Stair ascending and descending activities on the lifespan of hip implants

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(Associate Professor Dr. Senay Mihcin, Alican Alpkaya, Mehmet Yilmaz and Ahmet Sahin, Izmir Institute of Technology, 15. May, 2024 )

This study demonstrates the use of the AnyBody model to calculate the boundary conditions to feed into a dynamic hip implant wear model. 14 volunteers was recruited to perform walking, stair ascending (AS) and stair descending activities (DS) to extract kinematic and kinetic data for each cycle using a Qualisys marker based motion capture (MOCAP) system.

Multibody simulations were performed in the AnyBody Modeling System using the Calibrated Anatomical System Technique (CAST) full body marker set. The 3D generic musculoskeletal model used in this study was a full-body motion capture model (AMMR 2.3.1 MoCapModel) consisting of the upper extremity and the Twente Lower Extremity Model (TLEM2).

For dynamic wear modelling, Ls-Dyna modelling software was utilized to predict the linear wear rates of CoCr-on-XLPE bearing couple under AS and DS activities based on the walk-to-stair ratio (15.9:1) over 5 million cycles. The volumetric wear rates of XLPE liner under AS, DS, and walking activities over 5-Mc are predicted as 27.43, 23.22, and 18.84, respectively. The volumetric wear rate of XLPE is predicted as 22.02 which is equivalent to 19.41% of walking, which is concluded to be included in life span estimations of implants for realistic outcomes.


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