- Morton's Neuroma
- Morton neuralgia
- Morton metatarsalgia
- Interdigital neuroma
- Intermetatarsal neuroma
- This page refers to fibrosis of the digital nerves of the toes, commonly referred to as Morton's Neuroma (MN)
- 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
- 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)
- 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
- Not all neuromas are symptomatic
- Bencardino et al: mean diameter 4.1 mm in asymptomatic group, 5.3 mm in symptomatic group
- Diagnosis of MN is considered relevant when diameter exceeds 5 mm and correlates to clinical findings
- Size of lesion does not always correlate with symptom severity
- Smaller lesions respond better to steroid injections than larger lesions, although all do respond
- 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
- 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
- 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
- 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
- Neural edema
- Demyelination (axonal injury)
- Perineural fibrosis
- Hallux Valgus
- Causes overcrowding of the toes and increased pressure on the lesser toes
- Pes Planus
- Female > Male
- Due to the increased weight bearing through the forefoot
- Fractures & Osseous Disease
- Traumatic/ Acute
- Stress Fractures
- Other Osseous
- Dislocations & Subluxations
- Muscle and Tendon Injuries
- Ligament Injuries
- Paraesthesia within the affected digital nerve, accompanied by forefoot pain
- 17% of patients report a history of trauma
- 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
- Thumb Index Finger Squeeze Test: Symptomatic intermetatarsal space is squeezed between thumb and index finger
- Mulders Click Test: Clasp foot and apply pressure to the affected metatarsal neck
- Foot Squeeze Test: Metatarsal heads are squeezed together
- Plantar Dorsal Percussion Test: Dorsal and plantar intermetatarsal spaces are percussed with a finger
- Standard Radiographs Foot
- Useful to exclude other causes of foot pain
- Sensitivity up to 95%
- Systematic review and meta-analysis by Bignotti found no difference in sensitivity between the two modalities
- Gold standard
- Sensitivity: 87%
- Specificity: 100%
- Optimizing view
- Prone position MRI with foot in plantar flexion significantly enhances the visibility
- Most easily seen on T1 axial cuts
- Hypointense area on T2-weighted MRI images relative to fat
- Not applicable
- 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
- 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
- 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
- Mahadevan et al found no difference between CSI by palpation or US guidance
- Santiago et al. noted benefit with US guidance over palpation guidance at 3 months but not at 6 months
- Saygi et al: CSI superior to foot wear modification at 6 and 12 months
- Ethanol/ Alcohol Injection
- Multiple studies show improvement in patient reported outcome measures at 12 months, reduction in neuroma size
- Gurdezi et al: 84% report complete resolution of symptoms at 1 year, 29% at 5 years
- 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
- Campbell et al: small RCT found a benefit from capsaicin injection up to 4 weeks following the procedure
- Among patients who had cryoablation, 38.7% were completely pain free and 45.2% had reduced pain
- Yttrium Aluminium Garnet (YAG) laser
- Gimber et al found YAG laser therapy to improve US findings, symptoms in a retrospective review
- Extra Corporeal Shockwave Therapy
- Botox Injection
- In a small pilot study, 70% of patients reported improvement in symptoms at 3 months
- Prevention/ Avoid
- Footwear with high heels
- Tapered narrow toe box
- Cross-training firm outsole
- Failure of conservative management
- Surgical excision (neurectomy)
Rehab and Return to Play
- 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
- Nonoperative outcomes
- Patients tend to do better with conservative measures when the disease is detected in its early stages (need citation)
- Surgical outcomes
- Unable to return to sport
- Sports Medicine Review Foot Pain: https://www.sportsmedreview.com/by-joint/foot/
- Durlacher L, editor. Treatise on corns, bunions, the diseases of nails and the general management of the feet. London: Simpkin-Marshall; 1835
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- 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.
- 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.
- 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.
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- 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.
- 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.
- Bignotti, Bianca, et al. "Ultrasound versus magnetic resonance imaging for Morton neuroma: systematic review and meta-analysis." European radiology 25.8 (2015): 2254-2262.
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- 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
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- 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.
- 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.
- Saygi, Baransel, et al. "Morton neuroma: comparative results of two conservative methods." Foot & ankle international 26.7 (2005): 556-559.
- 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
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- Chuter, Graham SJ, et al. "Ultrasound-guided radiofrequency ablation in the management of interdigital (Morton’s) neuroma." Skeletal radiology 42.1 (2013): 107-111.
- 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
- Overview | Radiofrequency Ablation for Symptomatic Interdigital (Morton’s) Neuroma | Guidance | NICE.
- 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.
- 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.
- Gimber, Lana H., et al. "Ultrasound evaluation of Morton neuroma before and after laser therapy." AJR Am J Roentgenol 208.2 (2017): 380-385.
- 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.
- 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.
- 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
- 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