Knee

Question 1

Bones of the Knee

Answer 1

Femur:
Tibia: Medial bears most of weight and has a larger surface area (most common area of arthritis)/Lateral side is receptacles for femoral condyles
Fibula: serves as the attachment for knee joint structures/doesn’t articulate with femur or patella/not part of knee joint/not weight bearing
Patella: sesamoid bone/imbedded in quad and patellar tendon/serves similar to a pulley in improving angle of pull, resulting in greater mechanical advantage in knee extension (lengths the wrench)

Question 2

Knee articulations

Answer 2

Femoral condyles on tibial plateaus:
Patella with distal femurs:

Question 3

Role of fibula

Answer 3

-Serves as the attachment for knee joint structures/doesn’t articulate with femur or patella/not part of knee joint/not weight bearing
-Biceps femoris inserts primarily on fibula head
-LCL (fibula) originates on lateral femoral condyle and inserts on fibular head

Question 4

Role of patella in improving knee extensors

Answer 4

sesamoid bone/imbedded in quad and patellar tendon/serves similar to a pulley in improving angle of pull, resulting in greater mechanical advantage in knee extension (lengths the wrench)

Question 5

What are the boney landmarks?

Answer 5

-Tibial tuberosity
-Gerdy’s tubercle
-Superior/inferior poles of patella
-Medial/lateral femoral condyles
-Upper medial surface of the tibia
-Head of the fibula

Question 6

Tibial tuberosity

Answer 6

-Three vasti muscles if quadriceps originate on proximal femur and and insert on patellar superior pole
-Insertion is ultimately on tibial tuberosity via patella tendon

Question 7

Gerdy’s tubercle

Answer 7

-IT band of TFL inserts on Gerdy’s tubercle

Question 8

Superior/Inferior poles of patella

Answer 8

-Apex of patella is situated inferiorly
-Base forms the superior aspect of the bone
-Rectus femoris and vastus intermedius muscles insert at the superior pole of the body
-Patellar tendon originates from the inferior pole and inserts into the tibial tuberosity

Question 9

Medial/Lateral femoral condyles

Answer 9

-Articulate on enlarged tibial condyles

Question 10

Upper medial surface of the tibia

Answer 10

-Semi membranous inserts posteromedially on medial tibial surface
-MCL (Tibial) originates on medial aspect of upper medial femoral condyle and inserts in medial tibial surface and into medial meniscus

Question 11

Head of fibula

Answer 11

-Biceps femoris inserts primarily on fibula head
-Serves as the attachment for knee joint structures/doesn’t articulate with femur or patella/not part of knee joint/not weight bearing
-Biceps femoris inserts primarily on fibula head
-LCL (fibula) originates on lateral femoral condyle and inserts on fibular head

Question 12

Q-angle of knee

Answer 12

-Central line of pull for entire quadriceps runs from ASIS to the center of patella
-Line of pull of patella tendon runs from center of patella to center of tibial tuberosity
-Angle formed by the intersection of these two lines at the patella is the Q angle
-Normally angle will be 10 degrees for males and 20 degrees in females
-Generally, females have higher angles due to wider pelvis

Question 13

Valgus and Varus stress

Answer 13

-Normally on frontal plane
-Valgus (knocked knees, cave in)
-Varus (bow legged, cave out)

Question 14

Q-angle effect on ACL

Answer 14

-Higher Q angles generally predispose people in varying degrees to a variety of potential knee problems including patellofemoral syndrome (lateral patellar rubbing), and ligamentous injuries (ACL)

Question 15

Medial/Lateral meniscus

Answer 15

-Cushion between bones for shock absorption
-Deepen tibial fossa to enhance stability
-Increase surface area to decrease stress
-Medial torn more often as MCL inserts into it/bigger because of stress
-Menisci may be torn in serval different areas from a variety of mechanisms (tears often occur due to significant forces during rotation (quick directional changes in running)

Question 16

ACL

Answer 16

-One of the most common serious injuries to knee
-Mechanisms often involves noncontact rotary forces associated with planting and cutting, hyperextension, valgus collapse
-Get quad atrophy as a result and needs to be strengthened??
-Maintains anterior stability and rotary stability

Question 17

PCL

Answer 17

-Not often injured
-Mechanism of direct contact with an opponent or playing surface
-Maintains posterior stability and rotary stability

Question 18

LCL

Answer 18

-Infrequently injured because requires a varus stress which is difficult because it is protected by other leg

Question 19

MCL

Answer 19

-Maintains medial stability by resisting valgus forces or preventing knee from being abducted
-Injuries occur commonly, particularly in contact or collision sports
-Mechanisms of teammate or opponent may fall against lateral aspect of knee or leg causing medial opening of knee joint and stress to medial ligamentous structures

Question 20

Strengthening quads with ACL injury is not the best course of action

Answer 20

-Quads have been historically implicated in knee/injury disease as atrophy occurs once injured
-Therefore strengthening the quads given as treatment is wrong
-The quads crush the knee and strain the ACL when contracted, and can’t selectively activate quads
-If the knee hurts, look at the hip and ankle first

Question 21

Anterior drawer/Posterior Drawer

Answer 21

-ACL test, but biased by hamstring
-PCL test by pulling on tibia

Question 22

Lachman’s test

Answer 22

ACL special test with less hamstring influence (with flexion of knee)

Question 23

Varus test

Answer 23

LCL test, grab ankle and place stress inside of knee to push knee out laterally

Question 24

Valgus test

Answer 24

MCL test, grab ankle and place stress on outside knee

Question 25

Bursa Sacs

Answer 25

-More than 10 bursae in and around the knee
-Some are connected to synovial cavity
-They prevent friction
-Bursitis

Question 26

Knee Extensors

Answer 26

-Located on anterior compartment of thigh
-Rectus femoris: Origin- anterior inferior iliac spine
Insertion- groove (posterior) above acetabulum
-Vastus medialis: Origin- whole length of linea aspera and medial condyloid ridge
-Insertion: Medial half of the upper border of the patella and patellar tendon to the tibial tuberosity
-Vastus lateralis: Origin-intertrochanteric line anertior and inferior border of the greater trochanter, upper half of the linea aspera and the entire lateral intermuscular septum
Insertion- lateral border of patella, patellar tendon to tibial tuberosity
-Vastus intermedius: Origin- upper 2/3 of anterior surface of femur
-Insertion- upper border of patella and the patellar tendon to tibial tuberosity

Question 27

Knee Flexors

Answer 27

-Posterior knee flexion
-Semitendinosus: Origin- ischial tuberosity
Insertion- upper anterior medial surface of tibia
-Semimembranosus: Origin- Ischial tuberosity
Insertion- Posteromedial surface of the medial tibial condyle
-Biceps femoris long head: Origin- Ischial tuberosity
Insertion- lateral condyle of tibia, head of fibula
-Biceps femoris short head: Origin- Lower half of linea aspera lateral condyloid ridge
Insertion: lateral condyle of tibia, head of fibula
-Gastrocnemius

Question 28

Other muscles inserting at the knee

Answer 28

-Popliteus
-Gracilis
-Sartorius
-TFL