If The Orthotics Fit

Know which orthotic features are best to restore a balanced foot and reducethe force load transferred to the kinetic chain.

One of the most pleasantly surprising success stories in the annals of managing back pain is the orthotic. Imagine that—a shoe insert can actually help someone with difficult spinal distress. Best of all, orthotic support is a mostly passive process, other than the action of moving the orthotics from one pair of shoes to the next.

Assess for Success
The hallmark of this simple success lies in the assessment of the lower limb kinetic chain and the selection and manufacturing of a custom orthotic. Most likely, you and your office staff are inundated by the choices that orthotics manufacturers offer. New flyers from different companies arrive regularly. Even CDs that promote new product lines are couriered for the doctor’s attention. All of these options stem from the knowledge that the application of a properly designed custom orthotic actually gets the job done.

The most effective orthotics provide support to a kinetic system that has developed an altered balance.^1,2 A shift in the distribution of forces can cause a breakdown in the tissues of the foot and therefore a slackening of the integral fine control and support through the foot’s three arches. The goal of orthotic therapy is to restore a more balanced foot and reduce the injurious force load that is transferred to the kinetic chain. Remember that the benefit of an orthotic is supportive and preventative. This is the reason why patients continue to enjoy the benefits of orthotic support for their entire lives.

Length options. A variety of orthotic lengths are available for different types of shoes. In slip-on shoes and daily casual shoe wear, a 3/4-length orthotic is advisable. This provides all of the necessary support in the mid- and rear-foot and is easily transferred to other shoes. A full-length orthotic is recommended when a lace-up athletic shoe or work boot is the prime footwear. These full-length orthotics can replace factory insoles in shoes. Using a full-length prevents the orthotic from moving during periods of increased activity and also provides more cushioning. A newer 7/8-length can now be ordered that benefits women’s dress shoes. An interesting and valuable feature on a 3/4-orthotic is a dot fastener insert in the heel area. This anchoring system stops the shorter orthotic from migrating and allows for easier foot insertion into the shoe.

Orthotic application. There are three primary goals in the application of an orthotic:

1. Create a symmetrical, balanced foundation by blocking excessive pronation or supporting supination within the established normal angulation ranges.^1,2
2. Provide heel-strike shock protection. The natural heel-strike shock absorption mechanisms are compromised with faulty pedal biomechanics, making the individual more susceptible to bone marrow edema and stress fractures.³
3. Enhance sensory-motor reflexes. The sensory information from the feet affects muscular efficiency, balance, gait, and posture.^2,4,5

To accomplish these objectives, the orthotic must be created in a precise manner and afford a high degree of comfort so that patient compliance will not become an issue.

Support symmetry. If a symmetrical foundation is the first goal, then the orthotic must help to restore leg length equality.⁶ As practitioners, we commonly see an apparent short leg when evaluating the patient in the prone position. This is mostly due to pelvic distortion and is a clue to the persistent patterns of subluxation. However, there are occasional cases where, post traumatically, post surgically or developmentally, a leg is truly shortened. In these cases, a lift can be ordered to support the deficit. Heel lifts are one of the most beneficial additions to an orthotic when this situation is present.

The best way to improve the symmetrical foundation is to assess the patient for overpronation or supination. This correction is by far the centerpiece of orthotic therapy. As the plantar fascia stretches and distorts over time, a collapse of the medial longitudinal arch evolves. This slumping foot posture causes, among other things, an unleveling of the pedal base. Left in this unsupportive posture, muscles will strain to compensate and eventually weaken. Clinicians should be attentive to the tone of the iliopsoas and gluteal muscles, especially on the short leg side. These again are clues to the value of orthotic placement to assist in restoring the symmetry and balance.

The shank of the orthotic needs to provide pedal support while reducing torsional sway. In some orthotics, a dynamic support material in the mid-foot area works as a suspension system to handle variable loads and uneven surfaces. By being semi-flexible, a degree of comfort is available along with a small degree of deflection as the overpronation is blocked.

