Auswirkung der Schwingstrecke und des Platten-Winkels einer Doppelplatten-Osteosynthese in einem ovinen Tibia-Defektmodell - eine Finite-Elemente-Analyse

Background Segmental defects of the bone occur mainly as a result of therapy for osteomyelitis, pseudarthrosis, resection of tumors and from complex fractures. The critical sized defect (CSD) is characterized by its inability to heal without treatment within the lifespan of an animal. Ovine tibial defect models have been established for the study of CSD. Bone healing depends on biomechanical stimulation in the fracture gap. In this regard, the healing process can be influenced by scaffolds or implants. For non-load bearing properties, these often require additional osteosynthetic stabilization. Objectives The aim of this study was to determine a biomechanically optimized plate osteosynthesis of a CSD in the ovine tibial defect model for non-load bearing scaffolds that minimizes the risk of implant failure and still stimulates bone healing. Design and Methods Finite element analysis was performed in Abaqus 2018 (Dassault Systèmes). An ovine tibial defect model with a diaphyseal CSD (4 cm) was modeled according to the CT slice imaging performed. Twenty-four osteosynthesis models with double-plate osteosyntheses (DPO) with 120° or 40° plate angle with locking plates (3.5 mm LCP) were compared with single-plate osteosynthesis (4.5 mm LCP) with axial loading at 2000 N and torsion at 25 Nm. The models differed by plate length, plate-to-bone distance, number of screws and plate working length. Results Single-plate osteosynthesis in a CSD resulted in implant failure within the first loading cycles. In the DPO, the 120° configuration resulted in an 12.9 times higher shear stiffness and 39% higher torsional stiffness than the 40° configuration. Extending the plate working length of the DPO by 13 mm using longer osteosynthesis plates reduced shear stiffness by 6.3% and torsional stiffness by 17.1%. When the swing distance was increased by the same length by removing the innermost two screws, shear stiffness was reduced by 12.4% and torsional stiffness by 18.1%. Conclusion The main factor influencing the biomechanics of the DPO is the plate angle. In addition, the plate working length also has an substantial influence. The DPO allows a more homogeneous axial deformation in the defect gap, which can stimulate secondary bone healing as well as reduce the risk of implant failure. A large plate angle may result in high stiffness, which hinders adequate stimulation of secondary bone healing. The optimized biomechanical osteosynthesis of a 4 cm CSD was obtained by 40° DPO with 11- and 12-hole plate, 12 screws, with plate working length of 74 cm and 0.3 mm plate-to-bone distance.

Author dc:creator

• Becker, Luis Alexander

• finite element analysis
• double plate osteosynthesis
• plate working length
• critical sized defect
• ovine tibial defect model

Licence dc:rights.uri

• http://www.fu-berlin.de/sites/refubium/rechtliches/Nutzungsbedingungen

Language dc:language

ger

Identifier URI

http://dx.doi.org/10.17169/refubium-32004

OAI record oai:identifier

https://refubium.fu-berlin.de/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Arefubium.fu-berlin.de%3Afub188%2F32277