Normal bone renews itself by removing old bone and replacing it with new bone.
If too much old bone is removed and too little new bone is formed, bone loss can occur. I fracture a bone, I'll know it from the pain. For example, bones of the spine can fracture without causing pain. When the fracture does cause pain, it can be mistaken for arthritis. If you have back pain, it's important to find out if it's from osteoporosis so that it can be properly treated.