Morton’s Neuroma

Ankle and Foot Anatomy

The foot consists of the Hindfoot (calcaneus and talus bones), Midfoot (navicular, cuboid, cuneiform bones) and Forefoot (metatarsal and phalanx bones)

The ankle joint is a hinge joint with muscles crossing it to allow ankle range of motion (ROM) while muscles crossing the midfoot and forefoot area allow foot ROM.

Bones of Foot

Toe range of motion

Foot Muscle Anatomy

Morton’s neuroma

Morton’s neuroma is a painful forefoot condition that involves tissue thickening around one of the foot digital nerves with a compressive neuropathy at the plantar aspect of the transverse metatarsal ligament, usually at the 3rd (narrowest) / 4th webspace.

Histopatholgical changes with Morton’s neuroma:

Plantar digital nerve swelling near bifurcation.
Damaged myelinated nerve fibers with Schwann cell and fibroblast propagation.
Tenosynovial tissue thickening and fibrosis
Endarterial thickening of digital artery ± thrombosis

Morton’s Neuroma Presentation

Forefoot pain at the inter-metacarpal joint area with pain worsening with the wearing of tight-fitting shoes.
“Sensation of walking on a pebble”
Numbness or tingling in the toes and forefoot, most commonly between the 3rd and 4th toes

Causes:

Trauma to digital nerve.

Risk factors:

Repetitive trauma to digital nerve.
High heel (toe hyperextension) and/or tight-fitting shoes
Associated midfoot and forefoot disorders: toe deviation, inflammation of intermetatarsal bursa, thickened transverse metatarsal ligament, or space occupying lesions.

Clinical Test:

Local tenderness in webspace with palpation.
Mulder’s sign.

Investigations:

Standing foot X-rays to exclude other pathology.
Ultrasound: confirming diagnosis and can also be utilized as an adjuvant to aid topical guided steroid injection.
MRI: Morton’s neuroma appears as a dumbbell shaped soft tissue lesion with low T1 signal and low or intermediate T2 signal

Morton’s Neuroma Management

Conservative Treatment:

Non-operative measures include analgesia: Anti-inflammatory medication and medication like tricyclic antidepression amitryptiline and anti-epileptic medication like gabapentin can lessen nerve-related pain.
Shoe wear modifications with wider low heeled shoes with metatarsal head offloading orthosis. A Budin splint or a canopy toe strapping application may decrease secondary neuralgia.
Topical corticosteroid and local anaesthetic injection.
Activity modification with decrease in impact activities such as running and jumping.
Physiotherapy rehabilitation focuses on gastrognemius stretching and intrinsic foot strengthening exercises.

Surgery:

Definitive management is surgical decompression and neuroma excision: intermetatarsal ligament release and neuroma excision.

Complications after surgery:

Recurrence, 5% risk.
Numbness in toe web space.
Local infection.

Rehabilitation

Return to sport & match readiness:

After appropriate rehabilitation
Assess return to sport after completing a battery of testing

Intrinsic foot strengthening with towel

Calf stretching

Assisted calf stretching

Download ASSIC Performance Fingerprint or Strength & Conditioning apps to create or download guideline (pre and post surgery) rehab routines

Surgery for Morton’s Neuroma:

Dorsal incision of the involved webspace
Expose and cut transverse metatarsal ligament

Surgery principles for Morton’s neuroma:

Dorsal incision of the involved webspace (plantar incision reserved for recurrent revision cases due to potential painful plantar scar and keratosis)
Expose and cut transverse metatarsal ligament
Excise neuroma and resect nerve including proximal bifurcation branches
Consider suturing nerve ends to side of metatarsal or intrinsic muscles to prevent stump neuroma

References

Treatment of Morton’s neuroma: A systematic review. Silvia Valisena, Gianfranco John Petri, Andrea Ferrero. Foot Ankle Surg. 2018 Aug;24(4): 271-281.
Neuroma. Zabaglo M, Dreyer MA. 2021 Mar 17 StatPearls (Internert).
The effectiveness of non-surgical interventions for common plantar digital compressive neuropathy (Morton’s neuroma): a systematic review and metaanalysis. Barry G Matthews, Sheree E Hurn, Michael P Harding, Rachel A Henry, Robert S Ware. J Foot Ankle Res. 2019 Feb 13;12: 12.