REPAIR OF BROKEN BONES

Even though bones are strong and rigid, they can break under certain conditions. The process of repairing a broken bone is called bone healing or fracture repair.

$Learn how broken bones heal naturally through four stages: hematoma formation, soft callus, bony callus, and bone remodeling. Understand fracture treatment, closed and open reduction, and the complete bone repair process for biology students and medical learners.$

Why Bones Break (Causes of Fractures)

In young people:
Most fractures happen due to trauma (injury) such as sports accidents, car accidents, or falls.
In older people:
Bones become thin and weak (due to loss of minerals and less bone density), so even a small fall can cause a fracture.

Treatment of a Fracture

A fracture (broken bone) is treated by a process called reduction, which means realigning the broken bone ends into their correct position.

There are two main types:

Closed Reduction:
The doctor moves the broken bone ends back into place using hands only, without surgery.
Open Reduction:
Surgery is performed, and the broken parts are joined using metal pins, plates, or wires.

After reduction, the bone is immobilized (kept still) using a cast or traction (a system of weights and pulleys) to help the healing process.
👉 Healing time: 8–12 weeks (longer for older people or large bones due to slow blood flow).

🩹 Phases of Bone Repair (4 Stages)

1. Hematoma Formation (Blood Clot Stage)

When a bone breaks, blood vessels tear, causing bleeding (hemorrhage) at the fracture site.
The leaked blood forms a hematoma — a clotted mass of blood around the break.
The area becomes swollen, painful, and inflamed because bone cells are deprived of nutrients and begin to die.

🧠 Term:
Hematoma → (Clotted blood that forms when blood vessels break)

2. Soft Callus Formation (Fibrocartilaginous Callus Stage)

After 3–4 days, new capillaries (tiny blood vessels) grow into the hematoma and start cleaning up dead tissue.
Fibroblasts (cells that form fibers) and osteoblasts (bone-forming cells) migrate to the fracture site.
They form a soft callus, a flexible tissue made of collagen and cartilage, which temporarily connects the bone ends.

🧠 Terms:
Fibroblast → (Cell that produces collagen fibers)
Osteoblast → (Bone-forming cell)

3. Bony Callus Formation (Hard Callus Stage)

After 3–4 weeks, the soft callus gradually becomes a bony callus.
Osteoblasts keep forming new bone, while osteoclasts (bone-eating cells) remove damaged bone.
Within 2–3 months, a firm, hard connection forms between the broken bone parts.

🧠 Term:
Osteoclast → (Cell that breaks down old or damaged bone)

4. Bone Remodeling (Final Stage)

Over several months, the bony callus is reshaped by osteoclasts.
Excess material on the outside of the bone is removed.
The repaired bone regains its original shape and strength, adapting to normal mechanical stress.

🧠 Term:
Remodeling → (The process of reshaping or restoring the original structure)

🧾 Summary Table

Stage	Main Event	Time Duration
1. Hematoma Formation	Blood clot forms at fracture site	1–3 days
2. Soft Callus Formation	Fibroblasts and osteoblasts form soft tissue	3–4 weeks
3. Bony Callus Formation	Hard bone tissue replaces soft callus	2–3 months
4. Remodeling	Bone reshaped to original structure	Several months

💡 Key Points to Remember

Bone healing is a natural process involving both bone-building and bone-removing cells.
Proper blood supply is essential for healing.
Calcium, Vitamin D, and physical rest are very important during recovery.
In older people, healing is slower due to weaker circulation and low metabolism.