infant hip

Question 1

Bones, connective tissues and muscles originate from?

Answer 1

mesoderm

Question 2

Hip bone composed of ?

Answer 2

• ilium
• ischium
• pubis

Question 3

acetabulum?

Answer 3

• located at lateral aspects
• had triradiate cartilage
• creates articulation point for femoral head

Question 4

At the rim of the acetabulum sits a lip of cartilage called?

Answer 4

acetabular labrum

Question 5

femoral head at birth?

Answer 5

• catilaginous

- visible on u/s

Question 6

when does hemoral head begin to ostify?

Answer 6

• 2-8 months of age

Question 7

Maternal hormones contribute to?

Answer 7

the laxity of the fetal ligaments, which may in turn create vulnerable atmosphere for the hip to become subluxable or dislocatable

Question 8

Developmental Dysplasia of the Hip occurs most frequently?

Answer 8

at birth

- may occur during infancy

Question 9

cause of Developmental Dysplasia of the Hip?

Answer 9

• mechanical as a result of positional influences in utero and after birth
• physiological resulting from a response to maternal hormones in utero

Question 10

Risk factors for DDH?

Answer 10

Born in breech position
Positive family Hx
Living in cultures that swaddle infants in extension and hip adduction
Oligohydramnios
Metatarsus adductus (img) and torticollis associated with DDH
Firstborn, female, white, high birth weight, native North American

Question 11

DDH clinical assesment?

Answer 11

Clinical assessment of both hips done during routine neonatal screening

• Barlow maneuver
• Ortolani maneuver
• Visual assessment

Question 12

result of DDH?

Answer 12

Most instabilities in hip joint will become normal without treatment
Significant dysplasias may lead to disability / hip replacement surgeries in adulthood

Question 13

DDH barlow test?

Answer 13

Provocative test, determines if hip can be dislocated
The examiner attempts to push the femoral head posteriorly out of socket
Gentle adduction and push on the knee

Question 14

DDH- ortolani test?

Answer 14

• The examiner attempts to reduce/relocate a recently dislocated hip
• Gentle out and up movement

If positive both tests produce a sensation of clunk

Question 15

visual assessment of DDH

Answer 15

Positive Allis or Galeazzi sign:
- Relative shorteness of the femur with the hip and knees flexed

• Discrepancy in leg lengths
• Asymmetry of gluteal and thigh folds
• visual signs are useful only for unilateral DDH

Question 16

Sonographic evaluation of hip?

Answer 16

Linear transducer
12- 7.5MHz for birth to 3 mo
5.0MHz for older infants

Sonography of the hip is best performed up to 6 mo of age
6months to a year, radiography is more reliable due to increasing bony ossification

Question 17

Sonographic evaluation of hip imaging planes?

Answer 17

Coronal plane without stress

Transverse plane with and without stress maneuvers

Question 18

Sonographic evaluation of hip positioning?

Answer 18

• supine or decube

Question 19

coronal plane of the hip may be obtained how?

Answer 19

• May be obtained with the hip in a neutral (15-20o of flexion) or flexed position and the infant may be either in a decub or a supine
• probe placed at lateral aspect of hip providing a longitudinal image of hip from the coronal plane

Question 20

what is seen in coronal scan place of hip?

Answer 20

The femoral head can be identified sitting in the acetabulum

Iliac line will be identified superiorly, and the bony shaft of the femoral neck will be identified inferiorly

Iliac line should appear as a straight line - important in making an accurate assessment

Question 21

Answer 21

The first line is aligned with the ilium and extends through the head of the femur

The second line is drawn along the bony acetabulum

The third line extends from end of ilium line along the cartilaginous acetabulum (labrum)

Question 22

angle a and b?

Answer 22

• The α-angle has been used as the primary measure for hip dysplasia
  If the angle is > 60o - normal
• β-angle isn’t widely used
• Less than 55o is normal
• ‘big beta bad’

use GRAFF classification

Question 23

GRAFF classification type 1 hip?

