MSK Knee Quiz

what is the primary function of the knee?

-weight transfer to LE

-impact absorption and adaption

-shortening of lower limb to allow foot clearance during the swing phase of gait

what joints make up the knee complex

-proximal tibiofibular joint

-tibiofemoral joint

-patellofemoral joint

what is the resting position of the tibiofemoral joint

25* flexion

what is the closed pack position of the tibiofemoral joint

full extension with tibial ER

what occurs at the tibiofemoral joint in an open chain position/tibia on femoral extension

-tibia rolls and slides anteriorly

-menisci are pulled forward from quad activation

what occurs at the tibiofemoral joint in a closed chain position/femoral on tibial extension

-the femoral condyles roll anteriorly and slide posteriorly

-menisci pulled slightly posterior

what is the screw home mechanism in open chain vs closed chain?

-open chain: the last 5-10 deg of tibial ER that occur during terminal knee extension

-closed chain: femoral internal rotation on the tibia during terminal knee extension

what is the benefit of the screw home mechanism

provides increased stability during weight bearing

what is the purpose of the patellofemoral joint

serves as a lever to increase the movement arm of the knee extensor

when we are walking, what amount of body weight is going through the PFJ

0.3x

when we are using stairs, what amount of body weight is going through the PFJ

2.5-3.5x

when we are squatting, what amount of body weight is going through the PFJ

7x

at what degree of knee flexion does the PFJ have the most contact area with the femur?

60-90

when the knee is in 60-90* flexion, what percent of the patella's total surface area is in contact with the femur?

30%

what muscles will be active during knee flexion

-biceps femoris

-semimembranosus

-semitendinosus

-gracilis

-sartorius

-popliteus

-gastrocnemius

-plantaris

-TFL (in 45-145* flex)

what muscles will be active during knee extension

-rectus femoris

-vastus medialis

-vastus intermedius

-vastus lateralis

-TFL (in 0-30* flex)

what muscles are active during NWB medial rotation of flexed leg

-popliteus

-semimembranosus

-semitendinosus

-sartorious

-gracilis

what muscle is active during lateral rotation of the flexed leg NWB

biceps femoris

do the knee flexors or knee extensors produce a greater torque?

knee extensors

T/F: the knee extensors in the quadriceps produce a torque about 2/3 greater than that of the knee flexors

true

in an open chain knee exercise, where is the knee the strongest?

90* flexion

in an open chain exercise where is the knee the weakest

45* flex to full ext

in a closed chain exercise, where is the knee the strongest

full extension

in a closed chain exercise where is the knee the weakest

90* knee flexion

where does the ACL connect

medial aspect of femoral lateral condyle to anterior intercondylar tibial fossa

what is the purpose of the ACL

-limit anterior translation on the femur or excessive posterior translation of the femur

-provides rotational stability

where does the PCL connect?

lateral surface of femoral medial condyle to posterior intercondylar tibia

what is the purpose of the PCL

limits posterior translation of the tibia on the femur or anterior translation of the femur on a fixed LE

where does the MCL connect

medial femoral condyle to upper tibia

what type of forces will the MCL stabilize against?

Valgus forces

what type of movement will the MCL and LCL prevent?

ER

where does the LCL connect

lateral femoral condyle to head of fibula

what type of forces the LCL stabilize against

Varus

is the lateral or medial meniscus smaller?

lateral meniscus

what attaches to the medial meniscus

-MCL

-semimembranosus

-quads

what attaches to the lateral meniscus

-quads

-popliteus

-semimembranosus

what is the function of the menisci

-deepen the tibial fossa

-increase congruency between the tibia and femur

-provide stability to the tibiofemoral joint

-provide shock absorption and lubrication to the knee

-reduce friction and improve weight distribution

what occurs during a meniscectomy?

portions of the meniscus are removed surgically

what happens to the shock absorption capacity when a patient gets a meniscectomy?

reduced by 230%

during flexion/extension activities, which bony structures will the menisci follow?

tibia

during IR/ER activities, which bony structures will the menisci follow?

femoral condyles

What is the most common cause of knee pain in adults >50?

knee OA

where is the most common location for an individual to experience knee OA?

medial femoral condyle and patella articular surface

T/F: there is a high incidence of Knee OA in patients who have previously suffered an ACL/meniscus injury

true

what are the typical clinical findings from patient history for patients with knee OA

