<i>In vivo</i> measurements show tensile axial strain in the proximal lateral aspect of the human femur

Aamodt, Arild; Lund-Larsen, J.; Eine, J.; Andersen, Erik André; Benum, Pål; Husby, Otto Schnell

doi:10.1002/jor.1100150620

Cited by 112 publications

(75 citation statements)

References 15 publications

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“…At 30 Hz, strain rates of 0.0375 and 0.0675 per second are in effect at stress amplitudes of 25 and 45 MPa, respectively. This range is in agreement with those reported for the lower limbs physiologically for walking (0.01/second) to more strenuous stair climbing activity (0.08/second) [1,20,36].…”

Section: Discussionsupporting

confidence: 92%

Gamma Radiation Sterilization Reduces the High-cycle Fatigue Life of Allograft Bone

Islam

Chapin

Moore

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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Background Sterilization by gamma radiation impairs the mechanical properties of bone allografts. Previous work related to radiation-induced embrittlement of bone tissue has been limited mostly to monotonic testing which does not necessarily predict the high-cycle fatigue life of allografts in vivo. Questions/PurposesWe designed a custom rotatingbending fatigue device to answer the following questions:(1) Does gamma radiation sterilization affect the high-cycle fatigue behavior of cortical bone; and (2) how does the fatigue life change with cyclic stress level? Methods The high-cycle fatigue behavior of human cortical bone specimens was examined at stress levels related to physiologic levels using a custom-designed rotatingbending fatigue device. Test specimens were distributed among two treatment groups (n = 6/group); control and irradiated. Samples were tested until failure at stress levels of 25, 35, and 45 MPa. Results At 25 MPa, 83% of control samples survived 30 million cycles (run-out) whereas 83% of irradiated samples survived only 0.5 million cycles. At 35 MPa, irradiated samples showed an approximately 19-fold reduction in fatigue life compared with control samples (12

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Section: Discussionsupporting

confidence: 92%

Gamma Radiation Sterilization Reduces the High-cycle Fatigue Life of Allograft Bone

Islam

Chapin

Moore

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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“…This is especially important in the femur due to its biomechanics and the © C I C E d i z i o n i I n t e r n a z i o n a l i fact that the anatomic axis is in approximately 7 degrees valgus of the weight-bearing mechanical axis. Consequently, there is an eccentric load on the femur with the medial cortex receiving primarily compressive loads while the lateral cortex receiving tensile loads (40,41). When taking anisotropy into account, drill holes should be preferably placed on the medial cortex which is less prone to fracture than the lateral cortex, due to the fact that it is loaded by compression forces and not by tension.…”

Section: Discussionmentioning

confidence: 99%

Femur shaft fracture following osteoid osteoma radiofrequency ablation

Mazzawi

Militianu

Eidelman

et al. 2017

ccmbm

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SummaryIntroduction. Radiofrequency ablation is an effective modality in treating osteoid osteoma while avoiding the complications of an open procedure. Its complications are usually self-limited consisting mostly of local skin burns. This report presents a major complication, a femur shaft fracture following an osteoid osteoma radiofrequency ablation. The fracture occurred approximately one year after the ablation at the site of the osteoid osteoma. Discussion. Few case reports have been published regarding subtrochanteric femur fracture after ablation of an osteoid osteoma. To our knowledge this is the first report of a femoral shaft fracture following an ablation. Another unique characteristic of the presented case is the late presentation, approximately one year following ablation. Factors which may have contributed to the fracture include lateral entry point of the drill which may have weakened the femur when taking its biological and mechanical properties into account, and the fact that the patient was a soldier who was allowed to continue his military training only six weeks after the ablation. Conclusion. Radiofrequency ablation is an effective and relatively safe technique in treating osteoid osteomas, however the physician should be aware of the fracture risk involved, consider mechanical and biologic factors of the bone prior to drilling, and be very conservative when recommending return to high level activity. In addition, a close follow-up should be carried on after the procedure in order to supervise bone remodeling.

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“…What do we know? The joint contact forces have been measured in a small number of hip replacement patients (Bergmann et al, 1993(Bergmann et al, , 1995(Bergmann et al, , 2001 and there has been a single study where the strains have been measured on the lateral aspect of the femur of two patients for a limited range of activities (Aamodt et al, 1997). This data is insufficient to establish the stress/strain distribution within the femur for single legged stance, let alone dynamic activities of daily living.…”

Section: Development Of a Representative Model With Appropriate Loadmentioning

confidence: 99%

Four decades of finite element analysis of orthopaedic devices: Where are we now and what are the opportunities?

Taylor

Prendergast

2015

Journal of Biomechanics

140

106

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a b s t r a c tFinite element has been used for more than four decades to study and evaluate the mechanical behaviour total joint replacements. In Huiskes seminal paper "Failed innovation in total hip replacement: diagnosis and proposals for a cure", finite element modelling was one of the potential cures to avoid poorly performing designs reaching the market place. The size and sophistication of models has increased significantly since that paper and a range of techniques are available from predicting the initial mechanical environment through to advanced adaptive simulations including bone adaptation, tissue differentiation, damage accumulation and wear. However, are we any closer to FE becoming an effective screening tool for new devices? This review contains a critical analysis of currently available finite element modelling techniques including (i) development of the basic model, the application of appropriate material properties, loading and boundary conditions, (ii) describing the initial mechanical environment of the bone-implant system, (iii) capturing the time dependent behaviour in adaptive simulations, (iv) the design and implementation of computer based experiments and (v) determining suitable performance metrics.The development of the underlying tools and techniques appears to have plateaued and further advances appear to be limited either by a lack of data to populate the models or the need to better understand the fundamentals of the mechanical and biological processes. There has been progress in the design of computer based experiments. Historically, FE has been used in a similar way to in vitro tests, by running only a limited set of analyses, typically of a single bone segment or joint under idealised conditions. The power of finite element is the ability to run multiple simulations and explore the performance of a device under a variety of conditions. There has been increasing usage of design of experiments, probabilistic techniques and more recently population based modelling to account for patient and surgical variability. In order to have effective screening methods, we need to continue to develop these approaches to examine the behaviour and performance of total joint replacements and benchmark them for devices with known clinical performance.Finite element will increasingly be used in the design, development and pre-clinical testing of total joint replacements. However, simulations must include holistic, closely corroborated, multi-domain analyses which account for real world variability.

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In vivo measurements show tensile axial strain in the proximal lateral aspect of the human femur

Cited by 112 publications

References 15 publications

Gamma Radiation Sterilization Reduces the High-cycle Fatigue Life of Allograft Bone

Gamma Radiation Sterilization Reduces the High-cycle Fatigue Life of Allograft Bone

Femur shaft fracture following osteoid osteoma radiofrequency ablation

Four decades of finite element analysis of orthopaedic devices: Where are we now and what are the opportunities?

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