The elbow is a hinge joint, which is made up of three bones:
The humerus (upper arm bone)
The ulna (forearm bone on the pinky finger side)
The radius (forearm bone on the thumb side)
The surfaces of the bones where they meet to form the elbow joint are covered with articular cartilage, a smooth substance that protects the bones and enables them to move easily. A thin, smooth tissue called synovial membrane covers all remaining surfaces inside the elbow joint. In a healthy elbow, this membrane makes a small amount of fluid that lubricates the cartilage and eliminates almost any friction as you bend and rotate your arm.
Muscles, ligaments, and tendons hold the elbow joint together.
In total elbow replacement surgery, the damaged parts of the humerus and ulna are replaced with artificial components. The artificial elbow joint is made up of a metal and plastic hinge with two metal stems. The stems fit inside the hollow part of the bone called the canal.
There are different types of elbow replacements, and components come in different sizes. There are also partial elbow replacements, which may be used in very specific situations. A discussion with your doctor will help to determine what type of elbow replacement is best for you.