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Mortons Neuroma

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Other Names

  • Morton's Neuroma
  • Morton neuralgia
  • Morton metatarsalgia
  • Interdigital neuroma
  • Intermetatarsal neuroma

Background

  • This page refers to fibrosis of the digital nerves of the toes, commonly referred to as Morton's Neuroma (MN)

History

  • First described in the literature in 1876 by an American surgeon, Thomas George Morton. (need citation)
  • Note, Civinini and Durlacher preceded Morton in describing the condition in 1835 and 1845, respectively[1]

Epidemiology

  • There are no solid epidemiologic studies on MN, no descriptions of prevalence or incidence
  • It is known to most commonly affect middle ages women (need citation)

Introduction

The first, second, and third common plantar digital nerves arise from the medial plantar nerve, while the fourth nerve arises from the lateral plantar nerve. The third nerve often receives a communicating branch (white arrow). Each common plantar digital nerve divides into two proper plantar digital nerves. Morton’s neuromas occur at the bifurcation of the common plantar digital nerve.[2]
  • General
    • Fibrosis of the digital nerves due to pressure or repetitive irritation leading to fibrosis
    • Location is most commonly the 3rd intermetatarsal space
    • Degenerate tissue therefore causes localized pain and discomfort mainly on weight bearing
  • Size
    • Not all neuromas are symptomatic
    • Bencardino et al: mean diameter 4.1 mm in asymptomatic group, 5.3 mm in symptomatic group[3]
    • Diagnosis of MN is considered relevant when diameter exceeds 5 mm and correlates to clinical findings[4]
    • Size of lesion does not always correlate with symptom severity[5]
    • Smaller lesions respond better to steroid injections than larger lesions, although all do respond

Etiology

  • General
    • Overall, not well understood
    • Generally, though to be secondary to pressure or repetitive irritation leading to thickness of the nerve
    • About 17% of patients report a history of trauma[6]
  • Transverse metatarsal ligament
    • Has been implicated by some as a compressing structure (need citation)
  • Ischemic hypothesis
    • Proposed by Giakoumis et al. based on histological evidence of digital arteries luminal occlusion[7]
  • Foot wear
    • High-heeled shoes with tight toe box could lead to Morton’s neuroma
  • During sports
    • Repetitive hyperdorsiflexion of MTPJ may pull the interdigital nerve against the transverse metatarsal ligament leading to nerve irritation[8]
    • Significant dorsiflexion during running (toe-off phase of gait cycle), ballet dance maneuvers (demi-pointe, relevé and grand plié)
    • Cross-training and racket shoes may increase forefoot workload, avoid during distance running[9]

Pathohistology

  • Findings[10]
    • Neural edema
    • Demyelination (axonal injury)
    • Perineural fibrosis

Associated Conditions

Risk Factors

  • General
    • Female > Male
  • Sports
    • Running
      • Due to the increased weight bearing through the forefoot
    • Dancing
    • Racquet
  • Orthopedic

Differential Diagnosis

Clinical Features

History

  • Paraesthesia within the affected digital nerve, accompanied by forefoot pain
  • 17% of patients report a history of trauma[6]
  • The pain is typically characterized as burning, tingling, numbness
  • More than 50% of the patients report altered sensation, feeling of pebble in the shoe
  • Exacerbated by walking, use of tight or heeled shoe

Physical Exam: Physical Exam Foot

  • There are no visual cues to the presence of a neuroma
  • Hallux Valgus may be present
  • Abnormal light touch over the dorsal or plantar foot reproducing symptoms is 25% sensitive, 100% specific (need citation)
  • A pin can be used similarly to light touch

Special Tests

Evaluation

Radiographs

Ultrasound

  • Sensitivity up to 95%[11]
  • Systematic review and meta-analysis by Bignotti found no difference in sensitivity between the two modalities[12]

MRI

  • Gold standard
    • Sensitivity: 87%[13]
    • Specificity: 100%
  • Optimizing view
    • Prone position MRI with foot in plantar flexion significantly enhances the visibility
  • Findings
    • Most easily seen on T1 axial cuts
    • Hypointense area on T2-weighted MRI images relative to fat

