Congenital hip dislocation, more commonly called developmental dysplasia of the hip, or DDH, may occur at birth or may not develop for several months. The hip joint is a ball and socket joint, with the head of the femur, the long leg bone, fitting into the socket, called the acetabulum. One in 100 newborns has instability or subluxation of the hip joint, where the ball slides around within the socket, whereas 1 in 1,000 has a joint where the ball lies completely outside the socket, Dr. Jeffrey Hull, M.D. reports. Treatment aims to keep the ball and socket in close proximity.
Diapering
Putting double or triple diapers on an infant for the first six weeks helps keep the ball and socket joint in the proper position, with the hip flexed to 90 degrees and abducted, or kept apart, at least 90 degrees, eOrthopod explains. Triple diapering has fallen out of vogue because it places the hips in extension, which doesn’t promote good hip development, Hall states.
Harnessing
The Pavlik harness, the most commonly used device, or other splints are used to hold the hips in flexed and abducted position in children younger than 6 months. A three- to four-week trial of the harness is followed by X-ray to check for reduction of the defect. If the X-ray shows improvement, harnessing or splinting continues. The Pavlik harness works 95 percent of the time in subluxated hips and 80 percent of the time for true dislocations, Family Practice Notebook reports.
Hip Spica Casting
Hip spica casts hold the femur head in the socket by immobilizing the hips in a cast called a spica cast from waist to toes. Changing the cast every two weeks to one month requires general anesthesia in the operating room, a procedure called closed reduction. Hip spica casting may continue for 12 weeks or more.
Open Reduction
After 18 months, DDH often requires surgery, known as open reduction, eOrthopod reports. Tight ligaments and tissues preventing the ball and socket from fitting properly are cut, along with tight muscles and tendons preventing proper fit. Spica casting for several months after surgery keeps the joint stable. Recurrent dislocation and bone death, or osteonecrosis, can complicate surgery.
Osteotomy
Derotational surgery, where the femur is cut and rotated to allow it to fit into the socket, followed by spica casting, may help keep the femur in place in cases where casting fails, according to eOrthopod. Children older than 18 months may also require surgery to change the shape of the acetabulum, or socket as well as the femur head.
