DDH

Question 1

What are risk factors for DDH?

Answer 1

Mat HTN, FGR, oligo, PROM, prolonged gestation, increased birth weight, Potter’s syndrome

Question 2

How much more likely are breech babies to develop DDH?

Answer 2

four times

Question 3

How much more likely are females to develop DDH than males?

Answer 3

2.5 times

Question 4

How often is the left hip affected by DDH? How often is it unilateral?

Answer 4

Both 64% of the time

Question 5

How does birth order affect DDH?

Answer 5

more common in first born

Question 6

What ethnicities is DDH more common in?

Answer 6

Caucasians/North American tribes due to swaddling

Question 7

What causes DDH?

Answer 7

Unknown, possibly increased laxity within joint capsule

Question 8

What is the hormonal theory of DDH development?

Answer 8

Hormones affect connective tissue, maternal estrogen increase can increase muscle laxity

Question 9

What is the mechanical theory of DDH development?

Answer 9

Restricted mobility: Swaddling, oligo, breech, primigravid uterus

Question 10

What is the highest risk fetal position for DDH?

Answer 10

Frank breech

Question 11

What is the genetic theory of DDH development?

Answer 11

Higher risk with family history

Question 12

What clinical sign warrants hip US?

Answer 12

clicking sound

Question 13

What is hip dysplasia?

Answer 13

Acetabulum is too shallow in socket

Question 14

What age can the hips be evaluated until?

Answer 14

Until femoral head ossifies, up to 6 months, over 6mo xray

Question 15

What forms the pelvic girdle?

Answer 15

Ilium, ischium, pubis

Question 16

What is triradiate cartilage?

Answer 16

Connects 3 pelvic bones, made of growth plates that ossify at adulthood

Question 17

What does the triradiate cartilage become after ossification?

Answer 17

Part of acetabulum

Question 18

What forms the hip joint?

Answer 18

Femur and acetabulum

Question 19

What is the labrum?

Answer 19

Fibrocartilage surrounding acetabulum, forms extension of acetabular “roof”

Question 20

How much of the femoral head should be covered by labrum?

Answer 20

2/3

Question 21

Where does blood supply travel to the pelvis?

Answer 21

Acetabular notch, nerves & vessels travel through

Question 22

What is the transverse ligament?

Answer 22

Band of fibrous tissue surrounding nerves & vessels traveling through acetabular notch

Question 23

Where does the gluteus maximus lie?

Answer 23

Superior to other muscles and posterior to hip

Question 24

Where is the gluteus minimus located?

Answer 24

Immediate covering to upper hip joint

Question 25

Where is the gluteus medius located?

Answer 25

Starts superior to minimus, both travel to greater trochanter, covers minimus

Question 26

What is the Barlow maneuver?

Answer 26

Determines whether hip can be dislocated - Pt supine, hip flexed 90 deg, adducted - Press down & out - Feel femoral head move out of acetabulum

Question 27

What is Ortolani maneuver?

Answer 27

Determines whether dislocated femur head can be reduced back into place - Supine pt, hip flexed 90 deg, abducted

Question 28

What does a click during Ortolani maneuver indicate?

Answer 28

Does not indicate DDH

Question 29

What does a clunk during Ortolani maneuver suggest?

Answer 29

DDH

Question 30

What is the probe and patient position for transverse images?

Answer 30

Posterolateral over hip joint, hip flexed

Question 31

How should the normal transverse hip appear?

Answer 31

Femoral head centered between metaphysis and ischium, triradiate cartilage b/w M & I

Question 32

How does an abnormal hip appear in transverse?

Answer 32

Stress displaces femoral head, gap b/w fem head & ischium

Question 33

What does the coronal view determine?

Answer 33

Degree of labrum covering fem head and position of fem head within acetabulum

Question 34

What is the landmark for coronal flexion view?

Answer 34

gluteus medius

Question 35

What needs to be visualized in the coronal view?

Answer 35

Ilium: straight and parallel Labrum: included Femoral head: sitting in acetabular roof and covered at least half by ilium

Question 36

What are the appearances of the acetabular roof in coronal?

Answer 36

Sloped, irregular, rounded

Question 37

How should the femoral head sit in relation to the acetabular roof?

Answer 37

FH shouldn't be above AR, AR should cover FH by at least half

Question 38

Where is line 1 drawn?

Answer 38

Baseline, drawn along ilium extending through femur

Question 39

Where is line 2 drawn?

Answer 39

Drawn from bony edge of acetabulum at triradiate cartilage to lowest part of ilium

Question 40

Where is line 3 drawn?

Answer 40

From ilium along labrum

Question 41

What does alpha angle measure?

Answer 41

Acetabular depth, normal >60 degrees, between lines 1 & 3

Question 42

What is the normal beta angle?

Answer 42

Between 1 & 2, normal <55 degrees

Question 43

What are the Graf measurements for Type 1 hips? Modified & Graf classification

Answer 43

Modified: alpha >60 deg Graf: alpha >60 deg, beta <55 deg

Question 44

What are the modified and Graf classification measurements of a Type II hip?

Answer 44

Modified: alpha >50, <60 Graf: alpha >43, <60

Question 45

What is a Type IIa hip?

Answer 45

normal from 0-3 mo, may be physiological laxity, f/u

Question 46

What is type IIb hip?

Answer 46

up to 3 mo, indicates delayed development, f/u

Question 47

What are the modified and Graf measurements of Type III hips?

Answer 47

Modified: alpha >43, <50, mild dysplasia Graf: alpha <43, beta >77

Question 48

What are the modified and Graf measurements of type IV hips

Answer 48

Modified: alpha <43, significant dysplasia Graf: alpha <43, beta immeasurable

Question 49

How does the Pavlik harness treat DDH?

Answer 49

Subluxed hip in neutral position will reinsert itself with constant flexion and abduction, harness keeps femur in place