WEBVTT

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It is important to immobilize

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a broken bone to allow it to heal.

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Splints, casts, and surgery may be used,

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depending on the type and severity of the fracture.

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These serve two objectives –

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firstly, to prevent the bones from moving and,

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secondly, to keep the broken ends of the bone

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packed tightly together to facilitate fast healing.

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Doctors distinguish between two different

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types of healing processes for broken bones –

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direct (primary) and indirect (secondary).

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Direct healing is possible

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if the broken bone ends are close together –

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for example, when the bone is not completely broken

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or the broken bone ends are held together

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perfectly using screws or plates.

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Wherever the broken bone ends have direct contact

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with one another, bone tissue will grow from one border

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of the fracture to the other in both directions.

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During this process, certain bone cells

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called osteoclasts break down damaged bone tissue,

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producing hollows similar to drill holes.

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At the same time, osteoblasts form

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new bone tissue opposite each hollow –

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like “dowels” to fit into the “drill holes”.

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If there is a space of just a few millimeters

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between the broken bone ends,

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the periosteum and endosteum help with healing.

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The periosteum is a layer of membrane covering

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the outer surface of the bones, in which the tendons

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and ligaments are anchored.

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It also contains stem cells and blood vessels

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used for bone reconstruction.

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The endosteum is a membrane

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lining the inner surface of the bones

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and acting as an interface with the bone marrow.

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It is also involved in bone remodeling.

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From the endosteum and periosteum,

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tiny blood vessels and connective tissue cells

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penetrate into the fracture gap.

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The connective tissues cells develop into osteoblasts,

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which form new bone tissue along the fracture line.

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Bone degradation and formation processes

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work together so that new threads of

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bone tissue form on both sides of the fracture,

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orienting longitudinally along the bone axis,

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and closing the narrow gap.

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If the gap is large, indirect fracture healing occurs.

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It involves processes similar to wound healing.

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First, a fracture hematoma forms

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immediately after the bone breaks.

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It is produced by the bone marrow,

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which penetrates out of the bone into the

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surrounding tissues when the fracture occurs.

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This is sometimes mixed with

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blood from injured blood vessels.

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The same thing happens during direct fracture healing,

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but on a smaller scale.

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As a result, there is a local inflammatory response,

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which sets the healing process in motion.

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Damaged bone tissue is broken down,

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while soft scar tissue forms around the fracture site

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to stabilize the fracture.

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This scar tissue is called a callus.

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Over time, it is converted into cartilage and ossifies,

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becoming hard woven bone.

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Finally, the gap is completely filled

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from the outside inwards with new bone tissue,

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as in the case of direct healing.

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To recap:

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A fracture can heal directly

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if the broken bone ends are close together

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or the gap is no more than a few millimeters wide.

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This enables bone degradation processes

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in conjunction with bone formation processes

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to form new bone tissue in such a way that the

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broken bone ends grow back together directly.

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If the gap is larger, indirect healing is required.

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It involves processes that are similar to wound healing.

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An inflammatory reaction is produced

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and a callus is formed around the fracture.

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The callus, made of soft connective tissue,

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gradually turns into cartilage and bone

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until the gap is fully closed.