Fit Assessment of Anatomic Plates for the Distal Medial Tibia

Schmutz, Beat; Wullschleger, Martin; Kim, Henry; Noser, Hansrudi; Schütz, Michael

doi:10.1097/bot.0b013e31816b10ba

Cited by 46 publications

(66 citation statements)

References 9 publications

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“…Introduction Replacement of the joints by artificial ones showed great results during late eighties. However, problems were found with the standard uncemented femoral stems which were supposed to be related with a geometric mismatch between standard femoral stem and the medullary cavity [1]. To address these problems we have developed customized femoral stem to optimize the fit of the stem to the femoral marrow cavity and the biomechanics of the joint including the femur head ball.…”

Section: Resultsmentioning

confidence: 99%

“…Four nonlinear spring elements were attached to the front and back of the tibial component to reproduce real movement of TKA knee. The nonlinear load-displacement relationship of the spring element was obtained by considering effects of soft tissues [1]. The load data obtained from a deep squatting analysis was utilized as the mechanical boundary condition [2].…”

Section: Finite Element Analysismentioning

confidence: 99%

“…This restriction of motion by inserting the interspinous device may affect the intradiscal pressure, foramina area, and rotational angle of the instrumented level [1][2][3]. The aim of this study was to understand the biomechanical effects of lumbar spine with the interspinous device in different loading conditions.…”

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confidence: 99%

“…This paper reports that clavicle reconciled plates of titanium alloy are examined for mechanical properties. Especially, stress and strain curves are measured on axial direction, and properties of stress distribution are measured by infrared rays method [1] under dynamic compressive load. …”

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confidence: 99%

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2D1 Artificial Organs & Implants II

2007

JBSE

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IntroductionAn interspinous process decompression device has been developed to treat spinal stenosis by placing the stenotic segment in slight flexion and prevents extension. This restriction of motion by inserting the interspinous device may affect the intradiscal pressure, foramina area, and rotational angle of the instrumented level [1][2][3]. The aim of this study was to understand the biomechanical effects of lumbar spine with the interspinous device in different loading conditions. Materials and MethodsA finite element model of the lumbar vertebral body (L1-L5) was generated from the digitized CT scans using the image software-Amira (Mercury Computer Systems, Inc., Massachusetts, U.S.A.). The surface models of the vertebral bodies and discs were transferred to a finite element preprocessing program -Mentat (MSC Software Corp., Los Angeles, U.S.A.) and the finite element mesh of the intact L1-L5 vertebrae was generated with 44,906 8-node hexahedral elements as shown in Fig. 1. The interspinous process decompression device was inserted between the spinous process of L3 and L4. The material properties of the interspinous process decompression device were a titanium alloy. Accordingly, a modulus of 110 GPa and a Poisson's ratio of 0.3 were defined for the titanium alloy. The nucleus pulposus were modeled as incompressible element. The curved facet joints had a gap of 0.5 mm and could transmit only compressive forces. The ligaments were represented by tension-only cable elements with linear material properties. The inferior side of L4 endplate was regidly fixed. The model was loaded with the upper body weight (300N) to simulate four loading cases: compression, flexion, extension, lateral bending and torsion (10Nm). A commercially available FEA software -MARC (MSC Software) was used as a solver for these analyses. Analyses were performed using the computing facilities at the National Center for High-Performance Computing (NCHC, Taiwan) via internet connection. Analysis results were retrieved back and processed on a local personal computer. All analysis results for the models with interbody spacers were compared with the intact ones. Results and DiscussionThe intradiscal pressure at the L3-L4 disc was decreased in the posterior annulus and nucleus under the extension moment with interspinous process decompression device. (fig.2) In extension, the implant increased the foraminal height by 11%, and the foraminal width by 10%. The range of motion of the instrumented level was significantly reduced in extension. However, the range of motion of the instrumented level were not affected in flexion, axial rotation and lateral bending. (fig.3) The range of motion in flexion-extension, axial rotation, and lateral bending at the adjacent levels were not have significantly changes by inserting the interspinous process decompression device. The interspinous process decompression device could decrease the intradiscal pressure and rotational angle of the upper vertebra in extension but without changing in other loading conditi...

