In the News: 10/05
Bioreactor Repair: Rebuilding Damaged Bones, Painlessly
A new process has shown that it’s now possible to kindle the growth of new bone within the body. What’s more, the new bone material can be used to repair damaged bone elsewhere in the body. Called In Vivo Bioreactor, the procedure—recently described in Proceedings of the National Academy of Sciences—is a dramatic departure from the current, often painful, practice of removing small pieces of bone from a patient’s leg or pelvis and fusing them to a fractured bone. It also differs from such experiments as in vitro engineering—attempts to grow bone outside the body, all of which have failed— and in vivo engineering, which has been successful in stimulating bone growth inside the body but is a complex and somewhat unreliable procedure.
Researchers at Vanderbilt University, who performed their experiment on rabbits (which have bones similar to humans), used the body’s natural wound-healing response by creating a tiny hole in a healthy bone’s outer layer and injecting the space with a calcium-based gel in hopes that the body would respond by filling the space with new bone. And it did so, producing new bone of comparable strength as native bone, in a period of about six weeks.
Further studies on large animals and clinical trials will be necessary to determine if the procedure will work on humans. In the meantime, it promises to now become possible to grow new bone for all types of repairs instead of removing it from existing bones.
Shed Pounds, Avoid Knee Stress
You’ve heard it here—and often—before: Lose weight and do those arthritic knees a favor. But what has always seemed like good, intuitive advice has now been proven. A recent study published in Arthritis & Rheumatism found that in people with knee osteoarthritis who averaged a body-weight loss of 5 percent, each pound lost produced a 4-pound reduction in pressure on the knee and an 18 percent improvement in knee function. Researchers tested 142 overweight and sedentary subjects with knee OA in a gait-analysis study and monitored their body-mass index and knee function at six and 18 months. Results showed that each pound of weight loss resulted in a fourfold reduction in the load exerted on the knee. The study’s authors concluded that modest weight loss and moderate exercise should be the cornerstone for treatment of knee OA. Although the combination of weight loss and exercise did nothing to lessen or halt the disease, the authors claim that, as a non-invasive approach, it is an effective way of treating knee OA.
Hip Protectors Not So Protective—Especially When Not Wearing One
Do hip protectors—plastic shields or foam pads held in place with specially designed underwear—really work? Two studies say no—but they have their problems. A much publicized U.K. study found no evidence that they’re of any help in preventing fractures. The study, which appeared in Osteoporosis International and is the largest trial ever conducted on hip protectors, monitored 4,169 women (1,388 wearing a hip protector, 2,781 not wearing the device) of an average age of 78 years. After a two-year follow-up, results showed no significant difference between the two groups in the odds of sustaining a hip fracture. Another study, conducted in Holland and reported in the Journal of the American Medical Association, examined 561 people who had a high risk of hip fractures, with 276 wearing the protectors and 285 going without. After 70 weeks, 18 of those wearing hip protectors had suffered fractures, compared to 20 of those in the control group, a finding that the study’s authors considered “negligible.”
But hold on. In both studies, compliance was poor, with only 31 percent of the participants in the U.K. study reporting they wore their hip protectors on a daily basis. Further, it wasn’t known whether participants were wearing hip protectors at the time of a fall. A low compliance rate also cast the Dutch study in doubt. Of the 18 people who experienced fractures, only four were wearing hip protectors at the time.
In comparison to these studies, most trials have produced mostly positive findings about the value of a hip protector. The takeaway lesson: If you have, or plan to invest in, a hip protector, wear it 24 hours a day. And take additional measures—exercise, fall-proof your home, wear sensible shoes, take calcium and vitamin D—while you’re at it.