University of Twente Student Theses


The development of a non-migrating knee orthosis

Boiten, D.A. (2020) The development of a non-migrating knee orthosis.

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Abstract:The use of knee orthoses has seen a large rise since the 70’s, since their use for sport related injuries became more accustomed. A frequent problem all orthoses share is that they have the tendency to slide down, however, the position of the orthosis is critical for it to fulfill its function correctly. The two causes of this migration of an orthosis are the conical shape of the leg and a mismatch between the hinges used in orthoses and the knee joint. The knee joint is a very complex joint which rotates using a combined rolling and gliding motion. The combination of these two motions causes the rotation axis of the knee joint to move along a pathway of rotation, primarily in the sagittal plane. In this project it was tried to create a nonmigrating knee orthosis for anterior cruciate ligament injuries firstly by designing a suspension system to solve the conical shape of the leg and secondly by creating a new hinge that follows the natural pathway of rotation to eliminate any mismatch with the knee joint. A suspension system was created by developing multiple concepts which were produced into prototypes. These prototypes were used to evaluate all the possible designs. After the first prototype evaluation some prototypes were improved and reevaluated. A final suspension system was chosen from these improved prototypes. The chosen system avoids any migration of the orthosis and also supports the correct positioning of the orthosis. The biggest challenge in designing a hinge that follows the natural pathway of rotation of the knee was that this pathway is unknown. Literature is very divided on this topic, so there does not exist a generally accepted pathway. In an attempt to find the correct pathway motion tracking experiments were conducted. The results of these experiments showed that the used method was not precise enough to be able to determine a reliable rotation pathway. The method was, however, used to compare the pathway of the knee motion of different hinge prototype with the natural situation. Two final hinge designs were created. The first imposes a rotation pathway on the knee and allows some variation from this pathway to adjust to individual pathways. The motion tracking comparison showed a slight deviation from the natural motion pathway, but the hinge could provide the needed support to the knee. The second design that was created left the rotation free. The motion tracking of this prototype showed that the natural motion pathway was followed, however, less support was provided to the knee. Each design performs well in different categories and would be suitable for different client types, since a client is not yet known no final choice between the two hinges was made.
Item Type:Essay (Master)
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Mechanical Engineering MSc (60439)
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