caa a22 4500 605458170 CHVBK 20210128100227.0 cr unu---uuuuu 210128e20151001xx s 000 0 eng 10.1007/s00167-015-3771-9 doi (NATIONALLICENCE)springer-10.1007/s00167-015-3771-9 Novel approach to dynamic knee laxity measurement using capacitive strain gauges [Elektronische Daten] [Martin Zens, Philipp Niemeyer, Anke Bernstein, Matthias Feucht, Jan Kühle, Norbert Südkamp, Peter Woias, Herrmann Mayr] Purpose: Knee joint laxities are observed in patients after severe trauma to the joint, resulting in ligament tears. Specifically, injuries to the anterior cruciate ligament may cause a significant instability. The degree of these laxities is essential in diagnostics and may affect which treatment option is suggested. Methods: Polydimethylsiloxane (PDMS) strain gauges are proposed as a non-invasive, highly accurate and easy-to-use measurement method to quantify anterolateral and rotational laxities of the knee joint during active and passive motion. In this work, proof-of-concept measurements and a prototype of the proposed device are displayed. The measurements were taken using a knee test rig, which has specifically been designed for this purpose. This apparatus allows the simulation of isolated knee joint instabilities with a motor-controlled model of a human knee. Results: The absolute sensitivity $$\frac{{\Delta C}}{{\Delta l}}$$ Δ C Δ l of an exemplary sensor was determined to be 2.038 $$\frac{\text{pF}}{\text{mm}}$$ pF mm ; the relative sensitivity $$\frac{{\Delta C}}{\varepsilon }$$ Δ C ε was 1.121 $$\frac{\text{pF}}{\% }$$ pF % . Optimal positions of sensors to capture bone-to-bone displacement as projected displacement on the skin were identified. Conclusion: PDMS strain gauges are capable of measuring bone-to-bone displacements on the skin. We present an experimental in vitro study using an artificial knee test rig to simulate knee joint laxities and display the feasibility of our novel measurement approach. European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA), 2015 Knee joint nationallicence Laxities nationallicence Strain gauges nationallicence ACL ruptures nationallicence Joint displacement measurement nationallicence Pivot shift nationallicence Zens Martin Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut Niemeyer Philipp Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut Bernstein Anke Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut Feucht Matthias Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut Kühle Jan Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut Südkamp Norbert Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut Woias Peter Department of Microsystems Engineering (IMTEK), Albert-Ludwigs-Universität Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany aut Mayr Herrmann Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut Knee Surgery, Sports Traumatology, Arthroscopy Springer Berlin Heidelberg 23/10(2015-10-01), 2868-2875 0942-2056 23:10<2868 2015 23 167 https://doi.org/10.1007/s00167-015-3771-9 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00167-015-3771-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zens Martin Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut NATIONALLICENCE 700 1- Niemeyer Philipp Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut NATIONALLICENCE 700 1- Bernstein Anke Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut NATIONALLICENCE 700 1- Feucht Matthias Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut NATIONALLICENCE 700 1- Kühle Jan Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut NATIONALLICENCE 700 1- Südkamp Norbert Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut NATIONALLICENCE 700 1- Woias Peter Department of Microsystems Engineering (IMTEK), Albert-Ludwigs-Universität Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany aut NATIONALLICENCE 700 1- Mayr Herrmann Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany aut NATIONALLICENCE 773 0- Knee Surgery, Sports Traumatology, Arthroscopy Springer Berlin Heidelberg 23/10(2015-10-01), 2868-2875 0942-2056 23:10<2868 2015 23 167