SYMPOSIA PAPER Published: 29 January 2016
STP159120140146

On the Measurement of Three-Dimensional Taper Moments Due to Friction and Contact Load in Total Hip Replacement

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Unintended micromotions causing fretting and corrosion within the modular head-neck junction of total hip replacement are governed by hip joint contact forces as well as by the frictional moments during articulation. Frictional moments typically are measured in unidirectional sliding tests and not during complex joint articulation. The purpose of this study was to develop a test rig that allows for the measurement of three-dimensional (3D) frictional joint moments during simulated gait and to calculate the direction and magnitude of the resulting taper moments. Using a spherical air bearing, a new testing rig with several load sensors was designed to fit into an existing 3D hip simulator. Unidirectional motion cycles (for validation with the literature) and walking cycles according to International Organization of Standardization (ISO) 14242-1 were applied to investigate frictional moments and taper loads for both 28 and 48-mm all-ceramic and 28-mm ceramic-on-polyethylene hip bearings. The precision of the testing rig was better than 0.01 Nm for each axis. During unidirectional motion, the mean peak moments for the smaller and the larger head size compared well with the literature. ISO walking cycles generated highly dynamic moments, which increased with head size. For the smaller 28-mm head size, a 1.4-Nm rotational moment around the taper axis and a 2.0-Nm bending moment orthogonally were determined. For the 48-mm head size, the moments were 2.5 Nm and 4 Nm, respectively. Future studies are necessary to further validate the test setup.

Author Information

Kaddick, C.
EndoLab GmbH, Rosenheim, Bavaria, DE
Malczan, M.
EndoLab GmbH, Rosenheim, Bavaria, DE
Buechele, C.
EndoLab GmbH, Rosenheim, Bavaria, DE
Hintner, M.
EndoLab GmbH, Rosenheim, Bavaria, DE
Wimmer, M., A.
Rush University Medical Center Dept. of Orthopedic Surgery, Chicago, IL, US
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Details
Developed by Committee: F04
Pages: 336–350
DOI: 10.1520/STP159120140146
ISBN-EB: 978-0-8031-7628-7
ISBN-13: 978-0-8031-7627-0