Developmental Dysplasia of the Hip (DDH): Diagnosis Age, Methods, and Importance of Early Detection

At what age is DDH diagnosed?

Developmental Dysplasia of the Hip (DDH) is primarily diagnosed in infancy, most commonly through routine screenings during the newborn period and first year of life, though it can sometimes be detected later, particularly if initial signs are subtle or missed.

Understanding Developmental Dysplasia of the Hip (DDH)

Developmental Dysplasia of the Hip (DDH) refers to a spectrum of conditions where the hip joint has not formed properly. This can range from a mild instability or looseness of the joint to a complete dislocation of the femoral head (ball) from the acetabulum (socket). The hip joint, a classic ball-and-socket synovial joint, is crucial for lower limb mobility, stability, and weight-bearing. Proper formation is essential for efficient biomechanics and long-term joint health.

The Critical Window for Diagnosis: Infancy

The vast majority of DDH cases are identified during infancy due to universal screening protocols implemented in many countries.

• Newborn Period (0-3 months): This is the most crucial period for initial diagnosis. Pediatricians and healthcare providers routinely perform physical examinations of the hips at birth and during subsequent well-baby check-ups. Specific maneuvers are used to assess hip stability.
• Early Infancy (3-6 months): If initial screenings are inconclusive or if risk factors are present (e.g., breech presentation, family history), follow-up examinations and imaging are common.
• Late Infancy (6-12 months): As infants grow and begin to crawl or stand, new signs of DDH might emerge if it was not detected earlier.

Diagnostic Methods in Infancy

Early detection relies heavily on a combination of physical examination and imaging.

• Physical Examination:

  • Ortolani Maneuver: This test involves abducting (moving away from the midline) the infant's flexed hip while applying gentle upward pressure. A "clunk" or "click" may be felt or heard as a dislocated hip reduces back into the socket.
  • Barlow Maneuver: This test attempts to dislocate an unstable hip by adducting (moving towards the midline) and applying downward pressure. A "clunk" indicates the hip dislocating.
  • Galeazzi Sign (Allis Sign): Unequal knee heights when the infant lies supine with hips and knees flexed is a sign of potential unilateral hip dislocation, as the femur on the affected side appears shorter.
  • Asymmetrical Skin Folds: Uneven gluteal or thigh skin folds can be a subtle indicator, though not definitive.
  • Limited Hip Abduction: One of the most reliable signs in older infants is a restriction in the ability to fully abduct the hip.

• Imaging:

  • Ultrasound (Sonography): This is the preferred imaging modality for infants under 4-6 months of age. The hip joint is largely cartilaginous at this stage, making ultrasound effective for visualizing the soft tissues and bony relationships. It allows for dynamic assessment of hip stability.
  • X-rays: X-rays become more useful after 4-6 months, as the bones begin to ossify, allowing for clearer visualization of the bony architecture of the hip joint.

Later Diagnosis: When DDH is Missed in Infancy

While less common, DDH can be diagnosed later in childhood, adolescence, or even adulthood if the condition was subtle or missed during early screenings.

• Toddler/Preschool Age (1-3 years): If DDH is undiagnosed, children may present with:
  • A noticeable limp or abnormal gait (e.g., Trendelenburg gait if unilateral, waddling gait if bilateral).
  • Delayed walking.
  • Leg length discrepancy.
• School-Age Children and Adolescents: Undiagnosed DDH can lead to:
  • Pain in the hip, groin, or knee.
  • Fatigue with physical activity.
  • Persistent limp.
  • Early onset of osteoarthritis.
  • X-rays are the primary diagnostic tool at these ages.
• Adulthood: In some cases, mild dysplasia that was asymptomatic for years may lead to premature osteoarthritis, chronic pain, or instability, prompting a diagnosis of DDH in adulthood.

Why Early Detection is Paramount for Long-Term Function

The emphasis on early diagnosis of DDH is rooted in the principles of musculoskeletal development and biomechanics.

• Non-Invasive Treatment: When DDH is diagnosed in the newborn period, treatment often involves non-invasive methods like the Pavlik Harness. This harness gently holds the infant's hips in a flexed and abducted position, allowing the femoral head to mold the acetabulum into a deeper, more stable socket. This promotes proper joint development.
• Optimizing Joint Development: The hip joint's cartilaginous nature in infancy makes it highly adaptable. Early intervention capitalizes on this plasticity, guiding the bones into their correct alignment before they fully ossify.
• Avoiding Complications: Delayed diagnosis typically necessitates more invasive and complex treatments, such as closed reductions (manipulating the joint back into place under anesthesia) or open surgical reductions (requiring an incision). These procedures carry higher risks and longer recovery times.
• Preventing Long-Term Degeneration: Untreated or late-diagnosed DDH significantly increases the risk of developing premature hip osteoarthritis, chronic pain, and functional limitations later in life. This impacts an individual's ability to participate in physical activity, maintain an active lifestyle, and perform daily movements without discomfort.

Implications for Movement and Lifelong Health

From a kinesiology and exercise science perspective, early DDH diagnosis and effective treatment are foundational for ensuring optimal movement patterns and joint health throughout the lifespan. A properly formed hip joint is critical for:

• Efficient Gait Biomechanics: A stable hip allows for smooth, powerful, and balanced walking and running.
• Stability and Balance: The hip joint is a major contributor to core stability and overall balance, essential for all forms of physical activity.
• Strength and Power Production: Proper joint alignment ensures muscles can function optimally, generating force effectively for movements like squatting, jumping, and lifting.
• Reduced Risk of Injury: A healthy hip reduces compensatory movements and undue stress on other joints (e.g., knees, spine), minimizing the risk of secondary injuries.

In conclusion, while DDH can be diagnosed at various ages, the vast majority of cases are identified within the first year of life. This early detection is critical for enabling conservative, highly effective treatments that promote normal hip development, ensuring optimal musculoskeletal function and preventing debilitating conditions later in life.