Testing bone substitutes in a small animal model of revision arthroplasty
This study evaluated a modification of the rat-pin model to enable testing of bone substitute materials. The model was characterized using the ceramic, β-tricalcium phosphate (βTCP) as a filler. A 1 mm wide, 3.6 mm deep defect was created around a stainless steel (SS) implant in the proximal tibia of a rat. This defect was filled with a ceramic powder. Large particles (90–312μm) of βTCP were mixed with Gelfoam® to form a paste which was then molded around the proximal end of either an uncoated SS pin or a pin coated with hydroxyapatite (HA). The pin with its ceramic collar was then implanted into the proximal tibia of 16 male Sprague Dawley rats. Two animals with coated implants and two with uncoated implants were sacrificed at 3, 6, 14 and 26 weeks. Longitudinal sections of each tibia were stained with toluidine blue and labeled for tartrate resistant acid phosphatase (TRAP). There was initial fibrous tissue interposition around the implants which was completely remodeled around the HA coated pins but which persisted in apposition to the SS pins. The remodeling process peaked at 3 weeks around the HA coated pins and at 6 weeks around the uncoated implants. There was little remodeling around either implant by 26 weeks. There was considerable residual βTCP present which was well tolerated as the particles were often encased in bone. The model has several characteristics of revision arthroplasty and the results demonstrate the suitability of this model for testing bone substitutes.
KeywordsHydroxyapatite Toluidine Blue Proximal Tibia Bone Substitute Tartrate Resistant Acid Phosphatase
Unable to display preview. Download preview PDF.
- 1.B. N. Summers and S. M. Eisenstein, J. Bone Joint Surg.-Br. Vol. 71-B (1989) 677.Google Scholar
- 2.S. Louisia, M. Stromboni, A. Meunier, L. Sedel and H. Petite, J. Bone Joint Surg. Br. Vol. 81B (1999) 719.Google Scholar
- 7.T. Jensen, S. Overgaard, M. Lind, O. Rahbek, C. Bunger and K. Soballe, Bone 24 (1999) 428.Google Scholar
- 8.L. S. Beck, R. L. Wong, L. Deguzman, W. P. Lee, B. Ongpipattanakul and T. H. Nguyen, J. Pharmaceut. Sci. 87 (1998) 1379.Google Scholar
- 11.C. Niedhart, S. Koch, U. Maus, E. Redmann, C. H. Siebert and F. U. Niethard, Bone 24 (1999) 77.Google Scholar
- 14.R. Brooks, J. Sharpe, J. Wimhurst, B. Myer, E. Dawes and N. Rushton, J. Bone Joint Surg. Br. Vol. 82-B (2000) 595.Google Scholar
- 15.M. Allen, F. Brett, P. Millett and N. Rushton, J. Bone Joint Surg.-Br. Vol. 78B (1996) 32.Google Scholar
- 19.P. Laffargue, H. F. Hildebrand, M. Rtaimate, P. Frayssinet, J. P. Amoureux and X. Marchandise, Bone 25 (1999) S55.Google Scholar