Developmental Dysplasia of the Hip (DDH): Diagnostic Imaging with Ultrasound vs. X-Ray
Abnormal physical exam findings are common during newborn and infant visits. The challenge is distinguishing low-risk findings from those that warrant further investigation. How do we decide when reassurance is enough and when additional workup is required?
This week we’ll cover developmental dysplasia of the hip (DDH) - including high risk features, pros and cons of physical exam maneuvers, and when (and what) diagnostic imaging to consider.
Case: You are seeing a healthy 1 month old in the office. Everything is going well. The exam is normal until you feel a “clunk” with Barlow and Ortolani testing, suggesting hip instability. What do you do next?
What is Developmental Dysplasia of the Hip (DDH)?
Developmental dysplasia of the hip (DDH) refers to abnormal hip development resulting in acetabular dysplasia, subluxation, or frank dislocation. It occurs secondary to capsular laxity and mechanical instability.
Because DDH screening is part of routine well-baby visits, clinicians must understand how to detect it accurately and what to do when findings are abnormal.
Physical Examination for DDH
Barlow Test: Assesses whether a hip is dislocatable. The examiner adducts the hip while applying gentle posterior pressure. A palpable “clunk” indicates instability and the ability to dislocate the hip.
Positive Barlow: the hip is dislocatable.
Ortolani Test: Assesses whether a dislocated hip can be reduced. The examiner flexes and abducts the hip while lifting the greater trochanter anteriorly. A palpable “clunk” indicates relocation of the femoral head into the acetabulum.
Positive Ortolani: the hip is reducible.
The “Clunk: ” A true positive test produces a distinct palpable or audible clunk. A soft click is not diagnostic.
Diagnostic Performance of Barlow and Ortolani
Sensitivity is low, approximately 36 to 57%
Specificity is high, approximately 95 to 98%
The Ortolani maneuver has a higher positive predictive value
The Barlow maneuver often identifies hips that may stabilize spontaneously (1,2)
These maneuvers are most reliable from birth to approximately 3 months of age. After this period, soft tissue contractures reduce test reliability.
Additional Exam Maneuvers
Galeazzi Test: Used to assess for unilateral DDH. With the infant supine, hips flexed to 90 degrees, knees flexed, and heels touching the buttocks, the knees should normally be level. In unilateral dislocation, posterior displacement of the femoral head shortens the thigh, and the affected knee appears lower.
Limitations:
Ineffective for bilateral DDH, as both knees may appear symmetrically low
May be unreliable in infants younger than 3 months
Risk of false-positive results
It should be used in conjunction with Barlow and Ortolani testing (1,2)
Skin Fold Asymmetry: Asymmetry of inguinal or gluteal folds may suggest unilateral DDH. However, isolated thigh fold asymmetry is not associated with increased rates of DDH and should not be used alone for diagnosis.
Historical Risk Factors: History meaningfully alters pre-test probability. Key risk factors include
First-born infant
Female sex
Breech presentation
Family history of DDH
Oligohydramnios
Macrosomia
Limited hip abduction
Swaddling
Talipes equinovarus (clubfoot) (1,2)
When combined with exam findings, these factors strengthen clinical suspicion.
💡Bottom Line on Physical Exam: No single test is sufficient. When used together, physical exam maneuvers and risk factor assessment help support or refute the diagnosis of DDH.
Back to the case: we have positive Barlow and Ortolani findings for DDH – what’s the next step?
Diagnostic Imaging for Developmental Dysplasia of the Hip
Ultrasound
Ultrasound is the imaging modality of choice in infants younger than 4 months (1,2). It evaluates:
Acetabular morphology
Femoral head position
Labrum
Ligamentum teres
Hip capsule
Dynamic stability
Normal ultrasound in infants with isolated soft tissue clicks will demonstrate normal acetabular development.
Key ultrasound findings for DDH:
Alpha angle less than 60 degrees
Femoral head coverage less than 50 percent
Shallow or rounded acetabulum
Instability on dynamic stress testing (3)
Practice tip: All high-risk infants, specifically those with breech presentation or a family history of DDH, should undergo screening ultrasound at 6 weeks of age, even if the physical exam is normal (2).
Plain Radiographs
Pelvic radiographs are used after 4 to 6 months of age, once femoral head ossification occurs (1,2). Recommended view is AP pelvis. Radiographs evaluate:
Delayed ossification of the femoral head
Acetabular morphology
Hip alignment
Important radiographic landmarks include: Hilgenreiner line, Perkin line, and Shenton line
Radiographic findings suggestive of DDH:
Shallow, steep, or laterally directed acetabulum
Lateral or proximal migration of the femoral head
Disruption of Shenton line
Elevated acetabular index at 6 months
Delayed ossification of the proximal femoral epiphysis, and in severe cases, formation of a false acetabulum
Management Based on Imaging
Normal Imaging
If the infant was breech during pregnancy, obtain pelvic radiographs at 6 months to evaluate for acetabular dysplasia, even if earlier imaging was normal.
Perform serial hip examinations at each well-child visit until independent walking.
Repeat imaging if new abnormal exam findings emerge (1,2).
Abnormal Imaging: Refer to pediatric orthopedics (1,2).
💡Bottom Line: DDH is confirmed with imaging
Ultrasound in the first 4 months
Radiographs >4 to 6 months
Breech presentations: 6 week US regardless of physical exam / repeat x-ray at 6 months if abnormal physical exam and initial imaging was normal
Back to the Case: we have positive Barlow and Ortolani tests. Gluteal and thigh folds are symmetric. Galeazzi testing is not reliable at 1 month and was not performed. A hip ultrasound is obtained and is normal. There are no risk factors such as breech presentation or family history.
Plan: Serial hip examinations at follow-up visits + repeat imaging only if future abnormal exam findings occur.
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ReferencesRosenfeld SB. Developmental dysplasia of the hip: clinical features, screening, and diagnosis. In: Phillips WA, editor. UpToDate. Waltham (MA): UpToDate Inc.; 2026.Ahn L. Developmental dysplasia of the hip (DDH). Orthobullets. 2026. Available from: https://www.orthobullets.com/pediatrics/4118/developmental-dysplasia-of-the-hip-ddhShaw BA, Segal LS. Evaluation and referral for developmental dysplasia of the hip in infants. Pediatrics. 2016 Dec;138(6):e20163107. doi:10.1542/peds.2016-3107.Nandhagopal T, Tiwari V, De Cicco FL. Developmental dysplasia of the hip. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-.