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Overview of growth plates

Mō ngā wharanga papatupu

How children grow. Cartilage forms in the growth plate near the end of a bone. Over time it becomes solid bone and new cartilage forms above it.Growth plates (also called physes) are the parts near the ends of the long arm and leg bones of tamariki (children), where the bones grow.

They are discs of cartilage (a rubbery, flexible tissue) between the long, middle part of the bone (the shaft) and the area where the bone gets wider at its end (the metaphysis).

When our bones stop growing (called reaching skeletal maturity), these growth plates harden so the bones are hard and continuous.

Girls tend to reach skeletal maturity earlier than boys. Their growth plates usually harden when they are 13 to 15 years old, while boys' growth plates harden when they are around 15 to 17.

Before a tamaiti (child) stops growing, they can injure their growth plates just as they can injure the rest of their bones.

Types of growth plate injuries

Five types of growth plate injuries. They can be through the growth plate, through the growth plate and long part of the bone, through the growth plate and end of bone, through all three parts, or crush injuriesGrowth plate injuries are very common in tamariki children , making up 15 to 30% of all childhood bony injuries.

An adult whose bones have finished growing might simply pull a muscle or a tendon after a fall. But in a tamaiti, that same fall could injure a growth plate.

The effect of a growth plate injury on future growth depends on the type of injury, which bone is injured (knee growth plates are more likely to stop growing) and how much the tamaiti still needs to grow.

There are five different types of growth plate injuries, shown in the illustration on the right.

Causes of growth plate injuries

Most growth plate injuries happen from falling or twisting. They often happen during contact sports, like rugby or netball, or fast-moving activities like skiing, skateboarding or biking. They can also happen from repetitive training for activities like gymnastics, athletics, or throwing a cricket or softball.

Less common causes of growth plate injuries include exposure to extreme cold, medical conditions that affect bone growth (such as infection, tumours, and vitamin deficiencies), and medicines that can affect bone growth (such as treatments for arthritis or cancer).

Symptoms of a growth plate injury

The symptoms of a growth plate injury are the same as a broken bone. If your tamaiti child has injured a growth plate they may:

Diagnosing a growth plate injury

If you think your tamaiti has injured a bone, it's important to seek treatment. The doctor or nurse you see will ask you questions about your child's injury, and examine their arm or leg.

Most growth plate injuries are diagnosed from X-rays. But because growth plate injuries can be difficult to see on X-ray, your doctor may X-ray both arms or both legs for comparison. Often the joint above and below the growth plate will also be X-rayed, to make sure there are no other injuries. Very occasionally, a child might need extra imaging such as a CT, or MRI scan.

Treating a growth plate injury

Treatment for growth plate injuries depends on what type of injury it is. If the bones are still together and facing the right way (undisplaced injury) the first treatment is to rest, and not put any weight on the affected arm or leg. Often, this means wearing a cast, splint, or brace over the area to stop it moving.

If bones are out of place, they may have to be put back into place through a gentle procedure called a reduction. If needed, a reduction will usually be done in the after-hours clinic, hospital emergency department, or operating theatre, after the tamaiti has been given pain relief medication. Afterwards, the tamaiti may wear a cast, splint, or brace to make sure the bones do not move out of place.

If your tamaiti has a complicated injury, they may need surgery to realign the bones. The surgeon may insert surgical plates, screws, or wires to hold the bone in place so it heals normally. After surgery, some tamariki children will wear a cast or splint.

On the next page: Helping my child with a growth plate injury

Written by HealthInfo clinical advisers. Last reviewed March 2022.


Page reference: 371236

Review key: HIGPI-371216