👶 Babies swaddled tightly with hips/knees straight have a much higher risk of DDH. ⏰ Early detection is critical → late diagnosis often means major surgery, poorer outcomes, and long-term disability.

📖 About

Occurs in ~1–2 per 1,000 babies needing treatment.
A spectrum: from mild acetabular dysplasia → subluxation → frank dislocation.
Ball (femoral head) is unstable in socket (acetabulum) → may dislocate.

⚙️ Aetiology

Hip is a ball-and-socket joint but is malformed in DDH.
Femoral head may be loose, subluxed, or fully dislocated.
Multifactorial: mechanical (breech), genetic, intrauterine factors.

📌 Risk Factors

👧 Female sex, 🍼 first-born child.
🤰 Breech delivery (all breech girls need hip USS).
👨‍👩‍👧 Family history (parents/siblings).
💧 Oligohydramnios (reduced amniotic fluid).

🗂️ Classification

Dislocated: femoral head completely outside socket.
Dislocatable: head in acetabulum but easily displaced on exam.
Subluxatable: femoral head loose, moves within socket but not fully dislocated.

🔍 Key neonatal tests: - Ortolani’s test (reduce dislocated hip). - Barlow’s test (provoke dislocation).

🩺 Clinical Signs (<3 months)

Asymmetrical skin folds (inguinal, gluteal, thigh).
Klisic line: from greater trochanter to ASIS → should pass through umbilicus; falls below if DDH.
Ortolani & Barlow positive → USS indicated.
USS preferred <6 months (femoral head cartilaginous). X-ray useful >6 months.

🔍 Clinical Presentation

Routine hip screen: birth + 6–8 weeks.
Unequal leg length, asymmetric movement, limited abduction.
Older infants: limp, toe-walking, waddling gait.

🧪 Investigations

Ultrasound (USS): gold standard <6 months. Detects subtle instability.
X-ray (>6 months): - Hilgenreiner’s line (through triradiate cartilages). - Perkins line (perpendicular from acetabular edge). - Shenton’s line (should be continuous curve). - Acetabular index: normally 27.5° at birth → 20° by age 2;>30° abnormal.

🚨 Complications

Untreated → early hip OA, chronic pain, gait disturbance.
Leg length difference, persistent limp, “duck-like” gait.

🩹 Management

0–6 months: Pavlik harness or brace (keeps femoral head in socket).
6–12 months: Harness or brace, sometimes spica casting after reduction.
12–24 months: Closed reduction + spica cast. Skin traction sometimes pre-reduction. If fails → open reduction + spica cast.
>2 years / severe cases: Often require open surgery ± pelvic/femoral osteotomies.
Even after treatment → socket may remain shallow, may need later corrective surgery.

💡 Teaching Pearls

- Always check hip abduction in newborns. Limited abduction is a red flag. - Breech girls always get a hip USS regardless of exam findings. - Late presentation = much harder to treat and worse outcomes. - “Pavlik harness saves hips” – but only if used early!

📚 References

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Developmental Dislocation (Dysplasia) of the Hip (DDH)