Why does osteoarthritis pain?

Abstract

For osteoarthritic pain, patients are often provided explanations like, “it hurts because the articular cartilage has peeled off and bare bone is rubbing together” or “it hurts because of osteophytes.” However, the reality is more complicated. While structural changes in the bone, cartilage, and tissue around the joints can cause pain, there are various other contributing factors such as synovitis, nerve sprouting in aneural regions such as the cartilage and meniscus, central or peripheral sensitization, and abnormality of the descending pain control system. Although these elements are closely related, each has its own pathogenesis. Therefore, each one could independently develop into an abnormality. Osteoarthritic pain is complicated, and the main cause varies depending on the stage of the disease and the individual patient, and hence, treatment according to the abnormality is required. In a super-aging society, doctors will clearly have more opportunities to see patients with osteoarthritis. To provide a tailor-made treatment protocol for osteoarthritic pain, it is important to understand the changes occurring during osteoarthritis and the exact cause of the pain.