**4.10 Bone morphogenic proteins (BMPs)**

In orthopedics, recombinant BMPs were commonly used during distraction of long bones in order to accelerate osteogenic potentials, increase bone volume (both width and height), improve bone density, and reduce relapse possibilities. BMP-2 was commonly used with or without delivery systems as collagen sponge and chitosan hydrogel in sequential injections [75, 76] (**Figure 10**).
