This document describes the anatomy of the hip joint, including the ball-and-socket configuration of the femoral head articulating with the acetabulum. It further discusses hip dysplasia, noting that it results from an abnormal developmental relationship between the femur and acetabulum. Risk factors for hip dysplasia include genetic and intrauterine environmental factors. Ultrasound is useful for evaluating the hip joint before ossification occurs, using static and dynamic techniques to assess morphology and stability.

4. • A multiaxial synovial joint of ball-and-socket type
• Femoral head articulates with the
cupshaped acetabulum
• Acetabular fossa forms the
central floor-rough and non
articular
• Femoral head is covered by
articular cartilage, except for a
rough pit for the ligamentum
teres

5. • Approximately hemispherical cavity central on the lateral
aspect of the innominate bone
• Faces antero-inferiorly
• Deficient inferiorly at the
acetabular notch
• Starts to ossify at 12 yrs
• Fuses at 18 -25 years
 Os acetabuli : unfused 2
ossification centres of
the acetabulum

6. • Acetabular depth is increased by the acetabular labrum which
deepens the cup
• Transverse acetabular ligament bridges the acetabular notch

7. • Iliofemoral ligament
• Pubofemoral ligament
• Ischiofemoral ligament
• Transverse acetabular ligament
• Ligamentum teres

8. • Aka ligament of Bigelow
• Very strong and shaped like an inverted y, lying anteriorly and
intimately blended with the capsule
• Apex is attached between the anterior inferior iliac spine &
acetabular rim and base to the intertrochanteric line

9. • Triangular, its base attaching to the iliopubic eminence,
superior pubic ramus, obturator crest and obturator
membrane.
• It blends distally with the capsule and deep surface of the
medial iliofemoral ligament..

10. • Thickens the back of the capsule and consists of three distinct
parts:- 1) Central 2) Medial 3) Lateral

11. • Triangular, flattened band
• APEX: attached anterosuperiorly in the fovea on femoral head
• BASE: attached on both sides of the acetabular notch
between which it blends with the transverse ligament
• Ensheathed by synovial membrane

13. • Hip dysplasia is a result of abnormal development of the hip
when the relationship between femur, and acetabulum is
disrupted
• Formerly known as congenital dislocation of the hip joint
–term changed since DDH is a developmental process and is
not always detectable at birth.

14. • Multifactorial – genetic + intrauterine environmental factors
• Usually unilateral (80% of the time), occurs more frequently
in the left hip – since the left hip of the fetus usually lies
posteriorly against the mother’s L-spine, limiting abduction

15. • Native-Americans
• Family history (more in first degree relatives)
• Females (4 to 8 times more common)
• Breech delivery (extreme flexion at hip  stretching of
capsule & ligaments  Dysplasia)
• Oligohydramnios
• First born
• Persistent hip asymmetry

16. After last menstrual period in fetal development:
• 12 weeks – lower limb rotates medially after hip joint arises
at 7-11 wks – dysplasias are teratologic
• 18 weeks – hip muscle development – dysplasias d/t
neuromuscular disorders
• B/w perinatal period and 1st few weeks of birth – femoral
head grows faster than acetabulum, minimal coverage of
head – dysplasias d/t mechanical factors - oligohydramnios,
breech position
• Postnatal period – labral growth more rapid (more coverage
of femoral head) – dysplasias tend to be due to functional
factors instead – increased estrogens causing ligamentous
laxity, swaddling

17. • Loss of tight fit between acetabulum and femoral head in
the hip may result in dysplasia or dislocation
• Findings – shallow acetabulum with femoral anteversion
femoral neck version : angle of the femoral neck relative to the pelvic
horizontal (interischial line), with a normal range of 5-25 degrees of
anteversion
femoral neck torsion : angle between the femoral neck and posterior
condylar axis of the distal femur, with a normal range of 10-20 degrees
of antetorsion

18. • Capsule elongates and femoral
head displaced upwards &
laterally

19. • Capsule elongates and femoral
head displaced upwards &
laterally
• Abductor tightens

20. • Capsule elongates and femoral
head displaced upwards &
laterally
• Abductor tightens
• Acetabular dysplasia

21. • Capsule elongates and femoral
head displaced upwards &
laterally
• Abductor tightens
• Acetabular dysplasia
• Hip joint fills w/ fibrofatty
debris known as pulvinar

22. • Pain
• Early osteoarthritis
• Limb length discrepancy
• Abnormal gait/limping

