Growth plate fractures
Growth plates are areas of cartilage within the bone that allow a child’s bone to grow in length and width. The growth plate is weaker than the rest of the bone, and thus is a frequent area of injury. A growth plate fracture can occur quite unexpectedly due to the sensitive nature of this area of the skeleton, often from injuries that would cause only joint sprains in adults.
Growth plate fractures are very common injuries. Most fractures of the growth plate do not result in any problems, however, sometimes the fracture injures enough of the growth cartilage to prevent it from growing properly. Thus, it is important to seek care quickly for a growth plate fracture.
The growth plate, also known as the epiphyseal plate or physis, is composed of hyaline cartilage. It is present in all long bones of growing children. The growth plate is separated into several zones:
- Calcified cartilage zone
- Hypertrophic cartilage zone
- Ossification zone
- Proliferative zone
- Resting zone
Cartilage develops into bone when a fetus is in utero and during the earliest stages of life, as a result of an essential process known as “endochondral ossification,” which occurs in the growth plates. These bones continue growing in length throughout childhood and adolescence due to the same process.
Growth plates contain chondrocytes which are continuously dividing during the process of mitosis. This process involves the separation of the chromosomes in the nucleus into two separate but identical nuclei, or “daughter cells.” The new cells stack on top of one another facing the rounded end of the bone, or the epiphysis, and older cells are pushed out to the long midsection of the bone, or diaphysis, where they are ossified to create new bones. When humans go through puberty, the body produces increased levels of estrogen (both in boys and girls), which in turn leads to an increase in the process of programmed cell death, known as apoptosis. As puberty continues, ossification slows down, eventually stopping entirely when cartilage has been entirely replaced by bones and growth is no longer necessary. Once a person reaches adulthood, the growth plate evolves into what is known as an epiphyseal line, which no longer has the capacity for growth.
This is a very common type of fracture with a well-developed set of treatment options. Growth plates are involved in approximately 15 percent of all fractures that occur in children, often as a result of falls and injuries to the limbs. Growth plate fractures are most common in the fingers, forearms, lower legs and wrists. These are some of the most common growth plate fracture causes:
- Basketball, dancing, football, gymnastics, running and other sports
- Biking, skiing, skateboarding, sledding and other recreational pursuits
- Car accidents
- Overuse (common in children who train for sports)
The symptoms will vary depending on the type of growth plate injury and the severity of the fracture. Some of the most serious growth plate fracture symptoms include visible malformations in the arms and legs and difficulty playing sports or engaging in other physical activities. These are some of the other most common growth plate fracture symptoms:
- Acute and ongoing pain
- Inability to move the injured part of the body
- Inability to put pressure or weight on the injured part of the body
There are five major types of growth plate fractures, which are also known as Salter-Harris fractures:
- Transverse fractures through the growth plate (Salter 1)
- Fractures through the metaphysis and growth plate (Salter 2)
- Fractures through the epiphysis and growth plate (Salter 3)
- Fractures through the epiphysis, metaphysis and growth plate (Salter 4)
- Growth plate compression fractures (Salter 5)
The risk of growth problems is related to the type of growth plate fracture, the amount of force that resulted in the fracture, which bone is injured and the age of the patient. The more force that caused the fracture, the more likely the bone will stop growing. Some growth plates are much more sensitive to injury than others. While your surgeon may try to align the growth plate as perfectly as possible, this does not guarantee that a growth problem can be avoided.
If you believe a child in your care has suffered a growth plate fracture, it’s important to seek treatment right away, especially if they are experiencing pain and difficulty moving as a result of the injury. The method of treatment will depend on the type of fracture and the acuteness of the injury. In mild cases, the child may need only a splint or cast to heal, but in more serious cases surgery may be required.
Ongoing observation after healing may also be required to ensure proper growth. Returning to the doctor periodically to measure the injured limb’s growth in comparison to its corresponding limb is recommended in certain cases. With proper treatment and maintenance, most growth plate fractures will heal without significant problems.