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.
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.