Mortons Neuroma is a compressive neuropathy of the interdigital nerve, usually between the third and fourth metatarsals.

1. Mortons Neuroma
Mortons Neuroma is a compressive neuropathy of the interdigital nerve, usually between the third and
fourth metatarsals.
Interdigital neuroma was first described in 1845 by Durlacher, and, in 1876, Morton expanded the
clinical description and gave the condition its eponym, Morton Neuroma.
 Females are affected more commonly than males 8:1 (most likely from wearing high heels and
shoes with narrow toe boxes).
 The condition is usually unilateral
Pathophysiology
The pathophysiology of this condition is still poorly understood. Theories include:
1. Compression/tension around the intermetatarsal ligament,
2. Repetitive microtrauma,
3. Vascular changes,
4. Excessive bursal tissue,
5. Endoneural edema,
6. Eventual neural fibrosis.
Mortons Neuroma
Mortons Neuroma Symptoms
The diagnosis usually is made by careful history and physical examination, although various diagnostic
studies may be helpful in selected cases.
1. Patients will frequently report pain and burning on the plantar aspect of the web space, with
over 60% of patients noting pain radiating into the toe distally.
2. Numbness is reported in only 40% of patients.
These symptoms are exacerbated by footwear with narrow toe boxes and high heels.
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2. Patients often note that they feel better in their bare feet and get quick relief with removal of their
shoes.
Physical examination includes:
Palpation between and just distal to the metatarsal heads elicits plantar tenderness.
Tenderness in the web space is believed to be the most common finding in interdigital neuroma.
Palpating the web spaces with the patient standing sometimes is helpful in differentiating a second
web space neuroma from a plantar plate lesion at the second metatarsophalangeal joint. If the
tenderness is mostly in the web space and not in the plantar aspect of the base of the proximal phalanx
or the dorsolateral aspect of the second metatarsophalangeal joint, a neuroma is likely.
Compressing the medial and lateral aspect of the forefoot while palpating the web space structures
can provoke symptoms and occasionally a bursal“click” (Mortons Neuroma Test): This click is best
appreciated when the patient lies prone, and the examiner places the thumb dorsally and the index
finger plantarward over the appropriate web space (usually the third) and gently rocks the hand back
and forth.
Injection of the involved web space with local anesthetic is diagnostic if the neuritic symptoms are
relieved temporally.
Metatarsalgia and MTP synovitis often present similarly and should be ruled out.
See Also: Mortons Neuroma Test
Mortons Neuroma Test
Radiology Evaluation
 Plain films should be performed to rule out bony masses or deformity.
 Ultrasound has been reported to be 85% accurate in diagnosing of Mortons Neuroma.
 MRI can be used to identify other pathologies, but not required for diagnosis.
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3. Mortons Neuroma MRI
Pathological Findings
The following list summarizes reported pathological findings of Mortons Neuroma:
1. Perineural fibrosis.
2. Increased number of intrafascicular arterioles with thickened and hyalinized walls caused by
multiple layers of basement membranes.
3. Demyelinization and degeneration of nerve fibers with a decrease in the number of axis
cylinders.
4. Endoneural edema.
5. Absence of inflammatory changes.
6. Frequent presence of bursal tissue accompanying the specimen.
Interdigital nerve is greatly thickened by perineural fibrous tissue (hematoxylin and eosin stain)
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4. Vessels in
region often show degenerative changes such as fraying and duplication of internal elastic lamina
(Verhoeff-van Gieson stain)
Some axons are missing, and others show degenerative changes (Bielschowsky stain)
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5. Small bursa
may be found in region (hematoxylin and eosin stain)
Mortons Neuroma Treatment
The mainstay of Mortons Neuroma treatment is surgery by neuroma excision, but nonoperative
treatment is successful often enough to warrant at least a trial period.
Nonoperative treatment:
Nonoperative treatment of Morton's Neuroma include:
1. Shoewear modification (avoiding high heels and narrow toe boxes) is the most important and
effective intervention.
2. Metatarsal pads placed proximal to the focus of pain can prevent direct pressure and widen the
intermetatarsal space during weight bearing, thereby indirectly decompressing the nerve.
3. Corticosteroid injections into the affected web space can have moderate effectiveness (
≈50%
of patients report positive response).
For more see: Morton's Neuroma ORTHOFIXAR | By Dr.MhmadFarooq

6. Morton's
neuroma metatarsal pads
Operative treatment:
Detailed preoperative examination and careful patient selection for surgery is recommended. In
addition, the patient must be informed before surgery that some symptoms may remain after surgery
(caused by other causes of metatarsalgia that might coexist in a patient with an interdigital neuroma).
Mortons Neuroma is treated surgically by Excision via dorsal or volar approach:
1. Dorsal approach:
 The most common used approach.
 Incise the transverse intermetatarsal ligament, identify the common digital nerve and its
branches, and resect the nerve 2 to 3 cm proximal to the intermetatarsal ligament (proximal to
the small plantar branches), which allows the proximal stump to retract.
 This minimizes formation of stump neuroma, the most common complication of neuroma
excision.
 Difficult visualization results in a 4% rate of failure to excise the neuroma.
 Overall success rates approach 80%.
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7. 2. Plantar
approach:
 Decreases the rate of missed neuroma excision.
 Does not require incision of the transverse intermetatarsal ligament.
 Increased risk (5%) of painful plantar scar.
 Typically used for revision neuroma resection.
 For a recurrent interdigital neuroma, a plantar approach is recommended because the exposure
is excellent.
A Randomized Controlled Trial by Christian Akermark
1 of plantar versus dorsal incisions for
operative treatment of primary Morton's neuroma, he demonstrated 87% (plantar) and 83% (dorsal)
clinically good outcomes and no significant differences between the procedures in regard to pain,
restrictions in daily activities, and scar tenderness.
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8. Another prospective 2-year follow-up study2 of plantar incisions in the treatment of primary
intermetatarsal neuromas (Morton's neuroma), it shows that surgery with a plantar incision seems to
be a reliable and safe intervention of primary Morton's neuromas, with only limited number of minor
complications and a subjective satisfactory outcome, well in accordance with other studies, using
different, surgical approaches.
Notes
 In a strict sense, the term neuroma is incorrect because the haphazard proliferation of axons
seen in a traumatic
neuroma is not found and the deposition of hyaline and collagenous material accounts for the
enlargement.
 The term interdigital neuritis, rather than interdigital neuroma, has been suggested.
 The pathological process probably is degenerative, rather than proliferative, with repetitive
trauma against the deep transverse intermetatarsal ligament being the most likely cause, but
even this is uncertain.
 If symptoms occur after midfoot or forefoot trauma, surgical excision should only be
cautiously considered because it may require several months for tissue homeostasis to return
and symptoms to decrease or resolve.
References
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9. 1. Akermark C, Crone H, Skoog A, Weidenhielm L. A prospective randomized controlled trial
of plantar versus dorsal incisions for operative treatment of primary Morton's neuroma. Foot
Ankle Int. 2013 Sep;34(9):1198-204. doi: 10.1177/1071100713484300. Epub 2013 Apr 5.
PMID: 23564425.
2. Akermark C, Saartok T, Zuber Z. A prospective 2-year follow-up study of plantar incisions in
the treatment of primary intermetatarsal neuromas (Morton's neuroma). Foot Ankle Surg.
2008;14(2):67-73. doi: 10.1016/j.fas.2007.10.004. Epub 2008 Feb 21. PMID: 19083618.
3. Campbel's Operative Orthopaedics 12th edition Book.
4. Millers Review of Orthopaedics -7th Edition Book.
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