Hip and Knee Joint

Question 1

Acetabulum formed by fusion of

Answer 1

Ilium, ischium and pubis

Question 2

Which artery supplies the hip joint

Answer 2

Obturator artery to head of femur
Medial circumflex femoral- retinacular arteries
Ascending/transverse branches of lateral femoral circumflex artery (lateral pierces IF ligament)

Question 3

Iliofemoral ligament

Answer 3

AIIS to IT line of femur
Y shaped
Strongest ligament in the body
Prevents hyperextension

Question 4

Pubofemoral ligament

Answer 4

Obturator crest to IT line
Blends laterally with iliofemoral ligament
Prevents hyperextension
Primarily limits abduction

Question 5

Ischiofemoral ligament

Answer 5

Ischial part of acetabular rim to femoral neck
Weakest ligament in hip
Hip externally rotates better than it internally rotates

Question 6

Ligament of head of femur

Answer 6

Intra-articular ligament
Acetabular notch/transverse acetabular ligament to fovea of femur
Synovial fold conducting artery to head of femur (this artery contributes at birth but diminishes by age 4)
Minimal contribution to stability

Question 7

Labrum

Answer 7

Fibrocartilaginous rim to margin of acetabulum

Increases acetabular articular area by 10%

Question 8

Transverse acetabular ligament

Answer 8

Continuation of labrum inferiorly

Coursing over acetabular notch

Question 9

Hiltons law

Answer 9

Nerves supplying muscles directly overlying and acting at joint also innervate that joint

Question 10

Anterior hip muscles (flexors) innervated by

Answer 10

Femoral nerve

Question 11

Inf/posterior muscles (external rotators) innervated by

Answer 11

Nerve to obturator externus and Nerve to quadratus femoris

Question 12

Superior muscles (abductors) innervated by

Answer 12

Superior gluteal nerve

Question 13

Strongest hip flexor

Answer 13

Iliopsoas

Question 14

Flexors/adductors of hip

Answer 14

Pectineus
Gracilis
Adductor magnus/longus/brevis

Question 15

Primary extensor from sitting to standing and then what muscle takes over

Answer 15

Gluteus maximus from sitting to standing
Then hamstrings (semitendinosus, semimembranosus, long head biceps femoris)

Question 16

Internal rotators of hip

Answer 16

Gluteus minimus/medius

Question 17

What happens with weak/non-functional gluteus medius/minimus

Answer 17

Trendelenberg gait
Opposite side of pelvis sags, lean to weak side to raise opposite pelvis
Swing leg

Question 18

Log roll test

Answer 18

Patient supine, internally/externally rotate leg
Positive with pain
Helps with indeterminate radiographs in possible hip fracture

Question 19

Hip dislocation

Answer 19

Orthopedic emergency, especially in young children
Severe morbidity in elderly
Complex dislocation involves acetabular/femur fracture
Flexed hip is more susceptible to dislocation because of capsular laxity

Question 20

Resting position after posterior hip dislocation

Answer 20

Slight flexion, adduction, internal rotation

Question 21

Hip fracture position

Answer 21

Shortened and externally rotated

Question 22

Bipartite patella

Answer 22

Failure of superolateral portion to fuse
Commonly mistaken for fracture
8% of population

Question 23

Lateral collateral ligament

Answer 23

Extracapsular
Lateral femoral epicondyle to fibular head
Popliteus tendon passes deep

Question 24

Anterolateral ligament

Answer 24

Rotational stability to knee

From lateral epicondyle of femur to tibia posterior to Gerdys tubercle

Question 25

Segond fracture

Answer 25

Avulsion of anterolateral ligament from tibial insertion | Pathognomonic for ACL rupture

Question 26

Medial collateral ligament

Answer 26

Capsular Medial epicondyle of femur to proximal tibia Weaker than LCL Meniscal attachment

Question 27

Meniscus

Answer 27

``` Optimize force transmission across knee Shock absorption Secondary stabilizer of knee Lateral meniscus has 2x more excursion than medial Primary stabilizer in ACL deficiency Medial is C-shaped Lateral is circular shaped Inter-meniscal ligament connects the two Meniscofemoral ligaments ```

Question 28

Anterior cruciate ligament

Answer 28

85% stability to anterior tibial translation Lateral intercondylar ridge to anterior tibia between intercondylar eminences Anteromedial bundle is tightest during flexion Posterolateral bundle is tightest during extension

Question 29

Posterior cruciate ligament

Answer 29

95% stability to posterior tibial translation Posterior tibial sulcus below articulating surface to anterolateral medial femoral condyle Anterolateral bundle tight in flexion Posteromedial bundle tight in extension

Question 30

Blood supply to knee

Answer 30

Genicular anastomosis - Femoral - Popliteal - Anterior/posterior recurrent of anterior tibial - Circumflex fibular

Question 31

Middle genicular supplies

Answer 31

Cruciates, synovium, and posterior horns of meniscus

Question 32

Medial inferior genicular supplies

Answer 32

Peripheral 25% to medial meniscus

Question 33

Lateral inferior genicular supplies

Answer 33

Peripheral 25% to lateral meniscus

Question 34

Knee innervation

Answer 34

Femoral- anterior Common fibular- lateral Tibial- posterior Obturator/saphenous- medial

Question 35

"Screw home"

Answer 35

Tibia externally rotates 5 degrees in last 15 degrees of extension Allows cruciates to tighten and decrease quadriceps work while standing Popliteus "unlocks" tibia via internally rotating to initiate flexion

Question 36

Genu recurvatum

Answer 36

Hyperextended knee

Question 37

MCL/LCL exam

Answer 37

Test at both 0 and 30 degrees (to isolate superficial MCL/LCL) Instability at 0 degrees is capsular disruption or cruciate involvement

Question 38

MCL injuries

Answer 38

Most commonly associated with ACL Most common multi-ligament injury Intimately associated with medial meniscus as well

Question 39

Thessaly test

Answer 39

Patient stands on affected leg at 20 degrees knee flexion Rotates on leg + is pain or click Meniscus injury

Question 40

Meniscal tear

Answer 40

Most common indication for knee surgery Usually caused by twisting of knee and you hear "pop" Medial more common than lateral

Question 41

PCL injury causes

Answer 41

Fall onto flexed knee with foot in plantarflexion Hyperextension injury Dashboard injury/direct blow to anterior tibia