It's true that over 250,000 total knee replacements are done each year. This number is growing because the population of aging people is growing. Older adults are living longer. They are more active and want to stay active.
Joint damage and degeneration is common with aging. Medications and exercise can help. But there comes a time when the joint is rubbing bone against bone. This kind of severe osteoarthritis is very painful and limiting. A joint replacement may be the best and only answer.
New technology and better understanding of anatomy has given us improved joint implants. Surgery is faster and easier on the patients. In some places patients can go home within 24 hours of the operation. Recovery at home is usually faster and more comfortable than in a hospital.