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Stages of injury
Once tissue is
injured the process of healing begins immediately.
The healing process can be divided into 3
distinct phases: the inflammatory phase, the Proliferative phase,
and the remodelling phase. All of which will overlap.
The inflammatory stage (Acute) starts within hours and will
continue for up to 5 days.
The proliferate phase (Sub-acute) will start form the fifth day
and continue for up to 3 weeks.
The remodelling phase can start from the first week and can last
from 6mths to 1-2 year.
Stage 1 - inflammatory stage
Typically in a traumatic event injured blood vessels become
deprived of oxygen and die. Before repair and regeneration can
occur, debris must be removed.
Within the first 5-10 mins the vessels will constrict blood flow
(to stem bleeding) but this is rapidly replaced by dilation. The
first 24-36 hours you will see the area swelling. This is when the
body has dilated its blood vessels to allow a clean up of the
debris. Chemicals (histamine) are released and collectively work to
increase capillary width and decrease capillary density (allows
substances to travel through). However this increase in blood flow
can act as an irritant and produces pain and loss of function.
This release of chemicals attracts natural defence cells
(chemotaxis). This leads to migration of certain white blood cells
(leukocytes) the two most predominant are neutrophils (1st to injury
site neutralize harmful bacteria) and macrophages (engulf bacteria
and dead cells). These clear the area for new cells to grow and
arrive within 72hours and remain for a weeks.
Once cleansing has been achieved the damaged area can begin to
sprout new capillaries to bring blood to the region. Re-growth can
begin.
Stage 2 - proliferation
Repair and regeneration depend on three major factors:
elimination of debris, the regeneration of endothelial cells, and
the production of fibroblasts, which compose connective tissue
throughout the body and form the basis of scar tissue.
Stimulated by a lack of oxygen, capillary buds begin to form in
the walls of the intact vessels. From these buds grow immature
vessels that form connections with other vessels. As these vessels
become mature, more oxygenated blood is brought to the injured area.
Fibroblasts migrate to the injury and form collagen substances (type
3 immature collagen), often within a few days. New protein fibres
are laid down in a haphazard manner and are therefore weak and does
not possess a lot of tensile strength
Stage 3 - Maturation
This is the remodelling phase where scar tissue strengthens to
form type 1 collagen. This happens through being subjected to
controlled strain in a functional pattern. As this stage can last
for up to 2 years the area is in a vulnerable state and has a high
re-injury chance. The risk is reduced by providing additional
stability with strapping, strengthening of the muscle surrounding
the joint and proprioceptive exercise to increase the sense of joint
position. The tissues need to be stressed in the direction in which
the tissues are being used otherwise you will have loss of function
and the scar will be less pliable. Soft tissue release can works
very well in this stage.
Once laid down, the scar tissue begins to contract to close the
injury site. It is vital to use stretching to increase pliability of
the scar tissue and reduce the chances of range loss. muscle energy
techniques are very beneficial. |
