What Is an Orthotic Insole?
Orthotic insoles are prescription medical devices designed to correct foot mechanics and relieve pain caused by flat feet, high arches, plantar fasciitis, and gait abnormalities. In the retail market, the term “orthotic” is often used loosely to describe any type of shoe insert or arch support. However, a true orthotic is a durable, custom-made medical device fabricated by a healthcare provider—most commonly a Doctor of Podiatric Medicine (DPM).
Orthotics can help correct abnormal walking patterns, absorb shock, improve balance, reduce pressure points, and redistribute weight across the plantar surface of the foot. Their purpose is to reduce abnormal or excessive motion while supporting the normal motions of the lower extremity.
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Types of Orthotics
Functional Foot Orthotics
The type of orthotic I primarily use is called a functional foot orthotic. This device fits underneath the foot and slides into most conventional shoes. It is primarily used to treat foot problems by correcting abnormal biomechanics and improving stability.
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Ankle Foot Orthotics (AFOs)
An ankle foot orthotic (AFO) includes an orthotic plate underneath the foot but also has supportive bracing extending halfway up the leg. This is a more controlling orthotic used to treat significant foot, ankle, and lower extremity disorders, including weakness, instability, or certain neurological conditions.
How Is a Custom Orthotic Made?
There are several techniques used to create a custom orthotic. The first step is always to create an impression of the foot or lower extremity.
1. Foam Box Impression
The patient imprints their foot into a foam box while partially weight-bearing. In my opinion, this method is not ideal for creating a truly functional custom device.
2. Wet Plaster Casting
Wet plaster sheets are wrapped around each foot, and the foot is held in a neutral position until the plaster dries. The mold is removed and sent to the lab.
3. Electronic 2D Scanning
Similar to a copy machine, the foot impression is digitally scanned and sent to the lab.
4. 3D LIDAR Scanning (Preferred)
The technique I use is a three-dimensional scan using LIDAR software—often done directly from an iPhone. In my opinion, this is the most accurate and dependable method.
The Orthotic Prescription
Once the impression is complete, it is sent to an orthotic lab along with a detailed prescription. A standard orthotic prescription requires answering 50–75 questions about the patient’s:
- Foot structure
- Body weight
- Shoe size and shoe type
- Activity level
- Specific pathology or diagnosis
The prescription is tailored to the individual patient’s condition. Most labs take 2–4 weeks to manufacture a custom orthotic and return it to my office.
Fitting and Break-In Process
Once the orthotics arrive, the patient brings in the shoes they are most likely to use with them. The existing insoles are removed and used to trace and trim the custom orthotic for a perfect fit.
We recommend a gradual break-in period:
- Day 1: Wear for 1 hour
- Day 2: Wear for 2 hours
- Day 3: Wear for 3 hours
- Continue adding an hour per day
Within two weeks, most patients no longer notice the orthotic in their shoe—but they do notice increased comfort and support.
Common Reasons to Prescribe Custom Orthotics
1. Flat Feet (Pes Planus)
A flat foot occurs when the arch lowers excessively during gait. The foot contains 26 bones designed to maintain an optimal structure even under weight-bearing. When the arch becomes too low, those bones unlock, creating an unstable foot—a “bag of bones.”
This instability forces the muscles, tendons, and ligaments to overwork. A custom orthotic helps restore a stable base and reduce strain.
2. High Arch (Pes Cavus)
A high arch foot often functions like a tripod, placing pressure on two or three points at the bottom of the foot. Orthotics for cavus feet must match the entire plantar surface to distribute weight evenly. These orthotics do not always need to be rigid; semi-flexible materials can work well if they maintain full contact.
3. Achilles Tendinitis / Tendinosis
The Achilles tendon is the body’s largest and most powerful tendon. When it becomes inflamed or degenerative, resting it is essential.
A custom orthotic limits excessive pronation and abnormal motion that aggravate the Achilles. I also add a small heel lift—typically 2–3 mm—to reduce tension on the tendon during weight-bearing.
4. Hallux Limitus with Osteoarthritis
Hallux limitus affects the big toe joint and often develops due to flat feet. When the arch lowers, the position of the first metatarsal changes, altering joint function and increasing stress. Over time, this can lead to degenerative arthritis.
Custom orthotics stabilize the arch and improve the relationship of the big toe joint. A modification called a reverse Morton’s extension allows the first metatarsal to sit slightly lower than the others, improving motion and reducing pain.
Conclusion
A custom orthotic is a powerful tool for addressing a range of foot and lower extremity conditions, from flat feet to high arches and issues like Achilles tendinitis and hallux limitus. Unlike generic inserts, custom orthotics are designed specifically for each patient to provide tailored support, alignment, and comfort.
For best results, choose footwear with removable insoles and adequate depth to accommodate your orthotics.
Shop Orthotic Insoles
Explore our selection of orthotic-friendly insoles and supportive everyday styles:
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Shop Orthotic-Friendly Footwear
Pair your orthotics with supportive shoes that include removable insoles and adequate depth.
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Written by
Dr. Jeffrey S. Hurless
DPM, FACFAS – Board Certified Foot & Ankle Surgeon / Podiatrist