Hand surgeon here. I’ve repaired my fair share of tendons.

I assume you’re referring to a surgery where a tendon is ruptured or cut, and needs repair.

Repairs are pretty straightforward. You make a cut, find both ends, and suture them together.

If a tendon tore from its attachment to the bone, you usually need to drill a hole into the bone and attach it with an anchor of some kind. (There are a wide variety of implants and techniques for this, so it’s hard to give more detail.)

Surgery is usually easier if you get it done sooner, so the tendon doesn’t retract or get covered with scar tissue.

Similarly, as soon as it’s safe, you’ll want to start gently moving, so the tendon doesn’t get stuck in scar tissue. Especially in hands!

If it isn’t clear, this is all very simplified, and is not a substitute for talking to a doctor in person if you think you need surgery!

If you give me a more specific question, I may be able to help you better.