Many people are old and healthy, but gradually their lower limbs become heavy, their knees become stiff, and it is difficult to go up and down stairs or even walk. This is what people often say: "People get old when they get old."

After entering old age, all the organs of the body will age. Bones and joints are the most used and loaded exercise organs in daily life. In decades of life, the natural wear and tear of joints is particularly severe, so aging usually occurs first. In medicine, this phenomenon of bone and joint aging caused by natural wear is called "bone and joint degeneration", which is often called "long bone spur" Bone spurs are actually "wrinkles" that grow out of bone aging. The joints of the elderly are uneven, and there will be a "rubbing sound" during exercise, and the wear of the joint surface will cause pain. When synovitis occurs, there will be joint effusion, which is often called osteoarthritis.

The aging of bones is generally that the major joints are damaged first, and the knee joint is the largest joint of human beings. Long-term strain will be damaged first, so there is a saying that "people get old first."

In addition, the degeneration of bone and joint often occurs in the parts with heavy load such as lumbar spine and hip joint.