Author: Anushka Pradhan
Editor: Nicholas Jo
Overview
Morton’s Neuroma is neuropathic pain in the forefoot and is related to the interdigital nerve (Gougoulias, 2019). It commonly occurs between the second and third metatarsals (Zabaglo, 2020). It is associated with pressure distribution changes in the foot due to either a deformity or calf muscle tightness (Gougoulias, 2019).
Keywords
Morton’s Neuroma, Intermetatarsal Neuroma
Epidemiology
This condition frequently presents among middle-aged women. It is five times more common in females than in males (Munir, 2020).
Etiology
Morton’s Neuroma commonly occurs at the third interspace because it is relatively narrow (Munir, 2020). The interdigital nerve to the third space receives branches from medial and lateral plantar nerves and has increased thickness making it more prone to compression and trauma (Munir, 2020). The compression of the interdigital nerve against the distal end of the transverse metatarsal ligament can occur as a result of narrow footwear, hyperextension of the toes in high-heeled shoes, deviation of the toes, inflammation of the intermetatarsal bursa, or as a result of other factors (Munir, 2020).
Symptoms
The most common symptoms of Morton’s Neuroma include the following:
- Burning, stabbing, or tingling sensations at the bottom of the foot,
- Numbness between the toes,
- Pain at the bottom of the foot is aggravated by walking and wearing tight-fitting, high-heeled shoes and relieved by resting and removing shoes,
- Pain in hindfoot or cramping legs with prolonged walking,
- Sensation of walking on a stone or marble (Munir, 2020).
Risk Factors
Risk factors include trauma from a crush or penetrating injury to the foot, thickened transverse metatarsal ligament, enlarged bursa in the interspace, and repetitive trauma from running (Munir, 2020).
Diagnosis
Clinical Features
A thorough history and clinical examination are encouraged (Munir, 2020). During a physical exam, compressing the forefoot in the mediolateral direction while palpating the affected space can result in a crunching or clicking feeling and reproduction of symptoms (Munir, 2020). Weight-bearing radiographs, ultrasound scans or MRI can help rule out a differential diagnosis (Munir, 2020).
Pathological Features
The MRI imaging or sonographic evaluation would likely demonstrate a dumbbell-shaped soft tissue lesion within the intermetatarsal space (Munir, 2020). Additionally, the T1 signal is often low, and the T2 signal frequently low or intermediate (Munir, 2020).
Treatment Protocol
Pharmacological Treatment
It is recommended that initial treatment is nonoperative (Gougoulias, 2019). Anti-inflammatory medications, tricyclic antidepressants such as amitriptyline, and anti-seizure medications such as gabapentin can potentially lessen the severity of symptoms (Munir, 2020). Ultrasound-guided steroid injections or alcohol nerve injections may help short-term (Munir, 2020).
Non-Pharmacological Treatment
This may include recommended physiotherapy, less strenuous physical activities, use of wide-fitting footwear, cryotherapy, radiofrequency ablation, and shockwave therapy (Gougoulias, 2019). Morton’s Neuroma can also be removed surgically via a dorsal or plantar approach (Munir, 2020).
Articles on Misdiagnosis
Chaganti, S., Joshy, S., Hariharan, K., & M. Rashid. (2013). Rheumatoid nodule presenting as Morton’s neuroma. Journal of Orthopaedics and Traumatology, 14(3), 219-222. DOI: 10.1007/s10195-012-0215-x.
Davies, M.S. (2018). Failed Morton’s neuroma surgery. Orthopaedic Proceedings, 94-B, 2049-4416. Retrieved from https://online.boneandjoint.org.uk/doi/abs/10.1302/1358-992X.94BSUPP_XXII.BOFAS2010-003.
Robinson, C., Otter, S.J., & C. Bowen. (2003). Clinical misdiagnosis of Morton’s neuroma: a case of early rheumatoid arthritis. British Journal of Podiatry, 6(3), 85-87. Retrieved from https://researchoutput.csu.edu.au/en/publications/clinical-misdiagnosis-of-mortons-neuroma-a-case-of-early-rheumato.
References
Gougoulias, N., Lampridis, V., & Sakellariou, A. (2019). Morton’s interdigital neuroma: instructional review. EFORT Open Reviews, 4(1), 14–24. DOI: 10.1302/2058-5241.4.180025.
Munir, U., Tafti, D., & Morgan, S. (2020). Morton Neuroma. In StatPearls. Treasure Island (FL): StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK470249/.
Zabaglo, M., & Dreyer, M. A. (2020). Neuroma. In StatPearls. Treasure Island (FL): StatPearls
Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK549838/.
