Bones will often fix themselves following a fracture, but sometimes, with complex fractures, a bone graft is required to aid the healing process. Bone grafts are only really used when the fracture is particularly complex, pose a significant risk to the patient, or if the fracture fails to heal properly.
More than 2 million bone grafts are performed each year as a result of severe fractures. These fractures create a gap between two pieces of bone that is too big for the body toheal on its own. A problem though, with bone grafts is that healthy bone is not always available so it must be taken from other parts of the skeleton, usually the pelvis. These types of surgeries often lead to extensive pain, and long hospital stays. Not all grafts are successful. Sometimes, healthy bone is taken from a donor which means there is a risk of the new bone not integrating into the body properly, causing an unsuccessful graft.
A new method of treatment has been shown to work, involving gene and stem cell therapy. In the procedure, a matrix of collagen is implanted into the body where the fracture is, between the two pieces of bone. The procedure has been carried out for leg fractures in laboratory animals. The collagen matrix meant that the body’s stem cells were drawn to the site of the fracture over about two weeks. A bone-inducing gene was then delivered to the stem cells using ultrasound pulses that facilitated the entry of the gene into the stem cells.
After the surgery, it took the bone eight weeks to heal properly. The procedure was successful in every animal the team tested. There was no compromise in bone strength also, as the new bone was just as strong as the original bone.
This may mean that in the not so distant future, bone grafts may be the more high risk, almost ‘inferior’ procedure to the new ultrasound-mediated gene delivery method. Hopefully it won’t be too long before we see the results of the first human trials.