Martin Zens1,2, Philipp Niemeyer3, Anke Bernstein3, Matthias J Feucht3, Jan Kühle3, Norbert P Südkamp3, Peter Woias4, Herrmann O Mayr3. 1. Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany. martin.zens@imtek.uni-freiburg.de. 2. Department of Microsystems Engineering (IMTEK), Albert-Ludwigs-Universität Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany. martin.zens@imtek.uni-freiburg.de. 3. Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, 79106, Freiburg, Germany. 4. Department of Microsystems Engineering (IMTEK), Albert-Ludwigs-Universität Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany.
Abstract
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 [Formula: see text] of an exemplary sensor was determined to be 2.038 [Formula: see text]; the relative sensitivity [Formula: see text] was 1.121 [Formula: see text]. 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.
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 [Formula: see text] of an exemplary sensor was determined to be 2.038 [Formula: see text]; the relative sensitivity [Formula: see text] was 1.121 [Formula: see text]. 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.
Authors: Martin Zens; Johannes Ruhhammer; Frank Goldschmidtboeing; Peter Woias; Matthias J Feucht; Herrmann O Mayr; Philipp Niemeyer Journal: J Biomech Eng Date: 2014-12 Impact factor: 2.097
Authors: Thomas P Branch; Hermann O Mayr; Jon E Browne; John C Campbell; Amelie Stoehr; Cale A Jacobs Journal: Arthroscopy Date: 2010-05-21 Impact factor: 4.772
Authors: Martin Zens; Philipp Niemeyer; Johannes Ruhhammer; Anke Bernstein; Peter Woias; Herrmann O Mayr; Norbert P Südkamp; Matthias J Feucht Journal: Am J Sports Med Date: 2015-08-11 Impact factor: 6.202
Authors: Karthika Sheeja Prakash; Hermann Otto Mayr; Prachi Agrawal; Priyank Agarwal; Michael Seidenstuecker; Nikolaus Rosenstiel; Peter Woias; Laura Maria Comella Journal: Polymers (Basel) Date: 2022-06-08 Impact factor: 4.967
Authors: Hermann O Mayr; Georg Hellbruegge; Florian Haasters; Bastian Ipach; Hagen Schmal; Wolf C Prall Journal: Arch Orthop Trauma Surg Date: 2021-12-06 Impact factor: 2.928