Developmental dysplasia of the hip

Disease Description (Causes and Symptoms)

• Definition: Developmental dysplasia of the hip (DDH) is a condition in which the femoral head does not completely or partially fit into the hip socket due to underdevelopment of the acetabulum.
• Causes and risk factors
  • Genetic predisposition (family history), sex (4–6 times more common in girls than in boys)
  • Fetal position (breech presentation), oligohydramnios, intrauterine space constraints (small uterus)
  • Environmental factors such as swaddling methods immediately after birth (excessive fixation with the legs extended)
  • Ethnic differences (low prevalence reported in some population groups)
• Pathophysiology: Abnormal development of the acetabulum reduces the stability of the femoral head, and over time, deformity of both the acetabulum and femoral head, joint instability, and destruction of the articular cartilage may progress.
• Main symptoms
  • Infancy: Hip instability, asymmetry of skin folds, limited hip abduction
  • After walking begins: Limping in unilateral cases, leg-length discrepancy, waddling gait in bilateral cases
  • Examination findings: Positive Ortolani/Barlow tests, abnormal joint positioning on ultrasound or X-ray

Treatment Methods

• Principle after diagnosis: The goal is to reduce the joint (guide it into its normal position) as early as possible and immobilize it appropriately to promote normal development of the acetabulum.
• Treatment during infancy
  • Approximately 0–6 months of age (especially under 3 months): A Pavlik harness (maintaining the hips in flexion and abduction) is the first-line treatment. Regular follow-up ultrasound is required.
  • If the harness fails or the child is over 6 months old: Closed reduction under imaging guidance followed by long-term immobilization in a hip spica cast (approximately 3 months or longer), followed by use of a brace.
• Treatment during childhood
  • After age 2 or in cases of complex anatomical abnormalities: Corrective surgery such as open reduction and acetabuloplasty or femoral osteotomy may be required.
  • If discovered after age 4–5, treatment is more difficult, increasing the risk of complications and incomplete correction.
• Medication and supportive treatment
  • Postoperative pain control (analgesics), infection prevention (fat route/antibiotics if necessary)
  • Physical therapy: Recovery of strength and range of motion, gait retraining
• Complications and points of caution
  • Avascular necrosis of the femoral head (AVN), persistent joint instability, early osteoarthritis, leg-length discrepancy
  • Be alert for signs of skin pressure and nerve or vascular compression caused by the harness or cast (paleness of the limb, decreased sensation or movement of the extremity, etc.)
• Prognosis
  • Early diagnosis and appropriate treatment are associated with a good prognosis (normal joint development is possible)
  • Delayed diagnosis and treatment increase the risk of lifelong disability or early osteoarthritis

Outpatient Visit Checklist (Including Examples of Items to Bring and Records)

• Items to bring
  • List of currently used medications (including the mother's medications if breastfeeding), history of allergies
  • Birth and obstetric history (whether breech, amount of amniotic fluid, etc.) and family history (DDH or hip disease)
  • Previous test results (newborn hip ultrasound images or reports, X-rays, surgical records, etc.)
  • A photograph or description of the condition of any brace being used for treatment (e.g., a Pavlik harness)
• Symptom and progression records
  • Observed asymmetry of skin folds, leg-length discrepancy, age at which walking began, and walking pattern (whether limping or waddling is present)
  • Skin problems when wearing a harness or cast (rash, tenderness), and changes in the child's feeding, bowel movements, or sleep patterns
• Examples of questions to prepare for the outpatient visit
  • Advantages and disadvantages of each treatment option and the expected treatment duration
  • Necessary tests (ultrasound/radiation) and follow-up intervals

Examples of General Questions to Ask the Doctor

• "How severe is our child's hip condition (instability/partial dislocation/complete dislocation, etc.)?"
• "What treatment method do you recommend, and what is the expected treatment duration?"
• "What are the risks of complications from treatment (harness/cast/surgery), and how can they be prevented?"
• "Is physical therapy needed during or after treatment? If so, when should it begin?"
• "What is the long-term prognosis (joint function after growth and the risk of osteoarthritis)?"

Examples of Disease-Specific Questions

• "My child is using a Pavlik harness. If the ultrasound findings do not improve, when will the next step (closed reduction vs. open reduction) be decided?"
• "What is the plan for perioperative and postoperative management or monitoring to reduce the possibility of avascular necrosis of the femoral head (AVN)?"

Additional Information

• Standard newborn screening: Hip examinations (Ortolani/Barlow tests and newborn hip ultrasound) are recommended immediately after birth and during infant examinations.
• Prevention: Avoid swaddling with the lower limbs excessively extended and fixed, and maintain a natural position with the pelvis slightly flexed and abducted.