The Who, What, When, and Why of Hip Surveillance!
What is hip surveillance and why should I have my child’s hips checked?
Hip surveillance is important to identify and monitor for indicators of hip displacement. Children with cerebral palsy (CP), or other neurological conditions, are at a high risk of developing displacement of the hip joint. This can result in hip dislocation if it progresses. Studies have suggested that the rate of hip displacement in children with CP is around 30%. Children with reduced mobility, that are not able to stand or walk independently, are highest risk for hip displacement. Other factors such as spasticity and contractures of lower limb muscles also increase the risk of hip displacement.
Hip displacement may cause pain for your child. It can also reduce their functional independence by impacting their mobility and making it difficult to position them, which can decrease their quality of life. Therefore, early detection, referral to orthopaedic services, and treatment is important to prevent severity of pain they experience or loss of mobility.
Hip surveillance is an x-ray taken of the hip joint which comprises of the acetabulum (hip socket) and femoral head (top of the thigh bone.) From the x-ray, a migration percentage (MP) is calculated for the left and right hip. The MP is the amount of the femoral head that is not covered by the acetabulum (hip socket). The MP is one of the key measures of change that is monitored by your child’s health professionals to determine the severity of hip displacement and whether surgical interventions are indicated.
In addition to x-rays, physical assessment of your child will occur including assessing the hip joint range of motion, muscle tone, leg length discrepancies, and your child’s level of function.
How often should I have my child’s hips checked?
The timing of the hip x-ray is determined by the severity of your child’s CP or gross motor function, your child’s age, and the timing of previous hip surveillance (if have had). Typically, an x-ray is completed annually until your child’s hips are determined to be stable or your child’s x-ray indicates that they have reached skeletal maturity.
Your child’s physiotherapist will be able to help you understand the frequency of hip surveillance for your child based upon their function and age.
For further information about hip surveillance, please refer to the Australian Hip Surveillance Guidelines, which can be found here.