ultrasound of the infant hip with developmental dysplasia harry h. holdorf phd, mpa, rdms, rvt
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Ultrasound of the Infant Hip with Developmental Dysplasia
Harry H. Holdorf
PhD, MPA, RDMS, RVT
Objectives
• Identify normal vs. abnormal sonographic anatomy• Identify risk factors associated with DDH• Define the classifications of developmental dysplasia of the hip• Understand the use of hip angle measurement tools
Developmental dysplasia of the hip (DDH)• Developmental dysplasia of the hip ranges from mild acetabular
dysplasia to irreducible dislocation of the femoral head• Ultrasound is an excellent method in the diagnosis of DDH
Congenital Hip Displacement
• Developmental dysplasia of the hip (DDH) was formerly referred to as congenital dislocation of hip. • DDH is now the preferred term to reflect that DDH is an
ongoing developmental process, which is variable in presentation and not always detectable at birth. • Developmental dysplasia of the hip refers to a spectrum
of severity ranging from mild acetabular dysplasia with a stable hip, to more severe forms of dysplasia with neonatal hip instability, to established hip dysplasia with or without later subluxation or dislocation.
Epidemiology
• Developmental dysplasia of the hip affects 1-3% of newborns and is responsible for 29% of primary hip replacements in people up to the age of 60 years.• The left hip is dislocated more often than the right and 20% of cases
are bilateral.• It is more common in cultures that use swaddling of babies, forcing
the hips into extension and adduction.
• It has been reported that ultrasound screening seems to prevent many, but not all, operations for developmental hip dysplasia.• Selective ultrasound examination for babies with specific risk factors is
recommended. An ultrasound examination of the hips should be performed if: • There is a first degree family history of hip problems in early life, unless
DDH has been definitely excluded in that relative.• A breech presentation:• at or after 36 completed weeks of pregnancy, irrespective of presentation at
delivery or mode of delivery, or• at delivery if this is earlier than 36 weeks.• In the case of a multiple birth, if any of the babies falls into either of these
categories, all babies in this pregnancy should have an ultrasound examination.
Risk Factors of DDH• Female sex• Family history (parental or sibling)• Breech Presentation• Multiple Gestations• Certain neuromuscular disorders i.e.: congenital torticollis• Oligohydramnios• Hip click (on clinical exam)• Club foot deformity• Asymmetric skin folds• High birth weight
History of diagnosing DDH
• In the 1980’s Dr. Graf developed a technique using ultrasound to replace radiography to diagnose DDH. • Dr. Hacke introduced dynamic imaging to hip sonography in 1984.
Method
Coronal View
Baby in lateral Decubitis or supine position
Flex knee 90 degrees
Transducer parallel and lateral to hip
Image should show femoral head centered in joint space.Ilium appears as straight line perpendicular to femoral head and parallel to transducer
Coronal View (Non-Stress
Coronal View (non-stress)
• Includes the following anatomy• Ilium• Acetabular Rim• Femoral Head• Ischium• Labrum• Greater Trochanter
Anatomy (non Stress)
Femoral Head
Ilium
Acetabular Rim
Greater Trochanter
Labrum
Method Continued
Transverse view Infant in oblique positionKnee flexed 90 degreesRotate transducer 90 degrees from coronalFemoral head should be centered on triradiate cartilageStress the hip in this view
• Steps to Stress the HIP
Flex hip 90 degrees
Push the knee gently Posteriorly
Transverse View NON-STRESS
Include:Femoral ShaftGreater TrochanterIschiumFemoral Head
Anatomy (Non-Stress Transverse)
Femoral Head
Ischium
Ultrasound of the new-born HIP
• Birth to 4 months of age• High frequency linear transducer • Multiple focal zones• Output power at 100%• Feed baby during exam
Technique Continued…• Decubitus position• Place a small rolled up towel behind the back. • Hip is flexed 90 degrees• Use both hands to stabilize the baby • Foot pedal
Angle Measurement
• Baseline Passes through plane of Ilium.• Alpha Angle• Most common• Angle between baseline and roofline• Measures acetabular Concavity
Angle Measurement continued…• Beta Angle• Angle between baseline
And inclination lineIndicates acetabular roof
CoverageAnything less than 55 degrees
is normal
Graf Classification
Graf Type 1
• Covers femoral head• Acetabular rim is angular• Labrum is in normal position• Hip angle measurement is greater than 60 degrees
Graf Type 1Non Stress
Graf Type IIa
• Patients less than 3months of age• Femoral head is not displaced• Acetabular rim is rounded• Labrum in normal position• Hip angle measurement is between 50-59 degrees • Repeat scan in 6-8 weeks
Graf Type IIa Non-Stress
Graf Type IIb
• Patients greater than 3 months of age• Femoral head is not displaced• Acetabular rim is rounded• Labrum is in normal position• Alpha angle is 50-59 degrees• Orthopedic referral is suggested
Graf Type IIb (non stress)
Graf Type IIc
• Femoral head less than 50% covered• Acetabular is rounded• Labrum is everted, more horizontally positioned• Alpha angle is 43-49 degrees• Treatment and follow up suggested
Graf Type IIc
Graf Type IV non-stress
• Femoral head is almost completely displaced • Acetabular rim is flattened• Labrum trapped between femoral head and ilium• Hip angle is less than 43 degrees• Requires urgent referral and treatment
Graf Type IV non-stress
Example 1: Normal Graf Type I
Example 2:
• Graf Type IV• Femoral Head is displaced• Acetabular rim is
Flattened
Labrum is Trapped
Conclusion• While newborn screening for DDH allows for early detection of this
hip condition, starting treatment immediately after birth may be successful. • Many babies respond to the Pavlik harness, and/or casting. Additional
surgeries may be necessary since the hip dislocation can reoccur as the child grows and develops.• If left untreated, differences in leg length or a duck-like gait, and a
decrease in agility may occur. • In children 2 years or older with DDH, deformity of the hip and
osteoarthritis may develop later in life. DDH can also lead to pain and osteoarthritis by early adulthood.
The technique of examining the infant hip joint with real-time ultrasound is widely accepted. Since the cartilaginous femoral head is clearly imaged by ultrasound, anatomical structures and their relationships can be accurately determined. Dislocated hips are easily detected and subluxations also can be visualized.The method of examination using real-time ultrasound is considered to be reliable, accurate, and a useful adjunct to radiography. The advantages are that it is non-invasive, portable, and involves no exposure to radiation.
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