Orthotics

Orthotics is the field concerned with the application and manufacture of orthoses, devices which support or correct human function.

The term is derived from the Greek "ortho", to straighten. Sciences such as materials engineering, gait analysis, anatomy and physiology, and psychology contribute to the work done by orthotists, the professionals engaged in the field of orthotics. Individuals who benefit from a complex orthosis may have sustained a physical impairment such as a stroke, spinal cord injury, or a congenital abnormality such as spina bifida or a developmental disability such as cerebral palsy.

Simpler foot orthotics allow the muscles, tendons and bones of the feet and lower legs to function at their highest potential. When appropriately prescribed, orthotics can decrease pain, not only in the foot, but in other parts of the body such as the knee, hip and lower back. They can also increase stability in an unstable joint, prevent a deformed foot from developing additional problems, and improve overall quality of life.

More recently, the term cognitive orthotics has been applied to assistive technology to correct cognitive functions.

Custom/Prefabricated
Some professionals use the adjective orthotic as a noun, usually describing a foot-supporting device or insole. Orthosis (plural: orthoses) is the base word for orthotic and is grammatically more apt to describe the items or devices that provide direct contact with a portion of the external body surface, rendering resistance to unwanted movement. All orthoses are fabricated prior to or concurrent with being delivered or fitted to the person using them, even casts, as they are created on the patient and become effective for use prior to being used by hardening. Some of the devices are made or fabricated with specifications that derive directly from considerations of a single person end user. Other orthoses are made to fit by sizing (e.g. small, medium or large).

Different orthoses exist to directly support the knee, back, hip, and the upper extremity; manufactured by specialized technicians and fitted to the end user, often referred to as a patient, are delivered by orthotists. The orthotist generally works by prescription, as a pharmacist would. In fact, some prefabricated orthoses can be found in a pharmacy. Some prefabricated orthoses, or supports, are soft and can be purchased as a retail item. Care in proper fit of any device that applies force to the body must be taken to ensure good results and to prevent unwanted problems from an orthosis that is too tight or otherwise uncomfortable.

Sophisticated custom orthoses to more rigidly support compromised joints, weak muscles, and other medical conditions are often provided by orthotists. Plastic vs. metal and leather fitting, complex mechanical hinges, and fasteners to keep the orthosis affixed well to the portion of the body that the orthosis supports are a part of the process in delivering orthotic support.

Benefits
The following information, as with the third paragraph of the opening section of this entry, has to do most directly with foot orthoses, shoe inserts, or as referred to in this treatise- "orthotics". In addition to providing relief for painful foot problems or an injury, those who may benefit from orthotics include people who must walk or stand excessively on the job. For those who are active in sports, orthotics will often increase endurance, performance and strength. For overweight individuals, orthotics can help to counteract the extra stress on the feet, as minor problems are often magnified due to the increased weight. Orthotics are particularly effective in relieving foot fatigue and discomfort experienced by older adults, who may have developed arthritis in their feet. Orthotics may also be prescribed for children who have a foot deformity.

In athletic individuals, sports activities result in a great deal of movement and pressure on the foot. Slight imbalances in the foot that are not harmful or even detectable under usual circumstances may make one more vulnerable to injury with the extra stress of sports activity. By eliminating the need for one's muscles to compensate for imperceptible imbalances, orthotics can reduce fatigue and promote efficient muscle function to enhance performance. With enough functional correction, the foot structure can be aligned to give more propulsion, making walking, running and cycling more mechanically efficient.

