A broken bone in a child or adolescent should be treated more carefully than in an adult because of the risk of growth plate injury. A growth plate, also called an epiphyseal plate, is a section of cartilage located at the ends of the long bones of children and teenagers. It is here that new bone develops to add length as the child grows. Once a person has physically matured, usually in adolescence, these plates permanently close to form solid bone.
Growth plate injuries usually occur after a bone fracture (break), and they are a major cause of growth deformities in children and teens. Because the growth plate is where new bone develops, injury to this area can cause the plate to close prematurely and stop bone growth. Fractures in the proximal tibia (top of the shin bone) or distal femur (bottom of the thighbone) are the most common epiphyseal plate injuries that lead to growth stoppage. A child who breaks a leg and experiences a damaged growth plate may develop a limb-length discrepancy, where the healthy leg grows longer than the broken leg. (This type of growth deformity should not be confused with bowleg or knock knees, which are caused by other factors.) Growth plate injuries are also common in the long bones of the fingers, and can occur in joints such as the shoulder, wrist, ankle, or elbow.
Although the fractured bone will be clearly visible on an X-ray, growth plate damage can be harder to detect because the plate is not solid bone and so appears as space. Advanced imagery is usually required to fully assess the damage. It is often recommended that children or teenagers who break an arm or leg get a CT exam. If a growth plate injury is discovered, an MRI may also be useful to determine precisely where the plate has begun to close prematurely.
Fractures involving growth plate injuries usually require a doctor to set the bone. Most children respond well to these procedures. In a small percentage of patients, the bone or a portion of the bone will stop growing. This is called "partial growth arrest" or "physeal bar."
Since there is no way to regenerate the growth plate cartilage after a physeal bar, additional treatments are required. These may include resection (removal) of the partial growth arrest or a limb lengthening procedure. If a child is almost fully grown and experiences a complete growth stoppage in a limb on one side of the body, a pediatric orthopedic surgeon may recommend closing the growth plate in the limb on the other side so that both limbs remain the same length.