23. • Ortolani’s (reduction) and
Barlow’s (dislocation) maneuver

24. • Ortolani’s (reduction) and
Barlow’s (dislocation) maneuver
• Shortened leg (6-8 wks of age)

25. • Ortolani’s (reduction) and
Barlow’s (dislocation) maneuver
• Shortened leg (6-8 wks of age)
• Asymmetry of thigh folds (rare)

26. • Ortolani’s (reduction) and
Barlow’s (dislocation) maneuver
• Shortened leg (6-8 wks of age)
• Asymmetry of thigh folds (rare)
• Galeazzi’s/Allis sign (6-8 wks) -
affected knee is lower with
knees bent in supine position –
seen in unilateral DDH

27. MODALITY AGE OR INDICATION
ADVANTAGES &
DISADVANTAGES
ULTRASOUND Up to 4-5 months
Unossified femoral, head,
bony and non-bony
landmaks well evaluated
RADIOGRAPHY After 5-6 months
Once femoral head ossifies,
bony landmarks evaluated
CT
Problem solving, mostly
post-operative evaluation
Unnecessary radiation
MRI
Treatment planning and
monitoring, including
post-operative evaluation
No radiation

29. • Advantages - visualizes the nonossified cartilage of the
femoral epiphyses and the cartilaginous labrum
- permits dynamic assessment of stability
• Disadvantage - cannot be used > 12 months d/t acoustic
shadowing from developing ossification center of epiphysis
• Sonographic features to be noted include :
a. Femoral head - Position, coverage & change in position with stress
b. Assessment of acetabular dysplasia
c. Acetabular roof - horizontal or inclined
d. Acetabular edge - sharp, rounded or flattened
e. Labrum - everted or inverted
f. Acetabular fossa - +/- interposed soft tissues such as excessive fat or
hypertrophied ligamentum teres

30. Two methods –
 Static (Graf method) assessment with hip at rest
• emphasizes morphology and classifies the status of the hip
on the basis of angular measurements of the acetabulum
 Dynamic (Harcke method) assessment with hip under stress
• consists of a multipositional evaluation that resembles the
physical examination

31. • Done in Coronal view
• Infant lies supine or in the
lateral decubitus position
with feet toward the
sonographer
• When examining the left hip
the sonographer grasps the
infant’s left leg with left
hand and transducer is held
in the right hand & vice versa
• To get coronal view – the transducer is placed in coronal
orientation over the lateral aspect of the hip

32. • Transducer is positioned over greater trochanter and held
parallel to the table showing maximum depth of acetabulum
• Cardinal landmarks - 1) inferior edge of the ilium
2) lateral margin of ilium projected as horizontal line 3) acetabular labrum
[“ball on spoon” appearance, with the femoral head representing the ball, the
acetabulum, the bowl of the spoon and the ilium the handle of the spoon]
• False positive - when transducer is rotated anteriorly
• False negative - when transducer is rotated posteriorly
• Proper coronal view –
(a) echoes from bony ilium should be in a straight line parallel to transducer
(b) transition between ilium & triradiate cartilage should be seen definitively
(c) echogenic tip of the labrum should be in the same plane as the other two

33. • Coronal view
AC- acetabular cartilage, C- Capsule, G- gluteus muscles, GT- greater trochanter,
H-cartilaginous femoral head, IL- ilium, IS- schium, L- labrum, LT / P- Ligamentum
teres / pulvinar Complex, M- femoral metaphysis, Tr- triradiate cartilage

34. Alpha (α) and Beta (β) angles
• Baseline : drawn along the straight lateral margin of the ilium
• Inclination line : connects osseous convexity to labrum
• Roof line : connects lower edge of acetabular roof medially to
osseous convexity

35. Alpha (α) angle
• Angle between Base line & Roof line
• denotes inclination of acetabulum
• Small alpha indicates a shallow bony acetabulum
; Normally > 60

36. Beta (β) angle
• Angle between Baseline & Inclination line
• Normally < 55
• Large β angle indicates lateral migration of femoral head

