1. Infant Hip Ultrasound Developmental Dysplasia of the Hip 6/22/17
Jenelle Beadle

2. Hip Anatomy

3. Developmental Dysplasia of the Hip (DDH)
Abnormal development of the acetabulum
Acetabulum: “ball” of the ball-and-socket
Normal
DDH

4. Formation and development of the hip
Joint formation is completed by 11wks gestation
As growth occurs, the acetabulum requires contact and pressure from the femoral head to maintain and develop its shape into a deep socket

5. Factors affecting hip development
An abducted position maximizes the force of the femoral head on the acetabulum, and is ideal for acetabular development
There is an ideal position for this requirement of contact and pressure
Abduction
Directs force into joint
Optimal for development

6. Factors affecting hip development
An abducted position maximizes the force of the femoral head on the acetabulum, and is ideal for acetabular development
Sustained adduction positioning may result in a shallow acetabulum
Opposite is true for adduction
Abduction
Directs force into joint
Optimal for development
Adduction
Directs force away from joint
Bad for development

7. Factors affecting hip development
An abducted position maximizes the force of the femoral head on the acetabulum, and is ideal for acetabular development
Sustained adduction positioning may result in a shallow acetabulum
If the femoral head is dislocated, pressure on the acetabulum is completely removed and it begins to grow shallow
Dysplasia progresses if the femoral head does not reduce or “relocate”
Typically a prenatal cause of dysplasia
Even worse than an adducted position is dislocation

8. Factors affecting hip development
An abducted position maximizes the force of the femoral head on the acetabulum, and is ideal for acetabular development
Sustained adduction positioning may result in a shallow acetabulum
If the femoral head is dislocated, pressure on the acetabulum is completely removed and it begins to grow shallow
Dysplasia progresses if the femoral head does not reduce or “relocate”
Typically a prenatal cause of dysplasia
acetabulum requires contact and pressure from the femoral head to maintain and develop its shape
Lack of contact and pressure causes dysplasia:
dislocation
adducted position

9. Hip Dysplasia Causes 4 periods of development with increased risk:
12wks – fetal legs rotate medially
risk for dislocation

10. Hip Dysplasia Causes 4 periods of development with increased risk:
12wks – fetal legs rotate medially
risk for dislocation
18wks – hip muscles develop
neuromuscular problems may lead to dislocation

11. Hip Dysplasia Causes 4 periods of development with increased risk:
Frank Breech
20% Incidence DDH
4 periods of development with increased risk:
12wks – fetal legs rotate medially
risk for dislocation
18wks – hip muscles develop
neuromuscular problems may lead to dislocation
36-40wks – mechanical factors
oligohydramnios and breech presentation both force the fetus into an adducted position
Abducted
Adducted

12. Hip Dysplasia Causes 4 periods of development with increased risk:
12wks – fetal legs rotate medially
risk for dislocation
18wks – hip muscles develop
neuromuscular problems may lead to dislocation
36-40wks – mechanical factors
oligohydramnios and breech presentation both force the fetus into an adducted position
Postnatal - mechanical factors
positioning that forces the infant into an adducted position (worse if legs are extended)

14. Developmental Dysplasia of the Hip (DDH)
Abnormally formed acetabulum (shallow socket)
DDH
Normal Acetabulum
However it happens, these kids end up with DDH.

15. Developmental Dysplasia of the Hip (DDH)
Abnormally formed acetabulum (shallow socket)
results in instability of the joint (ball doesn’t stay in it)
A shallow socket results in instability

16. Degree of hip instability
Subluxation
Femoral head moves within the acetabulum
Dislocation
Femoral head has no contact with the acetabulum
Assessed by performing dynamic maneuvers with live ultrasound observation
Barlow test
We take measurements to assess how deep/shallow the acetabulum is,
But we have to dynamically exam the hip to assess it’s stability

17. Barlow Test Designed to stress and dislocate an unstable hip
Adduct and push posteriorly
monitor for subluxation or dislocation
Performed blindly by pediatricians as a routine screening
feel for a “clunk” that indicates dislocation
Pressure required is mild

