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Growing bones, growing concerns: A guide to growth plates

Published by , on Mar 21, 2019

Kids’ bodies are growing and changing every day and this includes certain parts of their bones. Because of this, the treatment for broken bones and bone injuries in children can be very different than the treatment for adults. Whenever a child has a broken bone or an overuse injury, growth plates – the areas in their bones that are still growing – need to be a special consideration. Here’s what can be helpful to know the next time your child needs an x-ray, cast, splint or other help for a bone injury.

Emergency Room Doctor Examines Girl's Injured WristWhat’s a growth plate? 

A growth plate is an area at the end of long bones that contains cells (called cartilage cells) that are dividing and maturing to become bone. The bone grows in length and width at these areas until the growth plates harden, or close, when a child stops growing. Until then, these areas are more easily injured because they’re not yet as strong as other parts of the bone around them.

On an x-ray, growth plates look like dark lines at the ends of the bones. At the end of growth, when the cartilage completely hardens into bone, the dark line will no longer be visible on an x-ray. At that point growth plates are considered closed.

Typically, girls’ growth plates close when they’re about 14-15 years old on average. Boys’ growth plates close by around the time they turn 16-17 on average. This occurs earlier in some individuals and later in others. Also, different bones’ growth plates close at different times.

What are common causes of growth plate fractures?

Injuries to the growth plates can happen with any type of injury to bones in children and are very common. The fingers, wrist and lower leg bones are where these injuries most often occur, but we see them in all long bones.

Growth plate injuries can occur with a single event like a fall, accident or sports-contact injury. (These types of acute injuries are the most common way they occur.) They can also occur with overuse injuries such as Little League Shoulder or Elbow where kids throw a baseball too frequently or too hard and injure the growth plate. Another example is gymnast wrist – when the growth plate receives too much pressure too frequently. Many of these injuries result from children playing year-round sports without a rest.

Why are growth plate injuries of special concern?

An injury to a growth plate has the potential to stop or alter bone growth if the growth plate is injured enough to stop growing. This typically only happens if there’s a significant enough injury to displace the growth plate (move it out of its normal position), but it can occasionally occur with more minor injuries or injuries to the nearby area.

If an entire growth plate is injured, it can cause growth to stop. If part is affected, the bone can grow in the wrong direction (called an angular deformity) as only part of the growth plate stops growing.

What happens when a growth plate is injured varies based on a child’s age and exactly where the injury occurs. Most often, the younger the patient is, the worse the effects can be. But sometimes, if a child has a fracture (broken bone) near or through the growth plate and it doesn’t injure the growth plate enough to stop growth, the growth plate can actually help to straighten a crooked bone as it grows. Treatment may differ based on the child’s age or the part of the bone that’s affected.

Fractures to the growth plates are less of a concern the closer a child gets to being fully mature, however there’s less room for correcting a deformity at later ages. The more growth a child has left, the more correction of deformity that can occur with growth.

Since growth plates are actively growing, they begin to heal themselves quickly so it’s important to find out within a week if a growth plate is displaced. If a displaced growth plate is found late (more than 7-10 days after the injury happened) there’s a risk of increased injury if it’s not treated properly. Further injury to the growth plate can occur with treatments that move the growth plate back to a normal position if the bone has already started to heal itself.

How are growth plate fractures diagnosed and treated?

Growth plate injuries can be difficult to see on an x-ray because the dark line of a fracture can look the same as the growth plate itself on the x-ray.

If a child is experiencing tenderness right over the growth plate, but the x-ray is normal, we may treat the child for a growth plate fracture even if we can’t see it. (This is called a non-displaced growth plate fracture.)

If the fracture displaces the growth plate, then it will be visible on the x-ray. Sometimes a CT scan, another type of medical imaging, can be helpful to determine the amount of displacement, particularly if the fracture goes through part of the growth plate and also into the joint.

Treatment for a growth plate injury can range from a cast or splint to surgery. Fractures that are not displaced or minimally displaced can be treated with a cast or splint. How much the growth plate is displaced will determine how the bone will need to be put back into a normal or more acceptable position, a procedure called a “reduction” that sometimes involves surgery. Fractures that go into the joint are treated more aggressively and are more likely to need surgery.

Are symptoms of a growth plate fracture the same as a broken bone?

Yes, the signs and symptoms are the same: pain, bruising and swelling with tenderness over the area. Our How do you know when it’s more than just a bump or bruise blog shares more about when to seek care.

Are there other health concerns that affect growth plates?

Since growth plates are areas where a lot of cells are growing and changing, they can be affected if the body doesn’t have enough of the vitamins and minerals it needs for the growth process. Metabolic disorders like rickets, which is associated with a lack of vitamin D or calcium in the body, can cause growth plate problems. Inadequate nutrition, or other issues related to not enough vitamins in the body, also lead to these types of issues.

Who can help with these injuries?

With so many complexities related to growth plates, and the potential for permanent changes that can occur if they’re not effectively treated, it’s important to have someone who’s knowledgeable about pediatric fractures and growth plates involved in a child’s care. There are specialists in pediatric orthopaedics with training and expertise managing these types of injuries if the general orthopaedist in your area does not treat many children.

By Dr. Victoria Kuester, orthopaedic surgeon

Recommended resource for more about growth plates: I Broke My Growth Plate

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