Support Systems and Bracing
It is a normal response for humans to
seek out external support systems when the body becomes
fatigued. People unconsciously seek a safe structure on
which to rest for efficiency when they are placed in
demanding or stressful situations. Observing people at
gatherings, you may notice some resting against a wall or
leaning back on a chair. Others may be leaning on counters
or walls without realizing they are doing it. This is
especially true during activities involving prolonged
standing. When such activities result in discomfort, balance
problems or fatigue, the sensory input will cause the
individual to react. In these instances, people without
physical limitations use support systems such as handrails,
armrests and backrests. Support systems are not used
exclusively by physically challenged individuals.
When someone has physical limitations and
the ability to stand and walk is compromised, the need for
support systems becomes more important. Support systems in
the form of custom bracing vary according to the design and
choice of materials. The objective of such a support system
is to provide for stability and mobility simultaneously. The
goal is to support involved body parts without undue
restriction and allow for efficient ambulation.
Support systems in all orthotic
applications need to be placed where they are needed most.
It is necessary to differentiate these systems according to
each person's needs. Custom braces should not
be the same for everyone. The location of support systems
combined with high tech materials is critical in achieving
efficient ambulation and maximizing potential. Traditional braces for ankle deficiencies
relied upon support behind the calf and were made of metal
and leather or plastic. In many cases where the knee was
involved a long leg brace was used keeping the knee straight
during ambulation. As new materials became available, metal
and leather were replaced with plastics; unfortunately, the
"old theory" remained and designs did not change.
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The old theory regarding
support systems has become the traditional approach when
treating people with physical limitations that affect
ambulation. It is necessary to reconsider the biomechanical
needs of each individual and design the most appropriate
orthosis for that person. New materials alone do not change
the functional characteristics of a support system. It is
the combination of design and materials based upon specific
biomechanical requirements that are essential to restoring
balance, security, and the ultimate goal of functional
efficiency in ambulation.
Support systems are intended to help the
individual. They can often impose limitations on balance, security and efficiency! This is important to
understand since the old theories have become entrenched in
our thinking as professionals and clients. A support system
that is applied below the knee has a profound effect on the
knee and hip musculature above as well as the entire body!
It is impossible to create a support system below the knee
and not affect the rest of the body! Since
this is a given, we must address the body as a
whole in our choice of design and material when creating
support systems. An orthosis should enhance
efficiency. It should not add to the
effort required to ambulate nor should it increase energy
expenditure. The term support system is more
descriptive than orthosis or brace as it implies a
functional process and the use of critical
thinking.
In order to achieve an efficient gait
that is balanced and secure, the knee and hip joints need to
be free to move through swing phase yet allow for stability
in stance. As stated earlier, the location of support in a standard AFO (ankle-foot-orthosis or short leg
brace) is behind the calf. In order to feel this support, it
is necessary for the individual to lean back into the
plastic shell or calf band. An efficient gait is fluid and
motion is always forward. Many people wearing such
conventional devices are leaning and often use muscle power
to maintain the leg back in the brace. The need to push back
while moving forward is counter-productive. Compensations
then need to be made because of the orthosis; consequently,
balance and efficiency are adversely affected. Complete
extension of the knee or hyperextension (recurvatuum) is not
part of a normal gait cycle. The knee maintains varying
degrees of flexion throughout. These compensations cause
increased energy expenditure, fatigue, balance problems and
insecurity. The overall inefficiency is being
caused by the brace! The mechanics are all
wrong!
The
use of free dorsiflexion in a support system would seem to
be consistent with the concept of moving forward throughout
the gait cycle. This design has gained popularity without
addressing security issues or efficiency. Video
documentation has shown the shortcomings of this design. The
support system behind the knee in combination with free
dorsiflexion creates a "drop off" at the knee, which
prevents full weight bearing on the affected side during
stance; in other words, it is an ineffective approach that increases difficulties with
balance, security and efficiency.
The issue of security takes precedence
over balance and efficiency. Humans need to be safe and feel
secure. Compensations for security reasons are made at the
expense of balance and efficiency. Habits develop that
become normal to the individual over time. This leads to a
further deterioration of function. It is a vicious cycle
that needs to be broken. Old movement patterns have to be
replaced by new or more natural patterns in order to reach
one's potential. An appropriate support system will allow
the body to assume more normal patterns required for
balance, security and efficient gait; however, retraining is
necessary to overcome the compensations established over
time.
Human locomotion is not a two dimensional
activity. We describe three planes of motion (triplanar)
necessary for normal ambulation. In actuality, the body
moves in an infinite and constantly changing number of
planes. For educational purposes we will discuss three:
forward and backward; side-to-side; rotation. Combinations
of these planes of motion make up the movement patterns for
all of our activities. The relationship and alignment of our
body segments continuously change over a period of
microseconds for efficient ambulation and other activities.
Education is an important part of the treatment plan.
Understanding the forces applied by an appropriate force
system and how the body interacts will allow for the gradual
replacement of old habits with better mechanics and
efficiency.
Orthotic design and technology has not
kept pace with the benefits realized in prosthetics.
(artificial limbs) Carbon graphite foot/ankle systems enable
amputees to walk with a normal gait and even to run. These
systems incorporate the use of energy storing
principles. Loading of the prosthetic foot stores
energy due to the materials used and the forces applied
during ambulation. This replaces the action of missing
muscles. As more pressure is placed on the component, it
deflects or yields to the weight of the force applied. In
this way movement is allowed while stability is maintained.
The precise combination of energy storing and energy
dissipation simulates normal gait
characteristics.
DynamicBracingSolutions™ offers similar attributes in an orthotic support system.
Each support system is planned and designed for each
individual's needs and requirements. The energy-storing
component assists weak musculature while the yielding motion
allows for forward progression necessary for efficient gait.
Stability is inherent in the system. The individual needs to
discard old habits and compensations and allow the new
support system to work for them rather than against them.
This is where the proper training becomes crucial. Time and
effort need to be applied to retrain the body to accept
normal loading of the extremities during ambulation. Once
more normal patterns are established, balance, security and
efficiency improve.
An analogy to sailboat racing can be made
to illustrate this theory. Sailboats today are very
sophisticated. Design principles and technology have come a
long way since the days Columbus first sailed the seas. In
his day, ships had wooden hulls and sails were made of
canvass and hung from crossbeams primarily in one plane.
This was not efficient. Today sailing vessels have hulls
made with graphite composites. Replacing materials alone
does not make for efficiency. New designs, materials and
movement strategies enable these new sailboats to go faster
into the wind than ancient ships could go with the wind! The
boats of today have become an integrated system using multi
dimensional sails that capture the wind's power in many
planes. Just as the wind changes direction constantly, the
human body is a complex system that works in many
planes.
The majority of people with AFO's have
learned to walk with conventional designs. Some did well
while others realized little benefit. Regardless of past
experience, the potential exists for improvement.
The knowledge and skills for
sophisticated lower limb orthotic support systems utilizing
new theories, designs, materials and movement strategies has
been developed. Outcomes once thought unattainable are now
being realized. More secure and efficient ambulation is
possible.
The orthotist of the future will need to
employ more sophisticated elements to stay abreast of the
advancements. People in need of bracing solutions will
greatly benefit. Outcomes now thought life changing, will
become the standard. The future client will have fewer
falls, better balance and more security. A more natural gait
appearance is the result with improved velocity, more
endurance, and enhanced functional gains. All these elements
are the quintessential result of improving efficiency of
human locomotion.