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Flashcards in The Knee Deck (44)
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1
Q

Articular Cartilage

A

avascular, receives nutrients via diffusion

2
Q

Meniscus

A
  • C-shaped wedges of fibrocartilage between tibial plateaus and femoral condyles
  • 70% type I cartilage
  • Peripheral 1/3 has rich blood supply–> tears in this area (longitudinal tears) have increased change for healing

*Inside 2/3 have no blood supply–> cannot heal

3
Q

Collateral ligaments

A

ACL- prevents tibia from moving forward
PCL- prevents tibia from moving backward
LCL- extremely stable
MCL

4
Q

What to look for on inspection?

A
  • effusion
  • inflammation
  • varus deformity
  • valgus deformity
  • patellar alignment
  • thigh atrophy
  • Q angle
5
Q

When does an effusion appear with ACL and meniscal injury?

A
  • ACL results in effusion <24 hours

- Meniscal injury results in effusion 24-48 hours

6
Q

Varus deformity a/w what?

A

Osteoarthritis (bow-legged)

7
Q

Valgus deformity a/w what?

A

Inflammatory arthritis

8
Q

Patellar alignment–> which direction does it deviate?

A
  • femoral torsion/anteversion (MCC of in-toeing in children from ages 3-10)
  • knee dislocation results in lateral deviation of the patella
9
Q

Normal Q angle?

A
  • normal is ~15 degrees
  • Increased Q angle increased risk of patellar subluxation and patellofemoral syndrome
  • Increased Q angle with femoral anteversion/tibial external torsion (toe in) and tight lateral retinaculum
10
Q

What is the Q angle?

A
  • line from ASIS to patella
  • line from tibial tuberosity to the patella

Measure the angle between those 2 lines.

11
Q

What should you think of with joint line tenderness?

A
  • medial meniscus tear

- osteoarthritis

12
Q

What is the pes anserine bursa?

A

-25 mm area near the medial tibial plateau

13
Q

What tendons insert at the pes anserine bursa?

A

-SGT (Sartorius, Gracilis, and semiTendinosus)

14
Q

How to test for pes anserine bursitis?

A

-Resisted adduction–> think of the function of the muscles that attach there

15
Q

Palpation

A
  • Superior pole of patella–> quad tendonitis
  • Inferior pole of patella–> patellar tendonitis (jumper’s knee)
  • Popliteal fossa–> baker’s cyst, usually results from knee effusion d/t posterior meniscal tear
  • Pre-patellar bursa on anterior patella–> “housemaid’s knee”
16
Q

Plica Syndrome

A
  • Plica is an embryological remnant

- Plica snaps over medial epicondyle

17
Q

Where do knee effusions collect?

A

-large effusions collect in the suprapatellar fossa (25-30ml)

18
Q

Tests/signs for effusion?

A
  • “Milking” techinique/wave sign: tap lateral compartment and look for fluid wave on medial side
  • Ballottement sign: compress all fluid to center of knee, force down patella with index finger, + test with clicking or tapping sensation (10-15ml)
  • Abnormal “heel to buttock” measurement
19
Q

What is the normal ROM of the knee?

What is the function ROM of the knee?

A
  • Normal: 0-145 degrees
  • Function knee flexion is 110 degrees
  • 65 degrees KF needed for ambulation at normal pace
  • 90 degrees KF needed to ascend stairs “step over step”
  • 110 degrees KN needed to arise from seated position
20
Q

Gait exam for knee pathology

A
  • Typically antalgic gait in knee OA- i.e. shortened stance time on affected leg
  • Heel/toe walking
  • “duck-walking” effectively excluded significant intra-articular knee pathology
21
Q

How to assess MCL?

A
  • Valgus stress test- hand on lateral knee and medial tibia; apply stress to lateral knee
  • check with knee flexed 25-30 degrees and in full extension
  • compare to opposite side
  • Increased laxity with knee flexed indicated MCL injury
  • Increased laxity with knee in full extension usually indicated other ligaments are injured as well (i.e. ACL)
22
Q

How to assess LCL?

A
  • Varus stress test- hand on medial knee and lateral leg; apply stress on medial knee to open up lateral joint space
  • Check with knee in full extension and 25-30 degrees of extension
  • Increased laxity with knee flexed indicated LCL injury
  • Increased laxity with knee in full extension usually indicated other ligaments are injured as well (i.e. ACL)
23
Q

If a patient reports a “pop” and knee effusion within 24 hours, what should you suspect?

A

-ACL injury

  • Usually non-contact injury
  • May also result in knee instability and “giving out” episodes
24
Q

Do ACL injuries need to be repaired?

