Developmental Dysplasia of the Hip (DDH) is a condition where the hip joint has not formed correctly, ranging from mild looseness to complete dislocation. The hip is a ball-and-socket joint, and in DDH, the socket (acetabulum) may be shallow, preventing the top of the thighbone from seating properly. This condition can be present at birth or develop during the first year of life. Understanding the factors that influence its development is the first step toward effective prevention and management.
Understanding Non-Modifiable and Modifiable Risk Factors
The predisposition for DDH is influenced by a combination of factors, some uncontrollable and others related to the infant’s environment. Non-modifiable factors include genetic and intrauterine influences present before or at birth. Being a firstborn child is associated with a higher likelihood of DDH, potentially due to the uterus restricting fetal movement.
Female infants are significantly more susceptible than males, with DDH occurring about six times more often in girls, possibly due to maternal hormones that increase ligamentous laxity. The baby’s position in the womb also plays a role; a frank or single breech presentation, where the feet are near the shoulders, is a risk factor. Additionally, having a family history of DDH, particularly a parent or sibling, increases the risk by roughly one-third.
Modifiable factors relate to external pressures and positioning after birth, which can promote healthy joint development or exacerbate existing instability. Swaddling or carrying an infant in a way that forces the legs into an extended or pressed-together position is an environmental risk. The developing hip joint is vulnerable, and restricting the natural ability for the legs to bend up and out can interfere with the proper formation of the hip socket. These post-natal positioning habits offer parents a direct opportunity to support hip health.
Positional Strategies for Hip-Healthy Development
Parents can directly influence hip development through mindful practices related to swaddling, carrying, and baby equipment. The goal of hip-healthy strategies is to mimic the natural, frog-like position infants instinctively adopt, allowing the hips to flex and the knees to spread. When swaddling, ensure the legs can bend up and out at the hips, maintaining the slight flexion and abduction that encourages stability.
The swaddling blanket should only secure the shoulders and arms, leaving a loose pouch around the hips and legs so the infant can move freely below the waist. Wrapping the legs tightly and straight down (the “straight jacket” method) can push the ball of the joint out of the shallow socket, increasing the risk of DDH. Parents should look for commercial sleep sacks and swaddles designed with a generous bottom area to facilitate this necessary leg movement.
When carrying a baby in a soft carrier, sling, or wrap, the proper position is often described as the “M” position, or spread-squat position. In this posture, the baby’s knees are positioned higher than their buttocks, and the thighs are supported and spread apart. This natural alignment helps seat the head of the femur firmly within the hip socket, promoting stability and healthy formation.
For the first six months, inward-facing carrying is often recommended to promote optimal hip alignment, as the baby is more likely to grasp the wearer’s torso with their inner thigh muscles. Care should be taken with other baby equipment, such as car seats, bouncers, and jumpers, to ensure the design does not force the legs into an unhealthy, straight, or adducted position for prolonged periods. Any device that keeps the legs dangling or tightly restricts hip movement should be used sparingly, if at all, during the first few months of life.
Medical Screening and Early Intervention Protocols
While parental action addresses modifiable risk factors, medical screening remains the primary defense against the long-term consequences of DDH. Routine physical examinations begin immediately after birth and continue at every well-baby checkup throughout the first year. Pediatricians use specific maneuvers, such as the Ortolani and Barlow tests, which involve gently moving the infant’s hips and knees to check for instability or the sensation of the hip dislocating or relocating.
These physical exams are most reliable in the first few months of life before the joints and surrounding soft tissues become less flexible. If a physical exam suggests instability, or if the infant has multiple non-modifiable risk factors, further imaging is often ordered. For babies under six months, when the hip bones are still primarily cartilage, an ultrasound is the preferred imaging method because it provides a clear picture of the cartilaginous structures and the relationship between the ball and socket.
If DDH is confirmed through imaging, early intervention is paramount for a successful outcome, typically avoiding the need for surgery. The most common non-surgical treatment for infants under six months is the application of a Pavlik harness. This soft brace consists of straps that hold the baby’s hips in the same hip-healthy position recommended for swaddling and carrying: flexed and abducted.
The harness maintains the femoral head securely within the acetabulum, allowing the socket to deepen and stabilize around the joint over several weeks to months. The success rate for the Pavlik harness is high, often exceeding 80% when treatment is initiated early in the infant’s life. Detecting and treating the condition before the child starts walking is a clear objective of these protocols, as it significantly reduces the likelihood of future gait problems, limb length differences, and early-onset arthritis.