A bone graft is a surgical procedure to transplant bone tissue. Surgeons use bone grafts to fix problems with bones or joints, to repair and rebuild diseased bones in your hips, knees, spine, and sometimes other bones and joints. Bone grafting or transplanting of bone tissue is beneficial in fixing bones after trauma, some fractures, problem joints, or growing bone around implanted devices, such as total knee replacement (TKR).
The bone used in a bone graft can come from your own body, from a donor, or could be entirely manmade. Once accepted by the patient, the bone graft provides a framework for growth of new, living bone.
The two most common types of bone grafts are:
- Allograft: Most allograft bone comes from donors who have died. This graft uses bone from the deceased donor or a cadaver that has been cleaned and stored in a tissue bank Tissue banks screen these donors and disinfect and test the donated bone to make sure it is safe to use.
- Autograft: this graft is made from a bone inside a patient’s body, such as the ribs or hips
The graft for allograft is not taken from your own body, so it does not contain any living cells and has fewer chemicals to stimulate growth of new bone. The advantage to using allograft is that you do not have to donate the bone graft. This makes the surgery shorter, and there may be less pain afterward. The allograft carries a very small risk of transferring infectious diseases even though it is rigidly tested.
Why is Bone Grafting Performed?
Bone grafting is done for numerous reasons, including injury and disease. There are four main reasons bone grafts are used:
- Fractures—in the case of multiple or complex fractures or those that do not heal well after an initial treatment, a bone graft is recommended
- Fusion—it helps two bones heal together across a diseased joint, most often in the spine
- Regeneration—used for bone loss due to disease, infection, or injury, which involves using small amounts in bone cavities or large sections of bones
- Implanted devices—a graft can be used to help bone heal around surgically implanted devices, like joint replacements, plates, or screws
Bone grafting is used in two main ways during orthopedic procedures:
- To stimulate the bone to heal
- To provide support to the skeleton by filling gaps between two bones
Stimulate Bone Healing
The bone graft is used to stimulate and speed the bone healing process. In the case of Allograft bone graft, tissue is placed around a fracture or a fusion site with chemicals in it to stimulate the nearby bones to heal. Chemicals like BMP (Bone morphogenic protein) is added to bone graft to enhance bone growth when added to a fusion site. If the bone is taken from your own body, as in Autograft, the osteocytes (living bone cells) that survive being transferred to the new location continue to do their work of making new bone.
Provide Support to the Skeleton
Bone graft is also used for structure, when larger pieces of bone are used to fill a gap between two bones. Because bone is rigid, it will hold the vertebrae apart while the body grows to the ends of the graft. With time the entire piece of bone that was grafted will be replaced by your body with new bone. The time it takes to fuse depends on the size of the piece of bone that was used. It is sometimes a slow process that may take several years.
The Risks of a Bone Graft
All surgical procedures involve risks of bleeding, infection, and reactions to anesthesia. Bone grafts carry these and other risks, including:
- nerve injury
- rejection of the bone graft
Preparation for Bone Grafting
Your orthopedic physician will perform a complete medical history and physical examination.
The doctor will ask you about any medications, over-the-counter drugs, or supplements you’re taking.
Unless it is an emergency surgery, you will most likely be required to fast before surgery, to prevent complications while you’re under anesthesia.
It is important to follow instructions from your doctor about what do to the days before and the day of your surgery.
How a Bone Graft Is Performed
Your doctor will discuss and determine the best type of bone graft for you.
You will be given general anesthesia, prior to surgery, which will put you into a deep, peaceful sleep. An anesthesiologist will monitor the anesthesia and your recovery.
Your surgeon will make an incision in the skin above where the graft is needed. He or she will then shape the donated bone to fit the area. The graft will be held in place using various pins, plates, or screws.
Your surgeon will close the incision wound with stitches and bandage the wound, once the graft is securely in place. A cast or splint will be used to support the bone while it heals.
Typical recovery from bone grafts depends on the size of the graft and other variables but can take anywhere from two weeks to three months.
- You will probably need to avoid vigorous physical activity for up to six months.
- Icing and elevating the area involved in the grafting can help prevent painful inflammation.
- During recovery, you should exercise as recommended by your physician or therapist to prevent muscle atrophy.
- Maintain a healthy diet, which will aid in the recovery process.
The Illinois Bone & Joint Institute has more than 90 orthopedic physicians, and 20 locations throughout Chicago.