By Dr Nicole Williams, Paediatric Orthopaedic Surgeon, researcher and Mum to two young girls.
As a paediatric orthopaedic surgeon, one of the most common conditions I treat in babies and young children is developmental dysplasia of the hip (DDH). In this condition, the ball and socket of the hip joint aren’t forming perfectly. Some cases are subtle, with only a slight change in the shape of the socket. In other cases, the ball of the hip joint ball is completely dislocated from the socket. If not treated, children can go on to develop a limp, pain and may need a total hip replacement for arthritis as a young adult. Around 1 in 150 Australian children will undergo treatment for DDH.
Most cases of DDH are detected by examining baby’s hips as a newborn, but rates of DDH diagnosed in children older than 3 months of age have been increasing in Australia. In South Australia where I work, this means we are seeing around 15 new “late-diagnosed” cases per year whereas we saw only 3 or 4 late-diagnosed cases per year up until 15 years ago. This is a concern, because while treatment started as a newborn usually involves a relatively short period of bracing or splinting, older babies and walking age children are much more likely to need surgery, casting and a much longer period in a brace. Also, older babies and children are less likely to have a completely normal hip after treatment.
We don’t know exactly why rates of DDH in older babies and children have risen. It is likely that many factors are at play. The good news is that there are things we can do to reverse this trend and something that just might help is wearing your baby in the right sort of carrier.
In cultures where the most common way to transport babies and children is in slings or wraps with their legs spread around Mum, such as in the native sub-Saharan African population, cases of DDH are rare. In fact, they are so rare that DDH cases diagnosed in certain cultural groups used to be written up in medical journals as a curiosity. By contrast, other cultures, such as the Canadian First Nations People and Native Americans, used traditional carriers such as cradleboards, with baby’s legs held out straight and swaddled together. In these cultures as many as 1 in 10 children were diagnosed with DDH.
A family history of DDH is also a strong risk factor for DDH but genetics cannot completely account for this phenomenon. This is because when these two contrasting groups abandon their traditional babywearing and adopt practices such as using prams, rates of DDH change to become more like the society into which they are integrating.
So how does appropriate baby or toddler wearing promote hip development? A newborn baby’s hips are mainly made of cartilage and the socket is quite shallow. As hips grow, the cartilage is replaced by bone and the socket deepens. This happens rapidly in the first few years. During this period of rapid hip development, the hip can be encouraged to develop optimally by ensuring the ball and socket are well-aligned. This is the principle behind using a splint or “harness” to treat DDH. When baby is put in a device with the thighs spread apart (abducted), legs bent a little at the hips (flexed) and allowed to bend at the knees, this is the position where the ball usually sits best in the socket. This also aligns the muscles around the hip so that when they contract, this helps to centre the ball in the socket. It makes sense then that wearing baby in a carrier that holds baby’s legs in a similar abducted and flexed position (sometimes called the “M” position) would be the healthiest position to encourage baby’s hips to develop nicely.
As a Mum, wearing my girls in a carrier which keeps the legs in the “M” position is a no-brainer for me. Who would have thought that something as convenient and enjoyable as having my small person snuggle against me in a carrier might also be giving her hips the best start possible?
Dr Williams has enjoyed carrying her big girl in Adapt and Ventus carriers and her little girl in an Adapt carrier, provided by Ergobaby.
Further information about DDH in Australia can be obtained from Healthy Hips Australia (www.healthyhipsaustralia.org.au). Further information about DDH and carriers can be obtained from the International Hip Dysplasia Institute (http://hipdysplasia.org/baby-wearing/).
Studer, K., N. Williams, G. Antoniou, C. Gibson, H. Scott, W. K. Scheil, B. K. Foster and P. J. Cundy (2016). “Increase in late diagnosed developmental dysplasia of the hip in South Australia: risk factors, proposed solutions.” Med J Aust 204(6): 240.
Loder, R. T. and E. N. Skopelja (2011). “The epidemiology and demographics of hip dysplasia.” ISRN Orthop 2011: 238607.
Graham, S. M., J. Manara, L. Chokotho and W. J. Harrison (2015). “Back-carrying infants to prevent developmental hip dysplasia and its sequelae: is a new public health initiative needed?” J Pediatr Orthop 35(1): 57-61.