infant hip joint Flashcards
bones, connective tissues and muscles originate from
mesoderm
hip bone composed of 3
ilium, ischium and pubis
acetabulum has the
triradiate cartilage
located at lateral aspects
articulation point for femoral head
At the rim of the acetabulum sits a lip of cartilage called
acetabular labrum
femoral head is ______ at birth
cartilaginous
femoral head begins to ossify at
2 to 8 months from the centre outwards
_____ contribute to the laxity of the fetal ligaments
maternal hormones
laxity of fetal ligaments may cause
create vulnerable atmosphere for the hip to become subluxable or dislocatable
developmental dysplasia of the hip occurs most freq when
at birth
sometimes happen during infancy
the cause of DDH may be mechanical as a result of
positional influences in utero and after birth
The cause of DDH may be physiological as a result of
resulting from a response to maternal hormones in utero
risk factors of 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
3 things done during clinical assessment of both hips
barlow maneuver
Ortolani maneuver
Visual assessment
do instabilities of hip need treatment
some but most become normal without treatment
significant dysplasia leads to
to disability / hip replacement surgeries in adulthood
explain 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
describe 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**
what is 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
allis or galeazzi sign are only useful when
for unilateral DDH
transducer freq for birth to 3 mo and older infants
12-7.5 MHz for birth to 3 mo
5.0 MHz for older infants
Sonography of the hip is best performed up to
6 months
what planes are used in hip scan
Coronal plane without stress
Transverse plane with and without stress maneuvers
what is seen coronal scan plane
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
how to obtain the alpha and beta angles in the coronal plane
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)
The α-angle is formed between the 1st and 2nd line
The β-angle is formed between the 1st and 3rd line
what is a normal alpha angle
more than or equal to 60 degrees
normal beta angle
less than 55
big beta bad
what are these angles compared to for diagnosis
graft classification
4 classifications on GRAFF
type 1: normal alpha more than 60
type 2: normal up to 3 mo, angle 44-60
type 3: dislocated hip, angle less than 43
type 4: gross dislocation, angle not measurable
what is femoral head coverage and what plane is it obtained in
Shows how well femoral head is contained in the acetabulum and whether or not the femoral head is in contact with the acetabular floor
coronal plane
normal femoral head coverage
60%
Hip instability (subluxation) will present with a FHC of approx
36-37%
whats more reproducible FCH or alpha angle
alpha angle
what is the classic normal appearance sign of the hip
ball on spoon
ball: femoral head
iliac line: handle
scoop: acetabulum
