Morton's Neuroma

Definition

 

Benign enlargement of the common digital branch

- usually 3rd webspace

 

Mortons Neuroma Common Site

 

Anatomy

 

Found at level of or just distal to MT heads

- deep to the deep transverse MT ligament

 

Epidemiology

 

Classically women between 40 and 60

 

Aetiology

 

Can be traumatic but usually degenerative

 

Pathology

 

Demyelination of nerve fibres with fibrosis

 

History

 

Pain with weight bearing

- worse with wearing tight shoes

- in the ball of foot

- may be shooting type pain

 

Numbness / tingling in the affected toes

 

Examination

 

Mulder sign

- palpate webspace with fingers superiorly and inferiorly

- with other hand compress metatarsal heads together

- either palpate the lump or feel a click

 

Mulders Sign

 

Xray

 

Usually normal

- can have splaying of MT heads

 

US / MRI

 

Aid in confirming the diagnosis

 

Management

 

Non operative

 

Wide toe box

Metatarsal Pads

HCLA - Temporary relief

Sclerosing injections / phenol

- can solve problem

 

Operative

 

Options

- resection (dorsal or plantar)

- decompression

 

Resection Technique

 

Dorsal incision

- beginning at webspace edge

- separate MT with lamina spreader / retractor

- divide deep MT ligament / can preserve especially in athletes

- identify common digital nerve proximally

- identify neuroma / place forceps under

- resect proximal to neuroma

- resect distal to bifurcation

- send to pathology to confirm

 

Mortons Neuroma IncisionMortons Neuroma 1Mortons Neuroma 2

 

Mortons NeuromaMortons Neuroma

 

Complications

 

Patient will have numbness

Painful stump neuroma (revise via plantar approach)

Hammer toe (inadvertant lumbrical resection)

Pain secondary to instability / division intermetatarsal ligament