Physical and mechanical characterization of a porous cement for metaphyseal bone repair.
OBJECTIVE
Macroporous cement with mechanical properties similar to cancellous bone may improve the treatment of large bone defects in relation to solid acrylic cement. The aim of this study was to compare physical and mechanical characteristics of a polymethyl methacrylate (PMMA) based porous cement with cancellous bone.


METHODS
Compressive strength and pore size, interconnectivity, and distribution of cylindrical porous PMMA cement samples containing 10% (G1), 20% (G2) or 30% (G3) effervescent components were analyzed. Results were compared to bovine cancellous bone (G4) and solid PMMA (G5) samples.


RESULTS
Scanning electron microscopy (SEM) of all experimental samples (G1 - G3) revealed a random distribution and a wide size variation of pores ranging from 50 µm to 3 mm. Micro-CT showed that G2 have high porosity and lower interconnectivity of pores. No significant differences in yield strength and Young's modulus were observed among G1, G2 and G3. G4 samples were slightly stronger and less elastic than the other groups. Solid PMMA is extremely strong and inelastic.


CONCLUSIONS
PMMA based porous cement met the expected characteristics. High porosity with large and interconnected pores may allow for bone ingrowth. Strength and elasticity similar to cancellous bone may enhance mechanical stimuli to bone remodeling. Observational Descriptive Study.
Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Laboratory of Bioengineering, Ribeirão Preto, SP, Brazil.
Bruno
B
Cimatti
Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Laboratory of Bioengineering, Ribeirão Preto, SP, Brazil.
Edgard Eduard
EE
Engel
Universidade de São Paulo Faculdade de Medicina de Ribeirão Preto, Division of Radiology and Diagnostic Imaging, Ribeirão Preto, SP, Brazil.
Marcello Henrique
MH
Nogueira-Barbosa
Instituto Federal de Educação, Ciência e Tecnologia, Campus Catanduva, SP, Brazil.
Paulo Donato
PD
Frighetto
Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Laboratory of Bioengineering, Ribeirão Preto, SP, Brazil.
José Batista
JB
Volpon
Bone neoplasms; Bone substitutes; Bone transplantation; Polymethyl methacrylate