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Plantar fasciitis
Specialty	Rheumatology, podiatry

Plantar fasciitis is an painful inflammatory condition caused by excessive wear to the plantar fascia of the foot. The pain usually is felt on the underside of the heel, and is often most intense with the first steps of the day. It is commonly associated with long periods of weight bearing. Obesity, weight gain, jobs that require a lot of walking on hard surfaces, shoes with little or no arch support, and inactivity are also associated with the condition. This condition often results in a heel spur on the calcaneus, in which case it is the underlying condition, and not the spur itself, which produces the pain.

Anatomy of the plantar fascia

The plantar fascia is a broad structure that spans between the medial calcaneal tubercle and the proximal phalanges of the toes. There is still some debate as to whether it is deep fascia or an aponeurosis. The Dorland’s Medical Dictionary defines an aponeurosis as:.(i) a white, flattened or ribbon-like tendinous expansion, serving mainly to connect a muscle with the parts that it moves, (ii) a term formerly applied to certain fasciae. Further, it defines the plantar aponeurosis as: bands of fibrous tissue radiating toward the bases of the toes from the medial process of the tuber calcanei; also called the plantar fascia. For the purpose of this article, however, the term plantar fascia will be used to link to the clinical condition PF. The plantar fascia is made up of predominantly longitudinally oriented collagen fibers. There are three distinct structural components: the medial component, the central component, and the lateral component (see the figure on your right)). The central component is the largest and most prominent.

In younger people the plantar fascia is also intimately related to the Achilles tendon, with a continuous fascial connection between the two from the distal aspect of the Achilles to the origin of the plantar fascia at the calcaneal tubercle. However, the continuity of this connection decreases with age to a point that in the elderly there are few, if any connecting fibers. There are also distinct attachments of the plantar fascia and the Achilles tendon to the calcaneus so the two do not directly impact on each other. Nevertheless, there is an indirect relationship whereby if the toes are dorsiflexed, the plantar fascia tightens via the windlass mechanism. If a tensile force is then generated in the Achilles tendon it will increase tensile strain in the plantar fascia. Clinically, this relationship has been used as a basis for treatment for PF, with stretches and night stretch splinting being applied to the gastrocnemius/soleus muscle unit

Biomechanics of the plantar fascia

The plantar fascia contributes to support of the arch of the foot by acting as a tie-rod, where it undergoes tension when the foot bears weight. One biomechanical model estimated it carries as much as 14% of the total load of the foot. In an experiment using cadavers, it was found that failure of the plantar fascia averaged at loads of 1189 ± 244 Newtons (121 ± 24 Kg/ 55 ± 11 Lb). Interestingly, failure most often occurred at the proximal attachment to the calcaneus, which is consistent with the usual location of symptoms (i.e. in plantar fasciitis, PF). Complete rupture or surgical release of the plantar fascia leads to a decrease in arch stiffness and a significant collapse of the longitudinal arch of the foot. By modeling it was predicted such conditions would result in a 17% increase in vertical displacement and a 15% increase in horizontal elongation of the foot when it was loaded at 683 Newtons (69.64 Kg/ 31.59 Lb). Surgical release also significantly increases both stress in the plantar ligaments and plantar pressures under the metatarsal heads. Although most of the figures mentioned above are from either cadaver studies or investigations using models, they highlight the relatively large load the plantar fascia is subjected to while contributing to the structural integrity of the foot.

The plantar fascia also has an important role in dynamic function during gait. It was found the plantar fascia continuously elongated during the contact phase of gait. It went through rapid elongation before and immediately after mid-stance, reaching a maximum of 9% to 12% elongation between mid-stance and toe-off. During this phase the plantar fascia behaves like a spring, which may assist in conserving energy. In addition, the plantar fascia has a critical role in normal mechanical function of the foot, contributing to the “windlass mechanism”. When the toes are dorsiflexed in the propulsive phase of gait, the plantar fascia becomes tense, resulting in elevation of the longitudinal arch and shortening of the foot (see pannel 3A n your left). One can likened this mechanism to a cable being wound around the drum of a windlass (see pannel 3B on your left); the plantar fascia being the cable, the metatarsal head the drum, and the handle, the proximal phalanx. Therefore, the plantar fascia has a number of roles, the most important of these including supporting the arch of the foot and contributing to the windlass mechanism.

