The Knee Flashcards
(44 cards)
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
What is the best test for ACL injury?
- 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
What are 2 other tests for ACL injury?
- 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
What should you think of with "dashboard" injury?
- PCL injury
| * isolated injury to PCL is rare
28
What are the 3 tests for PCL injury?
- 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
What is a positive test for meniscal injury?
Pain AND clicking!
30
What are the tests for Meniscal injury?
- McMurray test
- Appley's compression/grind test
- Bounce Home test
31
McMurray test?
- 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
Appley's compression/grind test?
-patient prone, knee flexed to 90, downward force with rotation applied to foot
33
Bounce Home test?
- 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
Patellofemoral Pain Syndrome
- 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
What causes PFPS?
- 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
What are 2 signs for PFPS?
- 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
What is the J sign?
- 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
When is one time you make see lateral OA?
-Flat feet
39
What is the patellar grind test?
- 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
What is the medial glide test?
-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
What is the Patellar tilt test?
- 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
Patellar instability Test?
- 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
Hamstring strain/tear symptoms?
- Hamstring strain/tear can cause posterior knee pain
| - Reproduction of pain with resisted knee flexion usually confirms the diagnosis
44
What does the popliteal angle assess?
- 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
