My twin brother is having an ankle fusion because of some terrible damage done to the bones in a car accident years ago. I hate to ask him too many questions when he’s already down. Can you explain to me why he has to have a metal plate and screws if they are using bone graft material to fuse the joint. Why would he need both?

Bone grafting is often used with severe fractures and/or the need to fuse a joint because it provides a basic structure called a scaffold.

Basically that means the bone graft as a scaffold functions like a garden trellis. But instead of plant vines climbing up and around the structure and filling in the holes, it’s bone cells. This process occurs in several stages.

In the first few weeks, the bone graft does its job of encouraging bone cells to form and fill in around it. Then the second phase begins. The new bone cells develop their own blood supply. That takes another four to eight weeks.

Then in the final phase, the new bone cells integrate with the bones of the body (in this case, your brother’s ankle bones) to create a strong, supportive structure. When used to fuse a joint, the intended goal is to stop all motion by filling in the joint with solid bone.

Fixation with hardware such as metal plates, screws, pins, and wires is a process called instrumentation. These devices provide support and stability until the fusion is solid and hardened. Putting weight on the bones while the bone graft is trying to fill in could disrupt the bone graft and prevent proper healing.