-hx of trauma or insidious onset of knee pain and stiffness

-worsening of symptoms in weight bearing

-pain with squatting

-painful after prolonged activity

-pain with colder weather

-diffuse pain tenderness

-morning stiffness <30 minutes

-stiffness after prolonged, static positions

-advancing age

-BMI >30kg/m^2

-female>male

-high level athletic activity

-heavy physical labor including kneeling, squatting, standing

what are typical findings from the clinical exam for patients with knee OA

-stiffness of relatively short duration

-flexion restricted more than extension

-decreased accessory mobility

-decreased strength in the glutes and quads

-possibly short/stiff hamstrings and gastroc

-may see a varus thrust in gait

according to the ACRR what is the clinical and laboratory data for the diagnosis of knee OA

-knee OA

-age >50

-stiffness <30

-crepitus

-bony tenderness

-bony enlargment

-no palpable worth

-ESR <40 mm/hr

-

according to the ACRR for clinical and laboratory findings, what amount of findings out of 9 should the patient have to diagnosis knee OA

5

according to the ACRR, what amount of clinical and radiographic findings should an individual have to diagnose knee OA

1 out of 3

according to the ACRR what amount of clinical findings should an individual have to diagnose knee OA

3 out of 6

what are the ACRR clinical and radiographic findings associated with knee OA

-age >50

-stiffness <30 minutes

-crepitus

-osteophytes

what are the ACRR clinical findings associated with the diagnosis of knee OA

-age >50

-stiffness <30 minutes

-crepitus

-bony tenderness

-bony enlargement

-no palpable worth

what is a grade 0 on the Kellgren Lawrence Grading System

no feature of OA

what is a grade 1 on the Kellgren-Lawrence Grading Scale

doubtful narrowing of joint space and possible osteophytic lipping

what is a grade 3 on the Kellgren-Lawrence Grading Scale

moderate multiple osteophytes, definite narrowing of joint space, and some sclerosis and possible deformity of bone ends

what is a grade 2 on the Kellgren-Lawrence Grading Scale

definite osteophytes and possible narrowing of joint space

what is a grade 4 on the Kellgren-Lawrence Grading System

large osteophytes, marked joint space narrowing, severe sclerosis and definite deformity of bone ends

what are some examples of nociceptive pain that a patient will feel in early OA

-pain on movement

-localized

-episodic/acute

typically what occurs with early OA

joint damage (malalignment, injury, mechanical) or inflammation

what are some examples of nociceptive pain seen in late OA

-pain at rest

-ongoing or chronic pain

-increased area of pain and may see referred/multifocial/widespread pain

when a patient with OA starts to undergo sensitization and centralization, what type of neuropathic pain features may they experience?

-burning/paraesthesia

-pins and needles

-mechanical and thermal hyperalgesia

-allodynia

-paroxysmal pain

-numbness

what is a grade 1 ligamentous injury

-stretch of ligament

-minor sprain

-on an MRI there will be a superficial high signal to the ligament but the ligament itself appears normal

-little or no instability

what is a grade 2 ligamentous injury

-severe sprain or partial tear

-on MRI a high signal is seen and there may or may not be partial disruption of the ligament

-minimal to moderate instability

what is a grade 3 ligamentous injury

-complete tear

-on MRI there is complete disruption of ligament

-extreme instability

at what rate do female athletes see an increased risk to rerupture within 2 years of ACL reconstruction?

4.5x

T/F: most ACL injuries are non-contact

True

what is the cost of ACL injury in the US per year

5 Billion

what are the typically clinical findings in the patient history for patients with an ACL injury

-sport participation that involves cutting, pivoting, or landing from a jump

-MOI: deceleration and acceleration motions with noncontact valgus load at or near full knee extension

-hearing a "pop"

-immediate effusion within 12 hours after injury

-feeling of instability/giving way with 2 or more ADLs

-difficulty with WB due to pain or edema

what are the typical clinical exam findings for patients with an ACL injury

-positive lachman's test with soft end feel or increased tibial translation

-positive pivot shift test

-decreased performance on hop tests (6m single limb timed hop test <80%)

-decreased quad strength <80%

-decrease ROM

-swelling

T/F: immediate surgery over conservative treatment/rehab can put an ACL patient at a higher risk for secondary injuries

