Tissue healing is made up of four stages. These stages do not occur in isolation to each other, rather there are certain parts of each stage that work together. The duration of each stage are individual to each injury, and the health professional should assess each injury as it presents - not by the calendar.
STAGE 1: BLEEDING
Can be internal or external - this means we might not see it!
Goal is to return the body to homeostasis - a state of steady internal functioning
Lasts for up to 24 hours post injury
Platelets - cells in the blood - form a clot to stop free bleeding
This stage can be painful as the body lets us know that we have done damage. Pain is not a bad thing, it is a great way of protecting us from doing more damage!
We need to be careful in this stage though as pain may not be present. If you take a heavy tackle in a football game and break a bone you might not know it and keep playing the game through to the end. Unfortunately the surprise at the end of the game is an injury that has been made a lot worse because you kept using it / playing with it.
STAGE 2: INFLAMMATION
Generally lasts up to Day 3 following the original injury
Is a normal and essential part of healing
Cleanses the wound of foreign matter - such as germs and dirt
Is evidenced by swelling and redness
Releases chemicals essential to the next stage of wound healing
This stage is generally the most painful! When the inflammatory fluid rushes into the area the extra pressure can increase the pain we are feeling.
Another reason this stage tends to be the most painful is because the danger has passed allowing the brain to focus on what is wrong and it works very hard to try to protect us from doing further damage. What’s the best way to stop us from doing something? Make it hurt!
STAGE 3: PROLIFERATION
Lasts approx. Day 3-21 post injury
New collagen is laid down - this is a strong protein that helps connect the tissue
The wound edges are pulled together
Cell growth occurs
This stage is essentially like the ‘rebuilding’ stage of wound healing. The body goes into construction mode, developing a new network of blood vessels through a process called ‘angiogenesis’. These bring oxygen and nutrients to the newly formed tissue. The tissue that is laid down in this stage is usually bumpy and uneven and can often be quite pink/red due to all that fresh blood flowing close to the surface.
Towards the end of this stage, little building blocks called ‘epithelial cells’ then pave over and resurface the wound to prevent any yucky stuff getting in there.
STAGE 4: MATURATION / REMODELING
Can last for years
Collagen fibres changes from being disorganised to organised to make the wound strong
Formation of scar tissue
This is effectively the long lasting ‘wind down’ stage of wound healing.
All the cells needed to repair the wound in the early stages are no longer needed and are removed.
The collagen fibres start to lie closer together and cross-link to make the wound strong.
This process also makes the scar thinner.
Unlike the other stages, this process can continue for a long, long time.
Even then, when the wound is healed, it tends to only regain 80% of the strength of it’s uninjured counterpart.