Physiotherapy for Morton's Neuroma


Original Editor - Ewa Jaraczewska
Top Contributors - Ewa Jaraczewska, Jess Bell and Kim Jackson

Introduction[edit | edit source]

Civinini Morton’s Syndrome (CMS) is more commonly known as Morton’s neuroma. Interdigital neuritis is another term proposed by Weinfield and Myerson[1] that better describes this condition's pathology. The presence of inflammatory tissue in histological examination justifies the description of Morton's neuroma as perineurial fibrosis. Pain and abnormal forefoot sensation are clinical symptoms that help with the diagnosis. Conservative treatment, including lifestyle adjustment, may not always be practical, and patients can choose surgery or various types of ultrasound-guided percutaneous injections as an option.

Foot innervation

Clinically Relevant Anatomy[edit | edit source]

Magnetic resonance imaging (MRI) shows the medial and lateral plantar nerves arising from the posterior tibial nerve. [2] The tibial nerve terminates in the foot by giving branches to the medial and lateral plantar nerves. This bifurcation occurs inside the retinaculum or proximal to the flexor retinaculum. [3] The two plantar nerves penetrate the tunnel made of the deep fascia of the abductor hallucis muscle and the fibrous septum connecting the fascia to the bone. [3]

The medial plantar nerve (MPN) is the larger of the two plantar nerves. It originates under the laminate ligament and passes between the abductor hallucis muscle and flexor digitorum brevis. Upon reaching the metatarsal bases, it divides into three common digital plantar nerves.[4]MPN innervates the abductor hallucis, flexor hallucis brevis, flexor digitorum brevis and the first lumbrical.

The lateral plantar nerve (LPN) innervates the abductor digiti minimi muscle, flexor digiti minimi brevis muscle, quadratus plantae, three lateral lumbricals of the foot, adductor hallucis muscle, plantar interossei muscles, and dorsal interossei muscles.

The common plantar digital (CPD) nerves pass under the intermetatarsal ligaments, go through the plantar aponeurosis and divide into two branches supplying the plantar skin of the toes. Smaller portions of the CPD nerves innervate the adjacent metatarsals, metatarsophalangeal joints and plantar skin under the metatarsal heads. [5]The third common digital nerve begins as the medial plantar nerve and receives a communicating branch from the lateral plantar nerve. Because it passes in the narrow space deep into the transverse metatarsal ligament, it becomes less mobile, especially during weight-bearing activities.

The branches of the common digital nerve in the third planter webspace are most commonly affected. The location of this nerve near the narrow space of the transverse metatarsal ligament may be a possible explanation for the development of Morton's Neuroma pathology within the third intermetatarsal space.[5]

Morton's neuroma

Neuroma[edit | edit source]

A neuroma is also referred to as a pinched nerve. Morton's neuroma is a compressive neuropathy of the common plantar digital nerve caused by an entrapment of the nerve between the intermetatarsal ligaments.

Aetiology[edit | edit source]

There are several aetiopathogenetic theories behind the development of Morton's neuroma. It includes:

  • chronic traction damage[6]
  • chronic, repetitive trauma [6]
  • ischemia of vasa nervorum[5][6]
  • entrapment or mechanical compression [7][8]
  • inflammation due to intermetatarsal bursitis [7]

One of the theories explaining the occurrence of Morton's neuroma is based on the notion that the third common digital nerve is thicker than the others due to an anastomosis between two nerve trunks. The inflammation theory is explained by the increased mobility of the fourth ray compared to the third.[5]The compression theory is based on the finding that the plantar nerve is compressed by the distal metatarsal transverse ligament.[7]

Epidemiology[edit | edit source]

Morton's neuroma is characterised by female predominance, with a female-to-male ratio of 5:1. [5] It affects about 30% of the population. An average patient's age is 50, the pathology affects both feet, and in most cases, the third intermetatarsal space is involved, followed by the second (Hauser’s neuroma). [9]Multiple locations are scarce. [5]

Mechanism of Injury / Pathological Process[edit | edit source]

The most frequent mechanism of injury supported by the literature is nerve entrapment. [8] The third common digital nerve is thicker due to the fusion between the medial and lateral plantar nerves. This leads to its entrapment by the surrounding ligament. [8] Entrapment neuropathy causes perineural fibrosis and nerve degeneration. [8]The thickening of the nerve progresses as a result of vascular hyalinisation, which causes more nerve trauma and entrapment. Adding to the pathological process is the use of high heel shoes forcing the excessive forefoot weight bearing.

