Ask the Doctors 10/5

Dear Doctor: I tripped on a curb and hit the pavement pretty hard. I didn’t break a bone, but after a few days, the area around my knee started to hurt and got very sensitive. I’m told this is a bone bruise, which is a term I’ve never heard. What is it, and how long will it take to heal?

Dear Reader: A bruise is a traumatic injury that results in localized damage to tissues within the body. And, although we’re most familiar with bruises to the skin and soft tissues, it turns out that bones can sustain bruises as well. The concept of a bone bruise arose when sensitive scans, such as an MRI, made it possible to visualize subtle areas of damage to bone tissue that don’t appear on an X-ray.

This type of bruise occurs when some kind of force, such as your fall onto hard pavement, results in damage to the structure of the bone. You can also get a bone bruise playing contact sports, in a motor vehicle collision and from a physical altercation. Conditions such as arthritis, in which the ends of the bones are not protected, can also result in a bone bruise.

Also known as a bone contusion, a bone bruise is not as severe as a fracture. Instead of a complete break in the continuity of the bone, it is marked by a localized area of microfractures. Depending on the type and severity of the bruise, these can involve one or more of the three layers of tissue that make up our bones. Unlike in a fracture, however, which requires the bone to be stabilized in order to heal, someone with a bone bruise can usually continue with their daily activities.

Symptoms of a bone bruise include pain and tenderness that you began to notice a few days after your fall. Direct pressure on the area often causes significant pain. Someone with a bone bruise may experience swelling or stiffness in the affected joint, the appearance of a hard lump and changes to skin and tissue color. Diagnosis includes a physical exam and a detailed description of how the injury occurred. Although the damage from a bone bruise won’t appear on an X-ray, your health care provider may request one in order to rule out a fracture.

Treatment typically begins with resting the affected limb. This includes keeping it raised above the level of your heart for a few hours per day in order to reduce swelling. The use of a brace to limit range of motion may also be recommended. Over-the-counter medications, such as acetaminophen, are usually adequate for pain. You may be asked to increase the protein, calcium and vitamin D in your diet to promote healing. Smoking impedes bone healing, so you’ll be advised to stop.

Because a bone bruise isn’t readily visible, it can be tempting to ignore the injury as soon as the pain begins to fade. However, this can slow the healing process, which takes at least one to two months. If your bone bruise fails to heal, it’s important to follow up with your health care provider.

Send your questions to askthedoctors@mednet.ucla.edu.