Influence of femur size and morphology on load transfer in the resurfaced femoral head: A large scale, multi-subject finite element study

Bryan, Rebecca; Nair, Prasanth B.; Taylor, Mark

doi:10.1016/j.jbiomech.2012.05.015

Cited by 31 publications

(18 citation statements)

References 34 publications

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“…Finite element analyses based on a single subject are unlikely to be representative of the entire THA population, yet, the majority of finite element studies have been performed on a single femur . Population FE studies, on the other hand, have the potential to compare different stem designs within the same cohort of femora for a range of different activities, allowing for subtle performance differences to be identified, if present. Despite this potential, most studies only consider level gait loads .…”

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confidence: 99%

Influence of collars on the primary stability of cementless femoral stems: A finite element study using a diverse patient cohort

Al-Dirini

Huff

et al. 2017

Journal Orthopaedic Research

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For cementless femoral stems, there is debate as to whether a collar enhances primary stability and load transfer compared to collarless designs. Finite Element (FE) analysis has the potential to compare stem designs within the same cohort, allowing for subtle performance differences to be identified, if present. Subject-specific FE models of intact and implanted femora were run for a diverse cohort (21 males, 20 females; BMI 16.4-41.2 kg/m , age 50-80 yrs). Collared and collarless versions of Corail (DePuy Synthes, Warsaw, IN) were sized and positioned using an automated algorithm that aligns the femoral/stem axes, preserves the head-center location, and maximizes metaphyseal fit. Joint contact and muscle forces simulating peak forces in level gait and stair climbing and were scaled to the body mass and applied to each subject. Three failure scenarios were assessed: Potential for peri-prosthetic fibrous tissue formation (stem micromotion), potential for peri-prosthetic bone damage (equivalent strains), and calcar bone remodeling (changes in strain-energy density). Comparisons were performed using paired t-tests. Only subtle differences were found (mean 90th percentile micromotion: Collared = 86 µm, collarless = 92.5 µm, mean 90th percentile interface strains: Collared = 733 µϵ, collarless = 767 µϵ, and similar remodeling stimuli were predicted). The slight differences observed were small in comparison with the inter-patient variability. Statement of clinical significance: Our results suggest that the presence/absence of a collar is unlikely to substantially alter the bone-implant biomechanics nor the initial mechanical environment. Hence, a collar is likely to have minimal clinical impact. Analysis using different femoral stem designs is recommended before generalising these findings. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1185-1195, 2018.

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confidence: 99%

Influence of collars on the primary stability of cementless femoral stems: A finite element study using a diverse patient cohort

Al-Dirini

Huff

et al. 2017

Journal Orthopaedic Research

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“…While this is indicative of the need for including multiple subjects in FE studies, this is a significantly smaller sample size than would be expected in equivalent in vitro studies or clinical work to investigate patient variability and there are limits to how much the results can be extrapolated to the population . Previously, studies comprising of large cohorts of FE models have investigated load transfer in a femoral resurfacing prosthesis and the primary stability of cementless tibial trays and short femoral stems . By using a large number of subjects, the spread of primary stability in a cup can be predicted and allow statistically meaningful analysis to be performed on the influence of patient‐related factors.…”

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Primary stability of a cementless acetabular cup in a cohort of patient‐specific finite element models

O’Rourke

Al-Dirini

Taylor

2017

Journal Orthopaedic Research

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The primary stability achieved during total hip arthroplasty determines the long-term success of cementless acetabular cups. Pre-clinical finite element testing of cups typically use a model of a single patient and assume the results can be extrapolated to the general population. This study explored the variability in predicted primary stability of a Pinnacle cementless acetabular cup in 103 patient-specific finite element models of the hemipelvis and examined the association between patient-related factors and the observed variability. Cups were inserted by displacement-control into the FE models and then a loading configuration simulating a complete level gait cycle was applied. The cohort showed a range of polar gap of 284-1112 μm and 95th percentile composite peak micromotion (CPM) of 18-624 μm. Regression analysis was not conclusive on the relationship between patient-related factors and primary stability. No relationship was found between polar gap and micromotion. However, when the patient-related factors were categorised into quartile groups, trends suggested higher polar gaps occurred in subjects with small and shallow acetabular geometries and cup motion during gait was affected most by low elastic modulus and high bodyweight. The variation in primary stability in the cohort for an acetabular cup with a proven clinical track record may provide benchmark data when evaluating new cup designs. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1012-1023, 2018.

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“…The advantage of active appearance models is that they can be used to generate 100s-1000s of synthetic instances based on a smaller training set of representative bones or joints. This has led to population-based finite element models of the implanted proximal femur (Bryan et al, 2012) and tibia . Probabilistic study designs now allow for failure processes to be properly explored.…”

Section: Design Of Computer Based Experimentsmentioning

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

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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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Influence of femur size and morphology on load transfer in the resurfaced femoral head: A large scale, multi-subject finite element study

Cited by 31 publications

References 34 publications

Influence of collars on the primary stability of cementless femoral stems: A finite element study using a diverse patient cohort

Influence of collars on the primary stability of cementless femoral stems: A finite element study using a diverse patient cohort

Primary stability of a cementless acetabular cup in a cohort of patient‐specific finite element models

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

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