What the Heck is a Growth Plate?

Children are not just “little adults” when it comes to examining their bones and joints.  The fact that they are in such a rapid period of growth makes their musculoskeletal system extremely unique.  You may have heard your pediatrician talk about your child’s growth plates in their bones, but here’s an explanation of what they are, why they are important, and common injuries.

What is a growth plate?  The growth plate (also known as the physis) is the soft part and area of growing tissue near the ends of the long bones in children and adolescents.  The important thing to remember is that because of their soft nature, growth plates are extremely vulnerable to injury, and are weaker than the surrounding tendons and ligaments.  The opposite is true in adults – once a growth plate closes, the bone is stronger than the surrounding tendons and ligaments. 

When do growth plates go close?  Not all growth plates in the body close at the same time.  However, growth plates are all closed at skeletal maturity, which means that a person’s growth is complete.  For women this means after they begin their menses (about 14-17 years), and for men this occurs at about 18-22 years.  Just prior to puberty, most growth plates increase their rate of contribution to growth.  Girls tend to reach their peak growth at around 13-14, while boys are slight later (around 14-15). 

What are growth plate fractures?  A fracture is the same as a break.  Just like any other part of the bone, the growth plate can sustain a fracture.  And because the growth plate is soft and weak, it is more susceptible to fracture.  A fracture can be just through the growth plate, or can be through both the growth plate and other parts of the bone at the same time.  Simple growth plate fractures cannot be seen on an x-ray because the growth plate is not calcified. 

How are growth plate fractures treated?  Growth plate fractures are treated like any other fracture – with immobilization and rest.  Your doctor will likely get follow-up x-rays as well to determine the fracture is healing appropriately. 

What other common growth plate injuries are there?  Overuse injuries involving growth plates attached to tendons are also very common, and is otherwise known as apophysitis (as discussed in an earlier post).  Common sites of apophysitis are the knee (Osgood-Schlatter’s disease), the elbow (Little League elbow), and the heel (Sever’s disease).

Kids don’t sprain stuff.  Because growth plates are the weakest part of joints in kids, it is more likely for your child to sustain an injury to the growth plate before he or she sustains a sprain to the ligament of a joint like the wrist or ankle. 

As a parent, it is usually clear if a child injures a growth plate – he or she will favor the involved joint and complain of pain.   Take note if your child complains of pain after a fall or injury and remember that there is a high likelihood that the growth plate is involved.

Rachel Brewer, MD