Micromotion measurement at the interfaces of cemented tibial endoprosthetic replacements: A new standardized in vitro model using open-cell rigid foam

• Published in: Medical engineering & physics Vol. 119; p. 104027
• Main Authors: Fölsch, Christian, Ulloa, Carlos Alfonso Fonseca, Harz, Torben, Schirmer, Julia, Glameanu, Cosmin, Scherberich, Jan, Krombach, Gabriele, Rickert, Markus, Martin, John Ryan, Kühn, Klaus-Dieter, Jahnke, Alexander
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2023
• Subjects: Cementation technique; Interface cement-bone and implant-cement; Loosening knee arthroplasty; Micromotion; Open-cell rigid foam; Cementation technique; Interface cement-bone and implant-cement; Open-cell rigid foam; Micromotion; Loosening knee arthroplasty
• ISSN: 1350-4533; 1873-4030
• DOI: 10.1016/j.medengphy.2023.104027

•Open-cell rigid foam is a suitable in vitro model for cemented implantation of arthroplasties.•Micromotion measurement differentiates fixation strength at different regions of the implant.•Effect of different load directions on micromotion of implants can be measured.•Influence of single parameter on cementation technique and cement quality can be shown in vitro.•This in vitro model measured accurate and reproducible results of micromotions at interfaces. Early aseptic loosening following primary total knee arthroplasty related to several factors might appear at the interface implant-cement or cement-bone. A standardized in vitro model might provide information on the relevance of single variable parameter of cementation including technique and cement respectively bone structure on fixation strength. Micromotion measurement using different directions of load should detect the primary stability of the interfaces. An open-cell rigid foam model was used for cementation of PFC-Sigma tibial trays with Palacos®. Pins were applied to the model for continuous non-destructive measurement. Relative micromotions for rotation, valgus-varus and extension flexion stress were detected at the interfaces as well as cement penetration was measured. The reproducibility of the measurement could be shown for all interfaces in extension-flexion movements. For rotation a negative trend was shown for the interface cement-prosthesis and cement-bone concerning varus-valgus stress reflecting varying surgical cementation technique. More micromotion related to extension-flexion force might reflect the design of the implant. Measurement of relative micromotion and cement distribution appear accurate to detect small differences of movement at different interfaces of cemented tibial implants and the results are reproducible for most parameter. An increased number of specimens should achieve statistical relevance for all measurements.