I have heard that it isn't good to have a hip replacement when you are too young. Why is that? You would think that a younger person is healthier for surgery.
The age at which a hip replacement, or arthroplasty is ideally performed has not so much to do with the age of the patient in terms of health, but in terms of how well the artificial joint would stand up to the amount of time and use that a younger person would require.

Most younger people demand more from their hip joints than do most seniors. A younger person may want to continue to be able to ski, for example or to travel and frequently walk long distances. Researchers are working on developing stronger, more robust artificial joints, but the concern lies with having to replace the joint later on as the younger patients age.