The growth plate (also known as the physis or physes (plural) is located at the ends of bones. It allows for normal joint function while leaving room for the bones to get longer.
The physis is a complex structure with many different types of cells (bone, cartilage, collagen) and multiple layers. There is a network of tiny blood vessels called capillaries to supply the area with nutrients and oxygen.
It is unique because it must be flexible enough to grow (i.e., it has not yet hardened into bone). But it must also be strong enough to withstand tension, compression, and shear loads placed on it during the many and varied activities of children.
One of the big dangers of physeal injury is the formation of a physeal bar. In the process of healing, bone is laid down across the break in the physis. A bar of bone is created that essentially stops any further growth of the physis on one side. The other side continues to grow causing angular deformities and uneven bone growth.
Scientists don’t know a lot about physeal bar formation. They have been able to show that if only a small part of the physis is damaged, then bar formation does not occur. Until it is known the exact mechanism by which this bar forms, we are powerless to stop it from happening. Research is actively seeking ways to unlock the mysteries of this problem.
Once they form, then what? The bar can be removed surgically. The surgeon must put a piece of graft tissue (often fat harvested from some other part of the body) in the space created by cutting the bar out.
Without this interposition tissue, the bone will just grow right back again. Animal studies are being done to find ways to stop physeal bar formation. Until that happens, research is also looking into finding better ways to support the physis after bar resection.