That's a question you and your orthopedic surgeon will have to answer together. But when elbow pain is so bad it actually interferes with the things you want or need to do, the time may be right.
Elbow replacement may be an option when nonsurgical interventions such as medication and physical therapy no longer help alleviate the persistent pain. Other possible signs such as: aching in the joint, followed by periods of relative relief; pain after extensive use; reduced elbow motion; joint stiffness after periods of inactivity or rest; and/or pain that seems to increase in humid weather may also lead you and your doctor to consider an elbow replacement surgery.
Your primary care doctor may refer you to an orthopedic surgeon who will help you determine when or if it's time for elbow surgery and which type of elbow surgery is most appropriate. Your surgeon may decide that elbow replacement surgery is not appropriate if among others you have an infection, you do not have enough bone, or the bone is not strong enough to support an artificial elbow.
Doctors generally try to delay total elbow replacement for as long as possible in favor of less invasive treatments. However, if you have advanced joint disease, you and your doctor may evaluate elbow replacement for a chance to relieve pain and return to normal activities.