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Plantar Fasciitis Biomechanics Common Conditions Health & Prevention |
Redefining Plantar Fasciitis Plantar fasciitis, the most common foot condition that walks, limps or shuffles into our podiatric offices, is often ill-defined and maltreated but not misdiagnosed. Of the patients who present in our offices with complaints of pain on the bottom of the heel, almost 90 percent of them have some form of plantar fasci-itis, -osis, or –algia. Almost 90 percent of those patients will respond well to conservative mechanical therapy with the appropriate use of support, balance and cushioning. Indeed, podiatrists and other medical professionals who evaluate and treat heel pain have significant success in the initial symptomatic treatment of plantar fasciitis. Unfortunately, this condition frequently becomes chronic because physicians do not address the mechanical causes of plantar fasciitis. Remember, the term plantar fasciitis describes a condition, not an injury. Chronic proximal plantar fasciitis is more related to inefficient function (pathomechanics) than a single traumatic event and it does require you to provide functional treatment. In order to provide the most effective treatment
course for all of our patients, we need to be clear on what plantar
fasciitis is and what it is not, how the plantar fascia functions
and how it fails. Looking at the Condition from Anatomical and Physiological Perspectives Plantar fasciitis is clearly associated with plantar calcaneal spurs, but it is not the spur that causes pain. It is actually the pull of the plantar fascia on the medial calcaneal tuberosity that causes the patient pain. In fact, by growing a heel spur, the body relieves the tension on the fascia. We have defined plantar fasciitis as an inflammatory process, but you usually won't see any clinical signs of swelling or obvious inflammation. Anatomically, the tough fibrous band on the
bottom of the foot has been defined as fascia, aponeurosis, "like
a ligament," "like a tendon," and more generally a "dense band
of fibrous connective tissue." The plantar fascia originates on
the calcaneal tuberosity and fans out to the plantar fat pad under
each of the five metatarsals and inserts into the connective tissue
at the base of the proximal phalanges of the five digits. Given
its origin and insertion, the plantar fascia stabilizes the medial
and lateral longitudinal arches. You'll find that the majority
of plantar fasciitis cases involve the medial slip of the fascia,
which is usually due to the mobility of the medial longitudinal
arch. How The Plantar Fascia Limits Subtalar Joint Pronation Not only does it assist in resupinating the subtalar joint during the propulsive phase of walking gait, the plantar fascia assists the deep posterior muscles by helping to limit subtalar joint pronation during standing and walking. The plantar fascia is under the greatest tension during the latter stages of midstance once the center of mass of the body has moved anterior to the ankle joint axis. When the plantar fascia is intact, the posterior tibial, flexor digitorum longus and flexor hallucis longus muscles do not have to contract as vigorously to decelerate pronation or accelerate supination of the subtalar joint.
