Validation of distal radius failure load predictions by homogenized- and micro-finite element analyses based on second-generation high-resolution peripheral quantitative CT images.
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ABSTRACT:
SUBMITTER: Arias-Moreno AJ
PROVIDER: S-EPMC6614386 | biostudies-other | 2019 Jul
REPOSITORIES: biostudies-other
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Project description:High-resolution peripheral quantitative computed tomography (HR-pQCT) based micro-finite element (μFE) analysis allows accurate prediction of stiffness and ultimate load of standardised (∼1 cm) distal radius and tibia sections. An alternative homogenized finite element method (hFE) was recently validated to compute the ultimate load of larger (∼2 cm) distal radius sections that include Colles' fracture sites. Since the mechanical integrity of the weight-bearing distal tibia is gaining clinical interest, it has been shown that the same properties can be used to predict the strength of both distal segments of the radius and the tibia. Despite the capacity of hFE to predict structural properties of distal segments of the radius and the tibia, the limitations of such homogenization scheme remain unclear. Therefore, the objective of this study is to build a complete mechanical data set of the compressive behavior of distal segments of the tibia and to compare quantitatively the structural properties with the hFE predictions. As a further aim, it is intended to verify whether hFE is also able to capture the post-yield strain localisation or fracture zones in such a bone section, despite the absence of strain softening in the constitutive model. Twenty-five fresh-frozen distal parts of tibias of human donors were used in this study. Sections were cut corresponding to an in-house triple-stack protocol HR-pQCT scan, lapped, and scanned using micro computed tomography (μCT). The sections were tested in compression until failure, unloaded and scanned again in μCT. Volumetric bone mineral density (vBMD) and bone mineral content (BMC) were correlated to compression test results. hFE analysis was performed in order to compare computational predictions (stiffness, yield load and plastic deformation field pattern) with the compressive experiment. Namely, strain localization was assessed based on digital volume correlation (DVC) results and qualitatively compared to hFE predictions by comparing mid-slices patterns. Bone mineral content (BMC) showed a good correlation with stiffness (R2 = 0.92) and yield (R2 = 0.88). Structural parameters also showed good agreement between the experiment and hFE for both stiffness (R2 = 0.96, slope = 1.05 with 95 % CI [0.97, 1.14]) and yield (R2 = 0.95, slope = 1.04 [0.94, 1.13]). The qualitative comparison between hFE and DVC strain localization patterns allowed the classification of the samples into 3 categories: bad (15 sections), semi (8), and good agreement (2). The good correlations between BMC or hFE and experiment for structural parameters were similar to those obtained previously for the distal part of the radius. The failure zones determined by hFE corresponded to registration only in 8 % of the cases. We attribute these discrepancies to local elastic/plastic buckling effects that are not captured by the continuum-based FE approach exempt from strain softening. A way to improve strain localization hFE prediction would be to use longer distal segments with intact cortical shells, as done for the radius. To conclude, the used hFE scheme captures the elastic and yield response of the tibia sections reliably but not the subsequent failure process.
| S-EPMC10999809 | biostudies-literature
Project description:High-resolution peripheral quantitative computed tomography (HR-pQCT) derived micro-finite element (FE) modeling is used to evaluate mechanical behavior at the distal radius microstructure. However, these analyses typically simulate non-physiologic simplified platen-compression boundary conditions on a small section of the distal radius. Cortical and trabecular regions contribute uniquely to distal radius mechanical behavior, and various factors affect these regions distinctly. Generalized strength predictions from standardized platen-compression analyses may not adequately capture region specific responses in bone. Our goal was to compare load sharing within the cortical-trabecular compartments between the standardized platen-compression BC simulations, and physiologic BC simulations using a validated multiscale approach. Clinical- and high-resolution images were acquired from nine cadaveric forearm specimens using an HR-pQCT scanner. Multiscale FE models simulating physiologic BCs, and micro-FE only models simulating platen-compression BCs were created for each specimen. Cortical and trabecular loads (N) along the length of the distal radius micro-FE section were compared between BCs using correlations. Principal strain distributions were also compared quantitatively. Cortical and trabecular loads from the platen-compression BC simulations were strongly correlated to the physiologic BC simulations. However, a 30% difference in cortical loads distally, and a 53% difference in trabecular loads proximally was observed under platen BC simulations. Also, distribution of principal strains was clearly different. Our data indicated that platen-compression BC simulations alter cortical-trabecular load sharing. Therefore, results from these analyses should be interpreted in the appropriate mechanical context for clinical evaluations of normal and pathologic mechanical behavior at the distal radius.
