Disease Description (Causes and Symptoms)
- Definition: A condition in which the interdigital nerve (a branch of the plantar digital nerve) located between the metatarsophalangeal joints of the foot (the base of the toes) becomes fibrotic and thickened due to repeated pressure and irritation (it is not a true tumor).
- Causes and pathophysiology: Compression by the deep transverse metatarsal ligament and adjacent structures, along with repeated mechanical stress and chronic inflammation, causes fibrosis around the nerve, resulting in nerve enlargement.
- Main symptoms: Burning pain in the forefoot, tingling (electric-like sensation), numbness or reduced sensation in the toes (mainly between the third and fourth toes), worsening when walking (especially when wearing high-heeled or narrow-toe-box shoes), and improvement after removing shoes or with massage or wearing wide shoes. On examination, pain and a clicking sensation may be elicited by compression of the web space (Mulder's test).
Treatment Methods
- Conservative treatment (recommended first)
- Shoe modification: Wear comfortable shoes with a wide toe box and relatively low heels.
- Functional insoles/metatarsal pads: Metatarsal pads (forefoot pads) or custom insoles that spread the metatarsals and reduce pressure on the nerve.
- Activity modification: Avoid high-intensity jumping or activities that place excessive weight on the forefoot; weight loss may be helpful.
- Physical therapy and self-care: Try to relieve pain through stretching, foot massage, cold compresses, and other measures.
- Medication and injections
- Nonsteroidal anti-inflammatory drugs (NSAIDs) may help relieve pain in the short term.
- Intralesional steroid injection: Nonsurgical and may provide immediate symptom improvement, but the effect may be temporary, and side effects such as skin atrophy and fat-pad atrophy may occur.
- Local anesthetic injection: Used for diagnostic and therapeutic purposes (temporary disappearance of symptoms may assist diagnosis).
- Procedures and surgery
- Surgical excision (neurectomy): Considered when conservative treatment fails or symptoms persist. Loss of sensation may remain after nerve excision, and recurrence (or stump neuroma) and transfer of pain to another area (transfer metatarsalgia) may occur.
- Surgical outcomes vary among individuals, and depending on the report, issues with satisfaction and recurrence may exist (long-term follow-up is necessary).
- Precautions and complications
- Repeated steroid injections carry a risk of tissue damage (skin/fat atrophy); the risk of infection is low but exists.
- Reduced sensation after surgery, wound complications, recurrence/stump neuroma, and increased pain in adjacent areas may occur.
- Self-care tips
- Prioritize wearing comfortable shoes and using metatarsal pads; consult a specialist if symptoms do not improve.
- Avoid strenuous exercise or wearing narrow shoes when symptoms worsen.
Outpatient Visit Checklist (Including Suggested Items to Bring and Sample Questions)
- Items to bring (recommended)
- A list of medications currently being taken (including over-the-counter medications and supplements)
- Copies of previous test results, if available (such as X-ray, ultrasound, MRI, or electromyography)
- Symptom diary: When the pain occurs, its frequency and intensity (pain score), and which shoes or activities make it worse or better
- Records of previous treatment (whether insoles, injections, or other surgery were received)
- Photos of shoes or information about the types of shoes usually worn
- Sample questions to consider in advance at the outpatient visit (self-check before the appointment)
- When did the pain begin, and how has it progressed?
- Which activities or shoes most frequently trigger the pain?
- Have you previously received conservative treatment such as injections or insoles? How effective was it?
Examples of General Questions to Ask the Doctor
- What are the possible causes of this condition, and what other differential diagnoses should be considered?
- Which test is most appropriate for my symptoms (ultrasound, MRI, etc.)?
- What initial treatment do you recommend, and how much improvement can be expected?
- What are the advantages, disadvantages, and side effects of steroid injections?
- If surgery is recommended, what is the expected recovery period and how high is the risk of complications?
Examples of Condition-Specific Questions
- How likely is it that my symptoms will improve with conservative treatment alone, without surgery? (For example, what is the treatment period and likelihood of improvement?)
- If I undergo surgery, what are the chances of sensory loss or recurrence after excision, and what precautions should I take during rehabilitation?
(The diagnosis and treatment decision may vary depending on the individual condition and test results. Please consult the treating specialist for detailed consultation and interpretation of test results.)