We are more than a little concerned about our daughter. She’s eight years old and has a cast on her arm because she broke both bones in her forearm. The problem is it’s been six weeks and the X-ray doesn’t show enough healing at the break. Why not and what can we do about it?

Young children in good health are known to heal quickly. This is generally true for many conditions from bug bites to bone fractures. Some bone fractures can be complicated by infection or joint dislocation. Forearm fractures affecting both bones in the forearm (the radius and the ulna) can present some unique problems. A delay in union like your daughter has is one of those complications.

Uncomplicated bone fractures of the forearm usually show X-ray evidence of a healing bone formation called a callus at the fracture site four weeks after the injury. Complete healing is often present by the end of eight weeks. Failure to callus formation or healing at the fracture site by 11 weeks is a signal that there is a delay in bone union.

There are some known risk factors that can contribute to this problem in some children. Infection, surgery, dislocation, multiple bone fragments account for most of the delays in healing. Surgery to correct the problem can also be a significant risk factor. There is some evidence that open reduction is a strong predictor of delays in healing forearm fractures. Open reduction means that an incision is made and the bones are realigned. Then the bones are held in place with hardware such as a metal plate, screws, and/or pins.

Children with stable fractures who wae treated conservatively with a forearm cast are much less likely to develop delayed bone union. Children who have unstable fractures requiring open surgery are the patients most likely to have delayed bone healing.

With this type of surgical approach, there is more risk of damage to the periosteum (outer covering of bone) and/or blood vessels in the area. Disruption of either of these anatomic features could contribute to the delayed healing observed with open reduction.

There may be other risk factors already identified that are specific or unique to your child. Your surgeon is probably the best one to give you an idea why this is happening (if there is a known reason). Sometimes there is no obvious reason. Other factors such as nutrition may be important. You may want to bring this up to your surgeon and possibly address any nutritional deficiencies in the next few weeks.