37. TYPE DESCRIPTION α β COMMENTS T/T
I Normal hip > 60 < 55 Good bony modelling None
II Concentric position Sufficient roofing of femoral head
a
Physiologic immaturity
(age < 3 months)
50 – 60 55 – 77
*Deficient bony modelling
*Cartilaginous acetabular roof is still
broad and covers femoral head
Observe until
mature
b
Delayed ossification
(age > 3 months)
Pavlik harness
c Concentric position 43 – 49 55 – 77
*Highly deficient bony modelling
*Cartilaginous acetabular roof is still
broad and covers femoral head
Pavlik harness
d Subluxation 43 – 49 > 77 *Labrum is everted
Pavlik harness
/ Reduction
III Low dislocation Bony roof deficient, labrum everted
a
No structural change
of Cartilaginous roof
< 43 > 77 Cartilage normal echogenicity,
Cartilaginous roof pushed upwards
Reduction
b
Structural change of
Cartilaginous roof
< 43 > 77 Cartilage increased echogenicity,
Progression of upward pushing
Reduction
IV High dislocation Can’t be
measured
Can’t be
measured
Flat bony acetabulum, interposed
labrum
Reduction

39. Supero-lateral displacement of femoral head

40. Pulvinar (P) = fibrofatty tissue b/w acetabulum and femoral head, more
evident in DDH d/t femoral head not pressing against it in the acetabulum

41. • This technique incorporates motion and stress maneuvers
that are based on accepted clinical examination techniques
• The multiview dynamic assessment emphasizes hip position
and stability, but it also includes an assessment of
acetabular development.
• With the dynamic method, an attempt is made to visualize
the Barlow and Ortolani maneuvers on the ultrasonography
screen.
• The technique is dependent on ligamentous or capsular
laxity, and, as with the physical examination, the study
quality depends on the operator performing the stress test

42. Normal Hip
• In the first few
week of life, the
femoral head is
reduced in the
acetabulum at
rest, but it may
show slight
displacement
under stress
• This should
resolve by the
time infant is
four weeks of age
Subluxation
• Displacement of
the head from the
acetabulum
• However, the
head is not
completely
dislocated
Dislocation
• The femoral head
is completely
dislocated
• Fibro-fatty tissue
with increased
echogenic
properties fills
the space
between the
head and the
acetabulum.

43. • The lateral approach for ultrasonography has been the most
widely accepted.
• Four basic lateral views are described –
– Coronal – neutral
– Coronal – flexion
– Transverse - neutral
– Transverse – flexion
• Neutral: The femoral shaft is in the position of rest, usually
15-20 degrees of hip flexion.
• Flexed: The femoral shaft is flexed 90 degrees at the hip

44. • The dynamic technique is performed with the infant in both
the lateral decubitus and the supine position, and imaging is
carried out in the coronal and transverse planes both with
and without stress
• At a minimum, the examination should consist of two
orthogonal views with one obtained during a stress
maneuver

45. TRANSVERSE FLEXION
• The hip and knee are flexed
90 and the ultrasound
transducer is placed
perpendicular to the lateral
aspect of the infants hip
• With the hip in this
position of flexion and
adduction, a posterior push
is analogous to the Barlow
test

46. : normally the femoral head (H)
remains in contact with the ischium (IS) during movement.
TRANSVERSE FLEXION
AC-acetabular cartilage; G-gluteus muscle; GT-greater trochanter; H-cartilaginous
femoral head; C-Capsule; FS-femoral shaft; IS-ischium; IL-ilium; L-labrum; LT/P-
Ligamentum teres / pulvinar complex; M-femoral metaphysis; Tr-triradiate cartilage

47. With instability and
displacement: the femoral
head moves laterally and
posteriorly. The laterally
displaced head (F, open
arrows) has no contact with
the ischium (solid arrows).
Fibrofatty tissue (T) with
increased echogenicity fills the
acetabulum.
TRANSVERSE FLEXION

48. • Positions of hip and
transducer.
TRANSVERSE NEUTRAL

49. Normal Subluxed femoral head posterolterally with
gap between pubis and femoral head
TRANSVERSE NEUTRAL

50. • Positions of hip
and transducer
CORONAL FLEXION

51. Displacement of femoral head lat & sup
with increased echogenicity of labrum
CORONAL FLEXION
Normal

52. • Positions of hip
and transducer.
CORONAL NEUTRAL

53. Displacement of femoral head
laterally with deformity of labrum
CORONAL NEUTRAL
Normal

54. • Avascular necrosis of femoral head is common complication
of DDH treatment devices
• Doppler ultrasound is used to assess the vascularity of
femoral head during treatment
• Normal hip show a radial pattern of flow from the center of
the unossified head

55. Normal radial pattern of flow from
the center of the unossified head
Power Doppler image obtained
during wide abduction shows
absent flow in femoral head

