Bone health is important in both the ambulatory and non-ambulatory phases of Duchenne. People living with Duchenne at all ages have weak bones, especially if they are taking steroids. Steroids cause bones to have a lower bone mineral density, increasing the risk of fractures (broken bones) compared to the general population. Muscle weakness and decreased mobility are also risk factors for weak bones.

Dual energy X-ray absorption (DEXA) is a non-invasive test that measures bone mineral density of the long bones (usually the leg or arm). Thinner bone is less healthy and is more susceptible to fractures. Measuring your bone mineral density is important in monitoring overall bone health. It is recommended you have DEXA scans at least every 2 to 3 years.

People living with Duchenne, especially those taking steroids, are at risk for vertebral compression fractures. Vertebral compression fractures occur when vertebrae (the bones of the spine) sustain small fractures, causing them to become misshapen and to collapse on one another. These fractures, and resultant vertebral collapse, can cause pain. Vertebral compression fractures can be seen on a lateral (side view) spinal X-ray, even without having back pain. Vertebral fractures may be treated with bisphosphonates, especially if pain is present. It is recommended you have lateral spine X-rays every 1 to 2 years or more frequently if you experience back pain.

Bone is constantly being broken down, reabsorbed into the blood stream and rebuilt. Steroids slow down the rebuilding phase of bone growth. Bisphosphonates are medications that bind to the surface of bone, slowing down the breaking down and reabsorbtion process, helping bone to be built more effectively. This process keeps bones thicker and, hopefully, healthier and less susceptible to fracture. The use of bisphosphonates may be discussed if there are signs of decreased bone density, long bone fractures that occurs without significant trauma and/or vertebral compression fractures (see figure 6).