Clinical Presentation[edit | edit source]

There are two types of clinical presentation in Morton's neuroma: clinically symptomatic and asymptomatic.

Clinically symptomatic Morton's neuroma presents with the following symptoms:[8]

  • Pain or paresthesias in the intermetatarsal region, toes, and dorsal web space. Pain is worsened by weight-bearing or the use of high-heeled shoes. Removing shoes and gentle massaging the forefoot usually relieve the pain.
  • Pain is usually sharp and can become debilitating to the point that the patient is afraid and anxious about walking or even putting their foot on the ground.[5]
  • The patient can complain of a burning sensation in the intermetatarsal spaces[10]
  • Mass can be palpated
  • Symptoms can be present as a result of trauma
  • The patient describes an altered sensation as a “pebble in the shoe”[11]
  • Pain worsens with walking or running[11]

The presence of the hallux valgus is considered a predisposing factor in the development of Morton's neuroma. [11]

Diagnostic Tests[edit | edit source]

[14]

Diagnostic Procedures[edit | edit source]

  • Ultrasound (US): high diagnostic accuracy. The technique and experience of a person performing the test are essential to make a proper diagnosis. [5][9]
  • Magnetic resonance imaging (MRI): the gold standard investigation to identify a neuroma. [11]Primary indications for MRI are unclear clinical assessment and cases when more than one intermetatarsal space (IMS) is affected. [5]
  • X-rays: essential as a first-line imaging approach to rule out tarsal–metatarsal joint stiffness, metatarsal hypermetria, Frieberg’s disease, toe deformities and MTP instabilities.

Differential Diagnosis[edit | edit source]

The differential diagnosis includes the following conditions:[8]

  • Intermetatarsal bursitis
  • True neuroma
  • Inflammatory arthritis
  • Pigmented villonodular synovitis
  • Osteomyelitis
  • Foreign body granuloma
  • Stress fracture
  • Freiberg's infraction
  • Metatarsophalangeal joint dislocation.

Physiotherapy Management / Interventions[edit | edit source]

Footwear[edit | edit source]

Goal: To limit the nerve compression in the early stages of Morton's neuroma

Tools: patient education, footwear modification

According to the study [5], after 4.5 months since the diagnosis and when the neuroma is larger than 5-6 mm, orthotics and/or shoe modifications are no longer effective in symptom management. They can offer a palliative solution to better manage a person's life with pain.[5]

Patient Education[edit | edit source]

Patient to be educated on :

  • avoiding narrow and high-heeled shoes
  • staying compliant with footwear prescription
  • activity modification[15]

Footwear modification[edit | edit source]

The most appropriate footwear should have the following design:[5][16]

  • sufficiently long[5]
  • wide toe box[5]
  • low heel[5]
  • thick external sole, which should not be excessively flexible[5]
  • metatarsal padding[16]
  • A rocker-bottom sole may be helpful[17]

Orthotics[edit | edit source]

Goal:

  1. To displace the pressure sites
  2. To provide pain relief
  • The most common orthotic provided initially is the metatarsal bar. Its purpose is to:
    • Spread the heads of the metatarsals to relieve pressure
    • Improve symptoms
  • Limited to no evidence of improvement in patient-reported outcomes with the use of 'inversion or eversion insoles (varus/valgus foot wedge). [11]
  • According to de Oliveira et al. [18], customised insole with metatarsal and arch support offers pain relief during ambulation and improves function. [18]
  • Custom-made toe inserts modelled in silicone rubber can be added when the claw-toe deformity is present. [8]
  • Custom orthotics through foam impression methods. The foot is placed in a neutral subtalar position, with a prolonged longitudinal vault to support the first metatarsal (flat support). Goal: to mimic the physiological pattern of the metatarsal weight bearing, from lateral to medial, before the pressure on the big toe. [5]

Steroid Injections[edit | edit source]

Goal: to provide pain relief

In the management of Morton's neuroma, steroid injections are pretty standard. The injection method varies: it is guided by ultrasound or a landmark technique.

