When Do OTC Orthoses Suffice?

Can over-the-counter arch supports play a role in the treatment armamentarium for our patients? Noting the impact of mass market commercialization on blurring the lines between over-the-counter arch supports and custom orthoses, this author discusses appropriate indications and pertinent considerations with orthotic fabrication.

The ongoing controversy and confusion involving expensive prescription custom orthotics versus relatively inexpensive over-the-counter (OTC) arch supports lies not only in the purported efficacy of OTC devices but in the plethora of choices offered online, in retail stores and medical offices.

In 2015, patients spent an estimated $4.7 billion on OTC orthotics in the United States alone.¹ Online marketers offer virtual doctor evaluations and send foam molds from which they make “orthotics.” Amazon lists no fewer than 20 different arch supports, wraps and braces for foot pain. A Parade magazine advertisement once touted a reflexology-like orthotic device guaranteeing weight loss with frequent use. CVS stores have partnered with Dr. Scholl’s to prescribe an “orthotic” based on data obtained from stepping on an in-store pressure measurement system with “foot mapping technology.”

There are also many varieties of prescription “custom” orthotics made at ski shops by boot fitters, in specialty shoe stores by shoe salesmen or orthotists, or by chiropractors, orthopedic surgeons, physical therapists or podiatrists as an integral part of patient care. Furthermore, divergent philosophies abound on how to take an accurate foot impression from which to fabricate the orthotic, whether to make the device accommodative or functional, and what materials to use.

Many use the terms “orthotic” and “arch support” incorrectly and interchangeably as they represent very different types of devices. Over-the-counter arch supports are prefabricated for different shoe sizes. Patients often seek out these OTC devices or physicians recommend them as a first-line treatment since they are much less expensive and readily accessible.

The best OTC device manufacturers are the ones with podiatric consultants who model their devices after prescription orthotics. These companies include ProLab Orthotics, Nolaro 24 (Quadrastep), Stable Step (Powerstep), Superfeet and Cascade. These companies utilize firmer plate materials and deeper heel cups in some of their models. Some devices offer different arch heights and contours. With some devices such as Kiddythotics (ProLab Orthotics), there are even sample trial sizes available for fitting children.

Over-the-counter prefabs are generally made of softer, more accommodative materials in comparison to most custom devices so most foot types more easily tolerate them. The prefab arches made for children are usually much firmer yet still mostly comfortable, a fact that is likely due to children’s feet being more reducible and adaptable. This is based on the “reverse of deformity theory” that suggests firmer OTC arch supports work best for flexible feet and softer ones are better for rigid feet.

The various designs of OTC arch supports cater to almost all shoe types, including women’s dress flats and heels. One can easily add OTC arch supports to non-supportive shoes to help limit mild pronation, reduce plantar arch fatigue and cushion bony prominences related to plantar fat pad atrophy that occurs in patients with arthritis. For this purpose, one can easily modify orthoses with other pads to offload pressure sensitive areas.

Research using in-shoe pressure measuring systems has proven that OTC insoles effectively reduce local peak pressures and the pressure time interval, and increase the surface contact area during gait.² Many studies have examined the effectiveness of insoles for the treatment of plantar fasciitis or heel pain in random patient samples and found that insoles were just as beneficial as prescription orthotics.^3-6 According to Michael Bozzaotra at Performance Labs, the “inherent limitation (of insoles) is an inability to modify the plate itself to address a person’s specific pathology such as a functional hallux limitus or a forefoot valgus or uncompensated/partially compensated forefoot varus.”⁷

Sometimes it is valuable to dispense OTC devices as temporary measures until the lab can process prescribed custom orthotics and dispense them for long-term use. Interestingly, since some OTCs may need replacement more often in comparison to most prescription orthotics that last for years with minimal refurbishment, custom devices can be more economical.

Prescription orthotics are usually classified as accommodative (more flexible) and functional (more rigid). These custom orthoses are patient specific and prescribed to address pathology diagnosed from a detailed clinical and biomechanical exam.

Key Considerations With Orthotic Fabrication
Orthotic fabrication usually happens at an outside lab after the lab receives a prescription as well as an impression of the patient’s foot taken with the subtalar joint in a neutral position and the midtarsal joint pronated on its oblique axis. Different professionals use different methods to accomplish this with varying degrees of success.

