Developmental Dysplasia of the Hip (DDH): Understanding Causes, Symptoms, and Treatments

What is the full form of DDH?

DDH stands for Developmental Dysplasia of the Hip. It is a condition where the hip joint has not formed properly, meaning the ball (femoral head) does not fit securely into the socket (acetabulum).

Understanding Developmental Dysplasia of the Hip (DDH)

Developmental Dysplasia of the Hip (DDH), previously known as Congenital Dysplasia of the Hip (CDH), refers to a spectrum of abnormalities affecting the hip joint, ranging from a mild looseness of the joint to a complete dislocation of the femoral head from the acetabulum. This condition primarily affects infants and young children, but if undiagnosed or inadequately treated, its effects can persist and manifest in adolescence or adulthood.

• Anatomical Basis: The hip is a ball-and-socket joint. In DDH, there is an abnormal development of the acetabulum (the socket part of the pelvis) and/or the femoral head (the top of the thigh bone). This can lead to instability, subluxation (partial dislocation), or complete dislocation of the hip joint.
• Progressive Nature: The term "developmental" emphasizes that the condition can develop or worsen over time, even after birth. The hip joint relies on proper alignment and forces for its healthy development. If the ball is not centered in the socket, the joint may not mature correctly.
• Impact on Function: A dysplastic hip can lead to altered biomechanics, uneven weight distribution, premature wear and tear of the joint cartilage, and ultimately, early-onset osteoarthritis.

Causes and Risk Factors

The exact cause of DDH is often multifactorial, involving a combination of genetic and environmental influences.

• Genetic Predisposition: A family history of DDH significantly increases a child's risk.
• Intrauterine Positioning: Certain positions in the womb can put pressure on the developing hips.
  • Breech presentation: Babies born bottom-first have a higher incidence of DDH.
  • Oligohydramnios: Low amniotic fluid can restrict fetal movement.
  • Firstborn status: First pregnancies may involve a tighter uterus.
• Postnatal Factors:
  • Improper swaddling: Swaddling techniques that restrict a baby's leg movement and keep the hips straight and adducted can interfere with proper hip development. "Hip-healthy" swaddling allows the hips to bend up and out.
• Gender: Girls are more commonly affected than boys, with a ratio of approximately 4:1.
• Associated Conditions: DDH can sometimes occur alongside other conditions like clubfoot or torticollis.

Signs, Symptoms, and Diagnosis

The signs of DDH can vary depending on the child's age and the severity of the condition. Early diagnosis is crucial for effective treatment.

• In Infants (0-6 months):
  • Asymmetry of skin folds: Uneven thigh or gluteal folds.
  • Limited hip abduction: One hip may not open out as far as the other when the baby's knees are bent.
  • Leg length discrepancy: One leg may appear shorter than the other.
  • Clicking or clunking sound: During specific hip maneuvers (Ortolani and Barlow tests performed by a healthcare professional).
  • Difficulty with diaper changes.
• In Older Children (walking age):
  • Limping or waddling gait: Due to an unstable or dislocated hip.
  • Toe walking on one side.
  • Uneven leg length.
  • Pain (less common in young children, more so in adolescents/adults).
• Diagnosis:
  • Physical examination: Routine newborn screenings include hip checks.
  • Ultrasound: The preferred imaging method for infants up to 4-6 months, as the hip bones are still largely cartilaginous.
  • X-ray: Used for older infants and children where bones are more ossified.

Treatment and Management

Treatment for DDH aims to correctly position the femoral head within the acetabulum and maintain that position to allow for normal hip development.

• Early Intervention (Infants):
  • Pavlik Harness: For infants diagnosed early, a soft brace called a Pavlik harness is often used. This harness holds the hips in a flexed and abducted (frog-leg) position, which encourages the femoral head to seat deeply into the socket and promotes proper development. It is highly effective when used consistently.
• Older Infants/Children:
  • Closed Reduction and Spica Cast: If the Pavlik harness is not effective or if diagnosis is later, the hip may be manually repositioned (closed reduction) and then held in place with a rigid body cast (spica cast) for several months.
  • Open Reduction Surgery: In more severe cases or when non-surgical methods fail, surgery may be required to reposition the hip joint. This is often followed by a spica cast.
• Adolescents and Adults:
  • Treatment for DDH diagnosed in adulthood often focuses on managing symptoms, correcting biomechanical issues, and potentially delaying or treating osteoarthritis through conservative measures, physical therapy, or surgical interventions like periacetabular osteotomy (PAO) or total hip replacement (THR).

Implications for Exercise and Physical Activity

For individuals with a history of DDH, or those living with undiagnosed or managed DDH, exercise and physical activity require careful consideration.

• Importance of Professional Guidance: Any exercise program for individuals with current or past DDH should be developed in consultation with a healthcare team, including an orthopedic surgeon, physical therapist, and/or an exercise physiologist.
• Focus on Stability and Mobility:
  • Strengthening: Exercises targeting the hip abductors, adductors, gluteal muscles (gluteus medius and maximus), and core musculature are crucial for providing stability to the hip joint.
  • Mobility: Gentle range-of-motion exercises, within pain-free limits, can help maintain hip flexibility. However, excessive or forced movements, especially into extremes of rotation or abduction, should be avoided if they cause pain or instability.
• Low-Impact Activities: Activities that minimize impact on the hip joint are generally preferred. Examples include swimming, cycling (with proper bike fit), elliptical training, and walking on softer surfaces.
• Avoid High-Impact or Repetitive Stress: Activities involving repetitive jumping, running on hard surfaces, or high-impact sports may exacerbate symptoms or accelerate joint degeneration in individuals with uncorrected or significantly dysplastic hips.
• Proprioception and Balance Training: Improving balance and body awareness can help individuals better control their movements and protect the hip joint.
• Considerations for Adults: Adults with DDH are at a higher risk for developing hip osteoarthritis. Exercise programs should focus on pain management, maintaining function, and preserving joint health. Modifications may be necessary for daily activities and sports to reduce stress on the hip.