Virtual trial to evaluate the robustness of cementless femoral stems to patient and surgical variation.

Autor: Al-Dirini RMA; Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide 5043, Australia. Electronic address: rami.aldirini@flinders.edu.au., Martelli S; Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide 5043, Australia., O'Rourke D; Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide 5043, Australia., Huff D; DePuy Synthes, Johnson and Johnson, Warsaw, USA., Zhang J; Auckland Bioengineering Institute, Auckland University, Auckland, New Zealand., Clement JG; Melbourne Dental School, University of Melbourne, Melbourne, Australia., Besier T; Auckland Bioengineering Institute, Auckland University, Auckland, New Zealand., Taylor M; Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide 5043, Australia. Electronic address: mark.taylor@flinders.edu.au.
Jazyk: angličtina
Zdroj: Journal of biomechanics [J Biomech] 2019 Jan 03; Vol. 82, pp. 346-356. Date of Electronic Publication: 2018 Nov 15.
DOI: 10.1016/j.jbiomech.2018.11.013
Abstrakt: Primary stability is essential for the success of cementless femoral stems. In this study, patient specific finite element (FE) models were used to assess changes in primary stability due to variability in patient anatomy, bone properties and stem alignment for two commonly used cementless femoral stems, Corail® and Summit® (DePuy Synthes, Warsaw, USA). Computed-tomography images of the femur were obtained for 8 males and 8 females. An automated algorithm was used to determine the stem position and size which minimized the endo-cortical space, and then span the plausible surgical envelope of implant positions constrained by the endo-cortical boundary. A total of 1952 models were generated and ran, each with a unique alignment scenario. Peak hip contact and muscle forces for stair climbing were scaled to the donor's body weight and applied to the model. The primary stability was assessed by comparing the implant micromotion and peri-prosthetic strains to thresholds (150 μm and 7000 µε, respectively) above which fibrous tissue differentiation and bone damage are expected to prevail. Despite the wide range of implant positions included, FE prediction were mostly below the thresholds (medians: Corail®: 20-74 µm and 1150-2884 µε, Summit®: 25-111 µm and 860-3010 µε), but sensitivity of micromotion and interfacial strains varied across femora, with the majority being sensitive (p < 0.0029) to average bone mineral density, cranio-caudal angle, post-implantation anteversion angle and lateral offset of the femur. The results confirm the relationship between implant position and primary stability was highly dependent on the patient and the stem design used.
(Copyright © 2018 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: