Growth Plates: What You Need to Know

Growth plates are zones of cartilage in children at each end of our long bones (the femur and tibia, for example), explains Robert Lark, MD, a pediatric specialist at Duke. These bones grow by the contribution of new bone from the growth plate.  Because of their soft nature, these parts of the bone are vulnerable to injury during the development of a child. This is a region of the bone that is sometimes weaker than the surrounding tendons and ligaments. Since injuries tend to happen through the weakest area, up to 30% of fractures in children can occur around the growth plates. Growth plates can also be affected by certain medical conditions.

It is difficult to predict exactly when each growth plate will close because of individual variation and because different bones stop growing at different times, explains Melissa Allen, MD, a Duke pediatric orthopaedic surgeon. There is an average time when the growth plates in the long bones usually close, though.

Most children grow an average of two years after they have completed their most rapid pubertal growth spurt. The age at which puberty starts is quite variable depending on many factors including race, gender, physique, and genetics. On average, females stop growing around age 13 to 15, and boys around age 15 to 17. Certainly, many children continue to gain some height into their late teen years, but the vast majority of growth is over by these ages.

Your pediatrician likely has been monitoring your child’s height and weight on growth charts. You can estimate remaining growth based on these charts. 

Orthopaedic surgeons also use multiple X-ray markers from the hand or pelvis to better estimate the amount of growth a child has remaining, explains Dr. Lark. A good rule of thumb is that once a child has reached the end stages of puberty, the growth plates are essentially closed.