Disease Description (Causes and Symptoms)
- Definition: Interdigital neuroma (Morton's neuroma) is a condition in which the interdigital nerve is repeatedly compressed and irritated between the metatarsal heads in the sole of the foot, causing fibrosis of the surrounding tissue and enlargement of the nerve. It is a hypertrophic lesion of the nerve, not a true tumor.
- Pathophysiology: When mechanical compression and microtrauma to the interdigital nerve accumulate due to narrowing between the metatarsal heads, repetitive trauma, or thickening of the transverse intermetatarsal ligament, fibrosis develops around the nerve, causing abnormal enlargement and resulting in pain and decreased sensation. It most commonly occurs between the third and fourth toes (the third web space).
- Main symptoms: Burning pain in the forefoot, sharp or shooting pain radiating toward the toes, tingling or numbness in the toes, worsening while walking (especially when wearing shoes with a narrow toe box and high heels), and relief after removing the shoes or massaging the area. Pain and clicking are commonly triggered by compression of the web space.
Treatment Methods
- Conservative treatment (performed first)
- Shoe modification: Comfortable shoes with a wide toe box and low heels are recommended. Avoid high-heeled shoes and narrow toe boxes.
- Orthoses and insoles: Use a metatarsal pad or functional insole that supports the midfoot and widens the space between the metatarsals.
- Activity modification, weight management, physical therapy (including ultrasound and stretching), and short-term use of anti-inflammatory pain relievers (NSAIDs).
- Injection treatment
- Intralesional injection of a local anesthetic and steroid: Has diagnostic and therapeutic effects. The duration of symptom relief varies by individual.
- Alcohol sclerosing injections (nerve injections) and other nonsurgical procedures (such as radiofrequency ablation and cryotherapy) are used at some centers, and their evidence and effectiveness vary.
- Surgical treatment
- Neurectomy: Excision of the affected portion of the nerve. Lifelong loss of sensation in the toes is possible.
- Neurolysis/decompression: Relieves compression by procedures such as cutting the transverse intermetatarsal ligament.
- Outcomes: Surgical satisfaction varies among individuals and studies (moderate satisfaction rates have been reported). Pain may persist after surgery, and recurrence or stump neuroma may occur.
- Recovery and rehabilitation
- If conservative treatment does not improve the condition, injections or surgery may be considered. Functional recovery generally occurs within several weeks to several months after surgery, with individual variation. Proper shoe management and use of insoles are recommended both before and after surgery.
- Precautions and risk of complications
- Steroid injections may temporarily cause infection, tissue atrophy, or elevated blood sugar (in patients with diabetes).
- Surgical complications: Decreased sensation (numbness in the toes), persistent postoperative pain, wound infection, and stump neuroma due to nerve regeneration.
- If pain persists despite conservative treatment, early consultation with a specialist is necessary.
Checklist Before an Outpatient Visit (Items, Records, and Example Questions)
- Items/documents to bring
- A list of currently used medications (including prescriptions, OTC medications, and supplements) and a history of allergies
- Records of previous foot-related surgeries or injuries
- Results of previous tests (X-rays, ultrasound, MRI), and photos or the actual insoles (orthotics) and shoes normally worn
- Pain diary: When symptoms began, activities or shoes that worsen them, the nature of the pain (burning, tingling, etc.), the location and intensity of the pain (quantified), and ways of relieving it
- Matters to tell the doctor in advance during the consultation (examples)
- When the symptoms began and which shoes or activities make them worse
- Treatments attempted so far (insoles, medications, injections, etc.) and their effects
- Whether you have diabetes, a blood-clotting disorder, a disease associated with infection risk, or are taking anticoagulants
Examples of General Questions to Ask the Doctor
- Is the cause of this symptom certain? Have other causes (stress fracture, arthritis, cyst, etc.) been ruled out?
- How long should conservative treatment be tried, and when would you recommend surgery if it does not improve?
- What are the advantages and disadvantages of steroid injections, and what side effects are possible?
- What degree of improvement can be expected from surgery, and how long will recovery take (including returning to daily activities and exercise)?
- What is the possibility of loss of sensation in the toes after surgery, and how should it be managed?
Examples of Condition-Specific Questions
- In my case (based on the symptom location, type of shoes, and test findings), how likely is improvement with conservative treatment alone?
- Which surgical method do you recommend (neurectomy versus decompression), and what are the respective risks of sensory loss and recurrence?
- Prevention and lifestyle management summary: Wear low-heeled shoes with a wide toe box, use insoles such as metatarsal pads, and avoid excessive weight-bearing on the forefoot.
- Prognosis summary: Many patients improve with conservative treatment or injections, but some require surgery, and sensory changes or recurrence may still occur after surgery; therefore, the advantages and disadvantages should be discussed thoroughly when choosing treatment.