Orthopedic surgeons often find it necessary to use bone graft material to fill in holes, defects, and gaps in bone. The most common reasons bone grafting are needed include fractures that don’t heal and surgical procedures that require removal of bone. Most of the time, it’s best to use the patient’s own bone as the donor graft materials. That’s called an autogenous bone graft.
In this article, two surgeons from the University of Cincinnati College of Medicine offer other surgeons a complete review of autogenous bone grafts. They cover topics such as when to use them and why to use them. They also discuss how to perform a collection and graft and then what to watch out for in the way of complications or problems.
With almost a quarter of a million bone grafts performed each year in the United States, this information is timely and helpful. Autogenous bone grafts are preferred over bone from a bone bank. The patient’s own bone won’t be rejected so it is said to be histocompatible.
Bone is taken most often from the pelvis because it is easy to access and it has different types of bone cells (e.g., osteoclasts, osteoblasts). The bone collected there is biologically active and stays alive long enough to create more bone cells. That’s important in order to have fast bone remodeling. Having both types of bone cells also means the graft site will stable immediately.
Donor bone can be taken from other areas such as the upper or lower part of the tibia (lower leg bone), radius (forearm bone) near the wrist, and the outer portion of the hip. With any autogenous bone grafts, there can be problems. The authors provide a detailed look at the pros and cons of each bone graft site.
The biggest disadvantage for any bone graft site is pain at the donor site. In fact, many patients say the donor graft site was the worst part of the entire procedure! Other complications of bone grafts include deep infection (which can cause graft failure), nerve damage, hematoma (pocket of blood), and bone fracture at the donor site. The surgeon can prevent graft failure with proper handling of the graft material. It must be kept moist and used right away whenever possible.
There are new ways now to prepare the graft site to make it “graft-friendly.” A special kind of cement is used to help foster bone growth once the graft in place. When the area of bone needing a graft is already infected, the donor graft can be mixed with antibiotic. Studies show this method can get rid of the infection in up to 96 per cent of patients.
Sometimes where and how bone is harvested depends on the volume (how much) of bone is needed. For smaller amounts of bone collection, the surgeon can scrape enough bone to use. This technique is called curettage. When larger amounts of bone graft material are needed, the surgeon may have to harvest bone from more than one place. Special tools have been developed for this procedure. For example, a reamer-aspirator-inspirator or IRA can get to deeper bone.
This is a fairly new technique so the authors describe when and how to use it in detail for other surgeons. The reamer is faster making operative time (and cost) less. In addition to the other types of complications already mentioned, the use of this tool adds its own potential problems.
The amount of blood lost during this procedure can be excessive, too. The reamer itself can malfunction during the procedure or get stuck in the bone canal. Failure to control the tool can also result in bone fracture. The surgeon can use fluoroscopy (real-time X-rays) to observe the path of the reamer and see where there are places of bone too thin to harvest.
One final bone graft technique is presented in this article called induced membranes. This is a two-stage procedure, which means two separate operations four to six weeks apart. It is used for large bone defects where there is infection or a complete failure to heal.
In the first operation, the surgeon removes infected or necrotic (dead) bone. The hole or gap that remains is filled with a cement spacer to provide stability. The body starts to make its own tissue (called pseudomembrane) to fill in the hole.
The pseudomembrane doesn’t harden into bone so a graft is still needed. The graft placement is the second procedure. The defect or hole is filled in with autogenous bone graft. The pseudomembrane is left in place because it contains cells that will protect the graft and promote rapid integration of the graft material. It’s a win-win situation.
The first study published on the induced membrane technique was in 2010 so more research will be needed before this becomes a standard bone graft procedure. Surgeons will find this article full of information about old (standard) ways of doing bone grafts as well as an update on the newer approaches. The authors of this review conclude that surgeons must remain familiar with when to use bone grafts, how to perform each technique, and the possible complications of each type.