Classification

  • Not applicable

Management

Nonoperative

  • Indications
    • Vast majority of cases
  • Metatarsal Bar
    • The most common treatment
    • Made by orthotists spreads the heads of the metatarsals to relieve pressure on the neuroma
    • Require the patient to wear broad toe box shoes
  • Toe Padding
    • Can help support the metatarsal arch
    • Keeps metatarsal bones apart from each other to relieve the relatively crushed nerve in between
  • Other Orthotic
    • No evidence for use of inversion/ eversion soles
  • Footwear modification
    • Substitute poor-fitting footwear with accommodative wide toe box shoes
    • For example, avoid cross training shoes[9]
  • Activity modification
    • Avoiding activities with a potential harm to the diseased nerve
  • Corticosteroid Injection
    • Likely considered standard of care for MN
    • RCT showed CSI superior to anesthetic injection alone[14]
    • At 1 year following CSI, about 1/3 of patients require surgical excision due to recurrence of pain (need citation)
    • CSI more effective if used within one year of onset of symptoms[15]
    • Mahadevan et al found no difference between CSI by palpation or US guidance[16]
    • Santiago et al. noted benefit with US guidance over palpation guidance at 3 months but not at 6 months[17]
    • Saygi et al: CSI superior to foot wear modification at 6 and 12 months[18]
  • Ethanol/ Alcohol Injection
    • Multiple studies show improvement in patient reported outcome measures at 12 months, reduction in neuroma size[19]
    • Gurdezi et al: 84% report complete resolution of symptoms at 1 year, 29% at 5 years[20]
    • Complications include burning pain associated with alcohol injections which in some cases lasted for weeks
    • Also note, fibrosis following alcohol injection can complicate surgical approach
  • Radiofrequency Ablation
    • Several small studies have reported good patient outcomes[21][22][23]
  • Capsaicin
    • Campbell et al: small RCT found a benefit from capsaicin injection up to 4 weeks following the procedure[24]
  • Cryoablation
    • Among patients who had cryoablation, 38.7% were completely pain free and 45.2% had reduced pain[25]
  • Yttrium Aluminium Garnet (YAG) laser
    • Gimber et al found YAG laser therapy to improve US findings, symptoms in a retrospective review[26]
  • Extra Corporeal Shockwave Therapy
    • Compared to placebo, patients in the ECST group had improved AOFAS and VAS scores[27]
    • Fridman showed benefit compared to placebo up to 12 weeks[28]
  • Botox Injection
    • In a small pilot study, 70% of patients reported improvement in symptoms at 3 months[29]
  • Prevention/ Avoid
    • Footwear with high heels
    • Tapered narrow toe box
    • Cross-training firm outsole

Operative

  • Indications
    • Failure of conservative management
  • Technique
    • Surgical excision (neurectomy)

Rehab and Return to Play

Rehabilitation

  • Post-operative
    • Weight bearing can begin immediately if dorsal approach was used
    • If plantar approach, must wait for surgical wound to heal before beginning weight bearing

Return to Play/ Work

  • Needs to be updated

Complications and Prognosis

Prognosis

  • Nonoperative outcomes
    • Patients tend to do better with conservative measures when the disease is detected in its early stages (need citation)
  • Surgical outcomes
    • The plantar approach is less commonly used, success ranges from 51% to 85%[30]
    • The dorsal approach is more well tolerated, success ranges from 61% to 85%[30]
    • Failure rate following surgical excision has been reported as up to 30%.

