2 fibers torn
3: all fibers of ligament torn
what is the anterior cruciate ligament (ACL)?
originates on the tibial plateau just anterior and medial to tibial eminence. extends from the tibia superiorly, laterally and posteriorly to posterior aspect of medial wall of lateral femoral condyle. intra articular extra synovial
what is the posterior cruciate ligament (PCL)?
originates on the tibial plateau posteriorly and laterally. extends from tibia superiorly and medially to attach on the medial femoral condyle. intra articular extra synovial
how common are ACL tears?
about 200,000 occur annually in the USA (100,000 need reconstruction)
females 2-8x > males
most common in 14-29 year age range
what is the MOI for ACL tear?
sudden cut if deceleration- often a non contact injury
rotational injuries with valgus or varus force applied to knee
hyperextension
what is the clinical picture we see with an ACL tear?
consistent mechanism of injury- feeling or hearing a pop
persistent pain (complete tear may be painless with partial tear painful)
feeling knee give out
swelling-hemarthrosis
loss of knee motion
how is an ACL tear diagnosed?
MRI
sensitive 95%, specific 98%
how do we heal ACL tears?
PT or ACL repair
what are the two types of ACL repair?
autograft or allograft
what occurs with an autograft ACL repair?
middle 1/3 patellar tendon- bone-tendon-bone
semitendinosus/gracilis tendon graft (hamstrings graft)
quadriceps tendon graft-seem more with revisions
what occurs with an allograft ACL repair?
cadaveric graft, often patellar tendon or achilles used
how often to PCL tears occur?
incidence is unknown PCL research is about 10 years behind ACL. 3-20% of all knee injuries involve the PCL
what is the MOI for PCL tears?
hyperflexion of knee- dashboard injury; soccer slide tackle into anterior leg
hyperextension of knee (posterior capsule, PCL, ACL)- may see bone contusions on inferior aspect of femoral condyle and anterior aspect of tibial plateau (kissing injuries)-visible on MRI
what is the clinical picture we see with PCL tears?
consistent with MOI- feeling or hearing a pop, trauma/traffic injury (>50%)
diffuse pain or posterior knee pain
swelling- hemarthrosis
inability to weight bear-severe injury
what is the medical management for PCL tears?
PT-partial tears, complete tears with no damage
PCL repair: necessary when injury is avulsion of ligament, indicated when other structures may also be torn (ACL, MCL, LCL, arcuate ligament complex)
what are the rotary instabilities at the knee?
anteromedial rotary instability
anterolateral rotary instability
posteromedial rotary instability
posterolateral rotary instability
what is the medial collateral ligament?
attaches proximally to medial femoral condyle and distally to medial aspect of tibia
deep and superficial portions- deep fiber originate from medial joint capsule and attach to the medial meniscus
ligament is taut throughout range
how often do we see MCL tears?
.24/1000 people
can occur at any age but peak age of injury is 20-34 years old and also a second peak at 55-65 years old
no correlation with race
twice as high in males as compared to females
what are MCL tears caused by?
acute valgus stress to the knee joint
excessive lateral rotation of the tibia can injure both medial and lateral collateral ligament
overuse syndromes
what is the clinical picture we normally see with MCL tears?
history of recent valgus force applied to the knee, pain (localized) and stiffness, ecchymosis may appear after several days, swelling
collateral ligament injuries are often seen in association with what other injury?
injury to other knee structures
how do we diagnose MCL tears?
x-ray of avulsion suspected, MRI
what is the lateral collateral ligament?
fibers of LCL are separated from meniscus by a small fat pad. ligament is taut in extension and loosens in flexion
what may LCL tears MOI may result in?
traction injury to the fibular nerve
what do we commonly see with LCL tears?
history of recent varus force applied to the knee
pain (localized) and stiffness
ecchymosis may appear after several days
swelling
what is the incidence for a knee bursitis?
adults M>F
children associated with septic condition
what are some risk factors for knee bursitis?
fall/trauma, occupation, history if repetitive trauma
what is the clinical picture we see with knee bursitis?
pain with any pressure to the bursa (kneeling) effusion directly over the patella
how do we diagnose knee bursitis?
follows the clinical picture
how do we medically manage knee bursitis?
rest/avoid repeated trauma to tissue, steroid injections, aspiration
what are some differential diagnoses for knee bursitis?
ligamentous injury at knee, OA, RA
what is a bakers cyst?
aka popliteal cyst
may be associated with arthritis (OA, RA, JRA, Gout)
history of knee trauma
what age range is most common for a bakers cyst?
35-70
what is the pathology of a bakers cyst?
accumulation of extrusion of synovial fluid between medial head of gastroc and semimebranosis
found on the medial side of the popliteal fossa inferior to crease (popliteal “hernia”, loose calcified bodies may be trapped in the cyst, can result in compression of popliteal vein)
how are bakers cysts diagnosed?
xray, MRI
what is the non operative management for bakers cysts?
rest/activity modification
NSAIDs
PT/rehab regimens are often effective in patients with minimal symptoms, and in the setting of smaller degenerative meniscal tears
aspiration and steroid injection
recurrence rates are much lower in younger patient populations and older patient populations and degenerative meniscal tears with associated cysts
what is the operative management for bakers cysts?
arthroscopic debridement, cyst decompression, meniscal repair vs partial menisectomy less invasive than the open approach (cyst recurrence, especially in older patients with moderate-advanced knee degenerative conditions)
open cyst excision (not indicated in the setting of underlying knee degenerative conditions secondary to the risk of cyst recurrence)
where can plica syndrome occur in the knee?
suprapatellar, mediopatellar, infrapatellar, lateral
what are the symptoms associated with plica syndrome?
anterior knee pain, clicking, clunking, catching, popping sensation
plica syndrome is most common among who?
both sexes through 30’s
what is the MOI for plica syndrome?
blunt trauma to the knee, twisting injury
what are some differential diagnoses for plica syndrome?
PFPS and meniscal tear
what are some aggravating activities for plica syndrome?
descending stairs, squatting, bending, rising from a chair, sitting for an extended period of time
how is plica syndrome diagnosed?
palpation of medial plica, MRI
what is the treatment for plica syndrome?
physical therapy (taping, exercise-therapy activity modification, intra-articular steroid injection, surgical excision)
what is synovitis of the knee?
inflammation of synovial membrane at the knee
what patients commonly have synovitis at the knee?
patients with RA
what are some causes of synovitis of the knee?
overuse, inflammatory arthritis
what are some symptoms of synovitis of the knee?
joint pain, little to no swelling
how is synovitis of the knee diagnosed?
MRI, MSk ultrasound
what is the treatment for synovitis of the knee?
NSAIDs, DMARDs, steroid injections, surgery- synovectomy
what are some causes of compartment syndrome?
swelling or bleeding within a compartment of lower leg, increased pressure, decreased blood flow, muscle and nerve damage
who is most common to experience compartment syndrome of the leg?
males > females
< 35 years old
what is acute compartment syndrome of the leg?
after trauma
requires immediate medical attention (may lead to permanent muscle damage if left untreated)
what is chronic compartment syndrome of the leg?
athletes
exertional injury
exacerbated by repetitive motion
not dangerous
how is compartment syndrome of the leg diagnosed?
test pressure in the compartment
> 30 mmHg threshold
what is the treatment for compartment syndrome of the leg?
acute- fasciotomy
chronic-
nonsurgical: physical therapy, orthotics, anti-inflammatories, activity avoidance
surgical: non-emergent fasciotomy
