Definition & Overview
Bone grafting is a surgical technique in which bone tissue is transplanted to repair damaged bones and joints and stabilise an implanted device. The bone used in the procedure can be taken from the patient’s body or a donor. In some cases, however, synthetic biocompatible bone is used. The key to a successful bone graft is for the body to accept the transplanted bone. Given the bone’s natural ability to regenerate, the natural bone will eventually replace the bone graft completely.
Who Should Undergo and Expected Results
Bone grafting can be recommended for patients suffering from bone damage or bone loss, which may occur due to injury or disease. These include:
- Complex or multiple fractures
- Any bone injury that does not heal properly
- Dental injuries
- Diseased joints, which is treated using a procedure called arthrodesis or fusion
- Severe injuries
- Bone cysts
- Bone tumours
- Dental infections
- Tooth decay leading to tooth extraction or missing tooth
- Periodontal disease
Bone grafting is also used to provide structural support for implanted devices, such as plates, screws, and even dental implants.
After a bone grafting procedure, the patient’s natural bone will continue with its natural regeneration process and will grow around the bone graft, which then integrates into the natural bone and absorbed by the body.
The recovery process following a bone injury and a bone grafting procedure tends to be long. Most patients begin to gradually resume their normal activities after 2 weeks, but the graft usually takes up to 3 months to heal. The natural bone will also gradually heal and regenerate in a process that usually takes up to 6 months.
The prognosis for bone grafting patients is relatively good, with statistics showing that most bone grafts positively help bone defects heal with minimal risks of complications.
How is the Procedure Performed?
There are three main types of bone grafts used in grafting procedures. The appropriate type of bone to use is heavily influenced by the kind of injury or condition being treated. These three types are:
Autograft – An autograft is a piece of bone taken from the patient’s own body usually from the ribs, pelvis, hips, or wrist. The advantage of this option is that it is highly unlikely that the body will reject the transplanted bone. However, the patient has to undergo two different procedures in order to acquire and later on, transplant the bone. These procedures may take several months to complete, as there should be a time interval between the harvesting and the final transplanting procedure.
Allograft – An allograft refers to a bone taken from a deceased donor or a tissue bank. These are often used in procedures that repair or reconstruct the hips, knees, and the long bones, or the arms and legs. Since an allograft is readily available, the patient does not have to undergo an additional surgery for the acquisition of the bone. This also means the patient will have fewer incisions upon the completion of the procedure.
Synthetic bone – A synthetic bone is usually created using hydroxyapatite and other substances that are naturally occurring and biocompatible. This biocompatibility is important as it ensures that the body will reabsorb the substance so that the bone graft is eventually replaced as the patient’s natural bone begins to regenerate.
The specific method used in transplanting bone grafts also depends on which part of the body is involved. Bone grafting surgeries are also referred to as reconstructive or bone replacement surgeries, such as total knee or hip replacement or proximal tibial bone graft, among many others.
There are also three general areas of bone grafting, namely:
Osteogenic stimulation – To ensure the success of a grafting procedure, there should be enough bone in the transplant area so that new osteogenic cells may be formed. This means that treatment areas with active infection, severe scarring, bone gaps, and have undergone radiation therapy in the past are not good candidates for a bone graft procedure. In such cases, however, surgeons perform an osteogenic stimulation wherein bone-forming cells are also added to the graft site, either by injecting bone marrow tissue into it or creating a composite graft.
Osteoconductive stimulation – This can help ensure the success of a bone grafting procedure by giving bone cells a material they can attach as they heal. There are now several materials in use and in development that serve as the main osteoconductive material for a transplanted bone. This is usually necessary for procedures that use an allograft.
Osteoinductive stimulation – In an osteoinductive stimulation, the natural capacity of bones to grow and mature is stimulated.
Traditionally, bone grafting procedures are performed by making one large incision in the skin above the affected bone. The surgeon will then shape the bone graft to fit the donor area. Once in place, it will be secured using plates, screws, pins, cables, and wires. The surgeon then closes the incision with stitches. To protect the bone during the immediate recovery period, the patient will be advised to wear a cast.
Bone grafting can now also be performed using minimally invasive surgical techniques. In such procedures, no incisions are required, and the grafting is performed only through a needle. Despite this, traditional open surgery is still more commonly performed, and is also required in many transplantation cases to ensure that the graft is properly positioned.
Possible Risks and Complications
Bone grafting procedures come with a number of risks and possible complications, which include:
- Graft rejection
- Allergic reactions to medications
- Difficulty breathing
- Nerve injury
- Pain, which is usually stronger at the site where the bone graft was taken from
To prevent complications, patients are given strict instructions for caring for their bone graft post-surgery. It is important to keep the treated area clean and dry. Patients are also advised to refrain from smoking as it may slow down the natural bone healing process and increase the risk of a bone graft failure.
Frohlick M., Grayson W., Wan L. et al. (2009). “Tissue Engineered Bone Grafts: Biological Requirements, Tissue Culture and Clinical Relevance.” Curr Stem Cell Res Ther. 2008 Dec;3(4): 254-264. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2773298/
Arora S. “Minimally-invasive bone graft harvesting technique.” Am J Orthop. 2014;43(1):45-46. http://www.amjorthopedics.com/the-publication/issue-single-view/minimally-invasive-bone-graft-harvesting-technique-without-sophisticated-instruments/606c6e63019c9d171847b861f80b00cb.html