Yes. Unfortunately, hip replacement can become loose or wear out with time. While most last decades, some need to be redone much sooner. Almost all hips can be revised if necessary, but the surgery is more complex and often doesn't come out as well as the first time.
Yes. A revision or "redo" of a previous hip replacement can be performed. A problem that leads to the potential need for a revision surgery should be evaluated by an orthopaedic surgeon specializing in joint replacement.