Complications

  • Unable to return to sport

See Also

Internal

External

References

  1. ↑ Durlacher L, editor. Treatise on corns, bunions, the diseases of nails and the general management of the feet. London: Simpkin-Marshall; 1835
  2. ↑ Mak, M. S., R. Chowdhury, and R. Johnson. "Morton's neuroma: review of anatomy, pathomechanism, and imaging." Clinical Radiology 76.3 (2021): 235-e15.
  3. ↑ encardino J, Rosenberg ZS, Beltran J, Liu X, Marty-Delfaut E. Morton’s neuroma. Am J Roentgenol. 2000;175(3):649e653. https://doi.org/10.2214/ ajr.175.3.1750649.
  4. ↑ Zanetti M, Strehle JK, Zollinger H, Hodler J. Morton neuroma and fluid in the intermetatarsal bursae on MR images of 70 asymptomatic volunteers. Radiology. 1997;203(2). https://doi.org/10.1148/radiology.203.2.9114115.
  5. ↑ Makki D, Haddad BZ, Mahmood Z, Saleem Shahid M, Pathak S, Garnham I. Efficacy of Corticosteroid Injection Versus Size of Plantar Interdigital Neuroma Level of Evidence: II, Prospective Comparative Study. doi:10.3113/ FAI.2012.0722.
  6. ↑ 6.0 6.1 Mahadevan D, Venkatesan M, Bhatt R, Bhatia M. Diagnostic accuracy of clinical tests for morton’s neuroma compared with ultrasonography. J Foot Ankle Surg. 2015;54(4):549e553. https://doi.org/10.1053/j.jfas.2014.09.021.
  7. ↑ Giakoumis M, Ryan JD, Jani J. Histologic evaluation of intermetatarsal Morton’s neuroma. J Am Podiatr Med Assoc. 2013; 103(3):218–22.
  8. ↑ Ferkel E, Davis WH, Ellington JK. Entrapment neuropathies of the foot and ankle. Clin Sports Med. 2015;34(4):791–801
  9. ↑ 9.0 9.1 Hockenbury RT. Forefoot problems in athletes. Med Sci Sports Exerc. 1999;31(7 Suppl):S448–58.
  10. ↑ Bourke G, Owen J, Machet D. Histological comparison of the third interdigital nerve in patients with Morton’s metatarsalgia and control patients. Aust N Z J Surg. 1994;64(6):421e424. http://www.ncbi.nlm.nih.gov/pubmed/7516653.
  11. ↑ Torres-Claramunt R, Gines A, Pidemunt G, Puig L, De Zabala S. MRI and ultrasonography in Morton’s neuroma: diagnostic accuracy and correlation. Indian J Orthop. 2012;46(3):321e325.
  12. ↑ Bignotti, Bianca, et al. "Ultrasound versus magnetic resonance imaging for Morton neuroma: systematic review and meta-analysis." European radiology 25.8 (2015): 2254-2262.
  13. ↑ Zanetti M, Ledermann T, Zollinger H, Hodler J. Efficacy of MR imaging in patients suspected of having Morton’s neuroma. AJR Am J Roentgenol. 1997;168(2):529–32.
  14. ↑ Thomson CE, Beggs I, Martin DJ, et al. Methylprednisolone injections for the treatment of morton neuroma. J Bone Jt Surg Am. 2013;95(9):790e798
  15. ↑ Markovic M, Bs M. Effectiveness of ultrasound-guided corticosteroid injection in the treatment of morton’s neuroma. Foot Ankle Int. doi:10.3113/ FAI.2008.0483.
  16. ↑ Mahadevan, D., et al. "Corticosteroid injection for Morton’s neuroma with or without ultrasound guidance: a randomised controlled trial." The Bone & Joint Journal 98.4 (2016): 498-503.
  17. ↑ Santiago FR, Mu~noz PT, Pryest P, Martínez AM, Olleta NP. Role of imaging methods in diagnosis an treatment of Morton’s neuroma. World J Radiol. 2018;10(9):91e99.
  18. ↑ Saygi, Baransel, et al. "Morton neuroma: comparative results of two conservative methods." Foot & ankle international 26.7 (2005): 556-559.
  19. ↑ Fanucci E, Masala S, Fabiano S, et al. Treatment of intermetatarsal Morton’s neuroma with alcohol injection under US guide: 10-month follow-up. Eur Radiol. 2
  20. ↑ Gurdezi S, White T, Ramesh P. Alcohol injection for morton’s neuroma: a five year follow-up. Foot Ankle Int. 2013.
  21. ↑ Chuter, Graham SJ, et al. "Ultrasound-guided radiofrequency ablation in the management of interdigital (Morton’s) neuroma." Skeletal radiology 42.1 (2013): 107-111.
  22. ↑ Moore JL, Rosen R, Cohen J, Rosen B. Radiofrequency thermoneurolysis for the treatment of morton’s neuroma. J Foot Ankle Surg. 2012;51(1):20e22
  23. ↑ Overview | Radiofrequency Ablation for Symptomatic Interdigital (Morton’s) Neuroma | Guidance | NICE.
  24. ↑ Campbell, Claudia M., et al. "A randomized, double-blind, placebo-controlled trial of injected capsaicin for pain in Morton's neuroma." Pain 157.6 (2016): 1297-1304.
  25. ↑ Caporusso, Eric F., Lawrence M. Fallat, and Ruth Savoy-Moore. "Cryogenic neuroablation for the treatment of lower extremity neuromas." The Journal of foot and ankle surgery 41.5 (2002): 286-290.
  26. ↑ Gimber, Lana H., et al. "Ultrasound evaluation of Morton neuroma before and after laser therapy." AJR Am J Roentgenol 208.2 (2017): 380-385.
  27. ↑ Seok, Hyun, et al. "Extracorporeal shockwave therapy in patients with Morton's neuroma: a randomized, placebo-controlled trial." Journal of the American Podiatric Medical Association 106.2 (2016): 93-99.
  28. ↑ Fridman, Robert, Jarrett D. Cain, and Lowell Weil Jr. "Extracorporeal shockwave therapy for interdigital neuroma: a randomized, placebo controlled, double-blind trial." Journal of the American Podiatric Medical Association 99.3 (2009): 191-193.
  29. ↑ Climent JM, Mondejar-Gomez F, Rodríguez-Ruiz C, Díaz-Llopis I, Gomez- Gallego D, Martín-Medina P. Treatment of Morton neuroma with botulinum toxin a: a pilot study. Clin Drug Invest. 2013
  30. ↑ 30.0 30.1 Bhatia, Maneesh, and Lauren Thomson. "Morton’s neuroma–current concepts review." Journal of Clinical Orthopaedics and Trauma 11.3 (2020): 406-409.2013;34(9):1198e1204
Created by:
John Kiel on 14 June 2019 08:41:56
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