Healthy joints rely on articular cartilage, a smooth tissue that covers bone ends and allows nearly frictionless movement. Under normal conditions, cartilage maintains itself through a balance of breakdown and repair. However, after age 40, cartilage loses approximately 1% of its volume per year, and the body's ability to regenerate this tissue progressively declines.
As cartilage thins, the underlying bone surfaces begin to experience increased mechanical stress, triggering an inflammatory response. The synovial membrane, which produces lubricating fluid within the joint capsule, becomes inflamed and thickened, producing excess fluid that causes swelling and further restricts movement. This cascade from cartilage loss to inflammation to structural change is what patients experience as worsening pain and stiffness.
The surrounding musculoskeletal system compounds the problem. When joint pain alters how you move, compensatory patterns develop in muscles, tendons, and ligaments. These imbalances place abnormal loads on adjacent joints, which is why knee arthritis often accompanies hip or lower back dysfunction, creating a chain of discomfort throughout the body.
