The importance of recognising hip dysplasia in new-borns

Developmental Hip Dysplasia (DDH) is a condition where a baby's ball and socket hip joint does not fit together as it should. There may be a complete dislocation of the femoral head and the acetabulum (socket of the hip bone) or there may be a partial dislocation, also known as a ''subluxation''. A failure to diagnose DDH during early childhood can result in disabilities in later life.

The Department of Health's ''Healthy Child Programme'' (HCP) recommends all new-born babies undergo a comprehensive new-born physical examination within their first 72 hours of life. Part of this is to check the baby's hips for DDH. This is normally done by laying the baby on their back and gently moving the legs apart. If there is a ''clunk'',  it may indicate that the femoral head and acetabulum are detached.

A six to eight-week GP examination (also known as the Child Health Surveillance) should also include a check of the baby's hips.

A familial history of DDH increases the chances of it occurring in subsequent new-borns. There is also an increased risk of DDH if the baby was in the breech position at or after 36 weeks and/or was born in the breech position. A first-born baby is also more likely to have DDH. The baby may show asymmetry in the creases at the top of the thighs and there may be a 'deeper' crease on the affected side.

There are various reasons why a child's DDH may not have been diagnosed in the first few weeks of life. It may be because the condition only presented itself later in life or because the baby was born without any risk factors and the dislocation was minimal and therefore difficult to pick up. Bilateral DDH (where both hips are dislocated) is often more difficult to pick up due to the lack of a normal 'comparator' hip. However a failure to diagnose DDH may represent substandard care.

As the child grows there may be a failure to reach certain milestones. Common signs of DDH to be aware of are:

1. an inability to sit independently
2. a ''dragging' of one leg when crawling (commando crawling)
3. walking late and/or walking with a pronounced limp
4. appearing excessively unstable when walking and difficulty with ascending and descending stairs
5. stiff hip or hips – i.e. a restriction of movement in both hips or in one hip compared to the other
6. leg length discrepancy
7. an abnormal gait
8. asymmetrical thigh creases

Early diagnosis often means straightforward treatment with the use of a splint for 6–12 weeks. Regular reviews over the following 2-3 years will ensure that the hip or hips are developing normally. Early diagnosis therefore may mean corrective surgery is not needed.

Late diagnosis of hip dysplasia can lead to various problems in later life, including increased pain and surgery during childhood (usually an osteotomy) and subsequent surgery to remove the plates and screws. As the child gets older they may suffer from premature arthritis and require hip replacement surgery (and revision surgeries) which includes associated risks such as infection, dislocation and creating or exacerbating leg length discrepancy. There will likely be a decrease in tolerance for exercise. There may be a requirement for care and assistance with daily tasks as the child becomes an adult.

There is no ''cut-off'' point for diagnosing DDH to avoid these problems; it will depend on the individual facts. But as a general rule of thumb, if a child is diagnosed before the age of two, effective treatment should allow normal development of the hips.