title: Performance of bioactive PMMA-based bone cement under load-bearing conditions: an in vivo evaluation and FE simulation.
abstract: In the past, bioactive bone cement was investigated in order to improve the durability of cemented arthroplasties by strengthening the bone-cement interface. As direct bone-cement bonding may theoretically lead to higher stresses within the cement, the question arises, whether polymethylmethacrylate features suitable mechanical properties to withstand altered stress conditions? To answer this question, in vivo experiments and finite element simulations were conducted. Twelve rabbits were divided into two groups examining either bioactive polymethylmethacrylate-based cement with unchanged mechanical properties or commercially available polymethylmethacrylate cement. The cements were tested under load-bearing conditions over a period of 7 months, using a spacer prosthesis cemented into the femur. For the finite element analyses, boundary conditions of the rabbit femur were simulated and analyses were performed with respect to different loading scenarios. Calculations of equivalent stress distributions within the cements were applied, with a completely bonded cement surface for the bioactive cement and with a continuously interfering fibrous tissue layer for the reference cement. The bioactive cement revealed good in vivo bioactivity. In the bioactive cement group two failures (33 %), with complete break-out of the prosthesis occurred, while none in the reference group. Finite element analyses of simulated bioactive cement fixation showed an increase in maximal equivalent stress by 49.2 to 109.4 % compared to the simulation of reference cement. The two failures as well as an increase in calculated equivalent stress highlight the importance of fatigue properties of polymethylmethacrylate in general and especially when developing bioactive cements designated for load-bearing conditions.
authors.affiliation: Department of Orthopedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Campus Grosshadern, Marchioninistraße 15, Munich, 81377, Germany. andreas.fottner@med.uni-muenchen.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Fottner
authors.affiliation: InnoTERE GmbH, Pharmapark Radebeul, Meissner Str. 191, Radebeul, 01445, Germany.
authors.forename: Berthold
authors.initials: B
authors.lastname: Nies
authors.affiliation: Department of Orthopedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Campus Grosshadern, Marchioninistraße 15, Munich, 81377, Germany.
authors.forename: Denis
authors.initials: D
authors.lastname: Kitanovic
authors.affiliation: Department of Orthopedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Campus Grosshadern, Marchioninistraße 15, Munich, 81377, Germany.
authors.forename: Arnd
authors.initials: A
authors.lastname: Steinbrück
authors.affiliation: Department of Orthopedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Campus Grosshadern, Marchioninistraße 15, Munich, 81377, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Mayer-Wagner
authors.affiliation: Department of Orthopedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Campus Grosshadern, Marchioninistraße 15, Munich, 81377, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Schröder
authors.affiliation: InnoTERE GmbH, Pharmapark Radebeul, Meissner Str. 191, Radebeul, 01445, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Heinemann
authors.affiliation: Walter Brendel Center of Experimental Medicine, Marchioninistr. 27, Munich, 81377, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Pohl
authors.affiliation: Department of Orthopedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Campus Grosshadern, Marchioninistraße 15, Munich, 81377, Germany.
authors.forename: Volkmar
authors.initials: V
authors.lastname: Jansson
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D001843:Bone Cements / Q000737:chemistry*; D005269:Femur / Q000601:surgery; D020342:Finite Element Analysis; D005898:Glass; D006622:Hip Prosthesis; D008422:Materials Testing; D009985:Orthopedics; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D011817:Rabbits; D013314:Stress, Mechanical; D016474:Weight-Bearing
chemical_list: D001672:Biocompatible Materials; D001843:Bone Cements; D019904:Polymethyl Methacrylate