GROWTH PLATE ARREST
Raymond Liu, M.D.
A growth plate is the area where bone grows. The growth plate, known as the physis, is typically located at both the top and bottom of most long bones in the body. A growth plate arrest refers to when the growth plate in the bone of a growing child is not functioning properly. This can lead to shortening and/or deformity of the bone. Growth plate arrest can occur after fracture through the growth plate, infection, or other processes affecting the growth region.
Growth plates are located in a child’s long bones, such as the femur or thigh bone, or the tibia or shin bone. Growth plates are generally located near the ends of the bones, between two regions of the bone terms the epiphysis and metaphysis. The epiphysis is the portion of the bone closer to the joint, and the metaphysis is the portion of the bone further from the joint. Growth plates appear as dark lines within the bone because they are made of cartilage, which is dark on x-rays.
In general, a growth plate arrest involves a physeal bar, which is where bone goes from one side of the growth plate to the other, preventing normal growth. There are two main types, complete and partial.
With a complete physeal bar enough of the growth plate is spanned by bone that it cannot grow at all. In this case, the bone ends up shortened compared to the opposite normal bone which is still growing normally.
With a partial physeal bar, one side of the growth plate doesn’t grow due to the bar, but the other side can still grow. This leads to a bone which is both angulated (crooked) and short.
A common cause of growth plate arrest is trauma. Certain types of fractures are more commonly associated with growth plate arrest. For example, there is a fairly high rate with fractures in the distal femur, which is the portion of the thigh bone close to the knee. Fractures which go through the growth plate but then continue into the joint region are also more commonly associated with growth arrest. In rare instances, a crush type fracture occurs and is initially associated with normal x-rays, but then leads to a growth arrest.
Other conditions can also lead to physeal arrest, although this is less common. Infection, tumors, radiation treatment, problems with blood supply, and surgery around the region can all lead to physeal arrest.
The growth plate arrest itself generally does not cause any symptoms. However, the shortening and angulation of the bone can lead to limping, obvious deformity of the arm or leg, or pain with activities.
Your surgeon will look carefully for signs of differences in bone lengths. In the legs this is generally done by adding blocks under the short leg until the pelvis is level. In the arms this is generally done by observing the upper arms from the backside with the elbows bent and comparing the heights of the elbows, as well as comparing the lengths of the forearms side by side..
Radiographs are important to measure the difference in limb lengths, evaluate for a physeal bar, and determine if there is any angulation in the bone. MRI or CT scans are very useful to further evaluate physeal bars, both to determine if they truly exist and to determine how big they are and where they are precisely located.
If the difference in limb lengths and any angular deformity is mild then simple treatments such as a small shoe lift to balance the two sides may be adequate. Sometimes physical therapy is attempted in a child with mild deformity to see if symptoms will resolve with strengthening.
A variety of surgical treatments might be employed in the treatment of growth plate arrest.
Epiphyseodesis: Epiphysiodesis is a surgery to temporarily or permanently stop further growth from a particular growth plate. In some cases of partial arrest the growth plate may be closed completely with epiphysiodesis to avoid angular deformity. The opposite and normal side may also be treated with epiphysiodesis to avoid further limb length differences from developing. Additional growth plates can be treated with epiphysiodesis on the healthy limb to help minimize the limb length difference.
Physeal Bar Resection: In certain cases physeal bars can be removed surgically. If necessary, the bone may straightened at the same time. Removing a physeal bar does not always work, and if the growth plate does not grow properly afterwards further surgery may be recommended. The decision for removing the bar depends on the location, size of the bar, age of the child, and amount of growth remaining in the bone.
Osteotomy: Osteotomy is a procedure where the bone is purposely broken and then straightened. This is an option if the bone is not significantly short but does have some angulation.
Lengthening: Lengthening is an option when the bone is significantly short. Angular deformity can be corrected at the same time. Lengthening can be done using an external fixator or an internal lengthening nail.