Design of a reverse shoulder implant to measure shoulder stiffness during implant component positioning

  • To avoid dislocation of the shoulder joint after reverse total shoulder arthroplasty, it is important to achieve sufficient shoulder stability when placing the implant components during surgery. One parameter for assessing shoulder stability can be shoulder stiffness. The aim of this research was to develop a temporary reverse shoulder implant prototype that would allow intraoperative measurement of shoulder stiffness while varying the position of the implant components. Joint angle and torque measurement techniques were developed to determine shoulder stiffness. Hall sensors were used to measure the joint angles by converting the magnetic flux densities into angles. The accuracy of the joint angle measurements was tested using a test bench. Torques were determined by using thin-film pressure sensors. Various mechanical mechanisms for variable positioning of the implant components were integrated into the prototype. The results of the joint angle measurements showed measurement errors of less than 5° in a deflection range of ±15° adduction/abduction combined with ±45° flexion/extension. The proposed design provides a first approach for intra-operative assessment of shoulder stiffness. The findings can be used as a technological basis for further developments.

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Author:Nikolas Förstl, Franz Süß, Carsten Englert, Sebastian DendorferORCiD
Parent Title (English):Medical Engineering & Physics
Document Type:Article
Year of first Publication:2023
Release Date:2023/10/11
Article Number:104059
Edition:Journal Pre-proof
Corresponding author: Sebstian Dendorfer
Institutes:Fakultät Maschinenbau
Regensburg Center of Biomedical Engineering - RCBE
Regensburg Center of Health Sciences and Technology - RCHST
Fakultät Maschinenbau / Labor Biomechanik (LBM)
research focus:Lebenswissenschaften und Ethik
OpenAccess Publikationsweg:Hybrid Open Access - OA-Veröffentlichung in einer Subskriptionszeitschrift/-medium
Funding:Publikationsfonds der OTH Regensburg
Licence (German):Creative Commons - CC BY-NC-ND - Namensnennung - Nicht kommerziell - Keine Bearbeitungen 4.0 International