Orthoses

Morton's neuroma: understanding the condition and the role of orthoses

Burning pain or numbness in the forefoot between toes 3 and 4? A PubMed-based summary of diagnosis, the treatment ladder and why insoles and metatarsal pads come first.

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Morton's neuroma: understanding the condition and the role of orthoses

Morton’s neuroma is a leading cause of sharp, burning or numb pain in the forefoot, usually between toes 3 and 4. The good news is that most people improve without surgery, and orthoses with suitable footwear are the first step and the foundation of treatment.

This article summarises the scientific studies on PubMed in plain language: what the condition is, how it is examined and diagnosed, how it is treated, how long it takes, and why orthoses matter from prevention to treatment.

What is Morton’s neuroma?

A small nerve branch running between two metatarsal bones is repeatedly compressed and irritated, and over time the tissue around the nerve thickens. Although called a “neuroma”, it is not a true tumour and it is not cancer.

Most common site: the space between toes 3 and 4. A study of 217 surgical patients found 83.5% in this space and 7.5% in the 2–3 space.
Nature: fibrous tissue around the nerve, oedema and damage to the nerve sheath. An inflamed bursa between the metatarsal bones is also thought to be an important source of pain.
History: described in 1876 by the American surgeon Thomas George Morton.

Picture the nerve as an electric wire trapped between two bars of bone. With every step, especially in tight shoes, the two bones squeeze the wire. Orthoses work precisely by widening this space and reducing pressure on it.

Causes and who is at risk

The disease is mainly mechanical: the forefoot is repeatedly squeezed and overloaded. Middle-aged women are affected at least 5 times more often than men; in large studies about 85% of patients are women.

Recognised risk factors:

Narrow-toed shoes that squeeze the toes together.
High heels, which bend the toes back and shift weight onto the ball of the foot.
Toe deviation, or a loose or deformed metatarsophalangeal joint (especially the 2nd).
Inflammation of the bursa between the metatarsals, a thickened transverse ligament.
Forefoot injury, and high-impact sport such as running and jumping.

Importantly, most of these factors are pressure and foot posture, which can be adjusted with footwear and orthoses.

Common symptoms

The typical symptom is burning or stabbing pain in the sole, between the heads of the metatarsals, radiating to the two toes concerned. Patients often describe:

A feeling of standing on a pebble or a fold of the sock under the toes.
Numbness, tingling or electric-shock sensations spreading to toes 3 and 4.
Pain that increases in tight shoes or high heels, and with prolonged standing or walking.
Pain that eases when the shoe is taken off and the foot massaged.

Usually no swelling or lump is visible from the outside, so many people put up with it for a long time before seeing a doctor.

Examination and diagnosis

Diagnosis rests mainly on clinical examination by an experienced person; imaging is needed only when doubt remains.

Test	How it is done	Suggestive sign
Thumb–index finger squeeze of the web space	Direct pressure into the space between two metatarsal heads	Pain at the exact spot
Mulder’s test	Squeeze across the foot while pressing the suspected space	A palpable or audible click, with pain
Squeezing across the foot	Pressing both edges of the foot together	Reproduces the pain

A 2020 review reported that clinical examination by an experienced physician is up to 98% accurate compared with ultrasound; the three tests above are listed in order of sensitivity.

Imaging and differential diagnosis

Ultrasound and MRI have similar accuracy. A meta-analysis found a sensitivity of 0.91 for ultrasound and 0.90 for MRI; ultrasound is cheaper and so is often preferred.
In a study compared with surgical findings, clinical examination was even more sensitive and specific than both imaging methods. A neuroma under 6 mm can still hurt as much as a large one.
X-ray does not show the neuroma but helps exclude other bone and joint disease.
Differential diagnosis: metatarsophalangeal arthritis, stress fracture, bursitis, pain under the metatarsal heads (metatarsalgia). Pain in several spaces at once suggests joint disease more than Morton’s.
Foot biomechanical assessment (the role of the orthotic engineer): gait, arch type (flat or high arch), foot width, high-pressure areas and the shoes worn. These data are used to design the right orthosis for each person.

How to read: an ultrasound of the forefoot. The dark (hypoechoic) oval area between two metatarsal heads, where the arrow points, is the Morton’s neuroma; the two + marks are the calipers used to measure the mass. Ultrasound has a sensitivity of about 0.91, similar to MRI (0.90) but cheaper (Xu et al., Eur Radiol 2015). Image source: dungcuchinhhinh.vn.

