Excessive foot pronation is one of the most common conditions that
affects the human frame. This is a condition where the foot rolls inward,
creating a foot that is flatter, wider and longer. A resultant subluxation
pattern of the various tarsals and metatarsals results.
As chiropractors, we understand that the foundation of the spine is the
pelvis, and any pelvic misalignment can affect the biomechanics of the
lumbar, thoracic and cervical sections of the spine. What we must remember
is that the pelvis is itself dependent upon the status of balance in the
lower extremities and the pedal foundation.
Effects of imbalance
Any structural imbalance -- such as an anatomical leg length
inequality, pes planus, etc. -- requires compensating movements in the
lower extremities and pelvis, in order to minimize as much as possible
stresses and strains that would affect the spinal column. Over time,
however, specific muscle imbalances and shortenings will develop.
Eventually, both the soft tissues and bones are damaged by microtrauma,
which can eventually lead to pain and discomfort. [1-5]
A functional imbalance, such as collapse of the arches of the foot,
also results in excessive motion during the various phases of gait. With
excessive pronation, the entire leg spends too much time in internal
rotation, placing twisting stresses on the pelvis with each step. In time,
this results in overstretching of the hip and pelvic support ligaments,
and can also be a cause of chronic pain and dysfunction.
Evaluation
An evaluation to check for lower extremity imbalance should be
performed on every patient who presents with chronic musculoskeletal
conditions of the spine or lower extremities. This can be done with a
quick and easy screening procedure, such as a weightbearing examination.
The following is a recommended series of observations to make while the
patient is barefooted and standing:
*** Foot flare – Toeing out while walking indicates
hyperpronation. Weight falls on the medial longitudinal arch, leading to
plastic deformation that weakens the foot's supportive qualities.
*** Knee rotation – Hyperpronation forces the patella
to rotate medially, indicating excessive leg movement. The tibia and femur
rotate medially, increasing the risk of abnormal hip rotation.
*** Bowed Achilles tendon(s) – The Achilles tendon bows
in on the side of hyperpronation. The calcaneus tilts inward, bringing the
talus with it. The stress can extend to the tibia and along the entire
kinetic chain.
*** Low medial longitudinal arches – With the patient
in a normal, relaxed stance, insert two fingers beneath each medial
longitudinal arch. Tight plantar fasciae, with possible pain or pressure,
indicate foot imbalance. As the patient shifts weight outward, note tissue
relaxation and absence of pain .
*** Shoe wear – With hyperpronation, excessive heel
wear on the outer edges occurs. Check also for lateral distortion in the
counter and/or shoe vamp. [6]
The 20-30 seconds required to perform the above exam is time well spent
in avoiding treatment frustration and improving patient outcome. The
information that you gather about the feet will be very helpful in dealing
with postural distortions and pain farther up the body. For example,
positive findings often indicate a need for custom-made, flexible foot
orthotics to help stabilize the spine and pelvis and absorb heel-strike
shock.
Typical subluxation pattern of the pronated foot
When the foot pronates, creating a longer, wider and flatter foot, the
tarsal bones subluxate in a predictable pattern. The first, second and
third cuneiforms will subluxate in an inferior direction.
Adjustment for inferior cuneiforms 1-2-3
The doctor stands on the involved foot side, facing the opposite foot.
The superior, or headward, hand makes a U-shaped contact over the talus-navicular-cuboid
area on the dorsal surface of the foot. The doctor applies inferior
traction with this hand while keeping the forearm as parallel as possible
to the tibia.
The medial-anterior border of the doctor's inferior or thrusting hand
contacts the plantar surface of the foot. A dynamic thrust is given in a
superior line of drive while the superior/headward hand applies inferior
traction.
Rotating the foot slightly internally or externally can bring about
relaxation, making this adjustment more effective.
References
1. Chambless KM, Knudtson J, Eck JC, Covington LA. "Rate of injury
in minor league baseball by level of play." Am J Orthop 2000;
29(11):869-872.
2. Kibler WB, Safran MR. "Musculoskeletal injuries in the young
tennis player." Clin Sports Med 2000; 19(4):781-792.
3. Kavanaugh J, Yu JS. "Too much of a good thing: overuse injuries
of the knee." Magn Reson Imaging Clin N Am 2000; 8(2):321-334.
4. Gabbett TJ. "Incidence, site, and nature of injuries in amateur
rugby league over three consecutive seasons." Br J Sports Med
2000; 34(2):98-103.
5. Hyland J, Yochum T, Barry M. "Posture and weightbearing
biomechanics: unproved theory or clinically important concept?" Dynamic
Chiropractic 1996; 14(16):21-24.
6. Charrette MN. "Examination of the foot and ankle: non-weightbearing
and weightbearing procedures." Success Express 1996; 16(3):20-22.
(Dr. Mark N. Charrette is a 1980 summa cum laude graduate of Palmer
College of Chiropractic. Over the past 15 years he has lectured
extensively on spinal and extremity adjusting throughout the United
States, Europe, the Far East, and Australia. He received a Bachelor's
degree from Illinois State University (summa cum laude) in 1976 where he
was an NCAA All-American in 1974. Dr. Charrette is a featured speaker in
Foot Levelers' 50th Anniversary Conference Series.
For information about Foot Levelers or to register for a conference,
call 800/553-4860 – from Canada 800/344-4860 – or visit the Foot
Levelers website at www.footlevelers.com.)