Modern Study Review (AI-Generated)
High-Yield Summary
Developmental Dysplasia of the Hip (DDH) encompasses a spectrum from acetabular dysplasia to frank dislocation, with early detection and treatment critical to optimize hip joint development and function. Post-reduction monitoring of acetabular development is essential, as persistent dysplasia can lead to instability and early osteoarthritis. Modern management balances conservative observation with timely reconstructive osteotomies to restore hip congruency and biomechanics, preventing long-term disability.
Key Diagnostic Findings
Anatomy
- Acetabulum: Normally a deep, concave socket providing coverage and stability to the femoral head. Dysplasia manifests as a shallow acetabulum with increased acetabular index and a more horizontal sourcil.
- Femoral Neck-Shaft Angle: May show coxa valga (increased angle) contributing to superior loading and instability. Femoral anteversion is often increased in DDH.
Clinical Presentation
- Infants: Limited hip abduction, asymmetric thigh folds, positive Ortolani/Barlow tests.
- Older children: Limp, leg length discrepancy, hip pain, or instability.
- Post-reduction: Persistent dysplasia or instability despite concentric reduction.
Imaging
- X-rays:
- Acetabular Index: Angle between the horizontal line through the triradiate cartilage and the acetabular roof; elevated in dysplasia.
- Abduction/Internal Rotation View: Assesses congruency and coverage of the femoral head within the acetabulum.
- Ultrasound: Useful in infants <6 months for dynamic assessment of hip stability.
- MRI/CT: Occasionally used for detailed anatomy preoperatively.
Classification Systems
| Classification | Description | Clinical Utility |
|---|---|---|
| Acetabular Index | Quantitative measure of acetabular slope; normal <25° in infants | Guides need for intervention |
| Severin Classification | Radiographic outcome grading post-DDH treatment | Prognostic for long-term hip function |
| Tönnis Classification | Grading of hip dislocation severity on radiographs | Surgical planning |
Note: Modern practice emphasizes dynamic and morphological assessment over purely static classifications.
Current Gold Standard Treatment
Non-operative
- Early DDH (Infants <6 months): Pavlik harness to maintain reduction and promote acetabular development.
- Post-reduction monitoring: Serial clinical and radiographic follow-up to assess acetabular remodeling.
Operative Indications
- Persistent acetabular dysplasia or instability after reduction and observation.
- Failure of conservative treatment with evidence of poor acetabular development or recurrent subluxation/dislocation.
- Older children with symptomatic dysplasia or deformity.
Operative Treatment
| Procedure Type | Indications | Key Points |
|---|---|---|
| Re-directional Osteotomies (Salter, Triple, Steel) | Congruent, reduced hips with acetabular dysplasia | Improve coverage by reorienting acetabulum |
| Acetabuloplasty (Dega, Pemberton) | Reduced but incongruent hips, often in neuromuscular populations | Reshapes acetabulum to improve coverage |
| Femoral Osteotomy | Address femoral deformities (excessive anteversion, coxa valga) | Varus osteotomy with medialization to avoid abductor weakness |
| Salvage Procedures (Chiari, Shelf) | Irreducible hips or advanced deformity | Improve stability when reconstruction is not feasible |
Modern Complications & Outcomes
Complications
- Residual or recurrent dysplasia leading to instability.
- Avascular necrosis (AVN) of the femoral head, especially with forceful reduction or osteotomy.
- Limp or abductor weakness from improper femoral osteotomy technique.
- Early osteoarthritis if dysplasia is untreated or inadequately corrected.
Outcomes
- Early, appropriate intervention yields excellent pain relief and functional outcomes.
- Osteotomies improve hip biomechanics and delay or prevent degenerative changes.
- Long-term follow-up is essential to monitor for late complications and guide secondary interventions.
Classic Clinical Notes
DDH – Dysplasia
Approach to DDH – Acetabular Dysplasia
- After treating the dislocation, you must follow the kid to see if the acetabulum is developing normally.
- Look to see what the pathology is:
- Is it dysplasia of the acetabulum with a shallow cup – acetabular index down, sharp angle down?
- Is it a coxa valga with superior loading?
- Is it both?
- Is the dysplasia causing recurrent instability? Then you better get on with an osteotomy.
- If reduced, it is somewhat controversial to decide when to do the osteotomy – wait for remodeling, or just go ahead and do it to encourage better remodeling? Probably a more aggressive approach is warranted – if the acetabulum is not developing normally after a couple visits to the clinic, pull the trigger.
Reconstructive osteotomies
- Cannot have degenerative arthritis.
- Should have a good range of motion (how good is debatable).
- Should check an abduction/internal rotation x-ray to assess two things: congruency and coverage. On this view the head and acetabulum should be CONGRUENT to proceed with a re-directional osteotomy (Salter, Triple, Steel). If reduced but not completely congruent, consider acetabuloplasty – Dega, Pemberton (more in the CMT or paralytic population). If not reducible – need a salvage procedure (Chiari or Shelf).
- Look at the femoral neck shaft angle – is the deformity there? Does it need a varus osteotomy? Most have lots of anteversion and not that much valgus, so a varus osteotomy runs the risk of elevating their GT and causing an abductor limp. If doing a varus osteotomy, remember to medialize the femur with the offset on the plate.
Last Updated on January 25, 2026 by orthonet
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