A reliable clean process for five-axis milling of knee prostheses

2021 ◽  
Author(s):  
Gaizka Gómez-Escudero ◽  
Aner Jimeno Beitia ◽  
Gonzalo Martínez de Pissón Caruncho ◽  
Luis Norberto López de Lacalle ◽  
Haizea González-Barrio ◽  
...  
Keyword(s):  
Knee Prostheses ◽  
Five Axis

Simulating Dynamic Activities Using a Five-Axis Knee Simulator

2005 ◽  
Vol 127 (1) ◽  
pp. 123-133 ◽  
Author(s):  
Lorin P. Maletsky ◽  
Ben M. Hillberry
Keyword(s):  
Sagittal Plane ◽  
Compressive Force ◽  
Knee Prostheses ◽  
Plane Model ◽  
Knee Simulator ◽  
Specific Loading ◽  
Total Knee ◽  
Five Axis ◽  
Cadaveric Knee ◽  
Good Agreement

This work describes the design and capabilities of the Purdue Knee Simulator: Mark II and a sagittal-plane model of the machine. This five-axis simulator was designed and constructed to simulate dynamic loading activities on either cadaveric knee specimens or total knee prostheses mounted on fixtures. The purpose of the machine was to provide a consistent, realistic loading of the knee joint, allowing the kinematics and specific loading of the structures of the knee to be determined based on condition, articular geometry, and simulated activity. The sagittal-plane model of the knee simulator was developed both to predict the loading at the knee from arbitrary inputs and to generate the necessary inputs required to duplicate specified joint loading. Measured tibio-femoral compressive force and quadriceps tension were shown to be in good agreement with the predicted loads from the model. A controlled moment about the ankle-flexion axis was also shown to change the loading on the quadriceps.

Loading Evaluation of Knee Joint During Walking Using the Next Generation Knee Simulator

2000 ◽  
Author(s):  
Lorin P. Maletsky ◽  
Ben M. Hillberry
Keyword(s):  
Knee Joint ◽  
Elderly Woman ◽  
Material Selection ◽  
Knee Prostheses ◽  
Younger Patients ◽  
High Occurrence ◽  
Knee Simulator ◽  
Total Knee ◽  
Five Axis

Abstract Even with the advances in material selection, processing, and articular geometry for knee prostheses, there is still a need for in vitro evaluation of these components. The high occurrence of revision surgeries for failed prosthetics suggests that the component designs can still be improved. While historically the typical total knee recipient was an elderly woman, components are being implanted in younger patients who wish to lead more active lives with their new artificial knees. Therefore, the testing of new prostheses must be more rigorous and demanding than done previously. For these reasons a new five-axis electro-hydraulic knee simulator was constructed.

The new CM-Series TEMs: integration of a five-axis motorized, fully computer-controlled goniometer

1993 ◽  
Vol 51 ◽  
pp. 258-259
Author(s):  
Marc J.C. de Jong ◽  
P. Emile S.J. Asselbergs ◽  
Max T. Otten
Keyword(s):  
Mechanical Design ◽  
Computer Control ◽  
Objective Lens ◽  
Access Port ◽  
Vibration Stability ◽  
Transmission Electron ◽  
Computer Controlled ◽  
High Degree ◽  
Five Axis ◽  
Five Axes

A new step forward in Transmission Electron Microscopy has been made with the introduction of the CompuStage on the CM-series TEMs: CM120, CM200, CM200 FEG and CM300. This new goniometer has motorization on five axes (X, Y, Z, α, β), all under full computer control by a dedicated microprocessor that is in communication with the main CM processor. Positions on all five axes are read out directly - not via a system counting motor revolutions - thereby providing a high degree of accuracy. The CompuStage enters the octagonal block around the specimen through a single port, allowing the specimen stage to float freely in the vacuum between the objective-lens pole pieces, thereby improving vibration stability and freeing up one access port. Improvements in the mechanical design ensure higher stability with regard to vibration and drift. During stage movement the holder O-ring no longer slides, providing higher drift stability and positioning accuracy as well as better vacuum.

