Developmental Dysplasia of the Hip (DDH)

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Developmental Dysplasia of the Hip (DDH) refers to a spectrum of hip joint abnormalities, ranging from mild acetabular dysplasia to complete dislocation of the femoral head from the acetabulum. It is most commonly diagnosed in infants and young children.

Aetiology

The exact cause of DDH is multifactorial, involving genetic, environmental, and mechanical factors. Key aetiological factors include:

• Genetic predisposition (family history of DDH)
• Intrauterine positioning (breech presentation)
• Oligohydramnios (reduced amniotic fluid)
• First-born children (due to tighter uterine space)
• Female gender (due to the influence of maternal hormones on ligament laxity)

Pathophysiology

The pathophysiology of DDH involves:

• Abnormal development or growth of the hip joint, where the acetabulum is shallow and the femoral head is misaligned.
• Progressive instability of the hip joint, leading to subluxation or dislocation.
• If untreated, this can result in abnormal gait patterns, decreased range of motion, and osteoarthritis in later life.

Risk Factors

• Family history of DDH or other hip abnormalities
• Breech presentation at birth
• Female gender
• First-born child
• Oligohydramnios during pregnancy
• Swaddling practices that keep the legs extended and adducted

Signs and Symptoms

The signs and symptoms of DDH include:

• Limited abduction of the hip
• Asymmetry of the gluteal or thigh folds
• Leg length discrepancy
• Clicking or clunking sound during hip examination (Ortolani and Barlow tests)
• In older children, abnormal gait (limping, toe-walking, or waddling gait)

Investigations

Specific investigations to diagnose DDH include:

• Clinical examination: Hip examination using the Ortolani and Barlow manoeuvres to detect instability.
• Imaging studies:
  • Ultrasound: Preferred method for infants younger than six months.
  • X-rays: Used for older infants and children to assess the hip joint structure.

Management

Primary Care Management

• Early detection and referral: Prompt referral to paediatric orthopaedics for further evaluation and management.
• Parental education: Educate parents on proper hip-healthy swaddling techniques and the importance of follow-up.

Specialist Management

• Pavlik harness: For infants up to six months old, to maintain the hip in a position that promotes normal development.
• Closed reduction and spica casting: For infants who do not respond to harness treatment or are diagnosed after six months of age.
• Open reduction surgery: For older children or when non-surgical methods fail to stabilise the hip joint.
• Osteotomy: Surgical realignment of the femur or pelvis in severe cases to improve hip joint congruity.
• Postoperative care: Regular monitoring with imaging and physiotherapy to ensure proper healing and joint function.

References

1. NHS (2024) Developmental Dysplasia of the Hip (DDH). Available at: https://www.nhs.uk/conditions/developmental-dysplasia-of-the-hip/ (Accessed: 24 June 2024).
2. National Institute for Health and Care Excellence (2024) Hip dysplasia. Available at: https://cks.nice.org.uk/topics/hip-dysplasia/ (Accessed: 24 June 2024).
3. British Medical Journal (2024) Developmental Dysplasia of the Hip: clinical features, diagnosis, and management. Available at: https://www.bmj.com/content/350/bmj.h3177 (Accessed: 24 June 2024).
4. American Academy of Orthopaedic Surgeons (2024) Developmental Dysplasia of the Hip (DDH). Available at: https://orthoinfo.aaos.org/en/diseases--conditions/developmental-dysplasia-of-the-hip-ddh/ (Accessed: 24 June 2024).

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