CONDITIONS AND TREATMENTS

THE USE OF ORTHOTICS IN MEDICAL PRACTICE

What are Orthotics?


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. It has been well demonstrated that a wide variety of foot pathology is the result of poor mechanics at the subtalar joint, which is comprised of the articulation between the talus and the calcaneus. This joint allows for pronation and supination of the foot, motions which involve all three body planes. 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', although this is far less common. Many foot pathologies occur directly as a result of hyperpronation, including plantar fascitis, posterior tibial tendonitis, Tarsal Tunnel syndrome, hammertoes, bunions, and neuromas. An orthotic will achieve efficacy by controlling this hyperpronation, thus eliminating the underlying pathology for numerous foot conditions. Used alone for treatment, the orthotic will not likely be beneficial as the inflammatory 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 to prevent pathology reoccurrence, the orthotic is likely to provide significant benefit. The orthotic design must accurately capture the patient'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-mediated foot pathology.


Orthotics are usually made of a thermoplastic plate, 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 distal to the metatarsal head. For example, an orthotic plate runs from the heel to just proximal to the metatarsal heads. To help offload the metatarsal heads further for neuromas or sesamoiditis, more accommodative padding is needed further distally to add further benefit to the orthotic's function. Without a topcover, this distal 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 hindfoot with the forefoot by changing how the orthotic is angled, and certain conditions require more dramatic modification to the standard subtalar joint neutral cast. These more dramatic modifications can include medial wedges, first ray cut-outs, higher heel cups and other significant changes to the orthotic's shell.


Who Provides Orthotics?


Many providers now produce orthotics or inserts claiming to be orthotics. Beyond podiatrists, some orthopedic surgeons, and traditional orthotists/pedorthists, orthotics are offered by physical therapists, chiropractors, shoe stores, and self-described insert stores. As with anything, quality is commiserate on the training of those providing the service. As long as a full biomechanical exam has been performed, and the foot has been casted in a subtalar joint neutral position, the orthotic will generally turn out sufficient for use. We have definitely seen good orthotics from therapists and chiropractors due to their knowledge of general biomechanics. Conversely, we have also seen accommodative padded inserts passed off as functional orthotics as well. Unfortunately, many non-traditional retail providers of orthotics and inserts have little understanding of how the foot actually functions, and cannot make an accurate assessment as to any compounding foot pathology that may need to be addressed in the orthotic fabrication. The devices produced are often inadequate to provide exacting support, and, although not uncomfortable initially, tend to fail in the long term. This is often at great cost to the patient. In some cases, patients are given what they are told are orthotics, when in actuality they are simply over-the-counter inserts that are matched to a patient's shoe size. Some retail locations charge hundreds of dollars for these devices, where actual orthotics may be covered by insurance, and may not even be as expensive if not covered.


It is still in your patient's best interest to have their orthotics produced under the direction of a podiatrist, assisted in fabrication by the orthotist. With rare exception, the device prescribed by the podiatrist will be properly casted for, with a full biomechanical assessment guiding the end result and ancillary treatment alongside biomechanical support. Orthotics are not used for general foot comfort, as they are a prescription device specifically for foot pathology. This pathology requires medical assessment, and a multifaceted treatment course. Using orthotics as a sole treatment modality in the hands of non-physician directed treatment will likely lead to treatment failure and dissatisfaction with the orthotics provided.


What Conditions Do Orthotics Benefit and What Are Their Limitations?

 

As discussed above, orthotics will benefit numerous conditions in which hyperpronation plays a central role in the overall pathology. By achieving maximal control of the subtalar joint, orthotics perform more effectively and efficiently than other insert designs. Orthotics may also have a role in the treatment of conditions requiring increased shock absorption, as seen with cavus, high arched feet where plantar fascitis is a direct result of poor shock accommodation (a normal function of anatomic pronation). When soft inserts do not provide enough shock absorption in these cases, the stiffness of these inserts absorbs the weight-bearing forces, and disperses them into the orthotic plate itself rather than the plantar foot. Orthotics are also used to transfer weight-bearing pressure in cases where painful keratosis, pressure ulcers, or arthritic joints require exacting structural support to avoid surgical intervention or more significant complications. In these cases, offloading of the specific part of the foot that needs to be addressed demands exacting casting technique and knowledge of how this offloading will effect the rest of the foot. Finally, orthotics are used successfully to reduce the fatigue created by hyperpronation, which can sometimes cause medial knee strain, as well as hip and back problems if severe enough. This fatigue is especially seen in kids, and the use of an orthotic in a flexible flat foot will eliminate the need for reconstructive surgery for a majority of these pediatric cases.


Orthotics do have their limitations, and a certainly not a panacea for all foot pathology. In nearly all cases they are ineffective in reducing deformity that has already developed. For example, many of our patients have been told by retail stores selling inserts that their 'orthotics' will reduce hammertoes and bunions. This is simply not true, as even a functional orthotic will only reduce the progression of such deformities by controlling the underlying factor- hyperpronation. The deformity itself as currently evolved is only correctable via surgery. Orthotics are also ineffective in patients with a rigid flat foot deformity, as there is little pronation left in those feet to support. In general, functional orthotics should only be used in conditions that have a biomechanical etiology, are not yet completely evolved from an osseous standpoint, and are from feet flexible enough for the orthotic to allow for motion reduction at the subtalar joint. Otherwise their benefit and efficacy may be dubious.


What About Over-the Counter Inserts?


Over-the-counter inserts have been used for many years for a variety of purposes. In general, they provide decent padding and cushioning to the arch and plantar foot, reducing shock and in some designs providing limited structural support. Typically, these devices consist of felt, foam, gel, or polymer padding designed to push bulk into the arch. Some designs are plastic, emulating orthotics in appearance, but not function. These inserts have firmer support, but are not as well tolerated as the unyielding plastic can irritate plantar tissue as it is not truly molded to the wearer's specific foot, much less to a proper subtalar joint neutral position. In certain conditions that simply need further cushioning or minimal support, over-the-counter inserts are a viable choice for therapy, and present a viable option as an initial treatment modality for conditions requiring further support as long as functional orthotics are eventually used for long term control.


These inserts can potentially belong to a class called accommodative orthotics. Although this generally implies inserts made of a mold of the foot without placing it into a subtalar joint neutral position, the definition has seemingly broadened to include most all over-the-counter inserts and soft orthotic-like inserts. These devices as a whole increase shock absorption, benefitting high arched feet. They also reduce pressure, beneficial for diabetics and those with painful rheumatoid arthritis. However, they are insufficient in providing adequate structural support over the long term, and are far inferior to traditional orthotics for that specific purpose.


In essence, over-the-counter inserts have a notable role to play in a foot treatment course, but are insufficient for those who need full biomechanical control.