The hip joint is formed by the ball at the top of the thigh bone (“femoral head”) sitting inside the socket of the pelvis bone (“acetabulum”). In Developmental dysplasia of the hip (or “DDH” for short) the socket is not properly formed, and is shallow. In mild cases, the cup is a little shallow, but still deep enough to cover the femoral head. In more severe cases, the cup is so shallow that the femoral head completely slips out of the cup (which we call “dislocation”).
Why does it happen?
We do not know. We know it is more common in babies who were in a breech position, and those who have a parent or sibling that have had DDH. We also know it can be more common in babies who were a bit squashed inside the womb (which may also have caused abnormal neck or foot position). However, most babies with DDH do not have any of these risk factors.
What needs to be done?
The ball needs to be put back into the centre of the cup, and kept there. This helps stimulate natural development of the cup, making its walls deeper, which makes the hip more stable. The younger the child, the greater this potential for normal development.
The first treatment method we use to achieve this is the Pavlik Harness. These simple straps are put onto babies of twelve weeks or younger, as soon as we have diagnosed DDH. The harness does not stop baby moving their hips completely, but limits how much they straighten or cross their legs, as these positions are bad for hip development. Baby will still be able to kick around in the harness, and that helps the hip develop. Remember, a properly fitted harness does not hurt baby, or cause them any distress.
Looking after baby and harness
The Pavlik harness will be specially fitted by a member of our team, as this is key to the treatment’s success. We therefore politely ask that you do not tamper with the harness, or remove it. This means that you will not be able to bathe them at home during their treatment. This treatment carries low complication rates (injury to nerves in the thigh, damage to the bone’s blood supply), but improper fitting can increase their likelihood. Baby will be seen in our clinic every two weeks to ensure that there are no problems, and to allow you to bathe them.
How long is the treatment?
All babies will need repeat ultrasound scans to decide whether the treatment is working. If the hip was dislocated, this will be after two weeks of harness treatment. If the cup is just a little shallow, it will be after six weeks. The harness treatment continues until the hips are seen to be completely normal on ultrasound scan. This is a minimum of six weeks in the mildest cases, but can be as long as three months. Once the harness treatment is completed, baby’s hip development will be checked with x-ray at age 6 months, 1 year and two years.
What if the harness doesn’t work?
The success rates for Pavlik harness treatment range from 90% for mild cases, to 60% for the most severe dislocations. If the ultrasound at two weeks of treatment shows that the femoral head is still dislocated, then we will stop the treatment, to avoid risk to the blood supply of that bone. We will then plan a minor surgical procedure for when baby is 5-6 months old (“closed reduction”).
Research & Audit
In order to continuously improve our service, we are keeping records of all babies that we treat. We analyse these at regular intervals to ensure that we are meeting current and national standards (Audit), and also to see how things could be improved (research). We hope you will be happy to participate in these processes, but if not, please do let us know.
The team
The DDH service at the Jenny Lind Children’s Hospital is delivered by a team of surgeons and physiotherapists. The physiotherapists do most of the harness fitting and checking, but discuss all cases and treatments with the Consultant.
Physiotherapists: Vicky Easton, Simone Hipperson, Beth Lotinga, Fran Sutton
Surgeons: Anish Sanghrajka
What if there are problems?
If you have a problem with a harness or are worried about your baby, please contact the Physiotherapy department at the Jenny Lind Children’s Hospital on 01603286334.
Outside of normal working hours (9am-5pm), please come to the Emergency Department of the main hospital.