When a fractured (broken) bone does not heal, it is referred to as a "nonunion" fracture. Although most fractures eventually heal, either by themselves or with surgery, approximately 5 percent do not heal, or have difficulty doing so (referred to as a "delayed union"). In order to properly treat a nonunion fracture, determining its cause is essential. The most common causes of nonunion are infection; not enough blood flow to the bone; separation of the fractured ends of the bone; and insufficient stabilization of the fracture.
Any bone can sustain a nonunion fracture. However, because blood flow to them is poor, certain bones are more prone to nonunion fractures. They are the scaphoid, which is in the wrist; the talus, which is in the ankle joint; the femoral neck, which is just below the ball of the ball-and-socket hip joint; and the fifth metatarsal, which runs from mid-foot to the base of the small toe.
Treatment for a nonunion fracture varies, but may include surgery to remove infection and stabilize the fracture. Stabilizing the fracture typically incorporates either internal or external fixation. A bone graft may also be performed to speed up the healing process. Nonsurgical treatment may include using a bone stimulator. An external device that delivers ultrasonic or pulsed electromagnetic waves, a bone stimulator is placed over the site of the nonunion fracture and worn every day, in some cases for hours at time, in order to promote healing. Injections of bone marrow into the fractured area are another effective nonsurgical treatment. After treatment, healing of a nonunion fracture takes 3 or more months.