How does a broken bone rebuild the damaged area?

Answer: Living repair cells form new tissue and bone across the break

A separate replacement bone grows beside the broken one — The body normally repairs the existing bone rather than growing a separate replacement beside it. A temporary thickened callus around the fracture can look like extra bone, but it is part of the repair and is remodeled over time.

The broken surfaces stick together without making new tissue — Bone healing requires new tissue, not just the original surfaces sticking together. Stability helps repair cells bridge the break, and the newly formed bone is later reshaped.

Living repair cells form new tissue and bone across the break ✓ — Living cells rebuild the fracture site by making new tissue and bone. In typical callus healing, a clot is followed by a soft bridge of repair tissue, then harder bone; remodeling continues after the break has joined.