18. Ortolani Test Designed to identify dislocated hips by manual reduction
Abduct while pulling slightly on the leg
Performed by pediatricians in conjunction with the Barlow test
feel for a “clunk” that indicates reduction
Not useful in sonographic evaluation

19. Treatment
Remember: A lack contact and pressure causes dysplasia of the acetabulum:
dislocation
adducted position
Designed to encourage natural acetabular growth and development
Improve contact and pressure of the femoral head on the acetabulum by:
reduction
abducted position
Treat by improving …

20. Treatment Double diapering Pavlik harness Spica cast Surgery
no longer recommended
Pavlik harness
1-6 mos old
Duration: 6+ wks
Spica cast
6-24 mos old
Duration:
Surgery
open reduction
repair femoral neck angle
osteotomy
>2yrs
spica cast used for recovery period

21. Infant Hip Ultrasound Indications
Evaluation for developmental dysplasia of the hip (DDH)
Assess progress during treatment
Establish normalcy and stability post treatment

22. When should US evaluation for DDH be performed?
Direct signs of DDH
positive findings on Ortolani or Barlow (clunk)
Secondary signs of DDH that persist >2 weeks
Leg length discrepancy
Asymmetrical thigh folds
Equivocal dynamic testing
Significantly increased risk for DDH
breech presentation
Mild risk factors alone are not considered significant enough to warrant an ultrasound screening
female
family history
Whenever it’s ordered…

23. Things to consider: Scheduling Scanning
Evaluation of infants <4 wks is not recommended
normal ligament elasticity can create false positive results
Evaluation of infants >6 mos (adjusted age) becomes limited
ossification of femoral head reduces accuracy
Scanning
Sonographer may perform entire exam
Radiologist required to participate in dynamic evaluation
Warm blankets, warm gel, pacifiers
warm, sterile gel is required for neonates
Older than 4wks, but younger than 6mos

24. Acetabulum Triradiate Cartilage Formed by the three pelvic bones
Ilium (40%) forms the upper “roof” – where US measurement is performed
Ischium (40%) forms the posterior and inferior portion
Pubis (20%) forms the anterior boundary
Triradiate
Cartilage
Left Lateral View
Formed where the three pelvic bones meet
Allows for growth of the acetabulum and pelvis
Closes off by 15yrs
Ilium = roof (where measurement is made)
Ischium = posterior
Pubus = anterior

25. Right Lateral View

26. Infant hip ossification
White = Cartilage
Shaded = Ossified Bone
Puberty
Birth
US of the hip is performed when the hip is largely cartilaginous

27. 9 Months
2 Months
Child
Adult

28. Coronal Plane Flexed or neutral
Degree of flexion will change visualized femoral anatomy
Head, GT, metaphysis P

29. Coronal Plane Ilium Triradiate cartilage Labrum
straight & parallel to the transducer
sharp ilium-roof angle
Triradiate cartilage
Labrum P

31. Coronal Plane Right Left
Right and left appear identical (label carefully)
Right
Left

32. Measurement: Alpha Angle
Angle that the acetabular roof makes with the ilium
reflects the depth of the acetabulum
Normal:
>60 degrees Rt

33. Measurement: Femoral Head Coverage
Percentage of the femoral head within the acetabulum
reflects how the femoral head is seated within the joint
Normal:
>50% Rt

35. Transverse Plane Flexed or neutral Barlow
Degree of flexion will change visualized femoral anatomy
Head, GT, metaphysis
Barlow

36. Transverse Plane

38. Transverse Plane
Right and left are mirrored
Right
Left

39. Transverse Plane Right Left Posterior Posterior Ischium Ischium Pubis
Tri Cart
Pubis
Tri Cart

40. Barlow Test Designed to stress and dislocate an unstable hip
Adduct and push posteriorly
monitor for subluxation or dislocation
2-3 mm of movement is normal

41. Transverse Plane - Barlow
Barlow forces the hip posterior
Right
Left
Posterior
Posterior