Our knowledge of orthopaedics. Your best health.

from the American Academy of Orthopaedic Surgeons

Diseases & Conditions



Staying Healthy



Some broken bones do not heal even when they get the best surgical or nonsurgical treatment. In some cases, certain risk factors make it more likely that a bone will fail to heal. When a broken bone fails to heal it is called a "nonunion." A "delayed union" is when a fracture takes longer than usual to heal.

Bone Healing


  • Blood supply. Blood delivers the components required for healing to the fracture site. These include oxygen, healing cells, and the body's own chemicals necessary for healing (growth factors). The blood supply to the injured bone usually comes back on its own during the healing period.
A broken bone stabilized with a plate and screws.



Risk Factors

Several factors increase the risk of nonunion.

  • Older age
  • Severe anemia
  • Diabetes
  • A low vitamin D level
  • Hypothyroidism
  • Poor nutrition
  • Infection
  • A complicated break that is open or compound

Blood Supply


  • Some bones, such as the upper thighbone (femoral head and neck) and small wrist bone (scaphoid), have a limited blood supply. The blood supply can be destroyed when these bones are broken.
  • Some bones, such as the shinbone (tibia), have a moderate blood supply, however, an injury can disrupt it. For example, a high-energy injury can damage the skin and muscle over the bone and destroy the external blood supply. In addition, the injury can destroy the internal blood supply found in the marrow at the center of the bone.



Doctor Examination

To diagnose a nonunion, the doctor uses imaging studies that provide detailed pictures of the bone and surrounding soft tissues. Depending on which bone is involved, these tests may include x-rays, computed tomography (CT) scans, and magnetic resonance imaging (MRI). Imaging studies let the doctor see the broken bone and follow the progress of its healing.


  • Persistent pain at the fracture site
  • A persistent gap with no bone spanning the fracture site




Nonsurgical Treatment

Some nonunions can be treated nonsurgically. The most common nonsurgical treatment is a bone stimulator. This small device delivers ultrasonic or pulsed electromagnetic waves that stimulate healing The patient places the stimulator on the skin over the nonunion from 20 minutes to several hours daily. This treatment must be used every day to be effective.

external bone stimulator


Surgical Treatment


  • Bone Graft. During this procedure, bone from another part of the body at the fracture site to "jump start" the healing process. A bone graft provides a scaffold on which new bone may grow. Bone grafts also provide fresh bone cells and the naturally occurring chemicals the body needs for bone healing.

    During the procedure, a surgeon makes an incision and removes (harvests) pieces of bone from different areas on the patient. These are then transplanted to the nonunion site. The rim of the pelvis or "iliac crest" is most often used for harvesting bone. Although harvesting the bone may be painful, the amount of bone removed usually does not cause functional, structural, or cosmetic problems.
bone graft from pelvis


    • Allograft (cadaver bone graft). An allograft (cadaver) bone graft avoids harvesting bone from the patient, and therefore, decreases the pain involved with treating the nonunion. Like a traditional bone graft, it provides scaffolding for the patient's bone to heal across the area of the nonunion. As time goes on, the patient's bone replaces the cadaver bone. Although there is a theoretical risk of infection, the cadaver bone graft is processed and sterilized to minimize this risk.




Nonunion treated with external fixator

An external fixator made of pins and wires stabilizes a nonunion of the tibia.

On the Horizon

To determine why a bone does not heal, scientists are investigating naturally occurring chemicals that the body needs for bone healing. These chemicals are called growth factors. When a bone breaks, they are normally produced in the body in a certain sequence. Other chemicals can decrease the chance of the bone healing. Researchers are concentrating on synthesizing these chemicals and determining the ideal way either to block the negative factors or increase the positive factors to the injured bone. Someday, physicians may be able to inject the chemicals directly into the nonunion to promote healing.

Last Reviewed

March 2014