57. • Line of Hilgenreiner
• Perkin's line
• Shenton's curved line
• Acetabular angle
• Andren Von Rosen line

58. Line of Hilgenreiner
• Line connecting supero-
lateral margins of triradiate
cartilage
H

59. Line of Hilgenreiner
• Line connecting supero-
lateral margins of triradiate
cartilage
Perkin's line
• Vertical line to
Hilgenreiner's line through
the lateral rim of
acetabulum
P
H

60. Femoral head position
• Normal ossified capital
femoral epiphysis lie in
lower inner quadrant (H-
and P- lines)
P
H

61. Shenton's curved line
• Arc formed by inferior
surface of superior pubic
ramus (top of obturator
foramen) and medial
surface of proximal femoral
metaphysis to level of
lesser trochanter
S

62. Acetabular angle
• Slope of acetabular roof
• Angle that lies between
Hilgenreiner's line and a
line drawn from most
superolateral ossified edge
of acetabulum to
superolateral margin of
triradiate cartilage
A

63. Acetabular angle
• The acetabular angle
using Hilgenreiner's line
should be less than 28
at birth.
• The angle should
become progressively
shallower with age, and
should measure less
than 22 at and beyond
1 year of age.
P
H
S
A

64. Head position : outer
lower quadrant
Broken Shenton’s line
Acetabular angle > 22

65. Andren Von Rosen line
• X-ray AP view is taken with
both hips Abducted,
Internally Rotated and
Extended
• Line is drawn along femoral
shaft, which intersect
acetabulum normally

66. Andren Von Rosen line
• X-ray AP view is taken with
both hips Abducted,
Internally Rotated and
Extended
• Line is drawn along femoral
shaft, which intersect
acetabulum normally
• In dislocated hip, it crosses
above the acetabulum

68. • Acetabular angle
• Acetabular Index
• Center-edge (CE) angle of Wiberg
• Refined CE Angle of Ogata
• Vertical-center-anterior margin (VCA) angle
• Femoral Head-Neck-Shaft Angle

69. Acetabular angle
• In adult, triradiate cartilages
are fused and therefore
inapparent, thus inferior
margin of the pelvic tear
drop is used instead.
• Pelvic tear drop (aka U-
figure) results from the the
end-on projection of a bony
ridge running along the
floor of the acetabular fossa

70. Acetabular angle
• In adult, it is measured as
Angle formed between a
horizontal line and a line
from the teardrop to lateral
acetabulum.
• Normal - 33 to 38
• > 47 - dysplasia
• 39 to 46 - indeterminate

71. Acetabular angle

72. Acetabular Index
• Aka Tonnis angle
• Measures the weight bearing surface of the acetabulum or
sourcil.
• The sourcil represents an area of subchondral osseous
condensation in the acetabular roof, which is a response
by the articular portion of the ilium to the stress provoked
by the compressive forces acting on it

73. Acetabular Index
• This angle is formed
between a horizontal
line and a tangential
line extending from the
medial to lateral edges
of the sourcil
• Normal ≤ 13°
• Dysplastic > 13°

74. • Angle subtended by one
line drawn from the
acetabular edge to
center of femoral head+
second line
perpendicular to line
connecting centers of
femoral heads
Center-edge (CE) angle of Wiberg

75. P
H
S
A
Center-edge (CE) angle of Wiberg
• Angle subtended by one
line drawn from the
acetabular edge to
center of femoral head+
second line
perpendicular to line
connecting centers of
femoral heads

76. • Normal
– 6-13 > 19
– Above 13 > 25°
• Borderline dysplasia=20–25°
• Dysplasia < 20 P
H
S
A
Center-edge (CE) angle of Wiberg

77. Severin classification system of DDH

78. • Used where lateral point
of osseous condensation
did not reach the lateral
rim of the acetabular roof
• Similar to CE angle of
Wiberg except the lateral
line is tangent to the
lateral point of bony
condensation
Refined (CE) angle of Ogata

79. Vertical-center-anterior margin (VCA) angle
• Aka anterior-center-edge angle
• Evaluates anterior coverage of
the femoral head by the
acetabulum
• Measured on a lateral or “false-
profile” view of the hip
• Obtained with patient in
standing position, affected hip
against the cassette and pelvis
rotated 65; The foot on affected
side should be parallel to the
cassette; beam is centered on
the femoral head

