Definition

Metatarsalgia is plantar pain within one or more of the metatarsal heads, metatarsophalangeal joints, and/or within the surrounding soft tissue structures.

Overview

Metatarsalgia generally results from excessive force or loading under the metatarsal heads. Multiple pathologies of mechanical origin that produce pain occur in the vicinity of the metatarsal heads are grouped into this category. Although commonly recognized as a symptom secondary to a more specific pathology, metatarsalgia is often both a symptom as well as a diagnosis. The exact location of metatarsalgia pain is frequently elusive and tends to migrate, often making it intractable. However, the source of the pain must be defined for a successful orthotic intervention.

Excessive eversion of the rearfoot can increase force under the first metatarsal head. This eversion causes first ray dorsiflexion, decreased first metatarsal weightbearing, and increased lesser met weightbearing, particularly the 2nd metatarsal. Long metatarsals, flat metatarsal heads, and fat pad atrophy can also increase ground reactive force (GRF) under selected metatarsal heads.

Many systemic diseases, including the seropositive and seronegative arthropathies, are also commonly associated with metatarsalgia pain. This pain does not originate within the metatarsal area, but the outside force produces problems or a mechanical imbalance affecting the metatarsophalangeal joint area.

Clinical Goal for Orthotic Treatment

The goal of orthotic therapy is to transfer forces away from the painful metatarsal heads and provide accommodation and  cushioning for localized areas, since increased GRF under one or more metatarsal heads can increase metatarsal pain.

Prescription

To prescribe this device check “Metatarsalgia” under the Pathology Specific Orthoses section (Part A) of the prescription form.

Metatarsalgia Prescription Recommendations

• Polypropylene Shell – semirigid with no distal bevel
  • The absence of distal bevel increases the distal edge thickness of the orthosis, transferring force from the metatarsal heads to the metatarsal necks.
• Wide Width
  • A wider width increases surface area under the arch aiding in the transfer of force off of the metatarsal heads
• Minimum Cast Fill
  • Minimum cast fill produces an orthosis that conforms to the arch of the foot and gently transfers pressure from the metatarsal heads to the arch area.
• Inversion – 2°
  • Inversion increases the orthotic arch height more effectively transferring force from the metatarsal heads onto the arch (metatarsal necks)
• Poron Metatarsal Bar
  • The metatarsal bar acts to transfer force off of the metatarsal heads by increasing force under the metatarsal necks and shafts
• Poron Forefoot Extension
  • A forefoot extension provides cushioning under the metatarsal heads to decrease velocity at forefoot contact resulting in decreased force under the metatarsal heads

Summary

Evidence-based literature supports the use of this orthosis for most metatarsalgia patients. Metatarsalgia is a common foot complaint. By using custom functional foot orthosis in conjunction with correct shoes, orthotic intervention can be an important component in improving the quality of life and reducing pain in individuals with metatarsalgia.

References

1. Chalmers AC, Busby C, Goyert J, et al. Metatarsalgia and rheumatoid arthritis-a randomized, single blind, sequential trial comparing two types of foot orthoses and supportive shoes. J Rheumat 27(7):1643-7, 2000.
2. Chang AH, Abu-Faraj ZU, Harris GF, et al: Multistep measurement of plantar pressure alterations using metatarsal pads. Foot Ankle Int. 15:654-60, 1994.
3. Holmes GB, Timmerman MD: A quantitative assessment of the effect of metatarsal pads on plantar pressures. Foot Ankle. 11:141-145, 1990.
4. Hsi WL, Kang JH, Lee X: Optimum position of metatarsal pad in metatarsalgia for pressure relief. Am J Phys Med Rehabil. 84:514-520, 2005.
5. Kang JH, Chen MD, Chen SC, et al: Correlations between subjective treatment responses and plantar pressure parameters of metatarsal pad treatment in metatarsalgia patients: a prospective study. BMC Musculo Skele Disord. 7:95-102, 2006.
6. Kelly A, Winson I: Use of ready-made insoles in the treatment of lesser metatarsalgia: a prospective randomized controlled trial. Foot Ankle Int. 19: 217-20, 1998.
7. Pawelka S, Kopf A, Zwick E, et al: Comparison of two insole materials using subjective parameters and pedobarography (pedar-system). Clin Biomech. 12:S6-S7, 1997.
8. Postema K, Burm PE, Zande ME, et al: Primary metatarsalgia -the influence of a custom moulded insole and a rockerbar on plantar pressure. Prosthet Orthot Int. 22:35-44, 1998.
9. Scranton PE: Metatarsalgia -a clinical review of diagnosis and management. Foot Ankle 1:229-34, 1981.