A nonunion is a broken bone that has not healed. Most fractures—broken bones—will heal effectively with standard treatment in about 6 to 12 weeks. Between 5 and 10 percent, however, may fail to heal completely.
Nonunited fractures are different from malunited fractures; a fracture malunion occurs when a broken bone heals in an abnormal position.
When a bone breaks, the body immediately goes to work trying to heal it. Fractures heal in three stages:
In the inflammatory stage, blood and immune system cells rush to the area to begin the healing process. Immune cells clear out disrupted blood, bone fragments and other signs of damage. The area around the broken bone is flooded with blood, fluid and immune cells, resulting in inflammation. This stage peaks a few days after the injury, can last for weeks, and is responsible for most of the pain and swelling after a broken bone.
The repair stage overlaps with the inflammatory stage. The body builds a callus made of immature bone to stabilize the broken ends of bones. At first, this callus is soft and rubbery and doesn’t contain calcium. This is why the early stages of fracture healing don’t show up on an x-ray.
Eventually, the body enters the remodeling stage. That’s when calcium starts to enter the callus, and the callus becomes more mature bone tissue. This remodeling stage can last months, but when the fracture is fully healed it may be almost undetectable.
Nonunion of fractures happen when this process gets disrupted. Fractures need three things to heal:
A nonunion can happen if there is too much motion at the fracture site, if there’s an inadequate blood supply or if it is disrupted (such as if the injury that caused the fracture also severely damaged blood vessels in the area), or if the fracture doesn’t get enough nutrients such as calcium or vitamin D during healing, or any combination of these causes.
Certain lifestyle factors and types of injuries make a nonunion more likely to occur. Some of these can include:
Nonunion fractures that cause symptoms often need to be fixed. Some can be treated nonsurgically, whereas others will require surgery. Nonsurgical treatments for nonunion fractures can include:
Surgical treatment may be necessary if nonoperative treatment is ineffective. Surgical and nonsurgical treatment may also be combined. Many surgeons will treat nonunions by resetting the bone with internal fixation, using plates, screws or nails to keep the broken ends of the bone lined up with each other (reduced) and adding bone graft to improve healing at the fracture site.
One common technique is affixing a plate that spans the fracture and is held in place by screws on either side of the broken bone. Another is known as an intramedullary nail, which is a rod that’s inserted through the middle of a bone and unites the two broken ends.
If you have pain from a fracture that occurred longer than 6 to 12 weeks ago, you may have a nonunion or delayed union. Request an appointment at UOA. Our trauma and fracture specialists can determine why your fracture isn’t healing and take steps to repair it.