Evaluation of Total Ankle Arthroplasty Using Highly Crosslinked Ultrahigh-Molecular-Weight Polyethylene Subjected to Physiological Loading

2019 ◽  
Vol 40 (8) ◽  
pp. 880-887 ◽  
Author(s):  
Jeffrey E. Bischoff ◽  
Mehul A. Dharia ◽  
Justin S. Hertzler ◽  
Oliver N. Schipper
Keyword(s):  
Fatigue Strength ◽  
Fatigue Testing ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Fatigue Loading ◽  
Strength Properties ◽  
Total Ankle Arthroplasty ◽  
Wear Properties ◽  
Ankle Arthroplasty ◽  
Walking Gait

Background: Highly crosslinked polyethylene (HXLPE) was developed for its superior wear properties in comparison to conventional polyethylene (CPE). Concern over fatigue resistance has prevented widespread adoption of HXLPE for use in total ankle arthroplasty (TAA). The aim of this study was to determine whether HXLPE has sufficient fatigue strength for total ankle arthroplasty under simulated physiologically relevant motion profiles and loading in the ankle. Methods: Physiologic load and motion profiles representative of walking gait were incorporated into a computational model of a semiconstrained, fixed-bearing TAA to determine the loading state with highest stresses in the HXLPE bearing. Subsequent fatigue testing to 10 million cycles (Mc) at 5600 N was performed to assess bearing strength. Results: Peak stresses in the bearing were predicted at peak axial load and peak dorsiflexion during gait, occurring near heel off. All samples withstood 10 Mc of fatigue loading at that orientation without polyethylene bearing fracture. Conclusion: HXLPE had sufficient fatigue strength to withstand 10 Mc of loading at more than 5 times body weight at the point of peak stresses during simulated gait in total ankle arthroplasty. Clinical Relevance: HXLPE may be mechanically strong enough to withstand the in vivo demands of the ankle. Improvements in wear afforded by HXLPE can be obtained without compromising sufficient polyethylene strength properties in total ankle arthroplasty.

scholarly journals Fatigue Strength of Highly Crosslinked Polyethylene in Total Ankle Arthroplasty

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0037
Author(s):  
Oliver N. Schipper ◽  
Mehul A. Dharia ◽  
Justin S. Hertzler ◽  
Jeffrey E. Bischoff
Keyword(s):  
Body Weight ◽  
Fatigue Strength ◽  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Peak Load ◽  
Total Ankle Arthroplasty ◽  
Polyethylene Insert ◽  
Worst Case ◽  
Ankle Arthroplasty ◽  
Surface Cracking

Category: Ankle Introduction/Purpose: Highly crosslinked polyethylene (HXLPE) was developed for its superior wear properties in comparison to conventional polyethylene (CPE). The higher dose irradiation required for HXLPE may also cause embrittlement, which reduces fatigue resistance and leads to surface cracking or fracture of the polyethylene bearing. Concern over fatigue resistance has prevented widespread adoption of HXLPE for use in in total ankle arthroplasty (TAA). The aim of this study was to determine whether HXLPE has sufficient fatigue strength for total ankle arthroplasty under simulated physiologically relevant motion profiles and loading in the ankle. Methods: A bicondylar, semi-constrained HXLPE TAA design was subjected to 10 million cycles (Mc) of fatigue testing under loading conditions representative of a walking gait. Kinetics and kinematics of gait were incorporated into a computational model (Dassault Systemes / SIMULIA, Johnston, RI), for prediction of peak stresses on the HXLPE insert. Based on predicted peak stresses, worst case component size and loading configuration were identified. Ten samples were tested on a closed loop servohydraulic test frame (MTS Systems Corp., Minneapolis, MN) for 10Mc. Testing was conducted to a peak load of 5600 N (1259lbs), representing approximately 5 times body weight for a 240 lb individual. Following testing, all samples were evaluated for evidence of polyethylene fracture or surface cracking. Results: Peak stresses in the HXLPE insert occurred during heel off, closely corresponding to both peak axial force and dorsiflexion during gait. The smallest sized component had the highest polyethylene insert stresses, whereas larger sized components had more material to bear the same load, resulting in up to a 30% decrease in stress. All 10 specimens completed 10Mc of testing at 5 times body weight without fracture or surface cracking of the polyethylene insert. Conclusion: HXLPE has sufficient fatigue strength to withstand 10Mc of loading at 5 times body weight at the point of peak stresses during gait in total ankle arthroplasty, and therefore, may be mechanically strong enough to withstand the demands of the ankle. Further clinical evidence is necessary to determine if these results translate to adequate fatigue strength with clinical use of HXLPE.

