Metatarsalgia

Metatarsalgia refers to pain surrounding the metatarsals, particularly the heads. The forefoot, in a normal foot, bears half the weight of an individual. The first metatarsal carries half of the load of the forefoot. Physiology can influence the potential for metatarsalgia. An elongated second metatarsal can exacerbate pressure under the first metatarsal head. So too can obesity, back problems, and certain shoes, for example. The condition is more often a symptom than a diagnosis. The etiology of the problem can be as simple as a strain or more complex. Metatarsalgia is not inherent to any particular demographic such as age, gender, or ethnicity. It can be caused by lifestyle choices as well as injury or disease. Pain in the forefoot does not always require clinical care. In many cases it can be self-treated with rest, compression, ice, and elevation.

Background

The foot is an intricate network of interdependent components. Because it has so many bones, it needs cartilage, which is connective tissue, as cushioning in the joints. The foot is wrapped with fibrous ligaments not only to enable movement, but also to keep the bones in a limited space. Both of these components can become irritated, resulting in painful conditions. The pain may be caused by local pathology or systemic disorders. It is not uncommon for the underlying reason for pain to be unknown. Unresolved metatarsalgia requires clinicians to delve deeper into the root diagnosis if conservative self-treatment fails.

The medical community has found three major categories leading to metatarsalgia: foot anatomy, gait mechanics, and ankle deformity. Differential diagnosis would rule out Morton’s neuroma, bursitis, torn plantar plate, capsulitis, stress fracture, Freiberg’s infraction, calluses, fat pad atrophy, rheumatoid arthritis, and sesamoiditis. There are more, but these are the most frequently diagnosed.

It should be noted that the most frequent etiology can be attributed to body mechanics. The foot is the source of propulsion and balance. It interacts with the walking surface and requires complex movements to move forward. When the body’s weight distribution is altered, such as a change in gait, it modifies the mechanics of the forefoot, as well as balance and forward motion. As an example, rheumatoid arthritis sufferers walk stiffly and painfully, often with a balance deficit. Those patients have a higher rate of metatarsalgia than patients without the chronic disease.

Morton’s neuroma is often associated with metatarsalgia, especially among diabetics. It has a direct comparison to carpal tunnel syndrome (disorder of the wrist and hand). The condition frequently has an unknown etiology and limited rate of resolution. Morton’s neuroma is similarly a nerve entrapment that is caused by a thickening of the nerve tissue between the third and fourth metatarsal. It is painful of itself, but as it grows it has a tendency to put pressure on the surrounding bones and fascia, causing metatarsalgia as well.

Genetics can play a role. Sometimes a combination of factors are responsible. In either situation, advanced diagnostic technology may determine treatment.

Overview

Metatarsalgia is not limited to one structure within the foot. Patients present with complaints of pain in or around the metatarsophalangal joints, metatarsal heads and soft tissue of the forefoot. The condition is not self-limiting.

Many treatments, including surgery as a last resort, have been attempted, some with little to no success and many with good results. Podiatric and orthopedic specialists have come to understand that metatarsalgia does not respond to the same treatment for every circumstance. Discovering the cause of the condition is a major factor in effecting resolution.

Lifestyle may be the easiest to remedy, among the causative factors. Improper shoe size, shape, and heel height are major stressors on feet. Cramped toes from shoes with inadequate toe boxes not only can result in misalignment of bones, but also bunions, blisters, and infections. Athletes in high impact sports are at increased risk for injury to their forefoot. Safran et al. reported that runners experience peak vertical forces of 275 percent of body weight, as well as absorb 110 tons per foot in a one-mile run.

Thomas B. Helal classified metatarsalgia as two entities, the primary being abnormal anatomic structure yielding increased pressure under the metatarsal heads. He offered as examples hallux valgus, hallux rigidus, and first ray hypermobility. For the secondary metatarsalgia, the pain originates outside the metatarsal region. That would include such variables as rheumatoid arthritis, Freiberg’ infraction, Morton’s neuroma, and equines deformities. However, it was Regnauld who classified metatarsalgia as "diffuse, localized, subcutaneous soft tissue and cutaneous tissue."

Treatment varies depending on etiology. In addition to the standard conservative option, clinicians may opt for metatarsal pads, heel cups, and other orthotics. It appears semi-rigid orthotics are superior to soft ones, and minimal arch fill yields better results than flat devices. Excessive rear foot eversion and fat pad atrophy also respond to appropriate orthotics. Biometric devices, including metatarsal pads, not only play a significant role in resolving metatarsalgia, but also serve as a prophylactic for those with foot anomalies and those in high impact activities.

Bibliograhy

Chang, Bao-Chi, et al. "Plantar Pressure Analysis of Accommodative Insole in Older People with Metatarsalgia." Gait & Posture 39.1 (2014): 449–454. Academic Search Complete. Web. 9 Jan. 2016.

Chang, Hsun-Wen, et al. "The Relationships Between Foot Arch Volumes and Dynamic Plantar Pressure During Midstance of Walking in Preschool Children." Plos ONE 9.4 (2014): 1–7. Academic Search Complete. Web. 9 Jan. 2016.

DiLiberto, Frank E., et al. "Individual Metatarsal and Forefoot Kinematics During Walking in People with Diabetes Mellitus and Peripheral Neuropathy." Gait & Posture 42.4 (2015): 435–441. Academic Search Complete. Web. 9 Jan. 2016.

"Metatarsalgia." American College of Foot and Ankle Orthopedics and Medicine. ACOFAUM.org, 2015. Web. 9 Jan. 2016. http://www.acfaom.org/information-for-patients/common-conditions/metatarsalgia.

"Metatarsalgia." Journal of the American Academy of Orthopedic Surgery 18.8 (2010):474–85. Web. 9 Jan. 2016. http://www.ncbi.nlm.nih.gov/pubmed/20675640.

Schuh, Reinhard, et al. "Comparison of Plantar-Pressure Distribution and Clinical Impact of Anatomically Shaped Sandals, Off-The-Shelf Sandals and Normal Walking Shoes in Patients with Central Metatarsalgia." International Orthopaedics 38.11 (2014): 2281–2288. Academic Search Complete. Web. 9 Jan. 2016.

Stellon, A. J. "Metatarsalgia: Treatment by Acupuncture." Acupuncture in Medicine 15.1 (1997): 17–18. Acupuncture in Medicine. British Acupuncture in Medicine Society, 2015. Print.

Yakel, Jamie. "Biomechanical Considerations In Treating Metatarsalgia " Podiatry Today 27.7 (2015). Web. 9 Jan. 2016. http://www.podiatrytoday.com/biomechanical-considerations-treating-metatarsalgia.