Also known as prescription orthotics, custom orthotics are made specifically for your feet. They differ dramatically from the shoe inserts you see advertised online or on television, or for sale at your local pharmacy. That’s because your podiatrist creates a plaster casting to manufacture an orthotic that fits the unique contours of your foot. This process is known as custom orthotics casting. It ensures that the orthotic not only matches the shape of your foot but is designed specifically for the way you move.
How Are Custom Orthotics Made?
There are three main steps to creating custom orthotics.
Step 1: Creating the Plaster Cast
The first step to making prescription orthotics is a visit with your podiatrist. He or she thoroughly examines your feet, ankles, and lower legs. This gives your doctor a solid understanding of your foot’s unique structure and pathology.
Next, the podiatrist takes a variety of measurements. He or she also questions about your lifestyle and will probably want to look at your preferred footwear.
Now your doctor is ready to create the plaster casting of your foot.
Custom orthotic casting should never occur with the patient in a standing position. Instead, you either sit or lie flat so your podiatrist can take a non-weightbearing cast. In addition, your doctor should make sure your foot is in a neutral position.
The podiatrist wraps wet plaster strips around your foot. Then, he or she sits with you, watching to ensure you maintain your foot position while the plaster hardens enough to remove it from your foot. This typically takes between five and 10 minutes.
The cast needs a full 24 hours to harden completely. Once it hardens, your podiatrist’s office sends the mold and relevant information from your exam to the lab.
Step 2: At the Lab
This type of cast is known as a negative foot mold. It is basically a shell that the lab fills to create a positive mold. This positive mold looks like your foot.
In addition to the cast, the lab uses the measurements taken by your podiatrist to create the orthotic. Your podiatrist also includes instructions for the orthotic’s design. Namely, what is needed to correct your particular issue.
Once the lab creates the positive cast, it presses it against the appropriate material (more on materials in a moment). Extreme heat is applied to ensure the material molds to the shape of the cast. Finally, the lab applies a durable yet comfortable material to the underlying structure.
Step 3: The Material
Choosing the right material for your custom orthotics depends on whether the purpose is functional or accommodative.
The design of functional orthotics helps control motion. These use semi-rigid materials, such as graphite or plastic. In addition to correcting abnormal motion, functional orthotics may be employed to treat shin splints and other injuries.
Accommodative orthotics provide cushioning and support, so they use softer materials. They are commonly prescribed to treat conditions that cause discomfort, such as plantar fasciitis, diabetic foot ulcers, and tendinitis.
Plastics and graphite form the core of the orthotics. Both materials have a wide range of rigidity. Much depends on the thickness of the material. Graphite ranges between 1/16″ and 1/8″ while plastic is a bit thicker, ranging from 1/8″ to 1/4″.
The outer material provides cushioning against the orthotic’s rigid interior. Neoprene, silicones, and other polyethylene foams are commonly used materials for the outer cushion.
Are Prescription Orthotics Better than Over-the-Counter Inserts?
In a word, yes. Prescription orthotics are custom-made to your foot and pathology. They will always be superior to anything you can buy over-the-counter. However, we understand that many insurers refuse to cover custom orthotics, making the cost prohibitive for many patients.