Dr. med. Philipp Heilig (Würzburg), Dr. Maximilian Heilig (Würzburg), Priv.-Doz. Dr. Sebastian von Hertzberg-Boelch (Würzburg), PD Dr. med. Martin Jordan (Würzburg), Prof. Dr. Uwe Gbureck (Würzburg), Prof. Dr. med. Rainer H. Meffert (Würzburg), Prof. Dr. Stefanie Hölscher-Doht (Würzburg)
Abstract-Text (inkl. Referenzen und Bildunterschriften)
Background: The use of polymethylmethacrylate cement for in-situ implant augmentation has considerable disadvantages: it is potentially cytotoxic, exothermic and non-degradable. Therefore, the primary aim of this study was to develop a magnesium phosphate cement which meets the requirements for in-situ implant augmentation as an alternative. Secondly, this experimental cement was compared to commercial bone cements in a biomechanical test set-up using augmented femoral head blades.
Methods: A total of 40 human femoral heads were obtained from patients who underwent total hip arthroplasty. After bone mineral density was quantified, specimens were assigned to four treatment groups. A blade of the Trochanteric Fixation Nail Advanced was inserted into each specimen and augmented with either Traumacem V+, Paste-CPC, the experimental magnesium phosphate cement or no cement. A rotational load-to-failure-test (0◦ to 90◦) was performed.
Findings: A conventional two-component magnesium phosphate cement failed in-situ implant augmentation consistently due to filter pressing. Only a glycerol-based magnesium phosphate paste was suitable for the augmentation of femoral head blades. While the blades augmented with Traumacem V+ yielded the highest maximum torque overall (22.1 Nm), the blades augmented with Paste-CPC and the magnesium phosphate paste also showed higher maximum torque values (15.8 and 12.8 Nm) than the control group (10.8 Nm).
Interpretation: This study shows for the first time the development of a degradable magnesium phosphate cement paste which fulfills the requirements for in-situ implant augmentation. Simultaneously, a 48% increase in stability is demonstrated for a scenario where implant anchorage is difficult in osteoporotic bone.
Fig. 1: Overview of specimen preparation steps: A guide wire and then the cannulated TFNA blade were inserted centrally in the femoral head. This was followed by augmentation of the blade with one of the three bone cements.