This study looks at people who have osteoarthritis at the base of the thumb. It examines how well the thumb can sense its position and movement.
The study has three goals:
1. To compare these measurements between people with thumb base osteoarthritis and healthy people.
2. To find out whether this ability changes from milder to more advanced levels of osteoarthritis.
3. To explore whether this ability is related to factors such as basic personal characteristics, thumb/hand muscle strength and hand use, pain and touch sensation, and emotional factors like fear of movement, anxiety, and depression.
This is an observational study. No treatment is given. Participants complete thumb measurements and several tests/questionnaires.