A worn-out knee, replaced.

Over years, arthritis can wear the smooth surface off a knee until bone rubs against bone. Walking, stairs and standing become painful, and simpler treatments stop helping.

A knee replacement resurfaces the worn joint with a smooth implant. For many people it brings lasting relief from that grinding pain and a return to comfortable, everyday walking.

Whether a replacement is the right step — and whether the whole joint or only part of it needs treating — is decided together, after the problem and the alternatives are explained.