Developmental Dysplasia of the Hip/Hip Dysplasia – what do you know about it?


June is the international awareness month for Developmental dysplasia of the hip (DDH).

DDH is a common and preventable cause of childhood disability. Unfortunately, a late diagnosis of the condition leads to a higher chance of needing surgery and a higher risk of long-term complications. Despite the introduction of national screening programmes, which in some cases also include universal screening of newborns, late diagnosis of the condition still occurs.

It is of vital importance that Steps, along with international organisations, work together to reduce late diagnosis and improve training and education of healthcare professionals involved in the physical examination of neonates and infants.

As a late diagnosis is usually detected after 3 months of age, a further assessment after the six to eight-week check should be introduced as part of the national guidelines.

What is hip dysplasia?

Hip Dysplasia is the most common paediatric hip condition. It impacts the baby’s hips as follows: one or both hips can be shallow, not lying fully in joint or dislocated.

The condition presents itself in approximately 1-3% of infants per 1000 births and is more common in girls and firstborns. It is estimated that you are 12 times more likely to develop it if there is family history of hip dysplasia. If left untreated it can get worse and need surgery.

The exact cause or causes of Hip Dysplasia are yet not known. The condition is defined as ‘developmental’ and this is because the condition is known to develop around the time of birth, after birth, or even during childhood.

When and how is hip dysplasia detected?

Hip dysplasia in babies is most frequently discovered at the time of the newborn physical examination by physicians, according to national screening pathways. The aim of the screening pathways is to identify all cases of hip instability and dysplasia so that observation and/or early appropriate treatment leads to normal hip development.

It is important to understand that 15% of children worldwide are born with some sort of hip instability. The challenge is to differentiate between a hip instability, which would spontaneously correct itself, from that which may lead to symptoms and a severe diagnosis.

To date, there is still no consensus as to which programme is best placed to detect DDH. In some countries all babies undergo universal screening, where every baby is subject to an ultrasound. Other national health providers prefer to apply selective screening programmes, whereby a baby is ‘selected’ for an ultrasound based on key risk factors.

The preferred option internationally seems to be neonatal screening with or without ultrasound. Universal ultrasound screening remains controversial as it might cause overtreatment of neonatal hips which should be avoided particularly if there is a risk that such treatment might harm the baby.

What are key risks factors?

DDH can happen to any baby but some factors, called ‘risk factors’, make the condition more likely. When risks factors are present, depending on the national pathway, a newborn baby might be referred for an ultrasound.

Unfortunately, to date there is no international consensus in deciding what constitutes a significant risk factor. National health systems will apply their own risk factors to determine if there is a need for an ultrasound. The most common risks factors are:

  • Breech presentation
  • Multiple Births
  • Hip instability and or physical signs suggesting of a possible dislocated hip
  • Positive Family History

Will DDH be always picked up during the neonatal physical examination?

The hip checks are not 100% accurate. The physical examination only detects hip instability at the time of the examination. DDH is a developmental condition therefore it can develop at a later stage. However, there is also the possibility to miss DDH in an infant if the clinical examination is performed by untrained or inexperienced examiners and especially in the absence of risk factors

Why is it difficult to detect DDH a later stage?

DDH is not painful and therefore it can be difficult to diagnose in infants. It is usually detected by parents or grandparents who seems to comment on the way a child walk.

Potential symptoms may include;

  • asymmetric buttock creases
  • inequality in leg lengths
  • hip clicks or pops
  • when changing a nappy one leg does not seem to move outwards as fully as the other or both legs seems restricted.
  • the child crawls with one leg dragging
  • history of incorrect swaddling

In older children a limp if one leg is affected or waddling walk if both hips are impacted.

A DDH diagnoses can only be confirmed by either ultrasound or x-ray imaging.