DEAR MAYO CLINIC:

Three years ago, when I was 17, I broke my collarbone. It healed quickly, but I still have a noticeable bump over the spot where the bone was broken. What's causing it, and will it go away eventually?

ANSWER:

Collarbone (clavicle) fractures usually heal quite well, and most do not require any surgical intervention. But it's not uncommon for a visible bump or bulge to remain at the fracture site after the bone has mended. This is a normal part of the healing process, and the bump will likely decrease and become less noticeable over time.

The collarbone connects the upper part of the breastbone (sternum) to the shoulder blade. A broken collarbone is a very common injury, particularly in children and young adults, because the collarbone doesn't harden completely until about age 20. Thus, people younger than 20 are at higher risk of a broken collarbone. In addition, young people are more likely to increase that risk by participating in sports such as football, basketball, soccer, wrestling, rugby, hockey, skiing and snowboarding. Sports injuries are among the most common causes of a broken collarbone. Other frequent causes are falls, and car, motorcycle or bike accidents.

The time required for a broken collarbone to heal depends on the severity of the injury. More severe fractures that cause the bones to be significantly out of position or result in an overlap of the broken bone fragments may require surgery to properly reposition them and promote healing. But most broken collarbones heal without surgery or complications within about six to 12 weeks for adults and about three to six weeks for children. An arm sling is generally all that's necessary to immobilize the bone for a short time to decrease discomfort and allow for healing. As in your situation, a bump may appear over the fracture site while the bone is healing, and it may remain afterward. This bump is a result of the process your body goes through to mend a bone.

When a bone is broken, the body produces fibrous tissue, called a bone callus, to protect the injured area. That's the bump you see. Then, bone cells begin to grow, reuniting and healing the bone segments that broke apart. Once the bone has mended, the bone callus is usually reabsorbed into the bone. The more extensive or severe the fracture, the more bone callus is produced during the healing process, and reabsorption can take more time. In some cases, the bump may never go away completely.

In your situation, as the bone matures, the callus likely will be remodeled gradually over time, decreasing the size of the bump and reducing its prominence. But you may always have a subtle bulge in the region of the fracture.

Fortunately, the strength of the bone in the area of a collarbone fracture usually returns to normal within a few months following the injury. Any remaining bone callus is harmless and won't have long-term effects on the healed bone or cause additional complications.

-- Edward Laskowski, M.D., Physical Medicine and Rehabilitation and Sports Medicine Center, Mayo Clinic, Rochester, Minn.

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