Flashcards in MSK Knee Deck (81):
The knee joint is a modified ____ joint.
Is the _____ joint in the body
largest joint in the body
Normal knee range of motion:
Internal rotation of the knee:
External rotation of the knee:
Name the knee extensors (4)
Quadriceps (femoral nerve L2-4)
- Rectus femoris
- Vastus Lateralis
- Vastus Intermedius
- Vastus medialis obliquus
all join with the patellar tendon.
Vastus medialis and lateralis draw the patella in their respective directions.
Name the knee flexors (7)
- semimenbranosus (sciatic nerve, tib div L4-S2)
- Semitendinosus (sciatic nerve, tib division: L4-S2)
- Biceps femoris
- Long head (sciatic nerve, tib div L5-S2)
- Short head (sciatic nerve, common peroneal div: L5-S2)
Sartorius (femoral nerve L2-3)
Gracilis (obturator nerve: L2-4)
Gastrocnemus (Tibial nerve S1,2)
Medial rotators of the knee (5)
Semitendinosus (sciatic, tib portion L4-S2)
Semimembranosus (sciatic, tib portion: L4-S2)
Sartorius (femoral nerve: L2,L3)
Gracilis (obturator nerve: L2-4)
Lateral rotators of the knee (2)
Biceps femoris (long and short heads)
The _______ is formed by the long axes of the femur and the tibia and reflects the natural valgus attitude of the knee.
Q angle - ASIS to middle of patella. Tibial tubercule.
Males 13 degrees
Females 18 degrees
How is tibial rotation with knee flexion accomplished?
the lateral tibial plateau is convex in shape. This allows the lateral femoral condyle to move farther than the medial condyle.
Efficiency of the knee extensor muscles is increased by ____% due to the mechanical advantage provided by the patella.
The ____ originates at the lateral femoral condyle, travels through the intercondylar notch, and attaches to the medial eminence.
Primary function of the ACL:
Limit anterior tibial translation
also prevents backward sliding of the femur and hyperextension of the knee. Limits internal rotation of the femur when the foot is fixed.
____ loosens the ACL. ____ tightens it.
full knee exteneion/internal rotation
ACL deficient knees create increased pressure on_____
the _____ originates from the anterolateral portion of the medial femoral condyle around the intercondylar notch and inserts onto the posterior aspect of the tibial plateau.
Main function of the PCL is:
TO restrain posterior tibial translation.
PCL is looser in ___- and tighter in _____
In flexion, the ACL pulls the femoral condyles_____
in Extension, the PCL pulls the femoral condyles ______
PCL deficient knees place more force on ____
the ____ originates from the medial femoral condyle and inserts onto the superior aspect of the medial tibia.
medial collateral ligament
Also has attachment to the medial meniscus.
In full extension, the MCL _____ .
Tension is increased with _____.
tightens to full tension. Tension is increased with abduction stress at increasing positions of flexion.
____ originates from the lateral femoral condyle posteriorly and superiorly and attaches to the superior part the lateral fibula.
Lateral collateral ligament
It does NOT have an attachment to the lateral meniscus
The LCL ____ during varus stresses.
Peak stress is achieved with _____
Peak stress is achieved with adduction when the knee is at 70 degrees of flexion
The ____ arises from the semimbranosus tendon and strengthens the fibrous posterior capsule of the knee joint. and resists knee extension. Name the attachemnts
OPL - oblique popliteal ligament
attached to capsule and lateral meniscus
The ______ provides attachment for the posterior horn of the lateral meniscus and reinforces the lateral aspect of the knee and gives posterior lateral rotary stability.
APLC arcuate popliteal ligament complex.
also provides restraint to the posterior tibial translation
This ligaments attachment can be mistaken for a tear of the posterior horn of the lateral meniscus on MRI.
APLC arcuate popliteal ligament complex.
The ____ part of the menisci is well vascularized
The ___ part is poorly vascularized and usually cannot be surgically repaired
peripheral outer 1/3
The ____ meniscus is C shaped while the _____ is O shaped
lateral meniscus covers a larger area than the medial meniscus. It is joined to the medial femoral condyle by the posterior meniscofemoral ligament
Name the anterior (4) bursae of the knee
- Prepatellar bursa: housemaids knee", located between skin and anterior patella. Most commonly damaged bursa. Inflammation is caused by prolonged kneeling.
