Developmental Dysplasia of the Hip (DDH)
February 27, 2021 | By : OrthoFixar | Pediatric
| Last updated on April 28, 2021
- Developmental dysplasia of the hip (DDH) generally includes subluxation (partial dislocation) of the femoral head, acetabular dysplasia, and complete dislocation of the femoral head from the true acetabulum secondary to capsular laxity and mechanical factors.
- Previously the disease was called congenital dysplasia of the hip, nowadays it’s called Developmental dysplasia of the hip (DDH).
- The incidence of developmental dysplasia of the hip has been estimated to be approximately 1 in 1000 live births.
- Most often in the left hip (67% of cases).
- Bilateral involvement is more common than involvement of the right hip alone.
- More common in girls (85%).
- In infants with a positive family history (≥20%).
- In the presence of increased maternal estrogens, and in breech births (30% to 50%).
- Several risk factors should arouse suspicion of Developmental Dysplasia of the Hip:
- Breech positioning.
- Female sex.
- Positive family history.
- Postnatal Positioning (swaddling with the hips in extension).
- Racial Predilection (whites and Native Americans).
- Firstborn child.
- Ligamentous laxity
Developmental Dysplasia of the Hip is associated with multiple congenital deformities:
- Congenital torticollis:
- Boys > girls
- Metatarsus adductus.
- Talipes calcaneovalgus.
- Clubfoot deformity:
- Screening hip physical examination and ultrasound evaluations for infants with clubfoot deformity is recommended.
Physical examination of Developmental dysplasia of the hip (DDH) varies based on the age of the child.
Newborns (<6 months old):
- The infant should be calm, relaxed, and pacified during the examination, and only one hip should be examined at a time.
- Barlow test dislocates a dislocatable hip.
- Ortolani test reduces a dislocated hip.
- Galeazzi sign: limb length discrepancy due to a unilateral dislocated hip with hip and knee flexed at 90 degrees.
Three phases are commonly recognized in Barlow / Ortolani test:
- Dislocatable: positive result of Barlow test.
- Subluxatable: suggestive result of Barlow test.
Children > 3 months
- Limitation of hip abduction in the affected hip as the laxity resolves and stiffness becomes more clinically evident.
- Predominate of leg length discrepancy.
- Asymmetrical skin folds:
- This sign is not always reliable because normal children may have asymmetrical skin folds and children with dislocated hips may have symmetrical folds.
Walking child > 1 year
- Waddling gait (bilateral dislocation).
- Trendelenburg gait (unilateral dislocation).
- Lumbar lordosis: due to hip contractures resulting from bilateral dislocations.
See Also: Hip joint Special Tests
- Useful for making the diagnosis of developmental dysplasia of the hip (DDH) in young children before ossification of the femoral head (which occurs at age 4-6 months).
- Also useful for assessing reduction in a Pavlik harness and diagnosing acetabular dysplasia or capsular laxity.
- Accuracy is dependent on examiner skill.
- Ultrasound findings before 6 weeks of age can be questionable because of ligamentous laxity in the early newborn period; treatment before 6 weeks of age should be based on physical examination rather than ultrasound findings alone.
- Angle α :
- It is formed by the intersection of the baseline and the acetabular roofline.
- Normal is less than 60 degrees.
- Angle β:
- It is formed by the intersection of the baseline and the inclination line.
- Normal is less than 55 degrees.
- It’s used in older children (after age 3 months after the femoral head begins to ossify).
- The most commonly used lines of reference are the:
- Vertical line of Perkins.
- Horizontal line of Hilgenreiner.
- Both used to assess the position of the femoral head.
- Shenton line is disrupted in an older child with a dislocated hip.
- Normally, the femoral head lies within the inner lower quadrant of the reference lines noted by Perkins and Hilgenreiner.
- Acetabular index (AI):
- Angle formed by a line drawn from point on the lateral triradiate cartilage to point on lateral margin of acetabulum and Hilgenreiners line
- Should be less than 25° in patients older than 6 months.
- Arthrography is used to help judge closed reduction and possible blocks to reduction in the treatment of Developmental Dysplasia of the Hip.