How to read: an axial MRI slice through the forefoot; the bright rings are cross-sections of the metatarsal bones. The arrow points to a low-signal (dark grey) mass between two bone heads, exactly where a Morton’s neuroma sits. MRI has a sensitivity of about 0.90, similar to ultrasound (Xu et al., Eur Radiol 2015). Image source: dungcuchinhhinh.vn.

How to read: an intra-operative photo with two retractors opening the web space between two toes. The arrow points to the thickened nerve segment (the Morton’s neuroma) exposed. Surgery is reserved for failed conservative treatment; the photo is only to illustrate the condition. Image source: dungcuchinhhinh.vn.

Treatment steps: from simple to complex

Doctors usually treat in a ladder: start with the simplest, safest measure, and move up only if there is not enough relief after about 3 months.

Step 1 – Footwear and orthoses: the foundation for every patient. These can be combined with painkillers, cold packs and reducing painful activity.
Step 2 – Injection: a randomised trial of 131 people showed that corticosteroid injection reduces pain and improves function for at least 3 months. About 5% had skin depigmentation at the injection site and 3% atrophy of the plantar fat pad. A 2019 review ranked corticosteroid injection and joint mobilisation as the two non-surgical measures with the strongest evidence for pain relief, though there is no “gold standard”.
Step 3 – Surgery: when conservative treatment fails. After nerve excision, 82% of patients had a good or very good result and 8% had no improvement. With nerve transposition, two thirds were pain-free in the long term. However, surgery can leave permanent toe numbness, and 71% still have limits in choosing shoes.

How to read: three steps rising from left to right. Start at step 1 and move up only if, after about 3 months, relief is not enough. STEP 1 – wide-toe shoes plus orthoses: about 41% improved enough not to need more treatment (Bennett 1995; 47/115 patients). STEP 2 – corticosteroid injection: pain relief and better function for at least 3 months (Thomson 2013; 131 patients). STEP 3 – surgery when conservative treatment fails: 82% good or very good results but 71% still limited in choosing shoes (Pace 2010). Orthoses accompany the patient at all three steps.

The key message: orthoses are not only step 1; they accompany the patient throughout, including after injection or surgery.

Orthoses: the pillar of conservative treatment

Orthoses are the first treatment step in the protocols, and the only method acting directly on the mechanical cause: reducing pressure on the nerve with every step.

How do orthoses help the foot?

They lift and separate the metatarsal heads, widening the space the nerve passes through.
They shift load from the overloaded forefoot toward the midfoot.
They support the arch, so the foot bears load more evenly and is steadier when stepping.
They reduce repeated friction and impact on the painful area.

The scientific evidence

Custom orthoses/insoles reduce pain and improve mobility. A double-blind randomised controlled trial in Brazil of 72 patients: one group used custom insoles with a metatarsal pad and EVA arch support, the other used flat insoles of the same material, colour and hardness. After 6, 12 and 24 weeks, the custom-insole group had clearly less pain when walking and better function. This is a rare high-quality trial dedicated to insoles for Morton’s.
A metatarsal pad reduces forefoot pressure. A plantar-pressure study in older adults with a history of forefoot pain: every pad placement reduced peak forefoot pressure compared with no pad. Placing the pad about 5 mm behind the metatarsal head gave the best balance: it reduced pressure at the painful spot without creating a new pressure point.
Footwear and a pad alone are enough for almost half of patients. In Bennett’s stepwise protocol, stage 1 consisted of education, a shoe change and a metatarsal pad placed behind the nerve. 47 of 115 patients (41%) improved enough not to need further treatment.
Results that last. In a study of 82 patients comparing injection with footwear change plus orthoses, after 12 months 63% of the footwear and orthosis group had complete or partial pain relief, versus 82% of the injection group. The injection group was more satisfied at early time points, but by 1 year the difference was no longer statistically significant. Note that this study has low methodological quality.
Insoles that only tilt inwards or outwards are not enough. In a small trial of 23 patients, after 12 months pain fell 50% with the lateral wedge and 45% with the medial wedge, with no difference. The 2020 review concluded there is no evidence for this type of angle-only insole and does not recommend it. So an insole for Morton’s needs a pad that offloads the right metatarsal area, not just a change of foot angle.

