Explore Bone Grafts: Purpose, Process & Types

Bone grafting refers to transplanting healthy human bone from one part of the body to repair and rebuild damaged or diseased bone in another part of the body. The bone graft acts as a scaffold or framework for the growth of new, healthy bone.

Sometimes, the bone used for a bone graft is obtained from another person (a living human donor), a deceased person (cadaver), or an animal such as a cow or pig. In addition, there are synthetic (man-made) bone substitutes and materials that can be used for bone grafting.

For example, a dental bone graft involves placing natural or synthetic bone graft material in an area of bone thinning or bone loss in the jaw before placement of dental implants. A surgeon might also use the transplanted bone to close a large defect in a badly fractured bone to aid healing.

Reasons for Bone Grafting

Medical and Dental Applications

Bone grafting surgery may be done for the following reasons:

To repair a broken bone and help a bone fracture heal.
To treat delayed unions, malunions, or nonunions of bone fractures (bones that don’t heal properly).
To treat bone diseases, such as osteonecrosis; areas of malignant tumor invasion (bone cancer); or bone infections, such as osteomyelitis.
To stabilize the spine with spinal fusion surgery.
To restore skeletal integrity in areas of missing bone.
To correct areas where congenital bone defects exist (defects present since birth), such as an abnormally small chin or uneven limb length.
To promote bone growth around surgically implanted devices and artificial joints, such as in total knee replacement.
To strengthen the jaw with a dental bone graft before replacing missing teeth with dental implant surgery.

Benefits of Bone Grafting

Bone grafts promote the body’s natural bone healing process. Benefits of bone grafts include:

Strengthen weak bones.
Repair broken bones.
Replaces missing bone.
Support a broken bone.
Stimulate bone growth to bridge gaps.
Promote bone fusion in areas of bone defects.

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Types of Bone Grafts

Autograft (Autologous)

An autograft is a bone graft done using your own bone tissue from another part of your body. A common donor site is the iliac crest (upper part of the hip bone). The advantage of autografts (also called autologous or autogenous bone grafts) is that there is a higher chance of successful fusion of the donor bone. However, only a limited amount of bone can be collected. Also, you may have pain at the donor site from where the bone graft is collected.

Allograft

A bone allograft is bone tissue that comes from another person (donor). There are strict guidelines to collect, clean, sterilize, and transport donated bone tissues to ensure safety. Allograft bone is commonly used in spinal surgery to fuse joints. The bone graft essentially provides a scaffold or framework on which natural bone grows.

Synthetic Bone Grafts

Synthetic bone grafts or bone graft substitutes are made from various types of artificial calcium materials called ceramics. In terms of consistency and shape, synthetic bone grafts resemble autograft bone. However, the advantage is that because they are synthetic materials, they are available in large quantities.

A bone substitute may also contain proteins to support new bone formation. But they don’t contain any cells that can become bone cells. Therefore, they must be combined with other materials for bone development to occur and successful bone graft surgery.

Demineralized Bone Matrix

Demineralized bone matrix (DBM) is bone that has been processed to remove the naturally occurring mineral calcium from the graft material completely. This bone graft material serves as an important source of protein for successful bone healing. However, like synthetic bone grafts, there are no cells in DBM that can form bone tissues. It must be combined with other bone grafting materials. Demineralized bone matrix only serves as a scaffold for bone to grow.

Bone Marrow Aspirate

Bone marrow is the spongy tissue inside bones. It contains osteoprogenitor cells and stem cells that can develop into living bone cells as well as either human growth factors or proteins to help in healing broken bones. To perform this type of procedure, the surgeon obtains a sample of bone marrow from the iliac crest (hip bone). The aspirate is either used alone or mixed with other bone graft materials such as autograft, allograft, or synthetic bone to promote tissue regeneration and new bone growth.

Learn more: What is a Bone Marrow Biopsy?

Other Bone Grafts (e.g., Xenograft)

Xenografts are tissues transplanted from one species to another. They are less commonly used compared to autografts and allografts because of less consistent results and more frequent graft rejection because of tissue incompatibility. Possible donor species include bovine (calf) and porcine (pig) bone.

Bone graft alternative

Biologics or Bone Protein

Bone morphogenetic protein (BMP) is a naturally occurring human protein that can naturally stimulate bone growth. It has been used in spine fusions and is one bone grafting option. BMP reduces surgery time and allows a quicker recovery. The powerful bone-forming properties of BMP may, however, cause excessive bone growth in unintended areas and increase cancer risk. Talk to your surgeon about the risks versus benefits of BMP if this is an option for you.