CT & MRI:
- Useful after closed reduction to determine concentric reduction.
- Treatment of developmental dysplasia of the hip is based on the child’s age:
Birth to 6 months:
- Hips with normal exam but abnormal ultrasound findings:
- Close follow-up,
- Repeat ultrasound at age 6 weeks, with treatment if continued signs of dysplasia.
- Ortolani-positive hips (dislocated but reducible):
- Should be treated with Pavlik harness.
- Barlow-positive hips (reduced but dislocatable):
- Should be watched closely
- Many authors advocate treating with Pavlik while observing
- Follow up check reduction after 3 weeks on ultrasonography:
- Not reduced: consider transition to rigid abduction orthosis vs. closed reduction and spica casting.
- Reduced: continue Pavlik Harness until findings of examination and ultrasonography are normal.
- Position of the hip is about 100 degrees of flexion and mild abduction (the human position).
- Position of the hip should be within the “safe zone” of Ramsey (between maximum adduction before redislocation and excessive abduction, which increases risk of avascular necrosis [AVN]).
- Pavlik harness treatment is contraindicated in teratologic hip dislocations.
- Excessive flexion may result in transient femoral nerve palsy.
- The Pavlik harness is usually worn 23 hours a day for at least 6 weeks after a reduction has been achieved and then an additional 6 to 8 weeks part time (nights and during naps).
- Risk factors for Pavlik Harness failure:
- Patient older than age 7 weeks at initiation of treatment.
- Bilateral dislocations.
- Absent Ortolani sign.
6 to 18 months:
- Closed reduction and spica casting w/out Percutaneous adductor tenotomy.
- Post-reduction CT or MRI scan used to confirm concentric reduction.
- If closed reduction fails then open reduction is considered.
18 months to 3 years:
- Open reduction and spica casting.
Obstacles to reduction in developmental dysplasia of the hip:
- Transverse acetabular ligament.
- In-folded labrum.
- Inferior capsular restriction.
- Psoas tendon.
3 to 8 years:
- Salter, Dega, Pemberton, or Staheli procedures.
Older than 8 years:
- Pelvic Osteotomy:
- If the growth plate is open:
- Triple (Steele)
- double pelvic (Southerland).
- Staheli procedure
- If the growth plate is closed:
- Ganz and Chiari procedures.
- If the growth plate is open:
- Total hip arthroplasty.
See Also: Hip Joint Osteoarthritis
Pelvic Osteotomy in treatment of developmental dysplasia of the hip
|Femoral||Intertrochanteric osteotomy (Varus derotation osteotomy)||Concentric reduction before the age of 8 years||– High neck-shaft angle|
– hip subluxation;
– usually performed in patients with cerebral palsy
|Salter||Open-wedge osteotomy through ileum||Concentric reduction before the age of 8 years||– Acetabular dysplasia without posterior wall loss; – redirection osteotomy|
|Pemberton||Through acetabular roof to triradiate cartilage; does not enter sciatic notch||Concentric reduction before the age of 8 years||– Acetabular dysplasia with a patulous cup;|
– volume-reducing osteotomy
|Dega||Through lateral ilium above acetabulum to triradiate cartilage; incomplete cuts through innominate bone||Concentric reduction; favored in those with posterior acetabular deficiency||Acetabular dysplasia with patulous cup; – volume-reducing;|
– favored in neuromuscular dislocations with posterior deficiency
|Sutherland (double)||Salter and pubic osteotomy||Concentric reduction|
Open triradiate cartilage
|– More severe acetabular dysplasia;|
– redirection procedure
|Steel (triple)||Salter and osteotomy of both rami||Concentric reduction|
Open triradiate cartilage
|– Most severe acetabular dysplasia;|
– redirection procedure
|Ganz||Periacetabular osteotomy||Surgeon’s experience|
Closed triradiate cartilage
|Acetabular dysplasia in a skeletally mature patient|
|Chiari||Through ilium above acetabulum (makes new roof)||Non-reconstructable acetabulum||Salvage procedure for asymmetric incongruity|
|Shelf||Slotted lateral acetabular augmentation||Non-reconstructable acetabulum||Salvage procedure for asymmetric incongruity|