Developmental Dysplasia of the Hip Diagnosis and Treatment

Importance of Early Detection

The American Academy of Pediatrics recommends hip examination at every well-baby visit, with a schedule of 2-4 days for newborns discharged in <48 hours, 1 month, 2 months, 4 months, 6 months, 9 months, and 12 months, as early detection allows for typically non-invasive and effective therapy, while late presentation is a major negative prognostic factor requiring more complex treatment and surgical intervention 1, 2, 3, 4
Physical examination is the most important screening method, with selective ultrasound screening recommended for high-risk infants, as the strength of evidence for physical examination is high, with a sensitivity of 85-90% and specificity of 90-95% 3, 5

The Barlow Test, which gently adducts the thigh and applies posterior pressure to attempt to dislocate an unstable hip, is a crucial examination technique, with a positive test implying a dislocatable hip, and is recommended by the American College of Radiology 2, 3, 5
The Ortolani Test, which abducts and gently lifts the flexed thigh while pushing the greater trochanter anteriorly, is also important, with a "clunk" indicating reduction of a dislocated hip back into the acetabulum, and is recommended by the American College of Radiology 2, 3, 6

Developmental Dysplasia of the Hip (DDH) ranges from mild acetabular dysplasia to complete dislocation, with risk factors including female gender (RR 2.5), breech positioning (RR 3.8), positive family history (RR 1.4), and infant swaddling, and is associated with a high risk of early degenerative joint disease, with a strength of evidence of high, based on multiple studies 4, 5
Immature Hip (Graf Type IIa) is a normal developmental variant in infants <3 months with alpha angle 50°-59°, and most resolve spontaneously without treatment, with a strength of evidence of moderate, based on several studies 3, 7, 5

Under 4 months, ultrasound is the preferred imaging modality, with the American Academy of Pediatrics recommending selective ultrasound screening at 4-6 weeks for high-risk infants, and two main ultrasound techniques: static (Graf method) and dynamic (Harcke method), with a strength of evidence of high, based on multiple studies 3, 5, 7
Over 4-6 months, radiography becomes more reliable as ossification progresses, with the acetabular index being the most commonly used measurement (normal is 30° in newborns, decreases with age), and the position of femoral head evaluated using Hilgenreiner and Perkin lines, with a strength of evidence of moderate, based on several studies 6, 5, 7

The American Academy of Pediatrics recommends selective ultrasound screening at 4-6 weeks for high-risk infants, as early diagnosis of developmental dysplasia of the hip (DDH) allows for non-invasive treatment with a brace, while late diagnosis requires complex surgical interventions and can lead to debilitating degenerative joint disease in adulthood 8
The American College of Radiology suggests that ultrasound should not be performed before 2 weeks of life, as joint laxity is common after birth and resolves spontaneously in 60-80% of cases identified on physical examination and >90% of cases identified on ultrasound 8, 9, 10

The American College of Radiology identifies several risk factors that require ultrasound screening, including first-born infants, large infants, and oligohydramnios, with relative risks of 1.4, 2.5, and 3.8, respectively 11, 12

The American Academy of Pediatrics recommends that infants with instability or significant dysplasia on ultrasound should be treated with a Pavlik harness, with the goal of achieving concentric reduction and stability of the hip joint 8
The treatment should continue until the hip joint is stable and shows concentric reduction on imaging, with the position of reduction-retention being >90° of hip flexion, but not more than 45-50° of abduction to prevent avascular necrosis of the femoral head 8

The American College of Radiology notes that mild dysplasia may not become clinically apparent until adulthood, while untreated subluxed and dislocated hips can lead to early degenerative joint disease and compromised function 9, 10
Early diagnosis and treatment can alter the natural history of hip dysplasia and significantly improve joint longevity, with the best long-term outcomes resulting from early diagnosis and treatment 9, 10

The American College of Radiology recommends the Pavlik harness as the first-line treatment for infants under 6 months of age with hip dysplasia, with 70-95% success rates when initiated early, ideally before 7 weeks of age 13
Treatment with the Pavlik harness is most effective when started before 6 weeks of age, with efficacy decreasing as age increases 13
The Pavlik harness can be used up to 6 months of age with overall success rates of 67-83% 13

Ultrasound is the preferred modality for monitoring harness treatment, performed to confirm concentric hip reduction, assess treatment response, and identify early signs of failure 13
Predictors of harness failure include low post-reduction alpha angle, poor femoral head coverage, nerve palsy, irreducible hips, initiation after 7 weeks, and certain hip classifications 13

For infants with Graf Type IIa hips, no treatment is required if they are under 3 months old and have an alpha angle of 50-59°, as 60-90% resolve spontaneously 14, 15
All other Graf types (IIb, IIc, IId, III, and IV) require immediate referral for treatment with Pavlik harness 13, 14

Universal ultrasound screening can lead to overdiagnosis and unnecessary treatment, increasing the risk of avascular necrosis of the femoral head 15, 16
Late diagnosis is a major negative prognostic factor, requiring more complex treatment and increasing the risk of long-term complications 15, 16

Unrecognized and untreated hip dysplasia inevitably leads to early degenerative joint disease, causing a significant proportion of total hip arthroplasties in patients under 60 years 15, 16