Osseointegration of bone cement

Details

Supervisors

Demoustier-Champagne, Sophie ; Tran Duy, Khanh

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical

Abstract

PMMA bone cement has been used for decades in surgical procedures. However, it does not meet all the medical requirements and possesses a significant rate of failure and complications. These include aseptic loosening in hip replacement, dislodgement in vertebroplasty and persistent infections of cranial implants, among others. Nevertheless, all these failures have a common root: a fibrous encapsulation. But, the latter does not appear with osseointegrable materials. In fact, osseointegration leads to a direct contact between the implant and the surrounding bone. On top of reducing the rate of failure of the bone cement applications cited above, producing an osseointegrable bone cement, usable as cranial implant, is very promising to improve the perspectives of cranioplasty in young children whose the skull keeps growing. In this paper, after a review of the literature about the potential materials usable as osseointegrable bone cements, it has been decided to investigate the loading of PMMA with osseointegrable fillers. This has been performed for the purpose of producing an cranial implant with mouldable capability and different cranial implant designs are suggested to optimise to the use of such bone cement. Tricalcium phosphate (TCP) granules are used as fillers and mechanical tests have been carried out on cements containing different amounts of them, ranging from 15 % to 60 % by weight in powder. The presence of cytotoxic unreacted MMA monomers has been analysed thanks to Raman and FTIR spectroscopies. Post-heating, allowing to lower the amount of residual monomers, has been investigated as well. It significantly improves the mechanical properties, by reducing the amount of monomers acting as plasticiser. The mechanical properties obtained are suitable for a cranial implant, independently of the amount of fillers. Therefore, bone cement consisting of PMMA with TCP fillers is promising as cranial implant in a first phase and potentially for arthroplasty and veterbroplasty afterwards. Nevertheless, the fillers exposure on the surface still needs to be improved and in-vivo osseointegration testing should be carried out to optimise the bone cement.