| S-EPMC5767139 | biostudies-literature
Project description:The estimation of local and structural mechanical properties of bones with micro Finite Element (microFE) models based on Micro Computed Tomography images depends on the quality bone geometry is captured, reconstructed and modelled. The aim of this study was to validate microFE models predictions of local displacements for vertebral bodies and to evaluate the effect of the elastic tissue modulus on model's predictions of axial forces. Four porcine thoracic vertebrae were axially compressed in situ, in a step-wise fashion and scanned at approximately 39μm resolution in preloaded and loaded conditions. A global digital volume correlation (DVC) approach was used to compute the full-field displacements. Homogeneous, isotropic and linear elastic microFE models were generated with boundary conditions assigned from the interpolated displacement field measured from the DVC. Measured and predicted local displacements were compared for the cortical and trabecular compartments in the middle of the specimens. Models were run with two different tissue moduli defined from microindentation data (12.0GPa) and a back-calculation procedure (4.6GPa). The predicted sum of axial reaction forces was compared to the experimental values for each specimen. MicroFE models predicted more than 87% of the variation in the displacement measurements (R2 = 0.87-0.99). However, model predictions of axial forces were largely overestimated (80-369%) for a tissue modulus of 12.0GPa, whereas differences in the range 10-80% were found for a back-calculated tissue modulus. The specimen with the lowest density showed a large number of elements strained beyond yield and the highest predictive errors. This study shows that the simplest microFE models can accurately predict quantitatively the local displacements and qualitatively the strain distribution within the vertebral body, independently from the considered bone types.
| S-EPMC5507408 | biostudies-literature
Project description:Background and purpose - The reliability of conventional radiography when classifying distal radius fractures (DRF) is fair to moderate. We investigated whether reliability increases when additional computed tomography scans (CT) are used. Patients and methods - In this prospective study, we performed pre- and postreduction posterior-anterior and lateral radiographs of 51 patients presenting with a displaced DRF. The case was included when there was a (questionable) indication for surgical treatment and an additional CT was conducted within 5 days. 4 observers assessed the cases using the Frykman, Fernández, Universal, and AO classification systems. The first 2 assessments were performed using conventional radiography alone; the following 2 assessments were performed with an additional CT. We used the intraclass correlation coefficient (ICC) to evaluate reliability. The CT was used as a reference standard to determine the accuracy. Results - The intraobserver ICC for conventional radiography alone versus radiography and an additional CT was: Frykman 0.57 vs. 0.51; Fernández 0.53 vs. 0.66; Universal 0.57 vs. 0.64; AO 0.59 vs. 0.71. The interobserver ICC was: Frykman: 0.45 vs. 0.28; Fernández: 0.38 vs. 0.44; Universal: 0.32 vs. 0.43; AO: 0.46 vs. 0.40. Interpretation - The intraobserver reliability of the classification systems was fair but improved when an additional CT was used, except for the Frykman classification. The interobserver reliability ranged from poor to fair and did not improve when using an additional CT. Additional CT scanning has implications for the accuracy of scoring the fracture types, especially for simple fracture types.