Treatment

Many different treatments have been effective, and though slow to respond, plantar fasciitis has a generally good prognosis. The mainstays of treatment are stretching the Achilles tendon and plantar fascia, rest, cold compression therapy, weight loss, arch support, and taping. One recent study has shown high success rates with a stretch of the plantar fascia. To relieve pain and inflammation, nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen are often used but are of very limited benefit. One small, placebo-controlled study has shown a beneficial effect from glucosamine.

Care should be taken to wear supportive and stable shoes. Patients should avoid open-back shoes, sandals, and flip-flops.

Local injection of corticosteroids often gives temporary or permanent relief, but may be painful, if not combined with a local anesthetic and injected slowly with a small-diameter needle. Recurrence rates may be lower if injection is performed under ultrasound guidance.

Night splints can be used to keep the foot in a dorsi-flexed position during sleep to improve calf muscle flexibility and decrease morning pain. Patients should be encouraged to lessen activities which place more pressure on the balls of the feet. Weight on the heel does not cause plantar fasciitis. Over-the-counter arch support may help, and prescription orthoses are often prescribed. These can be made of many different materials, some of which may be hard and may press on the origin of the plantar fascia. Softer, custom devices, of plastizote, poron, or leather, may be more helpful. Orthoses should always be broken in slowly.

Therapeutic ultrasound has been shown in a controlled study to be ineffective as a treatment for plantar fasciitis. More recently, however, extracorporeal shockwave therapy (ESWT) have been used with some success in patients with symptoms lasting more than 6 months. The treatment is a nonsurgical procedure, but must be done either under local anaesthesia either with or without intravenous sedation (twilight sedation). The basic premise behind ESWT is that in chronic pain (over six months) the brain no longer perceives the pain (even though the patient feels pain) and so no longer is sending signals to fight the pain. ESWT basically re-inflames the area and in doing so increases blood flow to the area as a means to heal the area. It can take as long as six months following the procedure to see results. Like any procedure there are varying degrees of success.

Surgical treatments, such as plantar fascia release, are a last resort, and often lead to further complications such as a lowering of the arch and pain in the supero-lateral side of the foot due to compression of the cuboid bone.

References

1. http://www.latimes.com/features/health/la-he-plantar13nov13,1,5726009.story
2. Lynch, D., Goforth, W., Martin, J., Odom, R., Preece, C., & Kottor M. (1998). "Conservative treatment of plantar fasciitis. A prospective study". Journal of the American Podiatric Medical Association. 88 (8): 375–380. PMID 9735623.{{cite journal}}: CS1 maint: multiple names: authors list (link)
3. Los Angeles Times, January 1, 2007, p. F9
4. Genc H, Saracoglu M, Nacir B, Erdem HR, Kacar M (2005). "Long-term ultrasonographic follow-up of plantar fasciitis patients treated with steroid injection". Joint Bone Spine. 72 (1): 61–5. PMID 15681250.{{cite journal}}: CS1 maint: multiple names: authors list (link)
5. Tsai WC, Hsu CC, Chen CP, Chen MJ, Yu TY, Chen YJ (2006). "Plantar fasciitis treated with local steroid injection: comparison between sonographic and palpation guidance". J Clin Ultrasound. 34 (1): 12–6. PMID 16353228.{{cite journal}}: CS1 maint: multiple names: authors list (link)
6. Crawford F (2004). "Plantar heel pain and fasciitis". Clin Evid (11): 1589–602. PMID 15652071.
7. Norris, DM, Eickmeier, KM and Werber B (2005). "Effectiveness of Extracorporeal Shockwave Treatment in 353 Patients with Chronic Plantar Fasciitis". Journal of the American Podiatric Medical Association. 95 (6): 517–524. PMID 16291842.{{cite journal}}: CS1 maint: multiple names: authors list (link)
8. Marc Mitnick. "(ESWT) Extracorporeal Shock Wave Therapy for heel pain". Foot Pain Explained. Retrieved 2006-10-09.

External Links

• FM Animted Injuries - arch tendon inflammation
• Sportinjuryclinic Planta fascitis
• On Magnetic Therapy and Acupoints

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