Feb 10, 2011 - The Long & Short of Bone Growth

Long Bone Growth

Long bones add materials at specific areas called growth plate. The growth plate, also known as the epiphyseal plate or physis, is the area of growing tissue called hyaline cartilage near the ends of the long bones in children and adolescents. Each long bone has at least two growth plates: one at each end. The growth plate determines the future length and shape of the mature bone. When growth is complete - sometime during adolescence - the growth plates close and are replaced by solid bone. In adults, who have stopped growing, the plate is replaced by an epiphyseal line. Because the growth plates are the weakest areas of the growing skeleton - even weaker than the nearby ligaments and tendons that connect bones to other bones and muscles - they are vulnerable to injury. Injuries to the growth plate are called fractures.

http://i39.tinypic.com/4qj1ih.jpg

This is the distal end of the tibia (left) and fibula (right).  

The thin lines most proximal on both bones are the epiphyseal (growth) plates.

http://upload.wikimedia.org/wikipedia/en/7/7a/Tib_fib_growth_plates.jpg

About 85 percent of growth plate fractures heal without any lasting effect. Whether an arrest of growth occurs depends on the treatment provided, and the following factors, in descending order of importance:

• Severity of the injury - If the injury causes the blood supply to the epiphysis to be cut off, growth can be stunted. If the growth plate is shifted, shattered, or crushed, the growth plate may close prematurely, forming a bony bridge or “bar.” The risk of growth arrest is higher in this setting. An open injury in which the skin is broken carries the risk of infection, which could destroy the growth plate.
• Age of the child - In a younger child, the bones have a great deal of growing to do; therefore, growth arrest can be more serious, and closer surveillance is needed. It is also true, however, that younger bones have a greater ability to heal.
• Which growth plate is injured - Some growth plates, such as those in the region of the knee, are more involved in extensive bone growth than others.
• Type of fracture

The most frequent complication of a growth plate fracture is premature arrest of bone growth. The affected bone grows less than it would have without the injury, and the resulting limb could be shorter than the opposite, uninjured limb. If only part of the growth plate is injured, growth may be lopsided and the limb may become crooked.

Growth plate injuries at the knee have the greatest risk of complications. Nerve and blood vessel damage occurs most frequently there. Injuries to the knee have a much higher incidence of premature growth arrest and crooked growth.   http://www.niams.nih.gov/Health_Info/Growth_Plate_Injuries/default.asp#8

      

     Using the principal that bone will grow (relatively) rapidly to fill in areas of fracture Ilizarov discovered that by carefully severing a bone without severing the periosteum around it, one could separate two halves of a bone slightly and fix them in place, and the bone would grow to fill the gap. He also discovered that bone regrows at a fairly uniform rate across people and circumstances.

     These experiments led to the design of what is known as an Ilizarov apparatus, which holds a severed bone in place, by virtue of a framework and pins through the bone, and separates halves of the bone by a tiny amount; by repeating this over time, at the rate of the bone's regrowth, it is possible to extend a bone by a desired amount.

http://en.wikipedia.org/wiki/Ilizarov_apparatus

Ilizarov Apparatus

• Bone infections
• Poliomyelitis Sequelae (limb lengthening and correction of deformities)
• Treatment of non-unions and malunited fractures
• Correction of deformities, both congenital & acquired, of the limbs 
• Badly comminuted fractures (multiple fragments) in the limbs, even with skin loss.

This procedure is accepted for the conditions listed above but is very controversial for cosmetic limb lengthening.  The article at the following link provides multiple viewpoints on the procedure.  It is very interesting.   http://www.shortsupport.org/News/0432.html 

Fun Fact:  I the movie GATTACA the character Vincent has this procedure done as he gets ready to take the identity of Jerome.  This is part of the plot that follows the following Title Cards:

[first title card]

"Consider God's handiwork; who can straighten what He hath made crooked?" - Ecclesiastes 7:13

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[second title card]

"I not only think that we will tamper with Mother Nature, I think Mother wants us to." - Willard Gaylin