Growth Plates
How Bones Grow
In a newborn, a bone starts out as a shaft with cartilage at each end. Slowly the cartilage at each end transforms into bone. At this point there is a thin section of cartilage at the end of the bone. This is the Epiphyseal Plate (or growth plate). The cells in this section grow in a different way than the rest of the bone and this allows it to get longer. This is also the weakest section, and it is here that injuries tend to occur when the bone is overloaded.
Injuries To The Growth Plate
When a growth plate is injured it causes it to close over prematurely, stopping the bone from lengthening any further. Damage to this section can be very painful and you’ll know about it immediately. You will also notice the difference in bone length over time as an injury to the right femur (thigh bone) will only stop the growth in the right femur, so the left femur will keep growing until it reaches its maximum length.
Fortunately, these injuries are not very common. If you follow some simple guidelines your child will have next to no chance of injury.
What Causes Growth Plate Injuries?
Growth plate injuries can be caused by an event such as a fall or blow to the limb, or they can result from overuse. For example, a gymnast who practices for hours on the uneven bars, a long-distance runner, and a baseball pitcher perfecting his curve ball can all have growth plate injuries.
Although many growth plate injuries are caused by accidents that occur during play or athletic activity, growth plates are also susceptible to other disorders, such as bone infection, that can alter their normal growth and development. Other possible causes of growth plate injuries include the following:
- Child abuse - More than 1 million children each year are the victims of substantiated child abuse or neglect. The second most common injury among abused children is a fracture, and growth plate injuries are pre
valent because the growth plate is the weakest part of the bone. - Injury from extreme cold (for example, frostbite) - Exposure to extreme cold can damage the growth plate in children and result in short, stubby fingers or premature degenerative arthritis (breakdown of the joint cartilage).
- Radiation and medications - Research has suggested that chemotherapy given for childhood cancers may negatively affect bone growth. Prolonged use of steroids for inflammatory conditions such as juvenile idiopathic arthritis can also harm bone growth.
- Neurological disorders - Children with certain neurological disorders that result in sensory deficit or muscular imbalance are prone to growth plate fractures, especially at the ankle and knee. Children who are born with insensitivity to pain can have similar types of injuries.
- Genetics - The growth plates are where many inherited disorders that affect the musculoskeletal system appear. Scientists are just beginning to understand the genes and gene mutations involved in skeletal formation, growth, and development. This new information is raising hopes for improving treatment for children who are born with poorly formed or improperly functioning growth plates.
- Metabolic disease - Disease states such as kidney failure and hormone disorders can affect the growth plates and their function. The bone growth of children with long-term conditions of this kind may be negatively affected.
Signs That Require a Visit to the Doctor
inability to continue play because of pain following an acute or sudden injury- decreased ability to play over the long term because of persistent pain following a previous injury
- visible malformation of the child’s arms or legs
- severe pain from acute injuries that prevent the use of an arm or leg.
What Are the Different Types of Growth Plate Injuries?
Since the 1960s, the Salter-Harris classification, which divides most growth plate fractures into five categories based on the type of damage, has been the standard. The categories are as follows:
Adapted from Disorders and Injuries of the Musculoskeletal System, 3rd Edition. Robert B. Salter, Baltimore, Williams and Wilkins, 1999. Used with the author’s permission.
Type I
Fracture through the growth plate: The epiphysis is completely separated from the end of the bone or the metaphysis, through the deep layer of the growth plate. The growth plate remains attached to the epiphysis. The doctor has to put the fracture back into place if it is significantly displaced. Type I injuries generally require a cast to protect the plate as it heals. Unless there is damage to the blood supply to the growth plate, the likelihood that the bone will grow normally is excellent.
Type II
Fracture through the growth plate and metaphysis: This is the most common type of growth plate fracture. It runs through the growth plate and the metaphysis, but the epiphysis is not involved in the injury. Like type I fractures, type II fractures may need to be put back into place and immobilized. However, the growth plate fracture heals a great deal, especially in younger children. If it is not too displaced, the doctor may not need to put it back into position. In this case, it will strengthen with time.
