Growth Plate Fracture
The epiphysis is located at each end of a long bone, the diaphysis is the middle of the bone, and the metaphysis is inbetween the epiphysis and diaphysis. The "physis" is the growth plate. Not how on the xray, the physis looks black - that is because the physis is made of cartilage and has no calcium. The calcium in the bone is what makes the bone appear white on an x-ray.
Fracture to growth areas are quite common during childhood. In any time of trauma situation, the structure that fails is the weakest structure. Cartilage is weaker than bone, and in young children, the surrounding ligaments are stronger than the surrounding physis. This is why young children rarely sprain their ankles (a sprain is a ligament injury). Instead, young children will break through the growth area of the bottom part of the fibula bone when they twist their ankles.
In the minor traumas, such as the ankle twist that results in a growth plate fracture, permanent growth problems rarely occur. However, in other injuries, such as a fracture to the bottom of the femur bone or top of the tibia bone, even if the fracture is perfectly fixed, it may result in a partial or complete growth arrest.
A partial growth arrest literally means that part of the growth area is growing, but another part is not. If this were to happen, rather than a limb growing straight, it would grow crooked. A complete growth arrest, on the other hand, denotes that the limb will not grow at all. Rather than a crooked bone, it will be shorter compared to the other side. It is important after a fracture to the growth area, especially if around the hip, knee, or ankle, to continue seeing your clinician until he or she has cleared your child. It may take up to 1 year to detect a growth problem, depending on the rate that your child is growing.