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Anatomy of an Orthotic and Materials

When it comes to custom orthotics, there are many layers of materials that come together to create a complete device. Every layer of the orthotic has a different function and each material has its own unique characteristics.

Unlike prefabricated orthotics, custom orthotics are made by hand to fit the needs and lifestyle of the individual patient. Every layer of a custom orthotic is customizable or interchangeable during the manufacturing process depending on what role the device is needed for.

Different combinations of materials will result in a different experience for the end user. Understanding the benefits of each material/layer will play an important role in the effectiveness of the final product and your overall customer satisfaction rate.

Top Cover Material

This is the first layer that the patient’s feet will come in contact with. The choice of top cover material will affect the aesthetic appearance, comfort, and function of the device.

Marine-grade with anti-fungi additives. This material is extremely long lasting and durable while also being thin and water-resistant. Low friction and grip can cause feet to slide around in shoe if used in certain sports.

Perforated polyethylene foam. Soft and durable while also resistant to compression. Perforations allow for increased air circulation and breathability of the orthotic in the shoe and increased moisture wicking.

Garment leather made from cow-hide. Very soft material that is comfortable, aesthetically pleasing and good for dress devices. Not recommended for sweaty feet, high activity patients, or wet environments due to decrease durability.

Soft, closed-cell rubberized foam that is compressible and not slick. Durable and easy to clean, provides great grip and forms to foot shape. Not recommended for patients prone to blistering because of high friction.

Neoprene foam with nylon fabric. Good cushioning and shock absorption, great for patients who are consistently on their feet or standing for long periods of time. This material can be prone to absorbing water/sweat.

3mm foam with that is similar to neoprene. The top fabric of this material is infused with silver. Anti-microbial benefits make this effective against a wide range of bacteria and can also help to reduce bad foot odor.

Top Cover Length

The length of the top cover comes in 3 different lengths and can be adjusted based on your customer’s lifestyle. Here are some of the top cover materials and options available at Forward Motion:

Top cover extension goes to the end of toes. Usually provides the most comfort and stability. All accommodations are available. Standard on athletic devices.

Material ends behind toes. Length makes it easier for patients to fit and move orthotics between shoes. Standard on most Accommodative and all Dress devices.

Material covers shell up to Meta length. Easiest to move between different shoes. Forefoot accommodations unavailable. Standard on Functional Devices.

Padding & Accommodations

A layer of padding goes under the top cover and is added to the orthotic to increase the patient’s comfort. Increasing the length and thickness of the padding can be helpful for patients with sensitive feet or other conditions.

In this layer of the orthotic, we can also use padding to create different types of accommodations to fit the needs of the patients. These accommodations address specific conditions that patients may have by providing support, correction, or by relieving pressure to certain areas of the foot. For a full list of accommodations, check out our lab cheat sheet for more information.

Padding is available in two thicknesses and is usually added to the entire device. The devices can be customized to have padding only on the shell area or forefoot area if needed.

In order to create a thinner device that will fit easier in shoes, doctors may reduce padding thickness or completely remove padding if the top cover material provides suitable padding. It is standard for our Dress orthotics to have little to no padding.

For most padding and accommodations, we use Poron as the main material.

​Poron is a premium offloading and padding material. It provides great shock absorption, comfort, and flexibility while being long-lasting and durable. Poron offers impressive levels of rebound and grip.

Orthotic Shell

This is the heart of the orthotic! The orthotic shell is the layer that sets custom orthotics apart from prefabricated. Shells are molded to the shape of the patient’s foot, and provide the support or correction to improve foot health. This is where doctors can customize things like arch height, orthotic width, heel cup depth, and flanges.

Our lab uses Performance RX or PRX Graphite shells as the core of our custom orthotics. Thinner, lighter and stronger than polypropylene, these shells are made by Forward Motion and available at no extra cost.

Shells come in different rigidities that cause the orthotic to be either more functional or accommodative while taking into account factors such as patients’ weight. Typically the more rigid the shell, the more foot control there will be. However, very rigid shells can cause discomfort and take longer to adjust to. It is important for doctors to balance function against the comfort of the patient.

Flexible shell, similar to 2.0 subortholin. Best for accommodative devices.

Medium control similar to 1/8″ polypropylene. Supportive & flexible.

Rigid control. Similar to 3/16″ polypropylene. Used in functional devices.

Rigidity is between PRX semi-rigid & rigid. Good for heavier patients and bigger sizes with some flexibility.

Standard shell for our functional orthotics. Rigid control, good for plantar fasciitis.

Our most rigid shell with extra firm control. Good for heavier patients that need a very functional orthotic.

Bottom Cover

The bottom of the orthotic is one of the most important parts of the entire device. Doctors can adjust the posting for things like limb length discrepancies, and even the angle at which the orthotic meets the ground to address patient pronation or supination. If no angle is specified, our lab technicians will automatically correct the foot to neutral position.

Posting can be made to the forefoot or rear foot area using extrinsic materials like crepe to adjust the angle of orthotic (standard on athletic and functional devices), or the shell can be ground directly to make an intrinsic posting (used on dress devices).

The final layer in manufacturing an orthotic is the Bottom Cover. This layer provides a finished look to the device. A device with no bottom cover added allows the shell area to be reheated more easily and is great for functional devices that are meant to aggressively correct foot shape.

​Soft but durable fabric used as a bottom cover. Great for grip and preventing squeaking in the shoe.


Forward Motion custom orthotics lab has been manufacturing custom orthotics since 2002. Our lab uses the highest grade materials available on the market, and we even created a few materials of our own to keep the quality of our custom devices high and the prices low. In addition, all accommodations, material upgrades, shipping, and adjustments are included in the set price.

Our exceptional customer service, crew of pedorthists, and innovative technology make the entire process of casting and ordering custom orthotics easy and stress-free. We are ready and able to help you with any custom orthotics and AFO need you may have.

We would be happy to help you build the perfect device for your patient! Call us at (435) 251-8500 to speak with one of our experienced pedorthists, or schedule a meeting with one of our dedicated account managers who will be able to answer any questions you may have.

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