Primary and long-term stability of a short-stem hip implant.
The new generation short-stem hip implants are designed to encourage physiological-like loading, to minimize stress-strain shielding and therefore implant loosening in the long term. As yet there are no long-term clinical studies available to prove the benefits of these short-stem implants. Owing to this lack of clinical data, numerical simulation may be used as a predictor of longer term behaviour. This finite element study predicted both the primary stability and long-term stability of a short-stem implant. The primary implant stability was evaluated in terms of interface micromotion. This study found primary stability to fall within the critical threshold for osseointegration to occur. Longer term stability was evaluated using a strain-adaptive bone remodelling algorithm to predict the long-term behaviour of the bone in terms of bone mineral density (BMD) changes. No BMD loss was observed in the classical Gruen zones 1 and 7 and bone remodelling patterns were comparable with hip resurfacing results in the literature.
Medical Device Research Australia, Suite 202, 121 Alexander Street, Crows Nest, NSW 2065, Australia. dane.d@mdresearch.com.au
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Dabirrahmani
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Hogg
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Kohan
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Gillies
D000368:Aged; D000369:Aged, 80 and over; D001698:Biomedical Engineering; D015519:Bone Density; D016723:Bone Remodeling; D002102:Cadaver; D003198:Computer Simulation; D019544:Equipment Failure Analysis; D020342:Finite Element Analysis; D006622:Hip Prosthesis; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009038:Motion; D011474:Prosthesis Design; D013314:Stress, Mechanical; D013997:Time Factors