Over the years, orthotics have come to describe a wide range of products designed to provide foot support and comfort. Despite this range, a true functional orthotic (as developed in the middle part of the last century) is defined by a device that is formed from a mold of one’s foot while that foot is held in a subtalar joint neutral position. The subtalar joint exists under the ankle joint, and allows for the foot to flatten and increase its arch depending on the direction of its motion. The neutral position is when the subtalar joint is not flattening (pronating) the foot, nor is it creating a higher arch (supinating). You may find more information at Pro Motion Healthcare
It has been well demonstrated that a wide variety of foot conditions are the result of poor mechanics at the subtalar joint. Hyperpronation occurs when the subtalar joint allows for excessive pronation than anatomically typical. The opposite occurs if too little pronation is available, as the foot becomes ‘cavoid’, or high arched, although this is far less common. Many foot problems occur directly as a result of hyperpronation, including plantar fasciitis, posterior tibial tendonitis, Tarsal Tunnel syndrome, hammertoes, bunions, and neuromas. An orthotic will be effective by controlling this hyperpronation, thus eliminating the underlying cause for numerous foot conditions. Used alone for treatment, the orthotic will not likely be beneficial as the inflammatory (pain) part of these conditions still need to be addressed. However, as part of a multifaceted treatment plan in which the orthotic is used for long term structural support, the orthotic is likely to provide significant benefit.
The orthotic design must accurately capture a person’s specific subtalar joint in a neutral position in order to provide the maximal amount of anatomic structural support. By doing this, the orthotic will reduce hyperpronation, allow the foot and leg to function more anatomically, and significantly reduce structurally caused foot problems. Orthotics are usually made of a thermoplastic, but other composite materials can be used to make them thin enough to fit into women’s dress shoes. Fabric topcovers can be used, not so much to increase comfort as to provide a platform to apply modifications to help the end of the foot. For example, an orthotic itself runs from the heel to just in front of the ball of the foot. To help offload the ball of the foot further for certain conditions, more accommodative padding is needed further down along the foot beyond where the orthotic itself ends. This adds further benefit to the orthotic’s function. Without a topcover, this padding cannot be attached to anything.
In most cases though, topcovers are not necessary and their absence helps the orthotic fit into a wider variety of shoes. As the orthotic is a prescription device, a full biomechanical exam by a foot specialist is needed in order to get the prescription ‘right’, as some patients require more adjustment in aligning the back of the foot with the front of the foot by changing how the orthotic is angled, and certain conditions require more dramatic modification to the usual cast. These more dramatic modifications can include wedges, cut-outs, higher heel cups and other significant changes to the orthotic’s plastic shell.