Prototyping of Costume Made Implants based on PMMA-Hydroxyapatite Composite

ANDRES OZOLS,; MATIAS FABRIZIO; RICARDO GREGORUTTI; ULISES GILABERT; CARLOS AUTORINO; MARCELO. BERLI; ANDRES OZOLS

Ciudad Autónoma de Buenos Aires

Conferencia; 6th International Conference on Science and Technology of Composite Materials; 2015

Instituto de Polímeros y Nanotecnología

The number of surgeries that required the bone fragment replacement, articular joint reconstruction, healing bone infections (employing joint spacers), saving the function of legs after catastrophic damage, reconstruction of vertebral bodies, between other issues, is steadily increasing. The solutions require the design and moulding of costume made prosthesis (CMP), when standard implants are not available. CMP are designed from the information provided by 3-D medical imaging, segmentation process, and construction of CAD meshes. These are employed to stereo-lithographic printing, copying in silicone rubber, or computer numeric control machining in aluminium alloys, which are used as moulds for injecting composite cements. They are frequently polymethyl methyl acrylate (PMMA), methyl acrylate, bioceramic (BC) and antibiotics blends with polymerize at temperature lower to antibiotic denaturation temperature. CMP are usually reinforced with AISI 316 L steel or Ti bars or Ti meshes. Additional strengthening are achieved with biphasic BC irregular particles (less than 45 µm size), combination of hydroxyapatite (HA) and β-tricalcium phosphate. These arrest crack propagation in polymeric matrix, as is observed by electronic microscopy and three bending tests of PMMA-xBC combinations (x is wt. %), which reach a maximum elastic modulus of 2.8 GPa at x ꞊ 40 %. Also, BC provides an additional source of water soluble antibiotics, absorbed inside, for their elution once implanted, and after different sintering temperatures (900-1200 °C) of BC. The fatigue resistance of PMMA hip spacer reinforced with Ti is evaluate at compared the spacer without BC. The clinical functionality of large bone, hip and knee spacers and cranioplasties is tested in different patients, showing the success of developments.