Definition

Morton’s neuroma is a swelling of the Schwann cells that surrounds the digital nerve leading to the toes and generally occurs in response to irritation, trauma or excessive motion of the medial column of the foot.

Overview

Morton’s neuroma often mimics the symptoms of metatarsalgia. Morton’s neuroma occurs as the nerve passes under the interdigital ligament and most frequently develops between the third and fourth toes. Pressure on the lesser metatarsals often increases in feet with an everted rearfoot. There is some anecdotal evidence that using a metatarsal or neuroma pad to separate the metatarsal heads may decrease pressure on the neuroma. The incidence is 8 to 10 times greater in women than in men.

Clinical Goal for Orthotic Treatment

Orthoses for Morton’s neuroma should reduce pressure on the painful metatarsal head area by transferring force to a larger area.

Prescription

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

Neuroma Prescription Recommendations

• Polypropylene Shell – semirigid
• Wide Width
  • A wider width through the arch increases surface area under the arch and limits medial column motion
• Minimum Cast Fill
  • An orthosis with minimum cast fill will tightly conform to the arch of the foot transferring pressure from the metatarsal heads to the arch area
• Inversion – 2 degrees
  • Inversion of the positive cast increases orthotic arch height, transferring force off of the metatarsal heads and onto the mid-arch.
• Poron Forefoot Extension
  • Provides additional cushion under the forefoot which helps decrease velocity at forefoot contact resulting in decreased force under the metatarsal heads.
• EVA Cover to Toes
• Neuroma Pad
  • This elongated metatarsal pad is designed to be placed between the affected metatarsal heads in order to separate the metatarsal heads to decrease pressure and trauma on the digital nerve

Summary

This orthosis is designed to decrease ground reactive force (GRF) under the lesser metatarsal heads and to separate the affected metatarsal heads. This will decrease pressure and trauma on the digital nerve. For additional help with orthoses for this condition, ProLab clients can speak with a Medical Consultant.

References

1. Hassouna H, Singh D. Morton’s metatarsalgia: pathogenesis, aetiology and current management. Acta Orthop Belg. 2005 Dec;71(6):646-55. Review.
2. Kilmartin TE, Wallace WA Effect of pronation and supination orthosis on Morton’s neuroma and lower extremity function. Foot Ankle Int. 1994 May;15(5):256-62.
3. 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 Rheumatology, 27:1643-7, 2000.
4. Postema K, Burm P, Zande M, et al. Primary metatarsalgia: The influence of a custom molded insole and a rockerbar on plantar pressure. Prosthet Orthot Int 22:35-44, 1998.
5. Bennett GL, Graham CE, Mauldin DM. Mortons interdigital neuroma: A comprehensive treatment protocol, Foot and Ankle International Dec 16(12) 760, 1995
6. Brantingham JW, Snyder J, Michaud T. Mortons neuroma. Journal of Manipulative Physiotherapy, June 14(5) 317, 1991