Answer 23

• normal

- alpha andle >60 degrees

Question 24

GRAFF classification type 2 hip?

Answer 24

• normal if newborn
• up to 3 months of age indicates slowed development
• alpha angle 44-60 degrees

Question 25

GRAFF classification type 3 hip?

Answer 25

- dislocated hip | - alpha angle <43 degrees

Question 26

GRAFF classification type 4 hip?

Answer 26

- gross dislocation | - alpha andle not measurable

Question 27

Answer 27

type 2 GRAFF

Question 28

Hip instability will present with a Femoral Head Concerage (FHC) of approx?

Answer 28

36-37%- SUBLUXATION

Question 29

normal FHC?

Answer 29

60 %

Question 30

Femoral Head Coverage?

Answer 30

- Alpha measurement is more reproducible - Applications have been developed to assess the percentage of FHC A qualitative assessment is considered to be sufficient - Shallow - Intermediate - Deep

Question 31

what is ball on spoon?

Answer 31

normal hip apperance ball: femoral head iliac line: handle scoop of spoon: acetabulum

Question 32

When the hip is subluxable what is seen?

Answer 32

superior or lateral displacement of the femoral head will be identified

Question 33

With hip dislocation what is seen?

Answer 33

femoral head will appear completely out of acetabulum

Question 34

In the flexed position the infant’s hip can be?

Answer 34

- stressed when scanning by exerting downward pressure and simultaneously adducting and abducting the hip slightly - Tests for instability - Demonstrates if subluxed or dislocated hip is reducible

Question 35

Answer 35

hip dislocation

Question 36

Answer 36

subluxation

Question 37

Hip Effusion clinical presentation?

Answer 37

Localized pain Limping or refusal to bear weight Limited movement Fever

Question 38

hip effusion sono features?

Answer 38

Evaluate for presence of effusion Aspirate of the effusion is analyzed to differentiate between - transient synovitis - septic arthritis

Question 39

Hip Effusion: transient Synovitis

Answer 39

- Relatively common cause of a painful hip in children - Self-limiting disease - can be treated with anti-inflammatory medication and rest - Most have no fever at the time of onset of hip pain - No long-term effects

Question 40

Hip Effusion: Septic Arthritis?

Answer 40

Serious bacterial infection More severe clinical symptoms than transient synovitis Clinical differentiation may be difficult Usually present with a fever

Question 41

Hip Effusion: Septic Arthritis s/s?

Answer 41

increased ESR increased WBC count ``` Medical emergency requiring rapid treatment to avoid long-term effects: Avascular necrosis of the femoral head Osteomyelitis Systemic sepsis Osteoarthritis of the hip joint ```

Question 42

Hip Effusion: Septic Arthritis treatment?

Answer 42

- Ultrasound guided arthrocentesis is utilized to aspirate the fluid for lab evaluation - if septic arthritis is confirmed, hospitalization occurs with intravenous A/B - Arthrocentesis can also relieve the pain

Question 43

arthrocentesis?

Answer 43

General or local anesthesia | Imaging performed from the anterior aspect of the leg with probe parallel to femoral neck

Question 44

Normal hip capsule is ?

Answer 44

2-5mm in thickness and symmetric on both sides

Question 45

abnormal capsular thickness of hip?

Answer 45

> 5mm or a 2mm difference between the two hips with unilateral process

Question 46

DDH treatment depends on?

Answer 46

``` Depending on the severity of DDH, including: mild instability subluxation dislocatable hip or frank dislocation ```

Question 47

DDH treatment?

Answer 47

``` U/S follow-up placing the infant in a Pavlik harness bracing the lower extremities casting surgical reduction ```

Question 48

Radiography?

Answer 48

- May fail to identify marginal abnormalities since the newborn hip is primarily composed of cartilage - Less costly - More effective at 6 months and older when the ossification starts

Question 49

CT?

Answer 49

primarily indicated for follow-up | especially useful when imaging casted patients

Question 50

MRI?

Answer 50

excellent for identifying MSK abnormalities no ionizing radiation expensive and long examination time requires sedation