Hip osteoarthritis

Disease Name

Developmental dysplasia of the hip (DDH) — synonyms: developmental hip dysplasia, developmental hip dislocation, congenital hip dysplasia/dislocation, etc.

1) Disease Description (Causes and Pathophysiology, Main Symptoms)

• Definition: A condition in which the femoral head partially or completely deviates from its normal position due to underdevelopment or deformity of the acetabulum (partial dislocation, complete dislocation, or instability).
• Causes (multifactorial): Genetic predisposition (family history), sex (more common in girls), fetal presentation (breech presentation), oligohydramnios and intrauterine space restriction, racial differences, and newborn care practices (such as swaddling with excessive extension).
• Pathophysiology: If the acetabulum is shallow or inadequately formed, it cannot stably support the femoral head, leading over time to dislocation or instability and, in the long term, femoral head deformity or early osteoarthritis.
• Main symptoms (by age)
  • Neonatal and infancy: Limited hip abduction (the legs do not spread easily), asymmetry of the thigh and buttock skin folds, Galeazzi sign (difference in knee height), positive Ortolani/Barlow tests, and developmental delay before walking.
  • After the walking stage: Limping (unilateral), waddling gait (bilateral), leg-length discrepancy, and pelvic tilting.

2) Treatment Methods and Precautions

• Principles of diagnosis and treatment: Early diagnosis and early treatment have a decisive impact on prognosis.
• Nonsurgical treatment
  • Pavlik harness (brace): Usually first-line treatment for instability or dislocation in infants younger than 3–6 months. The wearing period ranges from several weeks to several months depending on the condition (follow the physician’s instructions).
  • Closed reduction and hip spica cast: Usually performed between 6 months and 2 years of age. Immobilization for a certain period after reduction (usually at least 3 months), followed by use of a brace.
• Surgical treatment
  • Open reduction: For complex dislocations or when closed reduction fails.
  • Osteotomy (acetabular or femoral osteotomy): When correction of the acetabular or femoral axis structure is necessary.
  • When discovered after age 2, particularly after ages 4–5, surgical correction may be necessary and the prognosis may be unfavorable.
• Drug therapy: There is no direct drug treatment. Symptomatic medications may be used after surgery for pain control, infection prevention, and other purposes.
• Lifestyle management and precautions
  • During brace use, regularly inspect the skin and follow medical instructions to prevent skin necrosis, marks, and nerve compression.
  • During swaddling, feeding, and rest, maintaining the hips in a naturally flexed and abducted position is recommended (avoid excessive extension).
  • Long-term follow-up: Monitoring for bone growth and the development of avascular necrosis of the femoral head (AVN) is necessary.
• Complications
  • Residual dysplasia, redislocation, avascular necrosis of the femoral head, leg-length inequality, and early osteoarthritis.
• Prognosis
  • Good functional recovery is possible with early detection and appropriate treatment. If treatment is delayed, complete correction may be difficult, increasing the risk of chronic disability and early arthritis.

3) Checklist Before an Outpatient Visit (Including Examples of Items and Records to Prepare and Questions)

• Items to prepare
  • Birth records/obstetric records: Fetal presentation (whether breech), amniotic fluid volume (whether oligohydramnios was present), etc.
  • Family history: Whether there is a history of hip disease (DDH, early arthritis, etc.).
  • Current medication list and allergy information.
  • Copies or photographs of previous test results (newborn hip ultrasound, X-rays, medical notes, etc.).
  • Symptom records, photographs, and videos: Walking videos (limping, waddling gait) or recordings of leg movements.
  • Records of brace or cast use (start date of use and any problems).
• Records for the medical history interview
  • When symptoms began and how they have changed (when they started and factors that worsen or improve them).
  • Whether there have been skin problems or discomfort while wearing the brace.
  • Growth and motor development status (timing of sitting, crawling, and walking).
• Tests and information helpful to the doctor during the visit: Recent ultrasound images, radiographs, and notes on treatment progress.

4) Examples of General Questions to Ask the Doctor

• What is the condition and severity of my child’s hip (or my condition)?
• What are the recommended treatment options, and what are the advantages and disadvantages of each?
• How long will treatment take, and what is the expected recovery process?
• What precautions and complications should be considered when using a brace (or cast or surgery)?
• What is the long-term prognosis (joint function after growth and risk of osteoarthritis)?

5) Examples of Disease-Specific Questions (1–2)

• If a Pavlik harness is being used, how many hours a day should it be worn, and in what situations should we come to the hospital immediately (such as skin necrosis or abnormal sensation in the leg)?
• My child is currently over 6 months old, and instability remains on ultrasound. What are the criteria for recommending surgery instead of closed reduction and cast immobilization? How high is the risk of avascular necrosis of the femoral head (AVN) after surgery, and what care is needed to reduce this risk?

If you need additional explanations of examinations (ultrasound/radiographs and the timing of examinations by age), examples of photographs by symptom, or instructions for brace care, please let us know.