In vivo kinematics of fixed-bearing total ankle arthroplasty

2020 ◽  
Vol 26 (4) ◽  
pp. 371-377 ◽  
Author(s):  
Gloria Casaroli ◽  
Tomaso Villa ◽  
Alberto Bianchi ◽  
Eleonora Caboni ◽  
Francesco Malerba ◽  
...  
Keyword(s):  
Total Ankle Arthroplasty ◽  
Fixed Bearing ◽  
Ankle Arthroplasty ◽  
In Vivo Kinematics

scholarly journals Fatigue Strength as a Function of Preloading in Dynamic Fatigue Testing of Glass and Ceramics

1996 ◽  
Author(s):  
Sung R. Choi ◽  
Jonathan A. Salem ◽  
John P. Gyekenyesi
Keyword(s):  
Fatigue Strength ◽  
Failure Time ◽  
Fatigue Testing ◽  
Slow Crack Growth ◽  
Fatigue Loading ◽  
Soda Lime ◽  
Ceramic Materials ◽  
Soda Lime Glass ◽  
Testing Time ◽  
Dynamic Fatigue

The solution of fatigue strength as a function of preloading in dynamic fatigue testing was obtained analytically and numerically. The effect of preloading on dynamic fatigue strength decreases with increasing fatigue parameter (n), and for n ≥ 20 the effect is negligible up to a preloading of 90 %. The solution was verified by dynamic fatigue experiments conducted with soda-lime glass and alumina specimens in room-temperature distilled water. This result showed that one can apply a preloading corresponding up to 90 % of fatigue strength for most glass and ceramic materials, resulting in a dramatic saving of testing time in dynamic fatigue testing. The key feature that makes this technique feasible is that most of the slow crack growth under dynamic fatigue loading occurs close to failure time where a dynamic fatigue strength is defined.

scholarly journals Rescue Augmentation: Increased Stability in Augmentation After Initial Loosening of Pedicle Screws

2020 ◽  
pp. 219256822091912
Author(s):  
Lukas Weiser ◽  
Gerd Huber ◽  
Kay Sellenschloh ◽  
Klaus Püschel ◽  
Michael M. Morlock ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Bone Density ◽  
Fatigue Testing ◽  
Quantitative Computed Tomography ◽  
Pedicle Screws ◽  
Fatigue Loading ◽  
Cement Augmentation ◽  
Fatigue Load ◽  
The Impact

Study Design: Biomechanical study. Objectives: Failure of pedicle screws is a major problem in spinal surgery not only postoperatively, but also intraoperatively. The aim of this study was to evaluate whether cement augmentation may restore mounting of initially loosened pedicle screws. Methods: A total of 14 osteoporotic or osteopenic human cadaveric vertebral bodies (L2)—according to quantitative computed tomography (QCT)—were instrumented on both sides by conventional pedicle screws and cement augmented on 1 side. In vitro fatigue loading (cranial-caudal sinusoidal, 0.5 Hz) with increasing peak force (100 N + 0.1 N/cycles) was applied until a screw head displacement of 5.4 mm (∼20°) was reached. After loosening, the nonaugmented screw was rescue augmented, and fatigue testing was repeated. Results: The fatigue load reached 207.3 N for the nonaugmented screws and was significantly ( P = .009) exceeded because of initial cement augmentation (300.6 N). The rescue augmentation after screw loosening showed a fatigue load of 370.1 N which was significantly higher ( P < .001) compared with the nonaugmented screws. The impact of bone density on fatigue strength decreased from the nonaugmented to the augmented to the rescue-augmented screws and shows the greatest effect of cement augmentation on fatigue strength at low bone density. Conclusions: Rescue augmentation leads to similar or higher fatigue strengths compared with those of the initially augmented screws. Therefore, the cement augmentation of initially loosened pedicle screws is a promising option to restore adequate screw stability.

Wear Characteristics of Conventional Ultrahigh-Molecular-Weight Polyethylene Versus Highly Cross-Linked Polyethylene in Total Ankle Arthroplasty

2018 ◽  
Vol 39 (11) ◽  
pp. 1335-1344 ◽  
Author(s):  
Oliver N. Schipper ◽  
Steven L. Haddad ◽  
Spencer Fullam ◽  
Robin Pourzal ◽  
Markus A. Wimmer
Keyword(s):  
Particle Size ◽  
Wear Rate ◽  
Particle Shape ◽  
Polyethylene Wear ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Total Ankle Arthroplasty ◽  
Fixed Bearing ◽  
Ankle Arthroplasty ◽  
Ultrahigh Molecular Weight ◽  
The Mean

