Ways to Heal Broken Bones : Part 3

by Food and Drug Administration (FDA)

(Page 3 of 3)

Healing Helpers

FDA has approved seven electrical bone growth stimulators, mainly for fractures at the middle of long bones, such as the shinbone (tibia), that have not healed over at least nine months. Although exactly how the stimulators heal is unknown, manufacturers' studies showed the devices did in fact affect cellular processes.

Yahiro explains that loading (stressing) a bone produces in it a small electrical field called piezo electric force, believed to stimulate new bone formation. "It's believed that electrical stimulation does something like that on a large scale," he says.

For direct stimulation, an electrode is implanted at the fracture, linked through the skin to a generator. For indirect stimulation, electric coils outside the limb on the non-fracture side induce an electrical field at the fracture side.

In 1994, FDA approved the first ultrasound bone growth stimulator. The Sonic Accelerated Fracture Healing System (SAFHS) is for adults with small fractures in the lower leg or lower forearm. A cast or splint is used. It is the first stimulator for the treatment of fractures occurring within seven days before treatment. Studies suggest that mechanical forces of the ultrasound waves transform into electrical impulses as they travel through the tissues.

The SAFHS consists of a portable generator cabled to a small, square treatment module that emits ultrasound pulses at about the same low intensity as sonogram fetal monitors. In some instances, the patient may use the unit at home. Recommended treatment is 20 minutes once a day until the fracture heals.

The SAFHS is not for patients who need additional fixation or surgery, are pregnant or breast-feeding, have bone disease or circulatory problems, or take medicines that may adversely affect remodeling.

In studies, all treated patients — and especially older people — healed faster than those using a placebo. In those age 50 and older, arms healed 40 days faster, and legs 85 days faster. Six years' follow-up did not suggest long-term adverse effects.

Stimulation, grafts, manipulation, joint replacements, casts. Whatever the treatment, fracture healing is monitored by x-rays and physical examination to answer such questions as: Does it hurt or move when pushed on? On x-ray, does the fracture look healed? On x-ray, are the bones aligned?

For Wallace, healing is now complete. She is indeed walking again, using a cane as she did before the replacement surgery.

"If I don't use the cane, my leg aches," she says. "I'm still careful to use my good leg stepping up a curb, and my bad leg stepping down, like I learned in therapy."

Boning Up

The most important influences on fracture healing are nutrition and overall health, including bone health, before the injury, says orthopedist Martin Yahiro, M.D., a consultant to FDA. "That's why it's so important all your life to do weight-bearing exercise such as walking and get enough calcium and vitamin D, so you lay down as much bone as possible during growth and keep as much as you can later on."

The Recommended Dietary Allowance (RDA) for calcium is 1,200 milligrams a day for people ages 11 to 24 and for pregnant or breast-feeding women. For men and women older than 25 who no longer have to meet the greater demands of growth, the calcium RDA is 800 milligrams a day.

In general, genes decide bone shape and size. But mechanical stress by muscle, body weight, and physical activity influence bone shape and density — and health — throughout life.

Simply put, loaded (stressed) bone strengthens, and unloaded bone weakens. As examples, astronauts' bones weaken in outer space with no gravity pull on them, and the shaft of the humerus (long upper arm bone) in a professional tennis player's dominant arm gets denser and thicker from the extra load.

The body increases its bone mass until, usually, the mid-30s, after which a gradual loss begins.

Age-related bone loss can lead to osteoporosis, a condition of thin, weakened bone that fractures easily. The condition affects many postmenopausal women, because bone loss increases with menopause due to lower estrogen levels.

In announcing its recent approval of Fosamax and Miacalcin Nasal Spray for osteoporosis, FDA advised that patients also exercise and get adequate calcium and vitamin D. Drugs approved by FDA to prevent or treat osteoporosis are:

• estrogen — Premarin, Ogen, and Estrace tablets; Estraderm patch
• estrogen packaged with progestin hormone tablets — Prempro; Premphase
• alendronate — Fosamax
• calcitonin — Miacalcin Nasal Spray, Calcimar Injection, Miacalcin Injection, and Cibacalcin for injection.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.