Diagnosing Developmental Hip Dysplasia

Developmental hip dysplasia is a condition in which the ball-shaped top of the thigh bone, called the femoral head, doesn’t fit firmly into the hip socket, also known as the acetabulum. Most children are born with this condition, but it can also develop during the first year of life, especially if a child is swaddled tightly in a way that keeps the hips and knees straight instead of slightly bent.

Developmental hip dysplasia is more common in girls than in boys and can run in families. The risk of developmental hip dysplasia is increased in babies born in a breech, or feet-first, position and in newborns who had limited space in the womb or low amniotic fluid during development.

Babies with developmental hip dysplasia may have an asymmetrical buttock crease or uneven limb length. Parents may notice a clunking or popping noise in the hip when changing the baby’s diaper. Developmental hip dysplasia can cause pain and inflammation that may go unnoticed until the child begins to walk with a limp or waddles.

Mild to moderate developmental hip dysplasia, in which the femoral head fits loosely in the socket, can lead to partial dislocation of the hip. Children with more severe developmental hip dysplasia may have pain and complete dislocation. In this case, the femoral head moves completely outside of the socket. If left untreated, the condition often leads to arthritis in the hip during adulthood.

Doctors at Hassenfeld Children’s Hospital at NYU Langone focus on diagnosing developmental hip dysplasia as early as possible, when the least invasive treatments may be most effective.

Physical Exam

Pediatricians conduct well-baby exams within a week of birth and every couple of months during the child’s first year to assess his or her growth and development. During these exams, the pediatrician performs the Barlow and Ortolani tests, which involve moving your baby’s hip joint in and out of proper position. A clicking sound is heard if it’s misaligned. Your child may be referred to an orthopedic specialist if the pediatrician suspects a problem with the hip joint.

Our orthopedic experts usually repeat these tests and examine your child to look for other signs of developmental hip dysplasia. These may include a difference in limb length while your baby is lying on his or her back with hips and knees flexed at 90 degrees or uneven folds of fat on the thighs. Signs in toddlers include walking on the toes or with a limp.

Hip Ultrasound or X-ray

An ultrasound scan of the hip may be used to diagnose developmental hip dysplasia in infants younger than six months old, whose bones are still somewhat soft. The ultrasound, which uses sound waves to create images of soft structures in the body, allows the doctor to view the baby’s hip joint and surrounding muscles, tendons, and ligaments for signs of dislocation or unusual formation. After a baby’s bones have hardened, usually after six months of age, the doctor may use an X-ray to obtain an image of the hip joint.

Based on the results of these tests, our orthopedic care team can develop a treatment plan that best addresses your child’s symptoms and prevents future problems, such as complete hip dislocation and arthritis.