Heavier patients require more support and cushioning. Some orthotics incorporate a variable density compound to underpin the medial arch area. This added support improves the comfort in heavier individuals so they will not feel the sharpness of the medial ridge as they walk or stand. Superior orthotic companies have a more durable product that can withstand the stronger compressive forces in these patients.

Shock protection. Heel-strike shock protection is mostly achieved by the repositioning of forces as they traverse the three arches of the foot. When the medial and lateral longitudinal and metatarsal arches are properly oriented, the heel-strike and toe-off are naturally balanced. An orthotic can recreate the trampoline effect that a naturally balanced foot uses. If forces are properly distributed along the three arches, a trampoline-like springing motion will reduce the shock of heel strike. By focusing on the first goal of balanced symmetry, the second goal is mostly addressed. However, special polymers can be added to disperse these intense forces even more. Viscoelastic materials can be added, which significantly reduce the spiking forces when compared to hard leather soles or even the bare foot.⁷

Sensory motor reflexes. The third goal of an orthotic is to improve sensory motor reflexes. Chronic tissue damage and foot deformities can alter the sensory input. Ask any heel spur or bunion sufferer and they will tell you about sensory input. In fact, these intensely painful situations alter the mechanics and motor reflexes as compensations in gait occur.^8,9

Several features can be added to the orthotic to reduce this damaging load. A horseshoe-shaped cushion can be added to the heel area. This half ring supports the heel while opening up space around an inferiorly placed heel spur. For the bunion sufferer, a wedge can be cut from under the area of the first ray on a 3/4-length orthotic. This again reduces the compression on the bunion. Heel cups are popular features that are added to stabilize the heel. Newer orthotics are available for the diabetic foot with a consideration for the impaired microcirculation.

The choices that a clinician can make these days when selecting an orthotic are staggering. However, when the three primary goals of orthotic therapy are reviewed, the selection of options begins to be more orderly. You will find that there is an orthotic style, shape, and even color that will suit your patients’ needs. CP

David S. Fletcher, DC, FCCSS (C), a fellow of the College of Chiropractic Sport Sciences (Canada), has been in private practice for 22 years at The Fletcher Clinic, Pickering, Toronto, Canada. He is recognized internationally for blending traditional chiropractic principles with contemporary technologies and strategies. Fletcher can be reached at (905) 831-9696; fletch5@rogers.com;   www.chiroacademy.com. 

References
1. Kuhn DR, Yochum TR, Cherry AR, Rodgers SS. Immediate changes in the quadriceps femoris angle after insertion of an orthotic device. J Manip Physiol Ther. 2002;25(7):465–470.
2. Stude DE, Brink DK. Effects of nine holes of simulated golf and orthotics intervention on balance and proprioception in experienced golfers. J Manip Physiol Ther. 1997;20(9):590–601.
3. Subotnick SI. Forces acting on the lower extremity. In: Subotnick SI (ed) Sports Medicine of the Lower Extremity. New York: Churchill Livingstone, 1989:189.
4. Stude DE, Gullickson J. Effects of orthotic intervention and nine holes of simulated golf on gait in experienced golfers. J Manip Physiol Ther. 2001;24(4):279–287.
5. Freeman MAR, Wyke BD. Articular contributions to limb muscle reflexes. J Physiol. 1964;171:20.
6. McCaw ST, Bates BT. Biomechanical implications of mild leg length inequality. Br J Sports Med. 1991;25(1):10–13.
7. McPoil TG, Cornwall MW. Rigid versus soft foot orthoses. A single subject design. J Amer Pod Med Assn. 1991;81(12):638–642.
8. Michelson JD. Heel pain: when is it plantar fasciitis? J Musculoskel Med. 1995;12(3):22–29.
9. Pressman MN, Novicki DC. Stomping out heel pain. Biomech. 1995;2(10):59–61.