The plantar fascia assists the plantar intrinsic muscles and it prevents excessive interosseous compression forces on the dorsal joint surfaces of the bones of the medial and lateral longitudinal arches. It also helps maintain purchase of the digits during standing and prevents "floating toes," and acts to store energy within the arch structure of the foot during dynamic loading activities. Therefore, the plantar fascia may act somewhat like a spring around the plantar arch of the foot to first absorb energy during arch collapse and then return that energy during propulsion when the arch is rising. The Achilles tendon and plantar fascia work
synergistically to add power through lift-off. Any mechanical
condition (such as hallux limitus, sesamoiditis, an osseous equinus)
that disturbs the normal forward sagittal plane motion of the
foot will disturb the normal function of the plantar fascia. An Overview Of The Treatment Options In evaluating office records, it is clear that plantar fasciitis is the most common foot condition we see in our offices, as it affects over 20 percent of our patients. Most studies show that women outnumber men with heel pain. According to the literature, you'll also see a significant majority of pes cavus versus pronated feet. Less than 10 percent of heel pain patients require surgery. Treatment for plantar fasciitis may be mechanical, medical or surgical. Medical treatment such as NSAIDs, oral steroids, cortisone injections, acupuncture, and homeopathic remedies (such as Zeel™) will give your patients temporary, symptomatic relief. However, these options do not address the mechanical cause of plantar fasciitis. Typically, when you pursue surgical removal of heel spurs, you'll release the medial attachment of the plantar fascia. You may perform partial (open or minimal incision) or complete release (Steindler plantar fascia stripping) of the plantar fascia, an endoscopic plantar fasciotomy (EPF) or calcaneal osteotomies in order to realign the position of the calcaneal tuberosity. However, once the fascia is cut, the foot becomes unstable and begins to spread out as the arch collapses. Then you're dealing with new symptoms, from interosseous compression of the instep to lateral ankle joint impingement, cuboid displacement and frequent tarsal tunnel syndrome. There's also a relatively new procedure called
extra-corporeal shockwave therapy (also referred to as orthotripsy)
which was developed in Europe and has been approved by the Food
and Drug Administration for outpatient treatment of chronic proximal
plantar fasciitis. The results are very promising as patients
can reportedly expect over 60 percent relief following one treatment
(with 1,500 to 2,000 shocks applied locally under anesthesia at
approximately 18 to 22 volts). (Editor's Note: For more information
about shockwave therapy, see "Inside Insights On Shockwave Therapy,"
August, pg. 38.) Why Soft Shoes And Overuse Syndrome Frequently Cause Plantar Fasciitis Granted, there are many and differing opinions on the anatomy (what it is) and physiology (what it does) for the plantar fascia. Even within the same group of professionals, we differ on the evaluation, definition and treatment of the condition. However, after over 30 years in private practice and with teaching and writing experience in our profession, I have seen a significant increase in the number of patients with plantar fasciitis and the heel spur syndrome, which appear to be related to two major factors: soft shoes and overuse. The shank support of shoes has become more flexible and the public has become more active as they gain weight and become inflexible with age. Many women who used to wear elevated heels with solid shank support are now wearing low, cushioned flats throughout the day and the baby boomers have become weekend athletes with subsequent musculo-skeletal injuries. Overuse implies "under conditioned" or unfit for the event. The overuse syndrome involves impact shock, imbalance or hypermobility. Impact shock on heel contact jars the Achilles attachment and the origin of the plantar fascia. Imbalance of the foot, leg or body above requires compensation of the other proximal and distal structures. Hypermobility, excessive motion or motion at a time when there should be none during the gait cycle creates medial stress on the weightbearing limb. Normally, the foot pronates for shock absorption
during the contact phase, is stable during midstance and begins
to supinate during late midstance and into the lift-off phase
as the center of pressure moves through the foot at a constant
rate. If the foot pronates excessively or into the midstance phase
with eversion of the heel, adduction and plantarflexion of the
talus, the foot elongates and spreads out. Weigh The Conservative Treatment Measures However, before you even consider shockwave therapy or surgical treatment, you should initially focus on the following mechanical treatment options.
Tape strapping foot support is universally accepted as the most effective initial treatment for plantar fasciitis. Ralph Dye, DPM, developed taping techniques for treating mechanical problems of the foot. Specifically, he came up with the Low Dye technique, which supports the arch and heel (midtarsal, medial longitudinal and lateral longitudinal arches). He also gave us the High Dye, which includes using the Low-Dye technique plus additional straps that extend perpendicular to the axis of the subtalar joint up to the lower tibia (to control the subtalar and ankle joint frontal plane motions). You can often supplement the tape support with felt padding for additional cushioning and support, especially to the medial arch and to cup the normal protective fat pad around the heel. __________________________________________________________ Dr. Hlavac, the Past President of the American Academy of Podiatric Sports Medicine, has a private practice in Mill Valley, Calif. He is the author of two books, The Foot Book: Advice For Athletes and the forthcoming The Foot Book: Good Feet For Life. References 1. Solving the Puzzle of Heel Pain, Podiatry
Today, p. 30-58, October 2000. |
