Evaluation of Composites Comprising Spherical, Porous, Sintered β-Tricalcium Phosphate Particles and Cyanoacrylate as Bone Cement

Abstract

Bone cements based on polymethyl methacrylate (PMMA) remain the clinical standard for joint replacement and vertebral augmentation but suffer from several major challenges. These include excessive stiffness compared with cancellous bone, lack of resorption and osteoconductivity, and thermal necrosis during curing. Calcium phosphate cements (CPCs) are bioactive and resorbable but tend to exhibit low mechanical strength, poor injectability and brittle fracture. The work reported herein developed an injectable composite bone cement by combining spherical, porous, sintered β-tricalcium phosphate (β-TCP) particles with a cyanoacrylate adhesive. The β-TCP granules provided bioactivity and a favorable microarchitecture while the cyanoacrylate ensured strong adhesion and rapid setting. Ion substitution with Mg, Na and Si was found to modify the surface acidity of the material while also inhibiting cyanoacrylate polymerization, thereby extending the setting time and lowering the exotherm temperature. This composite exhibited high chemical stability, smooth injectability and early surface reactivity indicative of osteoconductivity. The compressive strength of the material stabilized at approximately 40 MPa and so exceeded that of cancellous bone. This new material also showed ductility, energy absorption and superior impact resistance, although its tensile and fatigue resistance remained limited. Importantly, the composite provided strength comparable to that of PMMA in cemented models during fixation tests and significantly outperformed CPCs in cementless tibial tray fixation experiments. These findings demonstrate that the present β-TCP/cyanoacrylate cement bridges the gap between PMMA and CPCs by combining injectability and mechanical reliability with bioactivity. This cement is therefore a promising next-generation option for minimally invasive osteoporotic fracture treatment and revision arthroplasty.

Affiliated Institutions

• Tokyo Metropolitan Industrial Technology Research Institute JP
• Chiba Institute of Technology JP
• Fukuyama University JP

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