Bone formation is a complicated process that requires osteoblasts (bone forming cells) to be signaled to form bone. A scaffolding is necessary for the bone cells to form bone. The signaling of osteoblasts is called osteoinduction and the scaffolding is termed osteoconduction.

Stem cells in bone marrow have osteogenic characteristics; in other words they can become osteoblasts. When stem cells are placed in an environment that has the qualities of osteoinduction and osteoconduction then the stem cells become osteoblasts and begin forming bone. In order to provide an environment for bone to form that can heal a fracture site, surgeons must stabilize a fracture with internal fixation, external fixation or casting. This keeps the site from moving so quality bone can form.

The surgeons with the Bone Healing team utilize the principals of bone healing to provide the best environment for difficult to heal fractures. Percutaneous bone marrow injection to stimulate bone formation is a treatment option offered at the Denver Clinic. Autologous bone marrow is taken (aspirated) from a patient’s iliac crest (pelvic bone). This aspirate is mixed with a demineralized bone matrix that contains the osteoinductive and the osteoconductive properties necessary for bone to form. The mixture is injected into the nonunion site under fluoroscopic guidance.

X-ray of woman with a humerus (arm) fracture.	Her x-ray when she was referred to the Bone Healing program. The fracture has not healed despite internal fixation (intermedullary rod).

	Images showing the steps in preparing the stem cells for injection into the nonunion site. The bone marrow is being aspirated from the iliiac crest (pelvic bone).
	The bone marrow is mixed with the demineralized bone matrix.
	Bone marrow mixture is injected into the nonunion site.  This is done under CT guidance.

X-ray a few weeks after the stem cell injection. There is an area of increased bone formation where the stem cells were injected.	X-ray showing the nonunion site has healed and the intramedullary rod has been removed

This procedure is typically done in an outpatient setting and patients are able to continue with the same level of activity they were participating in prior to the procedure. The appropriate patient for this procedure is someone with a rigid (no motion) nonunion that isn’t infected.