One of the most common causes of knee pain and loss of mobility is the wearing away of the cartilage lining. When this happens, the bones rub together causing significant pain and swelling - a condition known as osteoarthritis. Trauma and direct injury to the knee can also cause osteoarthritis.
Conservative treatments such as steroidal and nonsteroidal anti-inflammatory drugs, physical therapy and cortisone injections may effectively relieve pain and restore mobility. However, more severe pain and disability frequently require knee resurfacing surgery.