Value Village ／ Health
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As people spend longer using their phones one-handed, orthopaedic clinics in Japan report more complaints of "pain at the base of the thumb" and "pain on the thumb side of the wrist". The condition is nicknamed "smartphone tendonitis" or "text thumb", and left alone it starts to hurt in everyday movements too. Here is how to identify it and what to do.
| Condition | Where it hurts | Features | Simple check |
|---|---|---|---|
| De Quervain's disease (stenosing tenosynovitis) | Thumb side of the wrist (near the bony bump) | Pain on moving or spreading the thumb, or gripping. Swelling | Finkelstein test: tuck the thumb inside the other four fingers and bend the wrist towards the little finger — sharp pain |
| Trigger finger | Base of a finger (palm side) | The finger catches or snaps when bending and straightening; worst in the morning | Pain on pressing the base of the finger |
| Thumb CMC joint arthritis | The joint at the base of the thumb (where it meets the wrist) | Age 50 and over; pain when pinching or opening a jar lid. The joint starts to protrude | Pain on pressing the base of the thumb; deformity |
| Carpal tunnel syndrome | Numbness from the thumb to the middle finger, worse at night and early morning | Numbness is the main symptom; shaking the hand eases it | Tapping the wrist sends tingling into the fingers |
| Simple muscle fatigue | Palm, forearm | Heaviness; settles with rest | — |
| Stage | What to do |
|---|---|
| Onset (a few days) | Reduce the painful movement: hold with both hands, use your index finger, voice input, a stylus, rest the phone on a surface. Cool it (if swollen or hot). Over-the-counter anti-inflammatory patches |
| 1–2 weeks | Rest with a thumb-supporting brace (¥1,000–2,000) or taping. Warm it (chronic phase). Forearm stretches (palm facing forward, bend the fingers back, 20 seconds) |
| Over 2 weeks, or swelling, catching or numbness | Orthopaedic clinic. Splint, steroid injection (highly effective); if no better, surgery to open the tendon sheath (day surgery) |
[Verify] Check the description of the Finkelstein test and the place of steroid injections and surgery against materials from the Japanese Orthopaedic Association and the Japanese Society for Surgery of the Hand.
Inflammation of tendon and sheath keeps coming back as long as the movement that causes it continues. Change how you hold the phone; if it lasts over 2 weeks, see an orthopaedic clinic.
Massaging an inflamed tendon sheath can make it worse. Support, rest and forearm stretches suit it better.
A few weeks of support in the acute phase almost never causes a problem with strength. Immobilising the thumb for rest is part of the therapy.
Steroid injections are highly effective for tenosynovitis, and many people improve after 1–2. The number is limited, so pair them with changing how you hold the phone.
Day surgery under local anaesthetic taking about 15–20 minutes is usual, and it is the standard option when injections do not help.
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https://www.joa.or.jp/public/sick/condition/de_quervain_disease.html
https://www.jssh.or.jp/ippan/sikkan/
https://www.mhlw.go.jp/stf/newpage_05590.html
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
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