The possible causes of knee pain in the elderly include meniscus injury, chronic synovitis, osteoporosis and so on. 1. Meniscus injury: with age, the elderly meniscus is prone to degenerative changes, the elasticity becomes weaker, a slight external force can cause meniscus injury, resulting in elderly people with inner knee pain. 2. Chronic synovitis: may be the accumulation of perennial joint strain or acute synovitis treatment is not complete transformation of chronic synovitis, mostly in the elderly, joints often swelling and pain and other symptoms, may cause pain in the inner side of the knee of the elderly. 3. Osteoporosis: Osteoporosis is caused by the loss of calcium in the body of the elderly due to ageing, resulting in a decrease in bone density and bone quality. The knee is an important weight-bearing joint in the human body, and when osteoporosis occurs in the elderly, the inner side of the knee will hurt. There may be other causes of knee pain in the elderly, if the pain is not relieved or progressively aggravated, it is recommended to go to a regular hospital in time to improve the relevant examinations, to clarify the cause of the disease, under the guidance of the doctor for targeted treatment or therapy.