infant hip Flashcards
Bones, connective tissues and muscles originate from?
mesoderm
Hip bone composed of ?
- ilium
- ischium
- pubis
acetabulum?
- located at lateral aspects
- had triradiate cartilage
- creates articulation point for femoral head
At the rim of the acetabulum sits a lip of cartilage called?
acetabular labrum
femoral head at birth?
- catilaginous
- visible on u/s
when does hemoral head begin to ostify?
- 2-8 months of age
Maternal hormones contribute to?
the laxity of the fetal ligaments, which may in turn create vulnerable atmosphere for the hip to become subluxable or dislocatable
Developmental Dysplasia of the Hip occurs most frequently?
at birth
- may occur during infancy
cause of Developmental Dysplasia of the Hip?
- mechanical as a result of positional influences in utero and after birth
- physiological resulting from a response to maternal hormones in utero
Risk factors for DDH?
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
DDH clinical assesment?
Clinical assessment of both hips done during routine neonatal screening
- Barlow maneuver
- Ortolani maneuver
- Visual assessment
result of DDH?
Most instabilities in hip joint will become normal without treatment
Significant dysplasias may lead to disability / hip replacement surgeries in adulthood
DDH barlow test?
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
DDH- ortolani test?
- The examiner attempts to reduce/relocate a recently dislocated hip
- Gentle out and up movement
If positive both tests produce a sensation of clunk
visual assessment of DDH
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
Sonographic evaluation of hip?
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
Sonographic evaluation of hip imaging planes?
Coronal plane without stress
Transverse plane with and without stress maneuvers
Sonographic evaluation of hip positioning?
- supine or decube
coronal plane of the hip may be obtained how?
- 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
what is seen in coronal scan place of hip?
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
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)
angle a and b?
- 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
GRAFF classification type 1 hip?
- normal
- alpha andle >60 degrees
GRAFF classification type 2 hip?
- normal if newborn
- up to 3 months of age indicates slowed development
- alpha angle 44-60 degrees
GRAFF classification type 3 hip?
- dislocated hip
- alpha angle <43 degrees
GRAFF classification type 4 hip?
- gross dislocation
- alpha andle not measurable
type 2 GRAFF
Hip instability will present with a Femoral Head Concerage (FHC) of approx?
36-37%- SUBLUXATION
normal FHC?
60 %
Femoral Head Coverage?
- 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
what is ball on spoon?
normal hip apperance
ball: femoral head
iliac line: handle
scoop of spoon: acetabulum
When the hip is subluxable what is seen?
superior or lateral displacement of the femoral head will be identified
With hip dislocation what is seen?
femoral head will appear completely out of acetabulum
In the flexed position the infant’s hip can be?
- 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
hip dislocation
subluxation
Hip Effusion clinical presentation?
Localized pain
Limping or refusal to bear weight
Limited movement
Fever
hip effusion sono features?
Evaluate for presence of effusion
Aspirate of the effusion is analyzed to differentiate between
- transient synovitis
- septic arthritis
Hip Effusion: transient Synovitis
- 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
Hip Effusion: Septic Arthritis?
Serious bacterial infection
More severe clinical symptoms than transient synovitis
Clinical differentiation may be difficult
Usually present with a fever
Hip Effusion: Septic Arthritis s/s?
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
Hip Effusion: Septic Arthritis treatment?
- 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
arthrocentesis?
General or local anesthesia
Imaging performed from the anterior aspect of the leg with probe parallel to femoral neck
Normal hip capsule is ?
2-5mm in thickness and symmetric on both sides
abnormal capsular thickness of hip?
> 5mm or a 2mm difference between the two hips with unilateral process
DDH treatment depends on?
Depending on the severity of DDH, including: mild instability subluxation dislocatable hip or frank dislocation
DDH treatment?
U/S follow-up placing the infant in a Pavlik harness bracing the lower extremities casting surgical reduction
Radiography?
- 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
CT?
primarily indicated for follow-up
especially useful when imaging casted patients
MRI?
excellent for identifying MSK abnormalities
no ionizing radiation
expensive and long examination time requires sedation