Background: The aim of this study was to compare the polyethylene wear rate, particle size, and particle shape of primary semiconstrained, fixed-bearing, bone-sparing total ankle arthroplasty using conventional ultrahigh-molecular-weight polyethylene (CPE) versus highly cross-linked polyethylene (HXLPE) by applying a level walking input using a joint simulator. Methods: Two fixed-bearing total ankle replacement systems with different types of polyethylene liners were tested: (1) CPE sterilized in ethylene oxide, and (2) HXLPE sterilized with gas plasma after electron beam irradiation. Three implants for each design underwent wear testing using gravimetric analysis over 5 million simulated walking cycles. A fourth implant was used as a load soak control. Equivalent circle diameter (ECD) and equivalent shape ratio (ESR) were computed to determine particle size and particle shape, respectively. Results: The mean wear rate from 1.5 to 5 million cycles (MC) was 2.0 ± 0.3 mg/MC for HXLPE and 16.7 ± 1.3 mg/MC for CPE ( P < .001). The total number of particles per cycle generated for HXLPE and CPE were 0.17 × 106 particles/cycle and 0.53 × 106 particles/cycle, respectively ( P < .001). The mean ECD of HXLPE particles (0.22 ± 0.11 μm) was significantly smaller than the mean ECD of CPE particles (0.32 ± 0.14 μm) ( P < .001). HXLPE particles were significantly more round than CPE particles ( P < .001). Conclusions: HXLPE liners had a significantly lower wear rate and produced significantly fewer and rounder particles than CPE liners. The results of this study suggest that HXLPE has more favorable wear characteristics for total ankle arthroplasty. Clinical Relevance: Polyethylene wear particles have been linked to osteolysis after total ankle arthroplasty. There is no consensus on the importance of highly cross-linked polyethylene in total ankle arthroplasty with regard to implant wear. This is the first nonindustry study to compare the polyethylene wear rate, particle size, and particle shape of fixed-bearing total ankle arthroplasty conventional polyethylene versus highly cross-linked polyethylene. The lower wear rate and different particle size/morphology of highly cross-linked polyethylene could be beneficial in vivo to decrease osteolysis.

Fatigue Strength as a Function of Preloading in Dynamic Fatigue Testing of Glass and Ceramics

1997 ◽  
Vol 119 (3) ◽  
pp. 493-499 ◽  
Author(s):  
S. R. Choi ◽  
J. P. Gyekenyesi
Keyword(s):  
Fatigue Strength ◽  
Failure Time ◽  
Fatigue Testing ◽  
Slow Crack Growth ◽  
Fatigue Loading ◽  
Soda Lime ◽  
Ceramic Materials ◽  
Soda Lime Glass ◽  
Testing Time ◽  
Dynamic Fatigue

The solution of fatigue strength as a function of preloading in dynamic fatigue (constant stress-rate) testing was obtained analytically and numerically. The effect of preloading on dynamic fatigue strength decreases with increasing fatigue parameter (n), and for n ≥ 20 the effect is negligible up to a preloading of 90 percent. The solution was verified by dynamic fatigue experiments conducted with soda-lime glass and alumina specimens in room-temperature distilled water. This result showed that one can apply a preloading corresponding up to 90 percent of fatigue strength for most glass and ceramic materials, resulting in a dramatic saving of testing time in dynamic fatigue testing. The key feature that makes this technique feasible is that most of the slow crack growth under dynamic fatigue loading occurs close to failure time where the dynamic fatigue strength is defined.

scholarly journals Influence of Tibial Component Position on Altered Kinematics Following Total Ankle Arthroplasty During Simulated Gait

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0010
Author(s):  
Guilherme Saito ◽  
Daniel Sturnick ◽  
Jonathan Deland ◽  
Scott Ellis ◽  
Constantine Demetracopoulos
Keyword(s):  
Ankle Joint ◽  
Tibial Component ◽  
Joint Kinematics ◽  
Transverse Plane ◽  
Total Ankle Arthroplasty ◽  
Component Position ◽  
Ankle Arthroplasty ◽  
Ankle Kinematics ◽  
Joint Contact