A

No, but it may contribute to early arthritis.

25
Q

What is the best test for ACL injury?

A
  • Lachman Test- knee flexed 25 degrees, grab thigh with one hand and tibia with other hand; apply anterior force on tibia and posterior force on femur–> shucking motion
  • Positive test is lack of firm endpoint or increased translation

*Most sensitive test for ACL injuries.

26
Q

What are 2 other tests for ACL injury?

A
  • Anterior Drawer Sign: knee flexed to 90 degrees, sit on patient’s foot, pull tibia forward with both hands; + test is increased movement compared to opposite leg
  • Pivot shift test: Valgus and internal rotation force applied to knee in extension; hold theses forces while flexing the knee; + test reveals subluxation of tibia in anterior and lateral direction (usually done under anesthesia)
27
Q

What should you think of with “dashboard” injury?

A
  • PCL injury

* isolated injury to PCL is rare

28
Q

What are the 3 tests for PCL injury?

A
  • Posterior drawer test: same as anterior drawer sign except push tibia in posterior direction with both hands
  • Thumb sign: in complete PCL injury the tibia rests posterior and area to place thumbs on tibia plateau decreases; normally ~1 cm
  • Posterior sage sign: posterior displacement of tibia
29
Q

What is a positive test for meniscal injury?

A

Pain AND clicking!

30
Q

What are the tests for Meniscal injury?

A
  • McMurray test
  • Appley’s compression/grind test
  • Bounce Home test
31
Q

McMurray test?

A
  • Flex the knee with foot externally rotated, extend knee (stresses medial meniscus)
  • Flex knee with foot internally rotated, extend knee (stresses lateral meniscus)

+ test is pain AND clicking

32
Q

Appley’s compression/grind test?

A

-patient prone, knee flexed to 90, downward force with rotation applied to foot

33
Q

Bounce Home test?

A
  • patient supine, grasp heel and maximally flex knee, passively let knee fall to full extension
  • if pain is reproduced and/or knee does not fully extend (i.e. knee “bounces home” to full extension), this may indicate meniscal injury
34
Q

Patellofemoral Pain Syndrome

A
  • MCC of knee pain in outpatient setting
  • Common in runners
  • Patient reports increased pain with stairs, squatting, etc.

*Think young patient with bilateral knee pain

35
Q

What causes PFPS?

A
  • Imbalance of forces which control patellar tracking during knee flexion/extension
  • Need to assess kinetic chain to determine etiology (i.e. IT band, hip abductors, pes planus, etc.)
36
Q

What are 2 signs for PFPS?

A
  • Theater sign: increased pain and stiffness after prolonged sitting
  • Circle sign: patient often have difficulty localizing area of pain and make a circle around anterior knee with their finger
37
Q

What is the J sign?

A
  • evaluates patellar tracking
  • Normally patella moves slightly lateral to medial to lateral position with knee flexion
  • Increased arc of movement indicated patellar tracking problem (i.e. patellofemoral syndrome)
  • assess with single leg squat and stand.
  • may also assess with seated or supine knee flexion/extension
38
Q

When is one time you make see lateral OA?

A

-Flat feet

39
Q

What is the patellar grind test?

A
  • knee in full extension, quad relaxed, apply inferior force on patella and ask patient to contract quad
  • positive test is reproduction of pain, compared side to side
40
Q

What is the medial glide test?

A

-patella is divided into 4 quadrants; with knee extended force patella medially and assess degree of displacement

  • less than 1 quadrant indicated tight lateral structures
  • displacement of 3 or more quadrants indicated hypermobility
41
Q

What is the Patellar tilt test?

A
  • knee extended, grasp patella with thumb and finger, apply downward force on medial aspect
  • positive test if lateral patella is fixed and not elevated past zero degrees in horizontal plane–> indicates tightness of lateral structures
42
Q

Patellar instability Test?

A
  • Patellar apprehension test: patient sitting, extend knee and move patella laterally, then flex knee to 30 degrees while maintaining lateral force on patella
  • Positive test is feeling of apprehension or pain and indicates patellar instability/subluxation
43
Q

Hamstring strain/tear symptoms?

A
  • Hamstring strain/tear can cause posterior knee pain

- Reproduction of pain with resisted knee flexion usually confirms the diagnosis

44
Q

What does the popliteal angle assess?

A
  • test for hamstring tightness
  • test with 90 degrees of hip flexion
  • extend the knee as far as possible
  • normal is to lack 10-30 degrees from full extension in children, may be more in adults
  • greater than 50 degrees lacking is always abnormal