- Suprapatellar bursa - located between the quadriceps femoris muscle and the femur: usually communicates with the joint capsule
- Deep infrapatellar bursa - between patellar tendon and the tibia
- superficial or subcutaneous infrapatellar bursa - "vicar's knee) - located between the skin and the tibial tuberosity. Associated iwth kneeling in upright position (eg kneeling on a prayer bench)
How many bursae of the knee are there?
Name the 3 lateral bursae of the knee
- between biceps muscle and fibular collateral ligament
- between popliteus muscle and fibular collateral ligament
- between lateral femur condule and popliteus muscle
Name the 3 medial bursae of the knee
- Pesanserinus bursa - located between the tendons of the sartorius, gracilis, semitendinosus muscles and medial collateral ligament (say grace before tea)
- between MCL and semitendinosus
- Semimembranosus and the tibia
Name the 2 posterior bursae of the knee
- between lateral head of gastrocnemius and the capsule.
- between medial head of gastrocnemius and capsule extending under the semimembranosus.
* communicates with the joint cavity, can be irritated by abnormal strain, when distended is known as a BAKERS CYS.
_______ is a distension of the bursa between the medial head of the gastrocnemius and the capsule extending under the semimembranosus and outpocketing of the synovial membrane in this location. It can mimic a DVT due to the increased warmth and leg girth and associated pain.
can mimic a DVT due to increased warmth and leg girth and associated pain.
This test is used to diagnose meniscal tears and is especially useful in diagnosing posterior meniscal tears
Mcmurrays test - patient lies supine wiht the knee flexed. with flexed knee, internally and externally rotate the tibia on the femur. Place a valgus stress on teh knee with the leg externally rotated. Slowly extend the leg with the leg externally rotated in valgus position. If click is heard or palpated, the test is positive for a torn medial meniscus, usually in the posterior position.
If externally rotated with lateral force - checking medial meniscus
if internally rotated with varus force - checking lateral
____ is a test used to diagnose meniscal tears with the patient lying prone and knee flexed to 90 degrees. Examiner places force downward on the heel, compressing the menisci between the femur and tibia. Pressure is maintained downward as the tibia is rotated.
what is considered positive?
Apley's Grind test
pain elicited. Patient is asked to localize the pain to lateral vs medial.
_____ is a test for collateral ligamentous (MCL or LCL damage. Patient lies prone with knee flexed. Traction force is applied while rotating the tibia internally and externally. Pressure on menisci is reduced during this maneuver.
What is considered positive?
Positive test elicits pain indicating ligamentous rather than meniscal damage
____ is a test for decreased knee extension. With patient supine, examiner flexes the knee while holding the heel. The knee is allowed to extend passively and should have a definite endpoint. It should bounce into extension.
What is considered a positive test?
Bounce home test. - occurs when full extension cannot be attained and rubbery resistance is felt.
torn meniscus, loose body, intracapsular swelling, fluid in the joint
____ test evaluates the quality of the patella articulating surfaces. The patient is supine with the legs in a neutral position. The examiner pushes the patella distally and then asks the patient to contract the quadriceps against the resistance on the patella. The patella should glide smoothly cephalad.
Patella femoral grind test
yields pain and crepitation on patella movement.
____ test primarily tests the integrity of the ACL. With patient supine, the knees flexed to 90 degrees, the foot stabilized by the examiners body, the examiner grasps the patient's knee with the fingers in the area of the hamstring insertions and thumbs on the medial and lateral joint lines. The tibia is drawn toward the examiner.
Anterior drawer test.
occurs when the tibia slides from under the femur with no distinct endpoint. Some anterior translation is normal.
ER tightens the posteromedial portion of the joint capsule, thereby restricting anterior movement. If the anterior translation with the leg in the neutral position is equal to the anterior movement wit the leg externally rotated, the posteromedial joint capsule and the ACL may be damaged.
Not very sensitive because hemarthrosis, hamstring spasm, and other structures (ie posterior capsule) can limit forward movement of the tibia.
____ test is used to assess ACL integrity and anterior knee integrity. Anterior tibial translation is evaluated. The patient is supine. Knee flexed at 15-30 degrees. The examiner grasps the distal femur with one hand and the proximal tibia with the other hand. Femur is stabilized and anterior force is applied to the tibia.
positive test yields significant anterior movement with no distinct endpoint
a partial ACL tear may yield a test with a soft end point.
