Effect of first dorsal interosseous strengthening on clinical outcomes in patients with thumb osteoarthritis: a study protocol for a randomized controlled clinical trial.

Background: Thumb carpometacarpal osteoarthritis (CMC OA) is characterized by chronic progressive degeneration of the joint cartilage, with high prevalence. Patients present with pain at the base of the thumb, morning stiffness, and muscle weakness, symptoms that affect hand function and therefore interfere in activities and social participation. Movements that involve grip or lateral pinch are the most affected and directly impact independence, self-care, and leisure activities.