Category: Ankle Arthritis Introduction/Purpose: Correct positioning of total ankle arthroplasty (TAA) implants has been associated with superior clinical outcomes. Furthermore, biomechanical studies have demonstrated that poor alignment of the components may lead to early component wear, compromising the longevity of the prosthesis. Malpositioning of TAA implants affects ligament engagement patterns and joint contact mechanics, possibly leading to altered joint kinematics. However, the correlation between implant position and ankle joint motion is still unclear. The objective of this study was to assess the effect of tibial component position on ankle kinematics following TAA during simulated gait. Methods: Eight mid-tibia cadaveric specimens were utilized in this IRB approved study. The stance phase of gait was simulated both pre- and post-TAA in each specimen using a six-degree of freedom robotic platform. Ground reaction forces and tibial kinematic from in vivo data were replicated while physiologic tendon force profiles were applied to each extrinsic ankle tendons by linear actuators instrumented. Ankle kinematics was measured from reflective markers attached to bones via surgical pins. TAAs were completed using a common fixed-bearing total ankle system following the manufacturer recommended protocol (Salto Talaris, Integra LifeSciences). Using reconstructed CT data, 3D tibial component position relative to a standard ankle joint reference was characterized (Figure 1A). The effect of tibial component position on absolute differences in ankle kinematics (pre – post TAA) was assessed using linear regression with a level of significance set to p = 0.05. Results: Differences in ankle joint kinematics were only identified in the transverse plane, where internal talar rotation was significantly increased following TAA compared to the native condition (Figure 1B). The medial position of TAA tibial components was found to be positively associated with increased internal talar rotation (Figure 1C; β = 1.861 degrees/mm, R2 = 0.72, p = 0.008). No other measurements of tibial component position (anterior-posterior/inferior-superior position, sagittal/frontal/transverse plane angle) were found to be significantly associated with altered ankle kinematics following TAA (All β < 0.1 and p > 0.05). Conclusion: This study suggests that medial positioning of the tibial implant affects ankle kinematics. During operative procedures the tibial component is usually positioned in order to preserve bone stock of the medial and lateral malleolus. However, little attention is given to the position of the implant in relation to the center of the tibial axis. This finding could have clinical implications for techniques implemented during surgical procedures and for the development of new instrumentation systems.

scholarly journals Giga-Cycle Fatigue Behavior of the Nuclear Structure of 316L Weldments

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhihong Xiong ◽  
Engao Peng ◽  
Lianghua Zeng ◽  
Qirong Xu
Keyword(s):  
Fatigue Strength ◽  
Arc Welding ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Laser Beam Welding ◽  
Fatigue Loading ◽  
Testing System ◽  
Cycle Fatigue ◽  
Gas Tungsten Arc ◽  
Ultrasonic Fatigue

Some components made of 316L stainless steel in nuclear reactors are connected by welding, and these are under giga-cycle fatigue loading. Therefore, the giga-cycle fatigue behavior of 316L weldments, which are fabricated by Laser Beam Welding (LBW) and Gas Tungsten Arc Welding (GTAW), were investigated using an ultrasonic fatigue testing system. The results indicate that the fatigue strength of LBW-made weldments is almost the same as that of GTAW-made weldments even though the microstructure and mechanical properties of the weldments are different. For the LBW-made specimens, the LBW-induced internal pores with a diameter range of about 89–270 μm were observed in the fracture surface. However, an obvious decrease in fatigue life was not observed in such cases. For the GTAW-made specimens, the quality requirement of the weld seam has to be more strict to prevent fatigue strength from decreasing. The fatigue failure mode of the GTAW-made specimens is the same as that of LBW-made specimens in the high-cycle fatigue regime but different in the giga-cycle fatigue regime.

Benefits of Ultrasonic Peening Treatment in Fatigue Improvement of Welded Elements

2012 ◽  
Author(s):  
Jacob Kleiman ◽  
Yuri Kudryavtsev ◽  
Alexander Lugovskoy
Keyword(s):  
Mechanical Properties ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Loading ◽  
Surface Layers ◽  
Ultrasonic Peening ◽  
Weld Toe

The Ultrasonic Peening (UP) is one of new and promising processes for fatigue life improvement of welded elements and structures. During the different stages of its development the UP process was also known as ultrasonic treatment (UT), ultrasonic impact treatment (UIT), ultrasonic impact peening (UIP). The beneficial effect of UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The results of fatigue testing of welded elements made of regular and high strength steels in as-welded condition and after application of UP will be presented. The yield strength of considered materials varied from 250–350 MPa to 700–1000 MPa. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increased fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used. It allows using to a greater degree the advantages of the HSS in welded elements, subjected to fatigue loading.

Influence of Texture and Environmental Effects on Fatigue Behavior of Ti-6Al-4V Alloy

2017 ◽  
Vol 754 ◽  
pp. 39-42 ◽  
Author(s):  
Sergio Baragetti ◽  
Nedunchezhian Srinivasan ◽  
Ravi Kumar
Keyword(s):  
Fatigue Strength ◽  
Grain Boundaries ◽  
Environmental Effects ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Loading ◽  
Aged Condition ◽  
Air Samples ◽  
Secondary Cracks ◽  
Corrosive Environments

Ti-6Al-4V alloy in solutionized and aged condition was subjected to axial fatigue testing in air and corrosive environments respectively. Severity of the methanol damage as evidenced through fractographic studies, corroborates loss in fatigue strength of samples tested in methanol environment in contrast to samples tested in air. Samples subjected to fatigue loading in NaCl environment revealed extensive secondary cracks along alpha grain boundaries.

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