To be clear: systematic reviews of the evidence for Morton’s treatment in general are still limited, and no method is regarded as a “gold standard”. But orthoses are safe, non-invasive, with few side effects, and supported by double-blind trial data.

Common types of orthosis

Type	Main effect	Suitable when
Metatarsal pad/dome	Lifts and separates the metatarsal heads; offloads the painful space	Early stage; added to an existing insole
Custom foot orthosis	Arch support plus a metatarsal pad designed to each person’s foot	Prolonged pain, flat or high arch, long-term use needed
Metatarsal bar	A transverse bar behind the metatarsal heads that offloads the whole area; the most commonly used device in the early stage	Pain in several spaces, widespread forefoot overload
Wide-toe, low-heel shoes with a stiff or rocker sole	No more squeezing across the foot, less toe bending, less push-off force at the forefoot	Every patient; the foundation that lets the insole work

A custom insole (foot orthosis): the shell cradles the arch, a soft blue top layer contacts the foot, and a firmer base holds the shape. A metatarsal pad can be added inside to offload the painful space.

A left–right pair of orthotic insoles side by side: seen from above, the arch support is visible on the inner side of the sole.

Strap sandals with an arch-supporting orthotic insert on the footbed: suitable for everyday wear, especially when closed shoes are not an option.

Why does it need to be done right and individually?

A pad placed a few millimetres off changes the pressure distribution. A pad placed too far towards the toes can press right on the painful spot. So an orthosis should be assessed, measured and adjusted by someone with orthotic expertise, followed by review visits to fine-tune it.

The role of orthoses after injection or surgery

After injection: corticosteroid reduces symptoms for at least 3 months. But if the mechanical pressure remains, the nerve continues to be compressed. Orthoses help maintain the result.
After surgery: 71% of patients after nerve excision still have limits in choosing shoes. Suitable shoes and insoles keep helping comfortable movement and protect the foot.

The treatment pathway: how long does it take?

With orthoses, persevere for at least 3 months before judging whether another step is needed; this is the milestone the stepwise protocol uses. In the custom-insole trial, effect was followed at weeks 6, 12 and 24.

Stage	Time	What to do
Examination and assessment	Week 0	Clinical examination, ultrasound if needed; assess gait, arch, current shoes
Start the orthosis	Weeks 1–2	Receive the insole/pad; build up wearing time gradually so the foot adapts; switch to wide-toe, low-heel shoes
Review and fine-tuning	Weeks 4–6	Check pad position, adjust if there is still a sore or pressure spot
Assess effect	Month 3	Clearly better: continue. Not enough relief: the doctor considers injection while the orthosis continues
Maintenance	From month 6	Long-term use in everyday shoes; periodic checks, replace the insole when worn

Pain relief usually comes gradually. Follow-up shows satisfaction in the footwear-change group rising from 23% at 1 month to 63% at 1 year, although some people switched to injection after month 6. So do not give up after a few weeks.
Orthoses are a long-term solution. Morton’s does not go away by itself while the mechanical cause remains. Use the insoles regularly, not only when it hurts.
Insoles wear out too. The padding flattens with use, so it needs periodic checking and replacing when it no longer holds its shape.

Prevention and self-care

Prevention revolves around one principle: reduce squeezing and offload the forefoot.

Choose wide-toed shoes in which the toes move freely; try shoes on at the end of the day when the foot is widest.
Limit high heels, especially many hours in a row; prefer low heels.
Do not lace the toe area too tightly.
Use insoles with arch support and a metatarsal pad if you have a flat or high arch or often have forefoot pain.
Runners and sports players: use well-fitting, wide enough sports shoes with good cushioning left.
When numbness or burning between the toes begins, see someone early. Early intervention with footwear and orthoses succeeds more easily while the condition is mild.

When should you see a doctor?

See a doctor or an orthotic specialist when:

Pain, numbness or burning in the sole lasts more than a few weeks despite changing shoes.
Pain makes you limp, give up sport or miss work.
There is swelling, heat, redness, or pain after an injury: fracture and infection must be excluded.
You have diabetes or peripheral neuropathy: foot numbness may have another cause and needs careful examination.

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If you have burning pain or numbness in the forefoot, book an appointment for foot measurement and advice on custom orthotic insoles. Hotline +84 985 211 888. This article is for health education and does not replace an in-person examination.

References

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