Procedure and Preparation

Pre-Surgery Preparation

Your surgical team will give you detailed pre-surgical instructions to prepare for bone graft surgery. This might include:

Additional imaging tests such as X-rays, MRI (magnetic resonance imaging), or CT (computed tomography) scans.
Stopping certain medications such as blood thinners; some examples include aspirin, warfarin, rivaroxaban (Xarelto), apixaban (Eliquis), and others. You will receive detailed instructions from your care team regarding what medications should be placed on hold and when.
Smoking cessation to aid healing.
Not eating or drinking anything after midnight the night before the surgery.
Arranging for aftercare and living arrangements after the surgery (you may not be allowed to put weight on the area until it heals).

How Bone Grafting is Performed

A team of healthcare professionals led by an orthopedic surgeon or specialist in oral and maxillofacial surgery will do your bone grafting procedure. The exact details of the procedure will depend on the reason for the surgery. Generally speaking, the steps are as follows:

Induce anesthesia. You will be asleep during the procedure and won’t feel any pain.
Monitor vital signs, such as heart rate and blood pressure.
Clean the surgical site and make an incision (cut) in the skin and muscle to harvest (collect) the bone tissues from the donor site in case of an autograft.
Clean and prepare the area that will receive the bone graft.
Place the bone graft where two pieces of bone need to fuse or grow together.
Secure the bone graft with screws, rods, or plates, if needed.
Perform other repairs.
Close the layers of skin and muscle at the donor and recipient sites.

Post-Surgery Recovery and Aftercare

Hospital Stay: You may go home the same day or stay 1 or 2 nights in the hospital, depending on the extent of your injuries and other medical conditions.
Pain Control: There can be some pain after the bone graft surgery. This can usually be managed with pain medicines. However, some over-the-counter pain medicines can interfere with the healing of bone, so be sure to check with your healthcare team before taking something for pain.
Diet: Most people can resume a normal diet soon after the procedure. You will receive nutritional counseling. A diet high in calcium and vitamin D can help bones heal.
Return to Activity: Your surgeon will give you detailed instructions on the movement of the treated area. You may need to keep it immobile and avoid putting weight on it for a period of time. Your doctor may place you in a splint or brace.
Physical Therapy: You may need physical therapy to regain muscle strength and flexibility.
Medications: Your healthcare provider may prescribe a blood thinner to prevent blood clots after your surgery. They may also give you antibiotics to prevent infection.
Smoking Cessation: You will need to stop smoking in the postoperative period. Smoking can delay bone and wound healing.
When to Seek Care: You will get instructions on when to call your surgeon. For example, if you have increasing pain, redness, swelling, or drainage of pus at the surgical site, loss of sensation, or high fever.
Follow-Up: Keep all your follow-up appointments with your surgeon. They may order imaging tests to check if the bone graft was successful. You may also need to have the stitches removed.

Risks and Considerations

Possible Side Effects

Expected side effects after bone grafting include tenderness, swelling, bruising for 1-2 weeks. These side effects can usually be managed with over-the-counter pain relievers.

Potential Risks and Downsides of Bone Grafting

Bone grafting is a generally safe procedure, and most bone grafts heal without problems. But like all surgeries, the procedure carries certain risks. Rarely, people who undergo bone grafting can develop complications such as:

Bleeding
Blood clots
Infection from the surgical procedure
Very rarely, infection from donated bone
Nerve damage
Complications related to anesthesia

Additional risks include poor healing of the bone graft. This is more likely in people who smoke or have diabetes. Specific risks will depend on various factors such as your age, general health status, underlying medical conditions, type of bone graft, and severity of injuries or condition being treated.

Common Questions About Bone Grafting

How Painful is a Dental Bone Graft?

Dental bone grafts cause little to no pain. Post-procedure discomfort can usually be managed with over-the-counter pain relievers. Call your dental professional if you have severe or worsening pain after dental bone grafts.

How Long Do Dental Bone Grafts Take to Heal?

Initial healing of dental bone grafts takes 1-2 weeks. However, it can take up to one year for a dental bone graft to heal completely.

How Long Does a Dental Bone Graft Last?

Dental bone grafts are done to support dental implants and are designed to last a lifetime. However, dental bone grafting may shrink and the donor tissue may become less dense if you don’t get an implant to replace a missing tooth within 6-12 months of a dental bone graft. For this reason, your dentist will recommend dental implant placement soon after tooth extraction, gum tissue treatments, and dental bone grafting.

Does Bone Grow Back After a Bone Graft?

Yes, bone grows back after a bone graft. The harvested bone from the donor site acts as a scaffold or foundation for new bone cells to grow and replace the damaged or missing bone.