ARC syndrome

Disease Description (Causes and Symptoms)

• Summary: The plantar fascia is a thick, strong band of fibrous tissue that begins at the calcaneus (heel bone) and attaches to the base of the toes along the sole of the foot. It supports the arch of the foot and absorbs shock during walking. Plantar fasciitis is a condition in which repeated, localized stress to this structure causes inflammation and microdamage (including degenerative changes), resulting in pain in the heel area.
• Main causes and risk factors: prolonged standing, excessive exercise (running, hiking, jumping), a sudden increase in exercise volume, obesity, flat feet or high arches, inappropriate footwear (hard soles, heels that are too low), a shortened Achilles tendon, middle age (average approximately 45 years), and being more common in women. Underlying diseases such as diabetes and arthritis may also increase the risk.
• Pathophysiology: chronic repetitive microdamage → local inflammation and fibrosis (degenerative changes) → pain and tenderness of the fascia. A characteristic feature is that pain becomes worse when the fascia is suddenly stretched during the first steps in the morning while it is contracted during the night or at rest.
• Main symptoms:
  • Severe heel/sole pain during the first few steps in the morning or the first walk after sitting for a long time
  • Worsening after walking for a long time or after exercise
  • Localized tenderness in the medial area of the calcaneus
  • Frequently accompanied by shortening of the Achilles tendon
• Differential diagnosis: atrophy of the plantar fat pad, stress fracture of the calcaneus, bursitis, Achilles tendon rupture or tendinitis, neuropathy (e.g., Morton neuroma), and joint diseases.
• Diagnostic summary: Diagnosis is mainly made clinically (medical history and physical examination). When necessary, plain X-rays (to rule out a bony spur or fracture), ultrasonography, or MRI (when the diagnosis is unclear or treatment-resistant) may be used.

Treatment Methods

• Conservative treatment (more than 90% of most patients recover)
  • Rest and activity modification: Temporarily reduce activities that cause pain (such as long-distance running and jumping) or switch to alternative exercises (such as swimming and cycling)
  • Footwear and insole correction: Shoes with good cushioning, slightly elevated heels (avoid heels that are too low), and custom-made or supportive foot orthoses (custom-prescribed for flat feet or high arches)
  • Night orthosis (night splint): Keeps the plantar fascia passively stretched to relieve morning pain (symptoms improve within about 1 week after starting use; recommended for 2–3 months)
  • Stretching and physical therapy: Stretching of the plantar fascia and Achilles tendon, massage, contrast baths, ultrasound therapy, etc.
  • Pain control: NSAIDs (short-term), acetaminophen, etc.
  • Combined use of taping and a heel cup (silicone): Helpful for relieving pain during the acute phase
• Interventional treatment
  • Steroid injection: May be used when conservative treatment fails, but caution is needed (risk of fat-pad atrophy and fascial rupture). Repeated injections are not recommended.
  • Extracorporeal shock wave therapy (ESWT): Reported to be effective in chronic patients who do not respond to conservative treatment (recommendations vary depending on the institution and case).
  • Other injection treatments such as PRP: Used in some cases, but may vary depending on the evidence and indications.
• Surgical treatment
  • Considered when severe pain and functional impairment persist despite at least approximately 6 months of conservative treatment. Surgical procedures such as partial plantar fasciotomy may be performed. The principle is to provide sufficient conservative treatment before surgery.
• Lifestyle management and precautions
  • Weight loss, avoiding prolonged standing, and wearing appropriate footwear are recommended.
  • When receiving steroid injections, the number of injections should be limited, and the risks of fat-pad atrophy and fascial damage should be explained.
  • Athletes are advised to modify their training methods (reduce running distance and switch to lower-impact exercise).

Checklist Before an Outpatient Visit (Including Example Questions)

• Items/materials to prepare
  • List of currently used medications (including anticoagulants and antiplatelet drugs)
  • Timing of symptom onset and progression (when it first started and patterns of worsening or improvement)
  • Nature of the pain: whether there is pain during the first steps in the morning, whether it worsens during or after activity, and the location of the pain (exactly where it hurts)
  • Recent changes in exercise volume (whether a new exercise was started or increased), and occupational activities (prolonged standing)
  • Type of footwear and wearing habits (high heels, shoes with hard soles, etc.)
  • Weight, underlying diseases (diabetes, arthritis, etc.), and records of previous treatments (physical therapy, orthoses, injections, etc.)
  • Results of previous imaging tests, if available (X-ray, ultrasonography, MRI, etc.)
• Items that are helpful for patients to record themselves and bring to the outpatient visit
  • Pain score (numeric pain scale) and time of pain, recorded for several days
  • Activities that worsen the pain and methods that relieve it
• It is recommended to bring photos to show the healthcare professional (such as the worn condition of the shoe soles) or photos showing the actual shape of the foot.

General Example Questions to Ask the Doctor

• What are the expected side effects of this medication (the prescribed painkiller/anti-inflammatory), and how long should I take it?
• In my case, what is the likelihood of recovery with conservative treatment alone, and what is the prognosis?
• What lifestyle changes must I make? What would be an appropriate weight-loss goal?
• If you recommend a steroid injection, please explain its advantages, disadvantages, and risks (such as fat-pad atrophy and fascial rupture).
• How likely is it that surgery will become necessary, and what are the expected benefits and risks of surgery?

Examples of Condition-Specific Questions

• How long (how many weeks or months) should I wear the nighttime orthosis (night splint)? If it is uncomfortable to wear, how should it be adjusted?
• I have already received a steroid injection once, but the pain has returned. Is an additional injection possible? What alternative nonsurgical treatments (e.g., ESWT, PRP) would be appropriate?