| S-EPMC5694815 | biostudies-literature
Project description:For accurate analysis of bone formation and resorption during fracture healing, correct registration of follow-up onto baseline image is required. A per-fragment approach could improve alignment compared to standard registration based on the whole fractured region. In this exploratory study, we tested the effect of fragment size and displacement on a per-fragment registration, and compared the results of this per-fragment registration to the results of the standard registration in two stable fractures and one unstable fracture. To test the effect of fragment size and displacement, high-resolution peripheral quantitative computed tomography (HR-pQCT) scans of three unfractured radii were divided into subvolumes. Different displacements in x-, y, or z-direction or rotations around each axis were applied, and each subvolume was registered onto the initial volume to realign it. Next, registration of follow-up onto baseline scan was performed in two stable and one unstable fracture. After coarsely aligning the follow-up onto the baseline scan, a more accurate registration was performed of the whole fracture, i.e. the standard registration, and of each fracture fragment separately, i.e. per-fragment registration. Alignment was checked using overlay images showing baseline, follow-up and overlap between these scans, and by comparing correlation coefficients between the standard and per-fragment registration. Generally, subvolumes as small as 300 mm3 that were displaced up to 0.82 mm in x- or y-, or up to 1.64 mm in z-direction could be realigned correctly. For the fragments of all fractures, correlation coefficients were higher after per-fragment registration compared to standard registration. Most improvement was found in the unstable fracture and one fragment of the unstable fracture did not align correctly. This exploratory study showed that image registration of individual subvolumes, such as fracture fragments, is feasible in both stable and unstable fractures, and leads to better alignment of these fragments compared to an approach that is based on registration using the whole fractured region. This result is promising for additional analysis of bone formation and resorption in HR-pQCT studies on fracture healing.
| S-EPMC5526550 | biostudies-literature
Project description:Purpose We evaluated the feasibility of a juxta-articular-type volar distal radius plate for the surgical treatment of marginal distal radius fractures. Materials and methods Twenty marginal distal radius fractures, defined by the location of the fracture line within 10 mm of the joint line of the lunate fossa, were retrospectively reviewed between July 2020 and July 2022. The fractures were fixed using a juxta-articular-type volar plate (ARIX Wrist System). The characteristics of the implant and surgical technique, radiologic, and clinical outcomes, and related complications were evaluated. Results Bony union was achieved in all patients within six months. Acceptable radiological alignment was achieved with no significant differences between the fractured and the normal sides. The clinical outcomes were favorable, with satisfactory functional outcomes. There was one case of post-traumatic arthritis and two cases of carpal tunnel syndrome. No implant-related complications including flexor tendon problems were observed. Conclusion The juxta-articular distal radius plate of the Arix Wrist system is feasible for treating marginal distal radius fractures and achieves favorable clinical outcomes without implant-related complications in East Asian patients.
| S-EPMC10121617 | biostudies-literature
Project description:While weight-bearing and resistive exercise modestly increases aBMD, the precise relationship between physical activity and bone microstructure, and strain in humans is not known. Previously, we established a voluntary upper-extremity loading model that assigns a person's target force based on their subject-specific, continuum FE-estimated radius bone strain. Here, our purpose was to quantify the inter-individual variability in radius microstructure and FE-estimated strain explained by site-specific mechanical loading history, and to determine whether variability in strain is captured by aBMD, a clinically relevant measure of bone density and fracture risk. Seventy-two women aged 21-40 were included in this cross-sectional analysis. High resolution peripheral quantitative computed tomography (HRpQCT) was used to measure macro- and micro-structure in the distal radius. Mean energy equivalent strain in the distal radius was calculated from continuum finite element models generated from clinical resolution CT images of the forearm. Areal BMD was used in a nonlinear regression model to predict FE strain. Hierarchical linear regression models were used to assess the predictive capability of intrinsic (age, height) and modifiable (body mass, grip strength, physical activity) predictors. Fifty-one percent of the variability in FE bone strain was explained by its relationship with aBMD, with higher density predicting lower strains. Age and height explained up to 31.6% of the variance in microstructural parameters. Body mass explained 9.1% and 10.0% of the variance in aBMD and bone strain, respectively, with higher body mass indicative of greater density. Overall, results suggest that meaningful differences in bone structure and strain can be predicted by subject characteristics.
| S-EPMC6021193 | biostudies-literature
Project description:This study aimed to describe the intraosseous blood supply of the distal radius and its clinical implications in distal radius fractures. Twelve adult wrists from fresh cadavers (six males, six females, 50-90 years of age, mean 68 years) were injected through the brachial artery with latex. Dissections were performed using magnifying loupes and hands were processed using the Spalteholz technique. The distal radius was supplied by three main vascular systems: epiphyseal, metaphyseal, and diaphyseal. The palmar epiphyseal vessels branched from the radial artery, palmar carpal arch, and anterior branch of the anterior interosseous artery. These vessels entered the bone through the radial styloid process at level of the Lister's tubercle but palmar and sigmoid notch. The dorsal contribution to Lister's tubercle is to the dorsal epiphyseal vessels. The intraosseous point of entry to the dorsal epiphyseal vessels was from the fourth and fifth extensor compartment arteries. In the metaphyseal area, we found numerous periosteal and cortical branches originating deep in the pronator quadratus and the anterior interosseous artery. These branches provided the main supply to the distal radius. Vessels perforated the bone and formed an anastomotic network. In the diaphyseal area, only the nutrient vessel provided intraosseous vascularity in the distal radius. Numerous metaphyseal-epiphyseal branches arise within the pronator quadratus and the anterior interosseous artery and course towards the distal radius. These branches may be fundamental to the healing of the distal radius fractures and make nonunion a rare complication.