Type III
Fracture through growth plate and epiphysis: This fracture occurs only rarely, usually at the lower end of the tibia, one of the long bones of the lower leg. It happens when a fracture runs completely through the epiphysis and separates part of the epiphysis and growth plate from the metaphysis. Surgery is sometimes necessary to restore the joint surface to normal. The outlook or prognosis for growth is good if the blood supply to the separated portion of the epiphysis is still intact and if the joint surface heals in a normal position.
Type IV
Fracture through growth plate, metaphysis, and epiphysis: This fracture runs through the epiphysis, across the growth plate, and into the metaphysis. Surgery is frequently needed to restore the joint surface to normal and to perfectly align the growth plate. Unless perfect alignment is achieved and maintained during healing, prognosis for growth is poor, and angulation (bending) of the bone may occur. This injury occurs most commonly at the end of the humerus (the upper arm bone) near the elbow.
Type V
Compression fracture through growth plate: This uncommon injury occurs when the end of the bone is crushed and the growth plate is compressed. It is most likely to occur at the knee or ankle. Prognosis is poor, since premature stunting of growth is almost inevitable.
A newer classification, called the Peterson classification, adds a type VI fracture, in which a portion of the epiphysis, growth plate, and metaphysis is missing. This usually occurs with open wounds or compound fractures, and often involves lawnmowers, farm machinery, snowmobiles, or gunshot wounds. All type VI fractures require surgery, and most will require later reconstructive or corrective surgery. Bone growth is almost always stunted.
How Are Growth Plate Injuries Treated?
Treatment for growth plate injuries depends on the type of injury. In all cases, treatment should be started as soon as possible after injury and will generally involve a mix of the following:
Immobilisation - The affected limb is often put in a cast or splint, and the child is told to limit any activity that puts pressure on the injured area.- Manipulation or Surgery - If the fracture is displaced (meaning the ends of the injured bones no longer meet as they should), the doctor will have to put the bones or joints back in their correct positions, either by using his or her hands (called manipulation) or by performing surgery. Sometimes the doctor needs to fix the break and hold the growth plate in place with screws or wire. After the procedure, the bone will be set in place (immobilized) so it can heal without moving. This is usually done with a cast that encloses the injured growth plate and the joints on both sides of it. The cast is left in place until the injury heals, which can take anywhere from a few weeks to 2 or more months for serious injuries. The need for manipulation or surgery depends on the location and extent of the injury, its effect on nearby nerves and blood vessels, and the child’s age.
- Strengthening and Range-of-Motion Exercises - These are exercises designed to strengthen the muscles that support the injured area of the bone and to improve or maintain the joint’s ability to move in the way that it should. Your child’s doctor may recommend these after the fracture has healed. A physical therapist can work with your child and his or her doctor to design an appropriate exercise plan.
- Long-Term Followup - Long-term followup is usually necessary to monitor the child’s recuperation and growth. Evaluation includes x rays of matching limbs at 3- to 6-month intervals for at least 2 years. Some fractures require periodic evaluations until the child’s bones have finished growing. Sometimes a growth arrest line (a line on the x ray where the bone stopped growing temporarily) may appear as a marker of the injury. Continued bone growth away from that line may mean there will not be a long-term problem, and the doctor may decide to stop following the patient.
How To Ensure Your Child’s Safety when exercising
- Warm up properly - The warm up needs to start gently and slowly build in intensity. It should last a minimum of five minutes. A section of the warm up also needs to be specific to the task being undertaken in the main part of the program. For example, if your child was planning on playing basketball they may start by going for a five minute run then lightly running up and down the court in various directions, jumping, passing, blocking, etc. If they are training with weights they may ride a bike for five minutes then perform a light set of each exercise that they are planning on completing in that session.
Avoid highly repetitive activities - The most common injury to the epiphyses occurs in baseball when children are made to pitch too much. As their bodies are developing they need as much variety as possible. High repetition at a young age will always cause an injury to the bone, muscle, or joint.- Weight training should always be supervised - It is absolutely essential to have a qualified trainer available to supervise weight training sessions. This person should know the correct technique for all lifts and should also ensure the child never lifts heavy weights. A heavy weight would be something that could only be lifted 1-5 times. Lifts such as Shoulder Press and Squats should also be done using a lighter weight.
If you have any questions please consult your doctor or pharmacist