  • Based on a randomised control trial, Mahadevan et al. [19] found no statistical difference in patient outcomes after a steroid injection using ultrasound or without.
  • Choi and colleagues[20]demonstrated a satisfactory clinical outcome in pain reduction after corticosteroid injections, but 30% of patients eventually required surgery for pain management.
  • Lizano-Diez et al. [21]found no difference in pain and function between the injection of a corticosteroid plus a local anaesthetic versus local anaesthetic only.

Modality[edit | edit source]

Manipulation/Mobilisation[edit | edit source]

According to Cashley and Cochrane [23], foot manipulation and mobilisation of other foot and ankle joints can decrease foot pain in patients diagnosed with plantar digital neuralgia (Morton's neuroma). The authors recommend performing joint manipulation once a week for four weeks, followed by two more visits at 14-day intervals. [23]

Strengthening Exercises[edit | edit source]

According to Simpson [15], strengthening exercises for toe flexors and the intrinsics can help with muscle activation during the mid-stance of the gait cycle and prevent the metatarsal heads from dropping.

Other treatment option[edit | edit source]

Surgery is considered when conservative treatment fails, or the patient is no longer willing to adjust their lifestyle to manage symptoms of Morton's neuroma. The following operative and non-operative treatment options are available:

  • Surgical nerve excision (neurectomy)[24]
  • Surgical nerve decompression[25]
  • Ultrasound-guided percutaneous radiofrequency
  • Alcohol injection
  • Percutaneous electrostimulation-guided alcoholization with phenol[8]

Resources[edit | edit source]

  1. The effectiveness of non-surgical interventions for common plantar digital compressive neuropathy (Morton’s neuroma): a systematic review and meta-analysis
  2. The effectiveness of shoe modifications and orthotics in the conservative treatment of Civinini-Morton syndrome: state of the art
  3. Second and Third Metatarsophalangeal Plantar Plate Tears: Diagnostic Performance of Direct and Indirect MRI Features Using Surgical Findings as the Reference Standard

References[edit | edit source]