| S-EPMC2787224 | biostudies-other
Project description:Distal radius fractures (DRFs) occur in various complexity patterns among patients differing in age, gender, and bone mineral density (BMD). Our aim was to investigate the association of patient characteristics, BMD, bone microarchitecture, and bone strength with the pattern complexity of DRFs. In this study, 251 patients aged 50-90 years with a radiologically confirmed DRF who attended the Fracture Liaison Service of VieCuri Medical Centre, the Netherlands, between November 2013 and June 2016 were included. In all patients fracture risk factors and underling metabolic disorders were evaluated and BMD measurement with vertebral fractures assessment by dual-energy X-ray absorptiometry was performed. Radiographs of all DRFs were reviewed by two independent investigators to assess fracture pattern complexity according to the AO/OTA classification in extra-articular (A), partially articular (B), and complete articular (C) fractures. For this study, patients with A and C fractures were compared. Seventy-one patients were additionally assessed by high-resolution peripheral quantitative computed tomography. Compared to group A, mean age, the proportion of males, and current smokers were higher in group C, but BMD and prevalent vertebral fractures were not different. In univariate analyses, age, male gender, trabecular area, volumetric BMD (vBMD), and stiffness were associated with type C fractures. In multivariate analyses, only male gender (odds ratio (OR) 8.48 95% confidence interval (CI) 1.75-41.18, p?=?0.008]) and age (OR 1.11 [95% CI 1.03-1.19, p?=?0.007]) were significantly associated with DRF pattern complexity. In conclusion, our data demonstrate that age and gender, but not body mass index, BMD, bone microarchitecture, or strength were associated with pattern complexity of DRFs.© 2019 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. J Orthop Res 37:1690-1697, 2019.
| S-EPMC6767516 | biostudies-literature
Project description:PurposeCarpal tunnel syndrome (CTS) can present following distal radius fracture (DRF) and may progress to require carpal tunnel release (CTR). The primary aim of this study was to determine the incidence of CTS within 6 months of a DRF and the rate of CTR in this population.MethodsWe used the PearlDiver national insurance database to determine the incidence of CTS after DRF. Patients were identified by International Classification of Diseases-10 codes, and treatment modalities for DRF and CTS were determined by respective Current Procedural Terminology codes. Patients with less than 6 months of follow-up, bilateral DRF, or preexisting CTS were excluded. Patient demographic characteristics were recorded. The time from DRF diagnosis to CTS diagnosis and CTR was determined. A multivariable analysis was performed to determine the differences between patients who underwent a CTR compared with those who were treated conservatively.ResultsWe identified 23,733 patients (6,015 men; 17,718 women) who sustained a DRF. Of these patients, 79.1% were treated nonsurgically and 20.9% underwent surgical fixation. In total, 9.2% (N = 2,179) were diagnosed with CTS in their ipsilateral extremity within 6 months of sustaining the DRF. Of the patients whose DRF was treated nonsurgically, 6.3% (N = 1,198) developed CTS and 2.9% (N = 546) required CTR. Of those patients whose DRF was treated surgically, 19.8% (N = 981) developed CTS and 13.3% (N = 661) required CTR. Of those patients with symptoms severe enough to warrant CTR, 18.5% required a second surgical intervention for the CTR.ConclusionsDistal radius fractures severe enough to require surgical fixation are associated with a higher incidence of perioperative CTS. Accordingly, careful evaluation for and counseling on CTS during surgical fixation may decrease the chance of a second surgery. We have identified a cohort of patients with DRFs who may benefit from prophylactic CTR.Type of study/level of evidenceDiagnostic IV.
| S-EPMC9678711 | biostudies-literature