____ test checks for anterolateral rotary instability. Has very high specificity for ACL injury. How performed?
Pivot shift test
maneuver reproduces the inciting event that occurs when knees give way. The patient often recognizes this as buckling of the knee. Tibia is internally rotated while a valgus stress and axial load is applied. Begin in full extension and gently flex the knee.
anterolateral subluxation of the alteral tibial plateau indicates a positive test. Knee may be tested in full extension and at ~25 degrees of flexion to relax fibers fo the posterior joint capsules.
In pivot shift test ____ of motion is considered a grade I tear.
____ tests the PCL. Patient supine. knees flexed to 90 degrees and the foot is stabilized by the examiners body. Examiner pushes the tibia away from himself.
occurs when the tibia slides backward on the femur. Some posterior movement is normal; however, a distinct endpoint should be encountered.
___ is a test for integrity of the PCL. Patient is supine with knees flexed to 90 degrees with the foot on the exam table. The test can also be done witht he patient supine witht he hip and knee flexed to 90 degrees and the heel held in the examiners hand.
sag test. positive if the tibia is displaced posteriorly. Comparison should be done with the other side.
___ tests the integrity at the medial and lateral collateral ligaments (MCL and LCL) by imposing valgus and varus stresses. While the patietn is supine, the examiner tucks the patient's ankle under the examiner's arm. The thumbs of both hands palpate the medial and lateral joint lines. Valgus and varus stress applied to joint line.
Collateral ligament testing
If valgus is applied to medial joint line and it gaps, MCL may be damaged
If varus stress is applied and lateral joint line gaps, the LCL may be damaged
In collateral ligament testing
Can test in full extension and at ~25 degrees of flexion to relax fibers of the posterior joint capsule.
____ is Grade I tear
____ is Grade II tear
_____ is complete interstitial tear
mechanism for medial and lateral meniscal injuries
Medial: cutting maneuvers. Occurs with tibial rotation while the knee is partially flexed during weight bearing (closed kinetic chain); common in football and soccer
Lateral: squatting. full flexion with rotation is the usual mechanism (wrestling)
Posterior horn tears of the medial meniscus are common and occur with _____ and ____.
Effusion occurs within _____.
valgus and external rotation
____ is the gold standard for diagnosing meniscal tears.
Provocative tests? (2)
Sagittal views show Ant/Post meniscal horns
Coronal views are best for meniscal body
tears appear as a line of increased signal extending from articular surfaces.
Treatment of meniscal tears?
Inner 2/3 require sugical resection due to area's avascularity and resultant poor tissue healing.
Outer 1/3: meniscus are usually repared due to better vascular supply.
If repaired, generally the patient is NWB fqor 4-6 wks to allow for strengthening. If resected, patient is WBAT in 1-2 days
_____ is the most commonly injured knee ligament in athletics (football, soccer, downhill skiing) Mechanism?
Mechanism: cutting, deceleration, hyperextension of the knee.
Noncontact injures most common. If contact, other structures may be injured.
Greater than 50% of ACL tears occur with _____
What is the terrible triad (O'Donoghue's triad)
ACL, MCL, Medial meniscus - because of the attachment of the MCL to the medial meniscus
Occurs when a valgus force is applied to a flexed rotated knee.
Name two sits of avulsion fracture with ACL injury
insertion site of ACL on tibia or lateral capsular margin of tibia.
After ACL repair:
____ weight bearing is maintained initially
ROM is instituted to regain flexion at ____
Rehab then progresses to _____
Sports specific exercises can be started at ______.
Goal of completed rehab at _____.
Partial weight bearing
closed chain kinetics
Most frequent cause of PCL injury:
impact to the front of the tibia with the knee flexed (dashboard injury)
In athletics, hyperflexion is most common
much less common than ACL
With PCL injury, what exam finding is present in acute phase?
LCL injuries are usually the result of _____.
knee dislocations. Must consider associated vascular injuries and cruciate and peroneal nerve injuries.
ITB tightness is evaluated by ___ test.
Compensation for ITB tightness?
externally rotating the hip, internally rotating the lower leg, pronating the foot.
The stability of the patella is dependent upon what 3 characteristics?
