By Steve Smith
Our bones are constantly regrowing. They attain peak mass some time in our 20s before slowly getting weaker as we age. This increases many people’s risk of osteoporosis, a condition characterized by weak and brittle bones, and their subsequent risk of fractures from something as minute as a cough. To combat this decline in bone strength, researchers from France have developed an injectable foam that helps to repair bones.
Injectable calcium phosphate cements (CPCs) are often used in orthopedics and traumatology. They’re made of bioactive and biodegradable grafting materials that come in powder and liquid form. When mixed together, they create a calcium-like material similar to the calcium in our bones. This mixture allows surgeons to fix and harden degenerative bones over the course of their surgery with relative ease and flexibility. It’s also biocompatible, self-setting, and non-toxic. 
The new study, published in Acta Biomaterialia, builds on this material. Before, scientists had difficulty making CPCs macroporous, or having pores larger than 50 micrometers. While studies have found conflicting evidence regarding how porous bones should be to facilitate regrowth, the range seems to be between 100 and 300 micrometers — in people with osteoporosis, bones are far more porous.