Trigger thumb is a condition in which the flexor tendon cannot pass freely through the tendon sheath, causing it to get caught upon bending, or in some cases stuck in a bent position, notes the American Academy of Orthopaedic Surgeons. Rheumatoid arthritis is an inflammatory condition that affects the lining of the joints, and may result in bone erosion and deformity, states Mayo Clinic. People with rheumatoid arthritis are at risk of developing trigger thumb due to joint damage.
Researchers do not know the cause of trigger finger or thumb, as of 2015, but people who engage in activities that strain the hand, individuals diagnosed with diabetes or rheumatoid arthritis, adults between the ages 40 and 60, and women are at greater risk of developing the condition, notes the American Academy of Orthopaedic Surgeons. People can treat trigger finger with rest and over-the-counter medications, though in some cases doctors recommend corticosteroid injections or surgery.
Rheumatoid arthritis is an autoimmune disorder in which the body's immune system mistakenly attacks the synovium, the lining of membranes around joints, notes Mayo Clinic. As of 2015, researchers don't know exactly why the immune system attacks the synovium, but research suggests that people are more susceptible to the condition based on the presence of certain genetic factors. Women and those over the age of 40 are at greater risk of developing rheumatoid arthritis. Doctors treat rheumatoid arthritis with nonsteroidal anti-inflammatory drugs, corticosteroids, disease-modifying antirheumatic drugs, biologic agents and therapy. In severe cases, doctors recommend total joint replacement, tendon repair or joint fusion surgery.