Cyclic Damage Accumulation in the Femoral Constructs Made With Cephalomedullary Nails

Abstract

Background: The purpose of this study was to evaluate the risk of peri-prosthetic fracture of constructs made with cephalomedullary (CM) long and short nails. The nails were made with titanium alloy (Ti-6Al-4V) and stainless steel (SS 316L).Methods: Biomechanical evaluation of CM nail constructs was carried out with regard to post-primary healing to determine the risk of peri-implant/peri-prosthetic fractures. Therefore, this research comprised of, non-fractured, twenty-eight pairs of cadaveric femora that were randomized and implanted with four types of fixation CM nails resulting in four groups. These constructs were cyclically tested in bi-axial mode for up to 30,000 cycles. All the samples were then loaded to failure to measure failure loads. Three frameworks were carried out through this investigation, Michaelis–Menten, phenomenological, and probabilistic Monte Carlo simulation to model and predict damage accumulation.Findings: Damage accumulation resulting from bi-axial cyclic loading in terms of construct stiffness was represented by Michaelis–Menten equation, and the statistical analysis demonstrated that one model can explain the damage accumulation during cyclic load for all four groups of constructs (P > 0.05). A two-stage stiffness drop was observed. The short stainless steel had a significantly higher average damage (0.94) than the short titanium nails (0.90, P < 0.05). Long titanium nail group did not differ substantially from the short stainless steel nails (P > 0.05). Results showed gender had a significant effect on load to failure in both torsional and bending tests (P < 0.05 and P < 0.001, respectively).Interpretation: Kaplan–Meier survival analysis supports the use of short titanium CM nail. We recommend that clinical decisions should take age and gender into consideration in the selection of implants.

Is nail-plate docking worth the effort? A biomechanical analysis of docking a plate and a nail in peri-implant femur fractures

“…PIFFs are a rare yet severe complication that arises after nailing a proximal femur fracture. While clinical evidence has become more solid over the last few years, with attempts having been made to classify the fractures ( Chan et al, 2018 ; Egol et al, 2019 ; Videla-Ces et al, 2019 ) and to establish a treating algorithm ( Bidolegui et al, 2023 ), the general evidence on PIFFs is rare and has focused on the risk of secondary fracture rather than on treatment ( Daner et al, 2017 ; Hamandi et al, 2020 ; Breceda et al, 2021 ; Saggi et al, 2022 ). To our knowledge, no biomechanical study has thus far investigated the treatment of PIFFs with nail–plate docking.…”

Retrospective Evaluation and Framework Development of Bone Anisotropic Material Behavior Compared with Elastic, Elastic-Plastic, and Hyper-Elastic Properties

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Traumatic Brain Injury Biomarkers, Simulations and Kinetics

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