A 74-year-old woman has pain in her right hand and lower back, which started months ago, and is now interfering with her activities of daily living. The pain gets worse as the day progresses. There is no history of any trauma, and she is otherwise well. Taking over-the-counter acetaminophen usually relieves the pain. On examination, there is bony soft tissue swelling of her second and third DIP joints in the right hand and pain in her lower back on forward flexion. There is no erythema or joint effusion in any of the other joints. Which of the following is the most likely explanation for the joint pain of osteoarthritis?