(Disorders of the Growth Plate)
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What is a Growth Plate, and what is an Epiphysis?
When we're born,
our bones are quite small, and they need to grow in order for us to grow.
A growth plate, or epiphyseal plate, is the portion of bone
that grows as we go through childhood. It basically consists of
cartilage that gradually hardens into bone.
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To the left is a microscopic view of a growth plate. The cells are normally white, but have been stained pink to make them more easily seen. In this picture, the oval-shaped, pale bluish white coloured, cells are the cartilagenous cells--the cells within the growth plate that are growing. You can see that the cartilage cells at the top of the picture are fading into the surrounding pinkish colour. These are the older cartilage cells that are hardening and developing into mature bone. |
Is it possible to injure a growth plate?
Absolutely. Trauma, tumours, infection and other diseases can cause the growth plate to become injured, which can cause arthritis, deform how the bone grows, and even stop bone growth altogether--something called "premature closure" of the growth plate.
Usual treatment for a simple injured growth plate is rest, protection and immobilization, but surgery may be needed to lengthen, shorten, realign or otherwise correct arrested or abnormal growth plates. Fractured growth plates are treated based on the classification of the fracture.
What is the Salter-Harris Classification?
The Salter-Harris Classification is the most commonly used system to classify growth plate fractures.
Type I:
A complete separation of the growth plate. No disruption of growth. Treated with casting and immobilization for about 3 weeks.
Type II:
A fracture through the growth plate with a portion of the fracture extending into the shaft of the bone, creating the "Thurston-Holland" sign. There is usually no disruption of the growth plate, and it is usually treated like type I fractures.
Type III:
A fracture through the growth plate with a portion of the fracture extending into the joint. Because of the likelihood of injury to the joint and for growth plate disturbance means that these fractures are usually treated through surgical repair.
Type IV:
A fracture that is oriented from the shaft of the bone directly into the joint. It is primarily perpendicular to the growth plate. This fracture is unstable and requires surgical intervention.
Type V:
A crush injury involving the growth plate. Growth plate disturbance is common. These injuries are sually immmobilized for 3-6 weeks.
Type VI:
The creation of a crater in an area of the growth plate. These are usually treated conservatively, though surgical intervention is frequently done if premature closure of the growth plate occurs on the injured side.
Type VII:
A fracture involving the joint, but not the growth plate. Treatment is made on a case-by-case basis. Casting is usually done if the fracture is non-displaced. Surgical intervention is considered primarily then the fracture is displaced, unstable, or large.
What is Avascular Necrosis?
Avascular Necrosis is the name given to the condition where a portion of bone begins to die from lack of circulation. This may be caused from severe injury, surgery, or most commonly, from repetitive, low-grade trauma. When the condition occurs in a growth plate in a child, it is known as osteochondrosis. (The plural is "osteochondroses".)
There are many, many locations where this might occur, but a few of the most common are:
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The Tibia (the front of the shin bone): Osgood-Schlatter's Disease Most common in athletic boys 11-15 years of age. Differential diagnosis: Osteosarcoma
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The Navicular Bone (on the inside border of the foot): Kohler's Disease
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The Fifth Metatarsal Base (on the outside border of the foot): Uhke's Disease Seen most commonly in children 5-11 years of age.
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What is an Apophysis? An Apophysis is a certain type of growth plate that occurs at the end of a bone, when there is no other bones on the other side. The best example of an apophysis is on the heel bone. The X-ray on the right shows the heel bone (the calcaneus) and the calcaneal apophysis. What is Apophysitis? Apophysitis, or Sever's Disease, is a common inflammation of the apophysis on the heel bone. It occurs in both girls and boys, usually at about 8-14 years of age. |
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Sever's disease is usually treated by rest, protection, and immobilization, but medications, heel cups, over-the-counter inserts, prescription orthoses, accommodative orthopaedic devices, taping, padding, casting, or shoe changes may be necessary to control this condition.
What is Osteochondritis Dessicans?
Osteochondritis Dessicans is a condition where a fragment of cartilage and bone become loose and detached from the underlying joint surface. This may commonly affect the knee and ankle, or it may be associated with osteochondroses (the growth plate degeneration described above) when the joint is near the growth plate.
The most common example of this is in the ball of the foot, in bones known as the metatarsals. The most commonly affected metatarsal bone is the 2nd metatarsal, the longest one, and one that undergoes a great deal of stress. Osteochondritis Dessicans in this area is known as "Freiberg's Disease", and as the bone degenerates, it is characterized by a flattened appearance on radiograph. Again, treatment is aimed at protecting the injured bone through rest, immobilization, orthoses, orthopaedic appliances, taping, padding, casting, and shoe changes. Surgery is often required, however.
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