False

what is the most common causes of a PCL injury

-MVA dashboard injuries

-sports injury fo falling onto a fully flexed knee

is a PCL injury more likely to occur in males or females?

males

what is the typical clinical findings of the patient history for those with a PCL injury

-traumatic injurying causing the tibia to translate posteriorly on the femur

-immediate effusion within hours

-feeling of instability with weightbearing, especially with change of direction, pivoting activities

-localized posterior knee pain with kneeling or decelerating

-may report audible pop or snap

what are common clinical exam findings for patients with a PCL injury

-positive posterior drawer test with soft end feel or increased posterior tibial translation

-positive posterior sag sign

-decresed ROM

-swelling

-decreased performance on hop tests

-decreased quad strength

what is a grade 1 medial knee injury

tenderness, no instability

what is a grade 2 medial knee injury

broad tenderness, partially torn medial knee structures

what is a grade 3 medial knee injury

complete medial knee disruption, no end point to an applied valgus stress at 20* knee flexion

what occurs in the terrible triad

-ACL injury

-Medial Meniscus Injury

-MCL injury

what are the common clinical findings during the patient history for a patient with an MCL injury

-reports direct trauma to the lateral aspect of the knee creating a valgus force with a rotational component

-feeling of pain or instability with weightbearing and change of direction

what are common clinical exam findings for a patient with MCL injury

-medial knee pain and increased laxity with valgus stress test

-tenderness over MCL

-typically normal ROM if the injury occurs in isolation

-may see a positive stroke test for swelling

what sports have a higher risk of LCL injruy

-tennis

-gymnastics

what are common findings during the patient history for patients who have suffered an LCL injury

-direct trauma to the medial aspect of the knee joint causing a varus stress; fall, below the knee

-localized swelling over LCL

-report feeling of instability

what are common clinical exam findings for patients who have an LCL injury

-pain and possible laxity with varus stress test

-tenderness over LCL

-typically normal ROM

-may see a positive stroke test for swelling

what type of forces typically cause a meniscus injury

combination of tibiofemoral joint flexion, compression, and rotation placing abnormal shear stress in the meniscus

what are the two types of meniscus tear

-traumatic

-degenerative

which meniscus is more common to be torn in younger athletes

lateral meniscus

which meniscus is more common to be torn in older people

medial meniscus

what are the typical findings in the patient history associated with menisci pathology

-report of a plant and twist injury mechanism during sports

-possible hyperflexion or hyperextension trauma

-can be insidious onset in older individuals due to degenerative changes; early signs of knee OA

-history of delayed ACL reconstruction

-complaint of medial or lateral joint line pain

-delayed effusion; 6-24 hours of post injury

-reports "locking" or "clicking" and inability to fully extend the knee

what are some common clinical exam findings associated with meniscal pathology

-joint line tenderness with reproduction of symptoms

-may see some minor swelling

-paint at end ROM: flex and ext

-positive mcmurray's

-positive thessaly

what makes up the meniscal pathology composite score

-hx of catching or locking

-pain with forced hyperextension

-pain with maximum passive knee flexion

-joint line tenderness

-pain or audible click with mcmurray's

how many positive meniscal findings are needed to rule in pathology?

3 or more

at what age is a person likely to get a meniscal repair over a meniscectomy?

<35

at what age is a person likely to get a meniscectomy over a meniscal repair

>45

who is unlikely to respond to treatment

-higher BMI

-worse mental health

-greater knee pain at baseline

-poorer perceived knee function

-weaker quad/hamstring strength

-worse performance on functional tests

what is patellofemoral pain syndrome

a common MSK condition characterized by insidious onset of poorly defined pain, localized to the anterior retropatellar and/or peripatellar region of the knee that worsens with lower limb loading activities

what is considered overuse/overload PFPS

patient presents with a history suggesting an increase in magnitude and/or frequency of PFJ loading at a rate that surpasses the ability of the PFJ tissue to recover

what is a muscle power deficit for PFPS

patient presents with LE muscle performance deficits in the hips and quads

what is a movement coordination deficit for PFPS

patient presents with excessive or poorly controlled knee valgus during a dynamic task but not necessarily due to weakness of the LE musculature

what is mobility impairment for PFPS

patient presents with an increased foot mobility and/or flexibility deficits in 1 or more of the following: HS, quads, gastroc, soleus, IT band

what type of sports are more likely to have athletes with PFPS

running and jumping sports