Nigg once sent a long distance runner to five different practitioners who proceeded to prescribe five different orthotics with varying materials, plate thickness, degrees of posting, heel cup size, flanges, etc.² Many so-called prescription orthotics are really “pseudo-custom,” such as those typically dispensed widely by chiropractors. Although these devices are expensive, I have found they are actually no better than generic accommodative insoles.

The aforementioned pressure measurement system at CVS has the potential to individualize arch supports for each patient’s needs but the store’s devices reveal little perceptive differences and are no better than other mass-produced cushion insoles, a far cry from custom orthotics. Many ski shops and specialty shoe stores commonly use more supportive and rigid materials made from a foot impression. However, without a medical professional to ensure neutral foot position and take specific patient biomechanics, foot pathology and injury history into account, the resulting devices from ski shops and specialty shoe stores often lack functionality.

Obtaining an accurate foot impression from which to make the custom orthotic is crucial to the orthotic’s ultimate success. Orthoses are currently made from plaster or fiberglass casting, foam crates or computerized scans. Plaster requires more dexterity and training. There is also longer turnaround time because plaster scans have to go through the mail, which may subject them to heat and damage. Nevertheless, plaster casts “remain the preference of most labs because the plaster yields a more accurate three-dimensional image of the foot and is easier to evaluate for inconsistencies, the posting of the forefoot to the cast and to see deformities,” according to Bozzaotra.⁷

Fiberglass is fairly accurate but does not capture the arch as well as plaster and can be distorted by shrinkage and nonconformity if one does not size the cast correctly. Foam can be problematic because it is difficult to maintain the subtalar joint in neutral with any weightbearing.

Scanning technology continues to evolve and has the potential to be more efficient with its ease of use and faster processing via email, but the results are often inconsistent and non-reproducible. Even 3D scans lack the ability to see past the widest point of the plantar surface to truly reveal the shape of the heel and verify that the subtalar joint is locked in neutral. IPad scanners show some promise in capturing more of the contour of the foot but require coordination of the screen while holding the subtalar joint in neutral. Establishing an interactive relationship with a knowledgeable orthotic lab technician to share more relevant clinical data will further customize an orthotic to patient needs and ensure optimal results.

Raising Questions On Studies Comparing Custom Orthoses Versus OTC Devices
To most podiatrists, it would appear counterintuitive to note that the majority of published clinical studies overwhelmingly suggest that the effectiveness of OTC devices is comparable to that of prescription orthotics. Many of these studies, though, are flawed in that they investigate only plantar fasciitis in an average population or compare OTC devices with orthotics that are not truly custom.
Ferber and Benson found that OTC and prescription devices both equally reduced plantar fascial strain by over 30 percent.⁴ However, the study enlisted only 20 patients and used devices that were heat-molded to the patient’s foot. Accordingly, these devices were only “semi-custom.”

Studies by Landorf, Ring and Wrobel and their respective colleagues used improved evidence-based research standards, focusing solely on evaluating plantar fasciitis pain rather than an array of other foot pathologies.^5,6,8 The methodology and design of each previous and future study demands our close scrutiny to validate their results and avoid conclusions that may be misleading.

Identifying Patients Who Are Good Candidates For OTC Devices
To illustrate my basic philosophy to patients, I commonly invoke the analogy of OTC reading glasses versus prescription glasses. Of course, one needs to consider many variables when treating patients but to generalize, I present OTC arch supports as an initial, quick and easy, relatively inexpensive, off-the-shelf fix for minor issues, especially arch pain. These devices are ideal for average-sized people (105 to 120 lbs. for women and 135 to 165 lbs. for men) with average arch height (neither cavus nor moderately pronated feet), who engage in light standing or exercise (less than 30 minutes of weightbearing four days each week) and possess low grade foot pathology and relatively good lower extremity biomechanics. Prefab devices also work particularly well for young children under 8 years of age and their flexible feet without bony prominence to consider.

More complicated problems may necessitate a prescription. Over-the-counter devices do not adequately support the extremes (severe planus or cavus feet and their associated deformities) at any age. Prescription orthotics are preferable in those with higher or lower arches, increased body weight, greater activity, specific shoe fit issues, significant structural or biomechanical deformities, or more severe symptomatic pathology.