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Section: Resultsmentioning

confidence: 99%

Section: Finite Element Analysismentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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2D1 Artificial Organs & Implants II

2007

JBSE

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“…Implant fit tests often rely on synthetic rapid prototype models or cadaver bones. Virtual tests address the practicability, accuracy and longterm cost-effectiveness, particularly when performed semi-or fully automatically [32,33]. Such tests should resort to large databases covering the anatomical variation of a representative population.…”

Section: Discussionmentioning

confidence: 99%

Morphometric analysis of anatomical implant forms for minimally invasive acetabular fracture osteosynthesis

Maier

Kamer

Noser

et al. 2012

Computer Aided Surgery

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Introduction: Anatomical implants enable minimally invasive osteosynthesis (MIO) and represent ideal complements of computer-assisted surgical workflows. This 3D morphometric study analyzes anatomical implant forms (AIF) for acetabular fracture osteosynthesis (AFO). Materials and Methods: Three-dimensional pelvis models were created from clinical CT data of 99 European-Caucasian patients (50 females, 49 males). The mean age of the patients was 60.1 years (range: 20-89; SD 10.8). Definition of a referential region of interest (ROI) corresponding to an AIF for AFO was followed by automated ROI computation for each of the 198 hemipelvises. Three-dimensional statistical modeling and analysis of the resulting 198 homologous ROIs consisted of thin-plate spline transformation, generalized Procrustes fit, and principal component analysis. Results: The mean ROI length was 18.2 cm (range: 16.1-20.1 cm; SD 0.76). The first principal component (PC1) mainly modeled the ROI length, which correlated well with body height (r ¼ 0.325; p < 0.001). PC1 comprised 47.4% of the overall ROI form variation. PC2 primarily influenced the ROI curvature in the anterior-posterior (inlet) view. Curvatures were more pronounced in female patients compared to males (p < 0.001). There was no gender-specific ROI size variation. PC1-4 contained 80.2% of the total ROI form variation. Left and right ROI forms displayed symmetry. Conclusion: This 3D morphometric study demonstrates the feasibility of anatomical implants for minimally invasive acetabular fracture osteosynthesis. Implant size/length is by far the most important variable of form variation. The necessity of gender-specific implant forms requires further investigation. The non-fractured, contralateral hemipelvis can be used for preoperative surgical planning. Ultimately, the plate design will depend on prospective implant fit tests based on the required fit as defined by the clinician.

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Secular evolution of femoral morphology from a clinical perspective

et al. 2020

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IntroductionIntramedullary nailing is the surgical method of choice for the treatment of proximal femur or femoral shaft fractures. Implant manufacturers aim to design implants fitting for the broadest possible population segment. As complete morphological data sets of long bones are not widely available, anatomical collections of historical dry bone specimens may represent abundant additional sources of morphological three‐dimensional (3D) data for implant design, provided they are consistent with present populations. This study aims to investigate secular trends and age‐related changes of femoral morphology of the Caucasian population over the past 800 years.Materials and methodsComputer graphical measurements of 3D‐datasets of right and left femora derived from computed tomography (CT) scans, representative of the present Caucasian population, were compared to computer graphical measurements of 3D‐datasets of right and left femora derived from CT scans of specimens from a historical medieval European bone collection.ResultsClinically relevant parameters of historical medieval European femora were found mostly consistent with correlative data of the present Caucasian population. Additionally, for some of the evaluated parameters, particularly anteversion, morphological differences significantly correlated to individual age and sex could be identified, whereas other parameters such as caput‐collum‐diaphyseal angle or radius of anterior femoral bowing were not correlated to individual age or sex.ConclusionThe findings suggest that more recent historical specimen collections may be a convenient and easily accessible source of new 3D morphological data, as well as to complement existing data, to be used by researchers and manufacturers for the development of intramedullary femoral nails.

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Fit Assessment of Anatomic Plates for the Distal Medial Tibia

Cited by 46 publications

References 9 publications

2D1 Artificial Organs & Implants II

2D1 Artificial Organs & Implants II

Morphometric analysis of anatomical implant forms for minimally invasive acetabular fracture osteosynthesis

Secular evolution of femoral morphology from a clinical perspective

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