Arthroplasty is the term used by doctors to describe surgery on a joint to replace it. If both sides of the joint are replaced, it’s called a total joint arthroplasty. When only part of the joint is removed and replaced, it’s called a hemiarthroplasty.
Hips, knees, and shoulders are the main joints that allow for a hemiarthroplasty. Most joint replacements are total. The decision is made based on the condition of the bone, joint, and cartilage.
The doctor uses X-rays and CT scans before the operation to help with this decision. A final decision is made when the joint is opened or viewed from the inside with an arthroscope.