You may have a broken bone and are wondering, how does a bone heal after a fracture? The anatomy and physiology behind how fractures heal is fascinating.
Once the physician treats and realigns a broken bone, it generally takes about six to eight weeks for the process of bone growth and repair to complete.
Well look at this repair and remodeling process, along with common types of broken bones in this article. First, though, lets look at a broken collar bone in the process of healing.
Before that new growth can begin, though, the body must start the bone fracture healing process.
Bone fracture healing process
After you get a broken bone, your body reacts by forming a mass of clotted blood at the fracture site.
The clot is called a hematoma. (Hemat/o means blood, and oma means mass.)
The hematoma forms because blood vessels in the bone and surrounding tissue are torn and bleed profusely.
After a little time, the site becomes swollen and painful because bone cells no longer are receiving nutrition.
A few days after the initial break, a soft callus forms. During this phase, your body begins to grow capillaries into the hematoma and starts to clean up debris around the fracture site.
The body also has cells such as osteoblasts and fibroblasts that invade the site to begin the process of building new bone.
The fibroblasts are responsible for connecting the broken bones using collagen fibers. Once the bridge is formed, the osteoblasts get to work, forming spongy bone.
The spongy bone is composed of fibrous tissue and cartilage, which allows new blood vessels to form and reconnect both sides of the bone.
But those osteoblasts that are not near capillaries dont have the nutrition needed to create the spongy bone, so they begin creating an cartilaginous matrix that bulges out the side of the bone.
This buldge is called the external callus, which later calcifies hardens.
The entire mass is referred to as the fibrocartilaginous callus.
The fibrocartilaginous callus will slowly begin starting to change into bony callus in about a week.
During this bone regeneration phase, it takes about two months until the bony callus forms a strong connection between the two pieces.
Bone remodeling process
During the time the bony callus is hardening, it is also slightly remodeling. The bone remodeling process happens for several months afterwards as well.
The remodeling phase removes the extra material that formed on the bones exterior and within its interior wall as well. This allows it to reconstruct the interior shaft walls of the medullary cavity with compact bone.
As the remodeled area gets stressed through normal activities, it will to remodeled to resemble the original bone and become just as strong.
Now that we answered the question how does a broken bone heal and provided the steps in the bony injury and repair process, lets look at a few types of fractures and classifications.
Fractures can be described and classified a few different ways, including position, completeness of the break, orientation, and penetration of the skin.
Position: A nondisplaced fracture means the bone ends stay in their regular position after the break. A displaced fracture means the bone ends are no longer aligned in their regular position.
Completeness: A broken bone can also be classified by the completeness of the break. A complete fracture is one in which the bone is broken all the way through. An incomplete fracture means just the opposite: The bone is not broken all the way through. A greenstick fracture is an example of an incomplete fracture; these are common in children.
Orientation: A linear break is one that runs parallel to the long axis of the bone. A transverse break is one that is perpendicular to the long axis of the bone.
Penetration: A compound fracture also known as an open fracture is one in which the bone penetrates the skin. A simple fracture also known as a closed fracture is one in which the bone does not penetrate the skin.
In addition to the classifications listed above, fractures can be explained by the appearance and type of break. Six common types of bone fractures are below.
Comminuted fractures: Bone is fragmented into three or more pieces. These fracture types are common in elderly people, whose bones are brittle.
Compression fracture: The bone is crushed from trauma. An example is falling off a ladder. This happens mainly in porous bones, such as the vertebra.
Depressed fracture: The bone is pressed inward and is typical in a skull fracture.
Epiphyseal fracture: This fracture is when the epiphysis and diaphysis separate at the epiphyseal plate.
Greenstick fracture: The bone does not break completely. One side of the shaft breaks, and the other side just bends.
Spiral fracture: The bone is twisted from excessive force and creates a ragged break. This is a common fracture in sports.
A fun example about fracture classifications
What makes describing fractures really fun is that you can combine all these descriptions to get a very precise nature of break.
Example: Ron was playing soccer a competitive game of soccer. He was moving the ball down the field when an opponent came at him and tried to get the ball. The opponent hit Rons leg, which made a loud cracking noise and put him out of the game.
When Ron went to the doctor for X-rays, the doctor found the bone to be a fracture that was closed, displaced, complete, and transverse.
The broken bone did not break the skin (closed), but it was out of normal alignment (displaced). It was broken all the way through the bone (complete) and broken raggedly (spiral) down the perpendicular axis of the bone.
It is possible that a single break could exhibit all the fraction classifications.
If you found this information about types of fractures and the process of bone growth helpful, consider sharing it so other nursing and medical students may understand the answer to the question, how does a bone heal after a fracture?