The field of medical technology called “Biomechanics” is a highly technical branch that studies human motion and helps determine limits of normality and abnormality. Regarding foot biomechanics, such limits are controlled with a prescription device called an orthotic. Over the 30 years of clinical Podiatric Medical practice, I have been questioned about their necessity and effectiveness, that perhaps it may be a worthy topic for discussion.
Often, adult foot problems begin in childhood. Foot structure is inherited, and therefore the tendency for improper foot biomechanics and deformity is also inherited. It is therefore strongly urged that parents take a proactive approach to their children’s feet so that they have a good understanding in later years.
An orthotic is a custom made appliance, typically made from a plaster cast or 3D scan and moulded ideally when the foot is non-weight bearing. There are different types of orthotics, catering to the various activity, different shoe gear and specific foot ailments. Its purpose is to prevent abnormal motion of the foot, specifically subtalar joint hypermobility, while allowing for a more normal motion and function.
These devices are not designed to act as crutches. With an orthotic in the shoe, the muscles and tendons of the feet and lower legs will function normally but will be prevented from being stressed beyond their limits.
Orthotics are not just expensive arch supports. A simple arch support is designed to push up against the arch while standing. It is not meant for “static stance” or for “dynamic motion”. This means that an arch support is not designed to control the biomechanics of the foot. Everyone’s feet are different and because foot imbalances are so varied, a precise prescription for each patient is often required.
In summary, the important components ensuring a good quality device should include:
- Capturing an accurate neutral subtalar joint position
- Having a reputable lab manufacture the device, and
- Listening to your patient regarding activity and type of shoe they typically wear.
Jeffrey Liebman is a Doctor of Podiatric Medicine. Graduated from the Ohio College of Podiatric Medicine in 1982, and is a Fellow of the Academy of Ambulatory Foot and Ankle Surgery. His office is located on 37 Alvin Avenue at Yonge and St. Clair in Toronto, and has satellite clinics at 133 Richmond St. W. in Toronto and at Lionsgate Wellness Clinic in North Bay, Ontario.