A 55-year-old man presents to a rheumatologist with bilateral wrist and knee pain that has slowly progressed over the last 10 years. His joint pain gets worse with use and improves a little with rest. He also notes morning stiffness that lasts approximately 20 minutes. The patient was a professional athlete who retired at age 50. He denies joint swelling, color changes in his digits, dryness of mucous membranes, and constitutional symptoms such as fever and chills. On physical exam, the physician notes several non-tender nodules on the left 1st, 3rd, and 4th distal interphalangeal (DIP) joints. There is also tenderness to palpation at the base of both thumbs. The patient’s knees are enlarged, bilaterally, and he has pain and crepitus on passive range of motion. What is the most likely diagnosis?