The largest joint in the body is the knee, and many Americans' knees are not doing well. 

More than 600,000 knee replacements are performed each year. Knee pain is the most common complaint of joint pain or joint stiffness. Approximately 18 million patients seek medical care because of knee pain each year. 

The villain of knee pain is osteoarthritis (OA). One of the five leading causes of disability among older women and men in knee osteoarthritis. Other than arthritis that causes knee pain, there are other causes. 

The following are the cause of knee pain. 

Age

Arthritis of the knee is prevalent among adults 45 years and older. It increases with age due to wear and tear experiences, making it more prone to knee pain. The degeneration of joints is the characteristic of osteoarthritis.

Gender 

Women over the age of 50 are more likely to develop knee OA than men, and women over the age of 65 are twice as likely. Before age 50, men tend to have OA more than women. These differences may be related to less knee cartilage volume and more significant cartilage wear in women. 

Repetitive Movement

There is evidence that OA is associated with occupations and activities that involve repetitive stress. Assembly-line workers, miners, dock workers, and those who install floors or carpets have a higher rate. Lifting or moving objects that weigh more than 25 pounds as little as one day per month or repetitively kneel or squatting can cause osteoarthritis. 

Obesity

Approximately 70 million adults in the U.S. are obese, and this is directly attributable to obesity. Having 10 pounds overweight puts an extra 15 to 50 pounds of pressure on your knees. The excess weight makes it more likely to develop OA and makes OA worse if you already have it.