- Previously called 'congenital dislocation' of the hip
- Common features include:
- Dysplasia of the acetabulum
- Femoral neck anteversion
- Apparent incidence depends on age
- 20 per 1000 neonates have clinical evidence of hip instability
- Only one per 1000 have evidence of hip dislocation at 3 months
Pathophysiology
- Acetabulum develops from triradiate cartilage and three ossification
centres
- Normal growth dependent on normal intestinal apposition within
acetabulum
- Also requires presence of normal femoral head
- Ligamentous laxity may be be important
Aetiology
- Family history - increases risk by x 30
- Sex - female : male ratio is 5:1
- Breech presentation
- Foot deformity
- Torticollis
- Neuromuscular disorders
- Skeletal dysplasias
Clinical features
- Congenital dislocation of the hip can present as:
- Neonate with hip instability
- Infant with limited hip abduction
- Toddler with a limp
- Adult with degenerative hip changes
- All neonates should be screened for hip instability
- Hips are flexed to 90 degrees and instability detected by:
- Reduction of dislocation by abduction and forward pressure
(Ortalani's test)
- Dislocation of hip by adduction and backward pressure (Barlow's
test)
- Ultrasound my be useful but with a high sensitivity it results in
significant over diagnosis
- Plain x-rays not reliable until child is 3 months old
- In infant diagnosis should be suspected if there is a limp
- Examination may show limb shortening, extra thigh skin crease and
hip external rotation
- At older age Galeazzi sign may be elicited
- Sign of unilateral hip displacement
- Child is supine with hips and knees flexed and one leg is shown to
be shorted than the other
- Bilateral dislocation can be difficult to demonstrate
- X-ray will show shallow acetabulum with underdeveloped femoral head
Management
- The aim of treatment are:
- To reduce the dislocation by traction or open reduction
- To maintain reduction by harness, cast, soft tissue release or
osteotomy
- Need to achieve stable congruous reduction without damaging the
growth plate
- The above aims can be achieved by
- Pavlick hip harness or Von Rosen splint in a neonate
- Traction in a infant
- Open reduction +/- osteotomy or acetabuloplasty in an older child
Bibliography
Baucher H. Developmental dysplasia of the hip (DDH): an evolving
science. Arch Dis Child 2000; 83: 202.
Eastwood D M. Neonatal hop screening. Lancet 2003;
363: 595-597.
Harcke H T, Grisson L E. Pediatric hip sonography.
Diagnosis and differential diagnosis. Radiol Clin North Am
1999; 37: 7870796.
Hubbard A M. Imaging of pediatric hip disorders. Radiol
Clin North Am 2001; 39: 721-732.
McCarthy J J, Scoles P V, MacEwen D. Developmental
dysplasia of the hip (DDH). Current Orthopaedics 2005;
19: 223*230 |