I had the great fortune of helping out at a fantastic car seat check event a few weeks back where I met with 4 different families. While their car seats and children could not have been more different, all 4 of them asked me the same question: isn’t having bent legs (while rear facing) bad for a child’s hips?
I see this quite a bit on the internet- inevitably whenever a news source writes about a new law or rear facing evidence, someone comments that sitting with the legs bent is going to forever stunt the growth of a child or cause hip dysplasia or otherwise damage a baby’s developing bones. So it seems like it’s time to delve into the research and maybe dust off my physical therapy degree.
Myth: Having legs bent or in a frogged position when rear facing can cause damage to the hip/knee joints and associated bones.
First, let’s look at hip dysplasia. This is obviously a concern for many parents of infants. Hip dysplasia occurs when the hip “socket” is not deep enough, typically at birth. This is common in babies who are breech, first babies and in multiples. When babies have dysplasia, the first line of treatment is a harness. This harness attaches to the baby’s trunk and a series of straps pull the hip into flexion and abduction, basically a frog leg position.
Which is oddly similar to how big kids sit while rear facing. So it stands to reason that if the child sits in the position a hip dysplasia harness would hold them in rear facing, that there’s no significant risk of hip dysplasia from extended rear facing. Also worth noting is that by the time kids reach the age where their legs are scrunched, they are typically standing/walking, which helps deepen that hip socket and vastly reduces the risk of hip dysplasia.
Okay, so I feel like we’re good on the dysplasia part. So what about bone growth?