Presented in part at the American College of Veterinary Surgeons Symposium, Washington D.C., October 2009
Original Article - Research
Biomechanical Evaluation of Screw-In Femoral Implant in Cementless Total Hip System
Article first published online: 28 SEP 2011
© Copyright 2011 by The American College of Veterinary Surgeons
Volume 41, Issue 1, pages 94–102, January 2012
How to Cite
Kim, J. Y., Hayashi, K., Garcia, T. C., Kim, S.-Y., Entwistle, R., Kapatkin, A. S. and Stover, S. M. (2012), Biomechanical Evaluation of Screw-In Femoral Implant in Cementless Total Hip System. Veterinary Surgery, 41: 94–102. doi: 10.1111/j.1532-950X.2011.00890.x
- Issue published online: 23 JAN 2012
- Article first published online: 28 SEP 2011
- Manuscript Accepted: DEC 2010
- Manuscript Received: JUL 2010
To compare (1) proximal femoral axial strains, (2) femoral head deflection, and (3) failure mechanical properties, between Helica head and neck prosthesis implanted femora and normal femora.
In vitro study.
Cadaveric canine femora (n = 5 pair).
Femoral bone strains and head displacement during in vitro simulation of midstance of the gallop were evaluated using cadaveric femurs cyclically loaded in vitro. Strains and displacements were compared within femurs, before and after, prosthesis implantation; and throughout cycling to seek evidence of movement with cyclic loading. Subsequently, implanted femurs and contralateral, intact femurs were loaded to failure to compare failure mechanical properties and modes of failure.
Proximal femoral axial strains were significantly different between intact and implanted femora on all 4 cortical surfaces (P < .05). Compressive strains were lower in the implanted femur on all cortical surfaces, except on the caudal surface which was higher. No difference was noted for femoral head angle under an axial load corresponding to gallop (P > .05). Vertical head displacement was ∼0.1 mm greater for implanted femora than intact femora (P < .05). Yield and failure loads and yield energy of implanted femora were 39–54% lower than those for intact femora (P < .05). Mode of failure for both the intact and implanted femora did not appear to be different.
Helica femoral prosthesis alters strain distribution in the proximal aspect of the femur and exhibits initial micromotion. Failure load in axial compression of the Helica-implanted femur is less than that of the normal femur, but greater than that expected in vivo.