Structure and Function
Foot orthotics take various forms and are constructed of various materials. All have the goal of improving foot function and minimizing stress forces that could ultimately cause foot deformity and pain. There are three broad categories of orthotics: those that primarily attempt to change foot function, those that are mainly protective or accommodative in nature, and those that combine functional control and accommodation. While orthotics can be made by several different processes, most podiatrists make a plaster mold of the patient's foot and send it to a laboratory with a prescription. At the lab, technicians pour plaster into the mold, and when it hardens; it exactly reproduces the bottom of the individual's foot, although it is common for labs to "cast correct" by partially filling in the arch. This decreases the arch height of the orthotic and is done for comfort reasons. Once a reproduction of the individual’s foot is made, the technicians then use the doctor’s prescription to custom-make a device to meet the patient's specific needs. This process was first advocated by Root et al in the late 1970s and remains the preeminent standard. It is based on the neutral position model of correction.

Rigid orthotic devices are designed to control foot function, and may be made from a firm material such as plastic or carbon fiber. These types of orthotics are mainly designed to control motion in two major foot joints, which lie directly below the ankle joint. This type of orthotic is often used to improve or eliminate pain in the legs, thighs and lower back due to abnormal function of the foot. An example is an ankle-foot orthosis (AFO), used to treat foot drop. The AFO is molded to the patient's leg from below the Gastrocnemius muscle, running down the back of the leg, around the ankle and along the bottom of the foot. A velcro strap fastens the AFO to the shin, and the patient's shoe (or an additional velcro strap) secures it to their foot. This keeps the foot from dropping below 90 degrees from the leg, while the plastic or carbon fiber material of the AFO allows some springy movement to create a normal stepping motion.

Soft orthotic devices help to attenuate shock, improve balance and take pressure off uncomfortable or sore spots. They are usually made of soft, compressible materials. This type of orthotic is effective for arthritis or deformities where there is a loss of protective fatty tissue on the side of the foot. They are also helpful for people with diabetes.

Semirigid orthotic devices are often used to treat athletes. It allows for dynamic balance of the foot while running or participating in sports. By guiding the foot through proper functions, it allows the muscles and tendons to perform more efficiently. It is constructed of layers of soft materials, reinforced with more rigid materials.

Calibrated orthotic devices are those based on the correction model and manufacturing technique advocated by Glaser. It factors in the individual's body weight, foot flexibility and activity level to deliver a custom calibrated level of support that delivers firm but comfortable functional control while maintaining the properties of an accommodative device.

Foot Orthotics
Since feet are the major weight-bearing part of the body, foot pain is common; half of the Americans polled by the American Podiatric Medical Association had missed a day of work because of foot problems. The foot contains 26 bones, up to 2 sesamoid bones, and many small structures which support and balance the weight of the entire body. Walking puts up to 1.5 times one's body weight on the foot, and humans walk an average of 1,000 miles per year.

Foot pain is not normal and should not be ignored; problems can affect the functioning of other parts of the body, including the hips, knees, and back. These are foot-related problems that may be related to biomechanical issues. Podiatrists, physical therapists and sports medicine practitioners will often recommend custom foot orthoses as part of a treatment regimen.

Proprioceptive stimulation orthotics are an alternative approach to relieving musculoskeletal pain in the feet, legs and back by changing how the feet perceive the ground. Proprioceptive stimulation orthotics are based on 1] muscular control of the feet and 2] that the foot and body responds to subtle pressure to the sole of foot. Dr. William Rossi DPM suggests that shoes disrupt true feedback from the ground, and Dr. Brian Rothbart DPM suggests that true feedback can be disrupted by the foot structure itself. Proprioceptive stimulation alters feedback to the feet by strategically locating thin dimensions on a flat flexible insole. Proprioceptive stimulation insoles work for both supinators (weak ankles) and hyperpronators.

They are prescribed to:
 * Reduce the symptoms associated with many foot related pathologies.
 * Provide support
 * Accommodate foot deformity
 * Provide better positioning
 * Relieve pressure on a certain area of the foot
 * Improve the overall biomechanical function of the foot and lower extremity

Reference

 * Positano, Dr. Rock DPM, MSc, MPH Director of the Non-Surgical Foot and Ankle Service 2006, Hospital For Special Surgery, "Prescription Orthotics Can Help You Put Your Best Foot Forward"