Get latest articles and stories on Science at LatestLY. Rhizarthrosis, also known as trapeziometacarpal osteoarthritis, is a kind of osteoarthritis that affects the thumb. Treatment options include splints and surgery. Researchers discovered a number of genetic differences between those with rhizarthrosis who have surgery and those who choose nonsurgical therapies. Science News | Researchers Find How Genetics Affect Need for Surgery in Patients with Thumb Osteoarthritis.