NEW YORK (Reuters Health) – Hip protectors designed to absorb and disperse energy are not effective for preventing hip fracture among nursing home residents, according to trial results reported in the Journal of the American Medical Association for July 25.

In fact, the study was terminated after 20 months due to lack of effectiveness, Dr. Douglas P. Kiel, from Harvard Medical School in Boston, and his associates report.

In their paper, the investigators explain that most hip protectors either divert the energy of a fall using a hard shell or absorb the energy of a fall by using foam padding.

For the Hip Impact Protection Project (HIP PRO), Dr. Kiel and associates evaluated a hip protector that both diverts and absorbs energy. It is made of an outer layer of polyethylene over a hard polyethylene shield and backed by ethylene vinyl acetate foam.

The protectors were worn on only one hip, so that each patient would serve as his or her own control, Dr. Kiel’s group explains. The trial involved 1042 nursing home residents in 37 nursing homes. Mean age of the subjects was 85 years and most had significant cognitive impairment. Physical functioning and mobility varied widely.

Overall adherence to protocol was high at 73.8%. After 20 months, there were 2470 documented falls and 38 hip fractures. The incidence of fractures did not differ significantly between padded and unpadded sides (3.1% versus 2.5%).

Nursing home staff reported that, among those wearing the hip protectors at the time of the fracture, 13 occurred on the protected hips and 7 on the unprotected hips.

Despite the discouraging results of the HIP PRO project, Dr. Pekka Kannus and Dr. Jari Parkkari aren’t ready to give up on the search for truly effective hip protectors.

Writing in a related editorial, Drs. Kannus and Parkkari, both from the UKK Institute for Health Promotion Research at Tampere, Finland, recommend additional research to determine the biomechanical force attenuation capacity among different models, and controlled clinical trials to evaluate their anti-fracture efficacy.

"To help address the need for internationally recognized standards for biomechanical and clinical testing of hip protectors, Canadian researchers are now organizing a large International Hip Protector Research Group," the editorialists note.

They assert that "the importance of … falls and hip fractures among older adults should make the work a compelling ongoing priority for health research throughout the world."

JAMA 2007;298:413-422,454-455.

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