OSSIFICATION

Ossification

Osteogenesis and ossification: these terms are often synonymous in indicating the procedure of bone formation. Parts of the skeleton start forming during the very first weeks after conception. And by the end of the second month, the skeletal pattern transforms into cartilage and connective tissue membranes. And this is how ossification begins.

Bone development continues up to the stage of adulthood. Even after adult stature fully develops, bone development continues for repairing fractures and remodeling to cope with changing lifestyles. The three cell types involved in the development, growth, and remodeling of bones are Osteoblasts, osteocytes, and osteoclasts. Osteoblasts are bone-forming cells while osteocytes are mature bone cells. And osteoclasts break down and reabsorb bone.

The two types of ossification are intramembranous and endochondral. And quite obviously, ossification or osteogenesis plays a crucial role not only in the development and growth of bones but also in healing broken bones. Especially in children, broken bones have a brilliant ability to heal. New bone starts forming within a few weeks of the injury. However, complete healing tends to take longer.

How Do The Broken Bones Heal?

There are three stages of bone healing: the inflammatory stage, the reparative stage, and the remodeling stage.

The Inflammatory Stage 

When a bone breaks, the body sends signals to special cells to come to the injured area. Some of these cells cause inflammation in the injured area. It signals the body to stop using the injured part so that it heals better. During this stage, other cells come to the area and form a hematoma (blood clot) surrounding the broken bone. And this is the first bridge between the fragments of the broken bone.

The Reparative Stage

This stage starts within a week of the injury. A soft callus, a type of soft bone, replaces the blood clot that has already developed in the inflammatory stage. The callus helps hold the broken bone pieces together. However, that body part is not strong enough for use. The soft callus becomes harder over the next few weeks. And by the 2nd-6th week, this hard callus becomes strong enough to use that body part.

The Remodeling Stage

This remodeling stage starts around six weeks after the injury. During this stage, regular bone replaces those hard calluses. If you look at an X-ray of the healing bones, you will see that it looks uneven. However, by the next few months, the bone retains complete shape. And it again looks the way it did before the injury.

Types Of Ossification

The followings are the types of ossification that help in the growth and development during fetal development and whenever a bone breaks.

Intramembranous Ossification

Intramembranous ossification replaces the sheet-like connective tissue membranes with bony tissue. Bones that develop through this procedure are called intramembranous bones. This category includes certain flat bones of the skull and several irregular bones. The bones first develop as connective tissue membranes. Then, Osteoblasts move to the membranes and accumulate a bony matrix around themselves. At this stage, these are called osteocytes.

Endochondral Ossification

Endochondral ossification replaces the hyaline cartilage with bony tissues. Most of the bones develop in this way. These bones in the skeleton are called endochondral bones. In this procedure, the bones first develop as the hyaline cartilage models. After the third month of conception, blood vessels and osteoblasts fill the perichondrium surrounding the hyaline cartilage “models” and then, these change into a periosteum.

The osteoblasts create a collar of compact bone surrounding the diaphysis. Also, side by side, the cartilage in the center of the diaphysis begins to degenerate. Osteoblasts get into the degenerating cartilage and replace it with spongy bone. This develops a primary center of ossification. Ossification starts from this center and proceeds toward the edge of the bones. After a spongy bone grows in the diaphysis, osteoclasts break the newly formed bone to expose the medullary cavity.

Thus, the cartilage in the epiphyses keeps growing so the developing bone grows longer. Later, after birth, secondary ossification centers develop into the epiphyses. Ossification in the epiphyses is just like that in the diaphysis. However, the only difference is here the spongy bone remains. It does not break down to create a medullary cavity.

Once the secondary ossification is done, the bone completely replaces the hyaline cartilage except in two areas. An area of hyaline cartilage stays over the surface of the epiphysis. And the articular cartilage and another area of cartilage stay between the epiphysis and diaphysis. This is the epiphyseal plate aka growth region.

Bone Tissue Formation 

Ossification aka osteogenesis or bone mineralization plays a crucial role in bone remodeling. This is the procedure of placing new bone material with the cells called osteoblasts. This procedure is also known as bone tissue formation. Two processes form normal and healthy bone tissues. However, in fracture healing, endochondral osteogenesis is the most commonly occurring process, for example in healing fractures of long bones that are treated by plaster of Paris. On the other hand, intramembranous osteogenesis helps heal the fractures that are treated by open reduction and internal fixation with metal plates, screws, pins, rods, and nails.

Heterotopic ossification is a procedure that forms bone tissue that is often not typical, at an extraskeletal location. Calcification is often mistaken for ossification. Calcification describes the formation of calcium-based salts and crystals inside the cells and tissue. It is a procedure that happens during ossification.

Casts and Splints Help Broken Bones Heal

Casts and splints will help hold the broken bones in place during the healing period. After new hard bone forms within around 3–6 weeks, doctors usually remove the cast or splint. Considering the type and location of the fractured bone, our doctors may recommend various treatments:

Traditional cast

After repositioning the bone, doctors commonly immobilize the broken bone with the help of a plaster or fiberglass cast. A cast lets the bone heal in the right position. To treat fractures in the leg, foot, arm, and wrist bones, doctors often use casts.

Brace Or Functional Cast

A functional cast or brace is different from conventional cast immobilization which allows restricted and controlled movement of nearby joints. Typically, doctors put a primary cast on the body part with the broken bone, and then after some time, they will remove it. Thereafter, the specialists will put the limb in a functional brace which will allow early mobility and movement.

Surgery

When the bone fracture is severe, doctors will probably need to perform surgery to fix the break. Experts expose and reposition the bone with their hands in an open reduction process. A child may require open reduction if he has complex fractures that are difficult to treat with a cast.

There Are Two Types Of Open Reduction:

Open reduction with internal fixation: This process entails attaching special metal plates or screws to the external surface of the bone. A surgeon may also set metal rods at the center of the bone to hold the fragments together in place. Open reduction with external fixation: In this procedure, surgeons place an external device on the injured limb after surgery. Specialists will place metal pins or screws below and above the fracture site to immobilize the bone while it heals and also to provide support.

When The Bone May Not Be Healing Properly

In certain cases, a bone may not heal as expected if a person:

• Has a severe break
• Has got the muscles, skin, and nerves damaged in the same place as the broken bone
• Takes medicines such as corticosteroids
• Has a vitamin deficiency
• Has osteoporosis, diabetes, osteogenesis imperfecta, or anemia
• Consumes alcohol
• Smokes cigarettes

How Can I Help My Child Heal Broken Bones?

If you want to help your child recover from a broken bone, make sure that he or she:

• Follows a healthy diet with plenty of calcium and vitamin D
• Taking good care of the cast or splint is important
• It is crucial to follow the expert’s directions regarding rest and/or doing any exercises
• Do not miss any of the follow-up appointments

Conclusion

Since a broken bone is a common, treatable childhood injury, do not panic if your child gets bone injuries. In most cases, breaks heal well. Moreover, kids can get back to normal life and do all their favorite activities shortly. Just make sure you consult a doctor and follow all his instructions.