Total joint replacements (especially hip and knee replacements) are fairly common in adults over the age of 65. They are rare (but not unheard of) in patients older than 100 years old. In those patients, it’s often a matter of what’s referred to as nonelective surgery. In other words, they probably broke their hip and have to have the surgery.
Whenever possible, surgeons will pin a broken hip in someone so old. Replacing the entire joint isn’t always needed. This is especially true for the person who is bed or wheelchair bound and no longer walking.
But for some of today’s senior seniors (90 years old and older), otherwise good health and mobility suggest the need for a joint replacement in order to maintain this status. Losing function and losing independence may not be an acceptable option for these folks.
And in the long run, joint replacement is actually cost-effective. Being upright and moving reduces the risk of many other health care problems that can be quite costly to treat (e.g., bed sores, blood clots).