Do Babies Have Kneecaps When They Are Born?

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Jiaqi Zhou / Verywell

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If you are wondering if your baby has kneecaps, you are not alone. Lots of parents search the web for “do babies have kneecaps?” because they are just as perplexed as you are. 

The question makes sense when you think about it. Baby’s knees are very bendy and not nearly as firm as older children or adults’ kneecaps. This leaves many parents wondering what is going on with those sweet little knees.

So, do babies have kneecaps? When do their knees become more firm? Are baby’s knees more prone to injuries? What else do parents need to know?

We reached out to two doctors—Dr. Chris Airey, medical director at Optimale, and Dr. Pierrette Mimi Poinsett, medical consultant at MomLovesBest—to find out the answer to this question, and to get more information about babies and children’s kneecaps in general.

Do Babies Have Kneecaps At Birth?

According to our experts, baby’s definitely do have kneecaps at birth. However, parents are often confused about that fact for good reason.

“It is kind of a common misconception that babies are ‘born without kneecaps,’” Dr. Airey says. “But this isn't really true. Babies are born with kneecaps made entirely of cartilage, so their knees are called ‘cartilage patellae’ (literally cartilage kneecaps).”

It’s not that babies don’t have kneecaps. It’s simply that their kneecaps are made of different material than older children’s and adult’s kneecaps.

Dr. Airey explains that cartilage is a “flexible, soft substance that protects joints from friction.” If you consider the activities babies do with their little bodies from infancy and beyond, it stands to reason that they would have kneecaps made of this material.

“Less hard bone means an easier exit through the birth canal (for both baby and mom), and having soft, flexible knees is more conducive to all that crawling and toddling we do in our earliest years,” Dr. Airey says.

When Do Babies' Kneecaps Become Firmer?

At a certain point, though, we all develop firmer kneecaps. The process of the patella turning from cartilage to bone is called ossification, and is usually complete by the time your child enters the elementary school years.

“The kneecaps transition to bone between 2 and 6 years of age,” Dr. Poinsett explains. “The process is slow, starting in the center of the kneecaps and moving out to the edges." 

Since the knee joint is made to be flexible, some cartilage is still involved in its operation. The point at which the femur (leg bone) and patella (kneebone) connect is cushioned with articular cartilage. This helps the knee and leg move smoothly together, and protects your knees from injury.

Potential Issues

Though it may seem like your baby’s knee caps are more delicate and sensitive than an older child’s kneecaps, there is nothing to be concerned about. Dr. Poinsett assures that baby kneecaps are not more prone to injuries or health problems than an older child’s kneecaps.

Remember, your baby’s kneecaps are meant to be made of pliable and soft cartilage. No wonder they seem to be able to crawl around without being hurt, and to fold up into cute little balls as newborns!

However, in the transition from baby knees to more mature knees, there are some potential issues that can occur, explains Dr. Airey. Specifically, your growing child might encounter a condition called bipartite patella.

“Since the kneecap forms in pieces that fuse together over time, an issue that can occur is a bipartite patella, where the pieces haven't fused completely and result in a sort of ‘split’ double kneecap,” says Dr. Airey.

“This can sometimes solve on its own, or be managed with physiotherapy. The important thing is to watch for pain and swelling on your child's knee area, as this could indicate a knee issue such as arthritis, or an injury to the tendons or ligaments,” he adds.

Common Knee Injuries

Children, especially ones who are active in sports, are prone to injuries from time to time. However, it’s not usually the kneecaps themselves that become injured.

“Knee pain in children is more likely due to sprain or injury to the ligaments surrounding the knee,” explains Dr. Poinsett. “Kneecap injury occurs but is not common.”

Still, knee injuries do occur and are something parents need to be aware of. The most common types of knee injuries occur because of overuse, sudden twisting, or because of direct impact to the knee and joints surrounding it.

Some of the most common childhood injuries involving the knee, according to Children’s Healthcare of Atlanta, include:

  • Strains and strains
  • Fractures
  • Dislocations
  • Tendonitis
  • Anterior cruciate ligament tears
  • Meniscal cartilage tears
  • Bursitis
  • Patellofemoral Stress Syndrome
  • Articular cartilage injuries

Signs that your child may have a knee injury include:

  • Swelling at the knee location
  • Complaints of pain
  • Stiffness or inability to move the leg or bend the knee

If your child has any of these symptoms, or if you know that they may have suffered a knee injury, you should consult your doctor right away. They may be able to treat the injury themselves, or recommend a specialist, such as a pediatric sports medicine specialist.

A Word From Verywell

Parenting a newborn can be a wild ride, and it’s common to have all sorts of questions—some of which may seem totally random to anyone but you. The funny thing is that most parents wonder about many of the same exact things, and whether or not their wee ones have kneecaps at birth is no exception.

In fact, some parents become concerned about the kneecap question, and wonder if their babies are perhaps more prone to injury until their kneecaps become firmer.

Luckily, babies are born with just the right kinds of kneecaps for their developmental stage, and they are not more vulnerable to knee bumps, sprains, or other injuries.

1 Source
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  1. Children’s Healthcare of Atlanta. The Scoop On Knee Injuries in Young Athletes.

By Wendy Wisner
Wendy Wisner is a lactation consultant and writer covering maternal/child health, parenting, general health and wellness, and mental health. She has worked with breastfeeding parents for over a decade, and is a mom to two boys.