When To Prescribe Custom Orthotics
Patients who do not meet the aforementioned parameters for OTC arch supports will likely benefit more from the precision of prescription orthotics. For example, consider a symptomatic 200-pound male with collapsing pes plano valgus and hallux limitus who runs 50 miles a week outside on hard pavement. A custom fit to the foot allows for more brace rigidity to better affect lower extremity motion and alignment. A prescription device also facilitates customization of the type and thickness or combination of materials. For instance, one may choose Plastazote over flexible polypropylene for a heavyset patient with diabetes, lightweight carbon fiber for competitive runners, additional PPT arch fillers for shock absorption or durable pads over the shell for offloading plantar lesions. Customization of the orthotic to the patient’s foot and shoe is of even greater importance in a non-standard shoe like a soccer cleat, military boot, dress or bike shoe.

Patients who show improvement from OTC arch supports would likely derive even greater benefit from prescription orthotics. However, the fabrication of a custom orthotic varies widely from practitioner to place as the method of taking foot impressions, use of materials and prescription greatly affect what constitutes a true “custom” orthotic and its effectiveness for a certain condition. Clearly, we need to establish a more precise medical standard of care regarding custom prescription orthotics.

To the average consumer, there is often a blurry line of distinction between OTC and custom devices. Patient economics and practitioner level of expertise may end up being the decisive factors. David Levine, DPM, CPed, a partner in Foot and Ankle Specialists of the Mid-Atlantic, has an accredited pedorthic facility and shoe lab, and owns a retail New Balance running shoe store. He recommends both custom orthotics and OTC arch supports, admitting that “many people invariably opt, at least initially, for more OTC devices since they are comfortable, cheaper and immediately available, even when I would prefer a custom orthotic to better meet their specific needs.”⁹

It is not surprising to note that many prescription orthotic labs have recently begun promoting and developing their own OTC product lines. It is probably a good idea for all of us to have a full line of functional (or firm) as well as accommodative (or soft) OTC prefab devices in our office for convenient patient dispensing.

In Conclusion
Many of us clinicians who deal with an active, varied patient population yearn for more studies examining specific parameters that will yield more practical information to substantiate the enhanced value and medical necessity of prescription orthotics over OTC arch supports for those who require them. Some studies erroneously equate OTC arch supports with what are actually “pseudo-custom” orthotics or extrapolate OTC arch supports as a panacea for all types of patients and degrees of pathology. Such studies help determine practice guidelines and fuel insurance company justifications to reduce provider reimbursements unfairly.

With so many options available to the public and healthcare professionals, it is of paramount importance that we continue to emphasize the distinctive differences between OTC arch supports and prescription orthotics. Podiatrists remain the experts in foot biomechanics and foot pathology, and we need to include both in our treatment armamentarium.

Dr. Spector is a partner in Foot and Ankle Specialists of the Mid-Atlantic, and co-founded the multidisciplinary Montgomery County Road Running Clinic. He is the Chief of Podiatric Surgery at Holy Cross Hospital in Silver Spring, Md., where he has practiced for over 25 years.

References

1.     Collier R. Orthotics work in mysterious ways. CMAJ. 2011; 183(4):416-417.
2.     Tsung BYS, Zhang M, Mak AFT, Wong MWW. Effectiveness of insoles on plantar pressure redistribution. J Rehab Res Dev. 2004; 41(6):11-12.
3.     Nigg B. Biomechanics of Running Shoes. Human Kinetics Publishers, Champaign, IL, 1986, p. 1.
4.     Ferber R, Benson B. Changes in multi-segment foot biomechanics with a heat moldable semi-custom foot orthotic device. J Foot Ankle Res. 2011; 4(1):18.
5.     Landorf KB, Keenan AM, Herbert RD. Effectiveness of foot orthoses to treat plantar fasciitis: a randomized trial. Arch Intern Med. 2006;166(12): 1305-1310.
6.     Ring K, Otter S. Clinical efficacy and cost effectiveness of bespoke and prefabricated foot orthoses for plantar heel pain: a prospective cohort study. Musculoskeletal Care. 2014; 12(1):1-10.
7.     Personal communication, Michael Bozzaotra, Performance Labs.
8.     Wrobel JS, Fleischer AE, Crews RT, Jarrett B, Najafi B. A randomized controlled trial of custom foot orthoses for the treatment of plantar heel pain. J Am Podiatr Med Assoc. 2015; 105(4):281-94.
9.     Personal communication, David Levine, DPM, CPed.

For further reading, see “Do Prefab Orthoses Have A Place In Treating Plantar Fasciitis?” in the December 2007 issue of Podiatry Today, “Current Insights On The Benefits Of Custom Orthoses And AFOs” in the January 2014 issue or the DPM Blog “Using Prefab Orthoses To Determine If Patients Can Tolerate Custom Orthoses” at https://tinyurl.com/kko2tz9 .

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