  1. ↑ Weinfeld SB, Myerson MS. Interdigital Neuritis: Diagnosis and Treatment. J Am Acad Orthop Surg. 1996 Nov;4(6):328-335.
  2. ↑ Govsa F, Bilge O, Ozer MA. Anatomical study of the communicating branches between the medial and lateral plantar nerves. Surgical and Radiologic Anatomy. 2005 Dec;27(5):377-81.
  3. ↑ 3.0 3.1 Torres AL, Ferreira MC. Study of the anatomy of the tibial nerve and its branches in the distal medial leg. Acta ortopedica brasileira. 2012;20:157-64.
  4. ↑ Koo GB, Lee JH, Jang JH, Song IH, Kim JY. Superficial course of the medial plantar nerve: case report. Anatomy & cell biology. 2019 Mar 1;52(1):87-9.
  5. ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 5.11 5.12 5.13 5.14 5.15 5.16 Colò G, Rava A, Samaila EM, Palazzolo A, Talesa G, Schiraldi M, Magnan B, Ferracini R, Felli L. The effectiveness of shoe modifications and orthotics in the conservative treatment of Civinini-Morton syndrome: state of the art. Acta Biomed. 2020 May 30;91(4-S):60-68.
  6. ↑ 6.0 6.1 6.2 Hassouna H, Singh D. Morton's metatarsalgia: pathogenesis, aetiology and current management. Acta Orthop Belg. 2005 Dec;71(6):646-55.
  7. ↑ 7.0 7.1 7.2 Jain S, Mannan K. The diagnosis and management of Morton's neuroma: a literature review. Foot Ankle Spec. 2013 Aug;6(4):307-17.
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 Bencardino J, Rosenberg ZS, Beltran J, Liu X, Marty-Delfaut E. Morton's neuroma: is it always symptomatic?. American journal of roentgenology. 2000 Sep;175(3):649-53.
  9. ↑ 9.0 9.1 Mak MS, Chowdhury R, Johnson R. Morton's neuroma: a review of anatomy, pathomechanism, and imaging. Clinical Radiology. 2021 Mar 1;76(3):235-e15.
  10. ↑ 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 Jul-Aug;54(4):549-53.
  11. ↑ 11.0 11.1 11.2 11.3 11.4 Bhatia M, Thomson L. Morton’s neuroma–current concepts review. Journal of Clinical Orthopaedics and Trauma. 2020 May 1;11(3):406-9.
  12. ↑ Skalina T, Weerakkody Y. Mulder sign. Reference article, Radiopaedia.org. Available from https://radiopaedia.org/articles/mulder-sign (accessed on 14 Oct 2022)
  13. ↑ Cashley DG, Cochrane L. Manipulation in the Treatment of Plantar Digital Neuralgia: A Retrospective Study of 38 Cases. J Chiropr Med. 2015 Jun;14(2):90-8
  14. ↑ The Physio Channel. Metatarsal Squeeze Test for Mortons Neuroma and Mulders Sign. 2019. Available from: https://www.youtube.com/watch?v=yJ7LUCCmFAU[last accessed 15/10/2022]
  15. ↑ 15.0 15.1 15.2 Simpson H. Morton's Neuroma Course. Plus 2022
  16. ↑ 16.0 16.1 Matthews BG, Hurn SE, Harding MP, Henry RA, Ware RS. The effectiveness of non-surgical interventions for common plantar digital compressive neuropathy (Morton's neuroma): a systematic review and meta-analysis. J Foot Ankle Res. 2019 Feb 13;12:12
  17. ↑ Janisse DJ, Janisse E. Shoe modification and the use of orthoses in treating foot and ankle pathology. J Am Acad Orthop Surg. 2008 Mar;16(3):152-8.
  18. ↑ 18.0 18.1 de Oliveira HAV, Natour J, Vassalli M, Rosenfeld A, Jennings F, Jones A. Effectiveness of customized insoles in patients with Morton's neuroma: a randomized, controlled, double-blind clinical trial. Clin Rehabil. 2019 Dec;33(12):1898-1907.
  19. ↑ Mahadevan D, Attwal M, Bhatt R, Bhatia M. Corticosteroid injection for Morton's neuroma with or without ultrasound guidance: a randomised controlled trial. Bone Joint J. 2016 Apr;98-B(4):498-503.
  20. ↑ Choi JY, Lee HI, Hong WH, Suh JS, Hur JW. Corticosteroid Injection for Morton's Interdigital Neuroma: A Systematic Review. Clin Orthop Surg. 2021 Jun;13(2):266-277.
  21. ↑ Lizano-Díez X, Ginés-Cespedosa A, Alentorn-Geli E, Pérez-Prieto D, González-Lucena G, Gamba C, de Zabala S, Solano-López A, Rigol-Ramón P. Corticosteroid Injection for the Treatment of Morton's Neuroma: A Prospective, Double-Blinded, Randomized, Placebo-Controlled Trial. Foot Ankle Int. 2017 Sep;38(9):944-951.
  22. ↑ 22.0 22.1 Seok H, Kim SH, Lee SY, Park SW. Extracorporeal Shockwave Therapy in Patients with Morton's Neuroma A Randomized, Placebo-Controlled Trial. J Am Podiatr Med Assoc. 2016 Mar;106(2):93-9.
  23. ↑ 23.0 23.1 Cashley DG, Cochrane L. Manipulation in the Treatment of Plantar Digital Neuralgia: A Retrospective Study of 38 Cases. J Chiropr Med. 2015 Jun;14(2):90-8.
  24. ↑ Samaila EM, Ambrosini C, Negri S, Maluta T, Valentini R, Magnan B. Can percutaneous alcoholization of Morton's neuroma with phenol by electrostimulation guidance be an alternative to surgical excision? Long-term results. Foot Ankle Surg. 2020 Apr;26(3):314-319.
  25. ↑ Jain S, Mannan K. The diagnosis and management of Morton’s neuroma: a literature review. Foot & Ankle Specialist. 2013 Aug;6(4):307-17.
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