Knee replacement can be done at the age of 75 if the body can tolerate the surgery without contraindications. Knee replacement is mainly used to treat severe joint pain, significant limitation of joint movement and joint deformation caused by osteoarthritis, rheumatoid arthritis and traumatic arthritis. Knee replacement surgery can be performed for those who are in good health and can tolerate the surgery. If you are 75 years old, you will not be able to tolerate surgery if you have serious cardiopulmonary disease, serious osteoporosis, excessive obesity, and serious muscle atrophy. Therefore, whether 75 years old can do knee replacement needs a comprehensive assessment by the doctor, according to the condition to decide whether the operation can be done.