1. depth of the intercondylar groove
2. proper contour of the patella
3. Adequate muscular control
Patellofemoral weight bearing increases with knee flexion
ascending or descending stairs:
W: 0.5 x body weight
A or D stairs: 3.3 x BW
Squatting: 6.0 x BW
Which portion of the patella helps to prevent subluxation of the patella from the femur?
the lateral lip of the patellar surface of the femur. In hyperextension, there is a tendency for the patella to separate from the femur
1. If congenital malformation in lateral lip:
2. Increased genu valgum
3. Increased genu varum
4. excessive genu recurvatum:
5. Weak VMO
6. Tibial external torsion
7. shallow lateral femoral condyle
8. laterally attached inrapatellar tendon on the tubercle
Patella often resets at:
1. laterally in full extension
4. elongates the patellofemoral structures causing loss of patella condylar contact
5. lateral displacement
6. Lateral displacement
7. lateral displacement
8. Lateral displacement
25-30 degrees of flexion
____ is the most common cause of anterior knee pain
patellofemoral pain syndrome (PFPS)
cause of patellofemoral pain syndrome?
overuse injury caused by repeated microtrauma leading to peripatellar synovitis.
A low patella, AKA ______ is less common but may represent:
patella baja - quadriceps rupture.
With regard to patellofemoral pathology, evaluation at ____ degrees is important
last 30 degrees of extension.
Tight hamstrings can increase patellofemoral loading
tight abductors can alter gait
Rotation fo the patella indicated muscle imbalance:
Patellar internal rotation
Patellar external rotation
"frog's eye" patella
Normal Q angles:
Factors that increase it? 3
Women 18 degrees
Men 13 degrees
internal torsion of the femur
lateral insertion of the infrapatellar tendon on the tibia
genu varus deformity
Tests to perform when assessing patellofemoral pain syndrome
examination of knee extension - mostly last 30 degrees
thomas - tight hip flexors
Ober test - tight adductors
Straight leg raise
With patellofemoral pain syndrome, bone scan might be indicated when?
<4 months of uncertain diagnosis
In patellofemoral pain syndrome, can do patellar taping.
2. Provides ____
3. also helps with ___ forces
taped in a position to allow pain-reduced ROM
proprioceptive feedback to atler patellar tracking
helps to balance contractile forces between vastuc lateralis amd medialis
____ is an arthroscopic diagnosis and is characterized by softening of the patellar articular cartilage due to cartilage degeneration.
results from overlod and tracking dysfunctions but also possible infection, trauma, or autoimmune processes
____ is a condition marked by redundant fold of the synovial lining of the knee, which is susceptible to tearing as it passes over the condyles.
PLICA syndrome - synovial lining extends from the infrapatellar fat pad medially around the femoral condyles and under the quadriceps tendon above the patella and lateral to the lateral retinaculum
PLICA syndrome can occur in the mediopatellar, infrapatellar, or suprapatellar regions.
PLICA syndrome presents as ____ pain.
Becomes worse with ____.
anterior knee pain
increasing pain with prolonged knee flexion or sitting, made worse with standing and extension
after direct trauma, such as ACL tears or meniscal tears, the plica can become inflamed and symptomatic. Knee may give sensation of buckling if the plica is trapped between the patella and medial condyle. snapping with knee extension can occur if plica is fibrosed.
_____ is often associated with microtears of the patellar tendon. Considered to be an overuse syndrome of the patellofemoral extensor unit. Associated with high quadriceps loading.
Most common site of involvement:
patellar tendonitis (jumpers knee)
Inferior pole of the patella
____ is a process in localized segmental area of avascular necrosis of the end of a long bone. This results in formation of dead subchondral bone covered with articular hyaline cartilage.
osteochondritis dessicans - The overlying cartilage degenerates around the defect and an entire piece may detach from the rst of the bone, entering the joint space as a loose body.
Usual area of involvement for osteochondritis dessicans in knee joint?
Medial femoral condyle
tends to affect adolescents
The popliteus muscle arises from _____ and inserts ____
Along with ACL, limits ____
Inflammation can occur due to:
lateral face of the lateral femoral condyle and inserts into the triangular area in the posterior tibia
anterior translation of the femur
acute or chronic overload.
In popliteus tendonitis, pain is elicited when?
running downhill and excessive pronation - WATCH YOUR PATIENT WALK.
stress to popliteus is caused by forward femoral displacement. Point tenderness anterior to the fibular collateral ligament.