The connection between orthotics and low-back pain

Whenever a concern about low-back pain brings a person in to see a chiropractor, a careful examination of the spine is required.

Often neglected, however, is the importance of the feet to normal spinal function—especially in the lower back. When patients don’t respond as well as expected to their chiropractic care, a source of interference is frequently located in the pedal foundation.

No matter the cause, an abnormal gait contributes to musculoskeletal imbalances throughout the lower extremities, and eventually back pain develops.

In 2017, the Archives of Physical Medicine and Rehabilitation reported that Foot Levelers custom orthotics have been clinically proven to improve low-back pain almost immediately.¹ The peer-reviewed study offered the following practical applications:

• Six weeks of wearing custom orthotics reduced low-back pain by 34.5 percent, and improved function by 18.5 percent.
• The addition of chiropractic care to wearing custom orthotics led to higher improvements in function (32.3 percent).
• Improvements in pain and function were maintained through the 1-year study.

Biomechanics of the feet

The foundation provided by the feet and legs must bear the weight of the entire body (and considerably more load during running and other sports). If there is insufficient or inadequate support from the pedal foundation, the spine will be exposed to abnormal stresses and strains that eventually develop into low-back pain.

Excessive stresses on the spine can be the result of abnormal foot biomechanics, poor function of the foot-ankle complex, excessive shock transmission, or leg length asymmetry. Recognizing and then responding appropriately to these factors separate the doctors of chiropractic from the spinal technicians.

When some part of the foot is not moving properly (either insufficient or excessive joint motion) the resulting forces produce negative effects all along the kinetic chain.² The following are some examples of common foot problems that have been found to interfere with spinal function:

First MTP joint. When the metatarsophalangeal (MTP) joint of the first toe is stiff and doesn’t flex properly, the transition from midstance to toe-off is restricted. Studies have found that this movement limitation (called “functional hallux limitus”) is a “major gait abnormality that causes lumbar stress.”³ The best treatment for this condition is individually designed stabilizing orthotics that support the medial arch and yet still encourage motion at the first MTP joint.

Plantar fasciitis. When a patient complains of a sharp heel pain that radiates along the bottom of the inside of the foot, and especially when the pain is worse when getting out of bed in the morning, inflammation of the connective tissue that supports the underside of the foot must be considered.⁴ This causes a significant problem with comfortable walking, often resulting in a painful limp. A flexible, stabilizing orthotic with a heel spur cut-out will improve gait and lessen the impact of this condition on the pelvis and spine.

Dropped metatarsal heads. If there is no anterior arch to the foot, excessive weight bearing on the metatarsal heads will cause the transition from foot flat to toe-off to be painful. This alters the timing of the gait cycle, resulting in a rushed propulsion phase.

The effects are felt in the pelvis and spine, which are not able to move smoothly through the phases of gait. Orthotic support for the metatarsal arch can improve biomechanics in all weightbearing joints.⁵

Foot and ankle function

The biomechanics of the foot and ankle are complex, and this region must handle repetitive physical forces. There is normally a smooth transition from pronation following heel strike to supination at toe-off. But when there is excessive pronation or fixed supination, gait is affected and the entire musculoskeletal system is less efficient.

In the case of excessive pronation, the entire lower extremity undergoes excessive medial (internal) rotation, which can cause a range of effects on the pelvis, sacroiliac joints and spine. Individually designed stabilizing orthotics work to restore and support proper foot function.

Shock transmission and asymmetry

Whether a foot tends toward hyperpronation or excessive supination, the result can be excessive shock transmitted into the spinal joints. “A high-arched (cavus) foot with limited range of motion attenuates shock poorly,” as does a collapsed-arch (planus) foot.⁶ In either case, the forces are felt in the joints of the pelvis and spine.

Individually designed stabilizing orthotics with shock-absorbing materials can eliminate much of this damaging shock transmission.

When there is a leg-length discrepancy (whether anatomical or functional), the pelvis will tilt to one side. This asymmetry causes vertebral rotation and recurrent subluxation, and possibly even a functional scoliosis.

The correct use of orthotics (occasionally with added heel-lift) can provide substantial correction for structural short legs.

Back to the feet

When a patient exam reveals any of the deficits in the pedal foundation listed above, the exceptional doctor of chiropractic will recognize the need for supplementary treatment.

This frequently requires the use of individually designed orthotics for long-term stabilization. Flexible orthotics made from viscoelastic materials have now been shown to be the most useful approach.

As one investigator has commented, “The full rehabilitation of the back patient with chronic back pain must include reeducation in the optimal use of the spine in walking…”⁷

Often, even expertly applied spinal corrections will be only partially successful until the lower extremity problems are addressed and corrected.

Mark Charrette, DC, is a 1980 summa cum laude graduate of Palmer College of Chiropractic in Davenport, Iowa. He is a frequent guest speaker at twelve chiropractic colleges and has taught over fourteen hundred seminars worldwide on extremity adjusting, biomechanics, and spinal adjusting techniques. His lively seminars emphasize a practical, hands-on approach. He has authored a book on extremity adjusting and also produced an instructional video series. He has successful practices in California, Nevada, and Iowa and currently resides in Texas.

References

¹ Cambron JA, Duarte M, Dexheimer J, Freels S. Shoe Orthotics for the Treatment of Chronic low-back pain: A Randomized Controlled Trial. Archives of Physical Medicine and Rehabilitation. 2017;98:1752-62.

² Katoh Y, et al. Biomechanical analysis of foot function during gait and clinical applications. Clin Orthop Rel Res. 1983;177:23-33.

³ Dannanberg HJ, Guiliano M. Chronic low-back pain and its response to custom-made foot orthoses. J Am Podiatr Med Assoc. 1999;89:109-117.

⁴ Souza TA. Differential Diagnosis for the Chiropractor. Gaithersburg, MD: Aspen Pubs; 1997: 354.

⁵ Hayda R, et al. Effect of metatarsal pads and their positioning: a quantitative assessment. Foot Ankle Int. 1994;15:561-566.

⁶ Subotnick SI. Forces acting on the lower extremity. In: Sports Medicine of the Lower Extremity. New York, NY: Churchill Livingstone; 1989: 189.

⁷ Yekutiel MP. The role of vertebral movement in gait: implication for manual therapy. J Man Manip Therap. 1994;2:22-27.