In Vitro and in Vivo Characterization of Premixed PMMA-CaP Composite Bone Cements

Shant Aghyarian, Elizabeth Bentley, Thao N. Hoang, Izabelle M. Gindri, Victor Kosmopoulos, Harry K.W. Kim, Danieli C. Rodrigues

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Abstract

Acrylic bone cements, although successful in the field of orthopedics, suffer from a lack of bioactivity, not truly integrating with surrounding bone. Bioactive fixation is expected to enhance cement performance because of the natural interlocking and bonding with bone, which can improve the augmentative potential of the material in applications such as vertebroplasty (VP). In a recent study, two composite cements (PMMA-hydroxyapatite and PMMA-brushite) showed promising results demonstrating no deterioration in rheological and mechanical properties after CaP filler addition. In this study, the dynamic properties of the cements were investigated in vitro and in vivo. The hypothesis was that these composite cements will provide osseointegration around the implanted cement and increase new bone formation, thus decreasing the risk of bone structural failure. The effects of CaP elution were thus analyzed in vitro using these cements. Mass-loss, pore formation, and mechanical changes were tracked after cement immersion in Hank's salt solution. PMMA-brushite was the only cement with a significant mass loss; however it showed low bulk porosity. Surface porosity increases were observed in both composite cements. Mechanical properties were maintained after cement immersion. In vitro culture studies tested preosteoblast cell viability and differentiation on the cement surface. Cell viability was demonstrated with MTT assay and confirmed on the cement surface. ALP assays showed no inhibition of osteoblast differentiation on the cement surface. In vivo experiments were performed using a rat tibiae model to demonstrate bone ingrowth around the implanted cements. Critical size defects were created and then filled with the cements. The animal studies showed no loss in mechanical strength after implantation and increased bone ingrowth around the composite cements. In summary, the composite cements provided bioactivity without sacrificing mechanical strength.

Original languageEnglish
Pages (from-to)2267-2277
Number of pages11
JournalACS Biomaterials Science and Engineering
Volume3
Issue number10
DOIs
Publication statusPublished - 9 Oct 2017

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Keywords

  • PMMA
  • calcium phosphate
  • composite
  • composite bone cement
  • fracture augmentation
  • osseointegration
  • premixed bone cement
  • vertebral compression fracture
  • vertebroplasty

Cite this

Aghyarian, S., Bentley, E., Hoang, T. N., Gindri, I. M., Kosmopoulos, V., Kim, H. K. W., & Rodrigues, D. C. (2017). In Vitro and in Vivo Characterization of Premixed PMMA-CaP Composite Bone Cements. ACS Biomaterials Science and Engineering, 3(10), 2267-2277. https://doi.org/10.1021/acsbiomaterials.7b00276