Document Detail

Effect on the femur of a new hip fracture preventive system using dropped-weight impact testing.
MedLine Citation:
PMID:  9844113     Owner:  NLM     Status:  MEDLINE    
To reduce hip fractures during falls, we devised a new hip fracture preventive system to attenuate impact on the greater trochanteric region and studied the effects of the system on the femur. Twelve coupled, embalmed, cadaveric femora were used. Right femora were fractured without protection as a control and compared with left femora covered by the protection system, which consisted of a silicone gel pad or the silicone gel pad combined with a resin cover. The impact of a fall was simulated by mounting a femur in the horizontal plane and dropping an 8.4 kg mass on its greater trochanteric region. The impact load and time were measured using a load cell within the mass. The maximum strain during impact at the inferior side of the femoral neck was determined from an attached strain gauge. Trochanteric fractures were produced in 18 of the 24 femora (75%). The mean impact load for a drop height of 25 cm was reduced from 3117 N to 2176 N by silicone gel (p < 0.01) and to 1681 N by the addition of the resin cover (p < 0.01). The mean maximum strain was similarly reduced from 2276 microvarepsilon to 1872 microvarepsilon (p = 0.15) and to a mean 1559 microvarepsilon (p < 0. 05). The mean impact time was prolonged from 13 ms to 20 ms (p < 0. 01) and 22 ms (p < 0.01), respectively. The effect of the cover became more conspicuous as height increased. We concluded that the silicone gel pad provided effective impact attenuation, and the addition of the rigid cover was even more effective for impact reduction. This system was thought to be clinically useful in preventing hip fractures.
H Okuizumi; A Harada; H Iwata; N Konishi
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research     Volume:  13     ISSN:  0884-0431     ISO Abbreviation:  J. Bone Miner. Res.     Publication Date:  1998 Dec 
Date Detail:
Created Date:  1999-02-03     Completed Date:  1999-02-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8610640     Medline TA:  J Bone Miner Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1940-5     Citation Subset:  IM; S    
Department of Orthopaedic Surgery, Chubu National Hospital, Obu, Aichi, Japan.
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MeSH Terms
Absorptiometry, Photon
Aged, 80 and over
Bone Density
Femur / physiology*
Hip Fractures / pathology,  prevention & control*
Middle Aged
Physiology / methods
Stress, Mechanical
Weight-Bearing / physiology*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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