80. Vertical-center-anterior margin (VCA) angle
• Measured as the angle
formed between a vertical
line through the center of
the femoral head and a line
tangential to the anterior
margin of the acetabular roof
• Normal > 25°
• < 20° is diagnostic of hip
dysplasia.
• 20°-25° - borderline dysplasia

81. Femoral Head-Neck-Shaft Angle
• Aka caput collum
diaphysis (CCD) angle
• Measured at the
intersection of the
femoral neck axis
with the long axis of
the femoral shaft
• Normal 120° to 135°

82. Femoral Head-Neck-Shaft Angle
• Aka caput collum
diaphysis (CCD) angle
• Measured at the
intersection of the
femoral neck axis
with the long axis of
the femoral shaft
• Normal 120° to 135°
• > 135° - coxa valga

83. Femoral Head-Neck-Shaft Angle
• Aka caput collum
diaphysis (CCD) angle
• Measured at the
intersection of the
femoral neck axis
with the long axis of
the femoral shaft
• Normal 120° to 135°
• > 135° - coxa valga
• < 120° - coxa vara

84. Delta angle
• Used to quantify the position of the fovea capitis along
the femoral head
• The abnormal superior position of the fovea capitis, also
known as ‘Fovea alta’, is regarded as a potential
radiographic diagnostic marker of dysplastic hip

85. Delta angle
• The delta angle is formed
between the lines drawn
from the center of the
femoral head to the
medial edge of the sourcil
and to the superior edge
of the fovea capitis
• Normal > 10°

86. Delta angle
• The delta angle is formed
between the lines drawn
from the center of the
femoral head to the
medial edge of the sourcil
and to the superior edge
of the fovea capitis
• Normal > 10°

87. Delta angle
• The delta angle is formed
between the lines drawn
from the center of the
femoral head to the
medial edge of the sourcil
and to the superior edge
of the fovea capitis
• Normal > 10°
• Fovea alta ≤ 10°

89. • In children, most commonly used to document reduction
if child is placed in spica cast
• Can be performed preoperatively in the older child in
severe cases to help the surgeon in planning treatment
procedures
• In adults, CT is useful for characterizing hip dysplasia to
anterior, posterior, or global deficiency
• In addition, can be used to measure and confirm
correlates of radiographic center-edge angle, vertical-
center-anterior margin, and acetabular index

90. Measurements of Developmental Dysplasia of the Hip
• Anterior acetabular sector angle (AASA)
• Posterior acetabular sector angle (PASA)
• Horizontal acetabular sector angle (HASA)
 Values are measured on axial CT one cut above greater
trochanters

91. • Created by drawing lines through centers of femoral heads
and line tangential to anterior lip of acetabulum
• Normal > 50°
Anterior acetabular sector angle (AASA)

92. • Created by drawing lines through centers of femoral heads
and line tangential to posterior lip of acetabulum
• Normal > 90°
Posterior acetabular sector angle (PASA)

93. • Created by drawing lines from anterior lip of acetabulum
through center of femoral head and posterior lip of acetabulum
• Normal > 140°
Horizontal acetabular sector angle (HASA)

94. Right hip dysplasia

96. • Reserved for difficult cases
• Major advantage : can delineate soft-tissue structures as
well as osseous structures without ionizing radiation
• Many MRI studies are ordered in the postoperative
period, usually after reduction and spica cast placement

98. Axial T1-weighted images show interval reduction of right hip with mild
persistent posterior subluxation. Acetabulum is shallow. Compared with
normal left side (solid arrow, B), right femoral head ossification is
delayed (long solid arrow, A). Anterior labrum is mildly inverted (short
solid arrow, A). Significant pulvinar hypertrophy (dotted arrow, A).
A B

99. 32-year-old woman with hip dysplasia and labral disease
Coronal proton density–weighted (A) & sagittal fat-saturated proton
density–weighted (B) MR images show redundant patulous labrum
with extensive intrasubstance signal abnormality (curved arrows)
A B

100. 32-year-old woman with hip dysplasia and labral disease
Sagittal fat-saturated proton density–weighted MR images show
anterior acetabular subchondral cysts (dashed arrow)

101. Complications
• Subchondral fractures
• Osteoarthritis
• Avascular necrosis
A B

102. 28-year-old woman with left hip dysplasia and subchondral
impaction fracture
Coronal proton density–weighted (A) and coronal fat-saturated T2-
weighted (B) MR images show subchondral fracture line (arrow)
located in superior weightbearing aspect of femoral head
A B