This inflammatory condition of the thumb (running along the edge of the bone) involves 2 tendons (extensor pollicis brevis and abductor pollicis longus) that act to extend (straighten) and elevate. Almost all hand activities, will involve these tendons. Tenosynovitis, where the sheath of the tendon becomes inflamed, swollen and painful, can occur in arthritic conditions (e.g. rheumatoid arthritis). Friction in the tendon sheaths leads to inflammation. In sports, repetitive actions involving the thumb and wrist, such as racket sports (eg tennis, squash) or rowing, may lead to tenosynovitis. Diagnosis is usually clinical. Ultrasound or MRI can confirm the inflammation.
Treatment initially involves rest, topical anti- inflammatory medication and a splint with physiotherapy. Some cases may need cortisone injection. Surgery is reserved for cases that do not settle with other treatments.