Developmental dysplasia of the hip (DDH) is a condition where the hip socket (acetabulum) does not fully cover the ball portion of the upper thighbone (femoral head). This instability means the hip is loose, making it prone to partial or complete dislocation. While not every case of DDH can be prevented, proper care practices and early detection significantly reduce the condition’s severity and the need for invasive treatments. Focusing on preventative measures for infants is the most effective approach to promoting healthy hip development.
Understanding Vulnerability Factors
Certain non-modifiable factors increase an infant’s risk for developing hip dysplasia. Genetic predisposition is a factor, as a family history of DDH in a parent or sibling increases the risk. The incidence is also approximately four times higher in female infants than in males, likely due to increased ligamentous laxity caused by circulating maternal hormones.
The infant’s position in the womb is another major influence. Risk factors include first-born status (due to the unstretched uterus), breech presentation (especially bottom or feet first in the last trimester), and low amniotic fluid (oligohydramnios).
Best Practices for Hip-Healthy Positioning
The primary preventative measure involves ensuring the infant’s hips are positioned correctly during the first six months of life when development is most rapid. The healthiest position allows the hips to fall naturally apart, with the thighs supported and the hips and knees bent. This posture is often referred to as the “M” position, where the baby’s knees are splayed outward and positioned higher than the bottom.
When swaddling, avoid tightly restricting the legs or forcing them into a straight, adducted position. Swaddling should only secure the arms and upper body while leaving enough room at the bottom for the hips and knees to bend and move freely. This allows the femoral head to sit securely in the socket, promoting joint deepening.
Similarly, baby carriers, slings, and seats must support this hip-healthy posture, especially during prolonged use. Carriers should have a wide base that supports the infant’s thighs from knee to knee to maintain the “M” position. Devices that cause the baby’s legs to dangle straight down should be avoided, as this places pressure on the hip joint. Limit the amount of time an infant spends in car seats or bouncers that restrict natural leg movement.
The Critical Role of Early Screening
Preventing the progression of hip dysplasia relies heavily on early detection, as treatment is most effective when initiated in the first few months of life. Pediatricians perform routine physical examinations at well-baby visits to assess hip stability. These checks include specific maneuvers, such as the Ortolani and Barlow tests, which gently move the hip joint to check for instability or dislocation.
Parents also play a role in observation between clinical visits by looking for specific physical signs:
- A difference in leg lengths.
- Asymmetrical skin folds on the thighs or buttocks.
- Reduced flexibility when changing diapers.
- Any noticeable popping or clunking sensation (a simple clicking sound can occur in a normal hip).
When physical signs or strong risk factors are present, imaging is used for diagnosis. Hip ultrasound is the preferred diagnostic tool for infants typically under six months of age because their hip bones are still primarily cartilage. After about six months, as bone development progresses, an X-ray becomes the standard method for assessing the hip joint’s structure.