Hemophilic Bledding Evaluated by Blood Pool Scanning

1981 ◽  
Vol 45 (03) ◽  
pp. 208-210 ◽  
Author(s):  
D Green ◽  
S M Spies ◽  
N A Rana ◽  
J W Milgram ◽  
R Mintzer
Keyword(s):  
Blood Volume ◽  
Blood Pool ◽  
Invasive Technique ◽  
Scintillation Camera ◽  
Knee Prostheses ◽  
Hemophilic Patient ◽  
Chronic Arthropathy ◽  
Image Density ◽  
Regional Blood Volume

SummaryThe technique of blood pool scanning was used to examine 15 hemophilic subjects. Employing an in vivo method for erythrocyte labeling with Technetium-99 m, a dynamic perfusion sequence is obtained using a scintillation camera positioned over the area to be examined. This demonstrates the vascularity of the tissue. Subsequently, equilibrium blood pool images of the area are obtained and analyzed with a densitometer to assess relative regional blood volume. In patients who were not bleeding but had chronic arthropathy, vascularity was not increased, and the blood volume of comparable joints was similar. By contrast, marked increases in vascularity and image density were observed in studies of acutely bleeding joints. Chronic hemarthroses were associated with persistent, but less marked increases in joint perfusion. Transient increases in joint vascularity were demonstrated after insertion of knee prostheses. In a patient with a thigh hematoma, the dimensions of the hemorrhage were clearly delineated. Since only a tracer dose of nuclide is infused intravenously, there are no allergic reactions or other side effects of the procedure. Blood pool scanning is a safe, non-invasive technique that augments clinical and radiographic evaluations, and provides a new dimension in the assessment of the hemophilic patient.

Evaluation of aseptic loosening of knee prostheses by quantitative bone scintigraphy

2008 ◽  
Vol 47 (04) ◽  
pp. 163-166 ◽  
Author(s):  
D. Steiner ◽  
S. Laurich ◽  
R. Bauer ◽  
J. Kordelle ◽  
R. Klett
Keyword(s):  
Aseptic Loosening ◽  
Bone Scintigraphy ◽  
Revision Surgery ◽  
Predictive Value ◽  
Knee Prostheses ◽  
Treatment Regimes ◽  
Golden Standard ◽  
The Difference ◽  
Sensitivity Specificity ◽  
Asymptomatic Control

SummaryIn not infected knee prostheses bone scintigraphy is a possible method to diagnose mechanical loosening, and therefore, to affect treatment regimes in symptomatic patients. However, hitherto studies showed controversial results for the reliability of bone scintigraphy in diagnosing loosened knee prostheses by using asymptomatic control groups. Therefore, the aim of our study was to optimize the interpretation procedure and to evaluate the accuracy using results from revision surgery as standard. Methods: Retrospectively, we were able to examine the tibial component in 31 cemented prostheses. In this prostheses infection was excluded by histological or bacteriological examination during revision surgery. To quantify bone scintigraphy, we used medial and lateral tibial regions with a reference region from the contralateral femur. Results: To differentiate between loosened and intact prostheses we found a threshold of 5.0 for the maximum tibia to femur ratio of the both tibial regions and a threshold of 18% for the difference of the ratio of both tibial regions. Using these thresholds, values of 0.9, 1, 0.85, 1, and 0.94 were calculated for sensitivity, specificity, negative predictive value, positive predictive value, and accuracy, respectively. To get a sensitivity of 1, we found a lower threshold of 3.3 for the maximum tibia to femur ratio. Conclusion: Quantitative bone scintigraphy appears to be a reliable diagnostic tool for aseptic loosening of knee prostheses with thresholds evaluated by revision surgery results being the golden standard.

scholarly journals Five Axis Control Machining of Surface Texture with Regular Pattern

2009 ◽  
Vol 75 (12) ◽  
pp. 1459-1463 ◽  
Author(s):  
Akira HAYASHI ◽  
Yoshikazu KOBAYASHI ◽  
Kenji SHIRAI ◽  
Yasuhiko HARA
Keyword(s):  
Surface Texture ◽  
Regular Pattern ◽  
Five Axis

Feedrate scheduling of a five-axis hybrid robot for milling considering drive constraints

2021 ◽  
Vol 112 (11-12) ◽  
pp. 3117-3136
Author(s):  
Guangxi Li ◽  
Haitao Liu ◽  
Wei Yue ◽  
Juliang Xiao
Keyword(s):  
Feedrate Scheduling ◽  
Five Axis

scholarly journals Sensing and Decentralized Control of a Five-Axis Monolithic Nanopositioning Stage

2020 ◽  
Vol 53 (2) ◽  
pp. 9087-9092
Author(s):  
Meysam Omidbeike ◽  
Yuen K. Yong ◽  
Andrew.J. Fleming
Keyword(s):  
Decentralized Control ◽  
Five Axis

scholarly journals Accuracy comparison of various quantitative [99mTc]Tc-DPD SPECT/CT reconstruction techniques in patients with symptomatic hip and knee joint prostheses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Martin Braun ◽  
Michal Cachovan ◽  
Felix Kaul ◽  
Federico Caobelli ◽  
Markus Bäumer ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Quantitative Data ◽  
Diagnostic Tools ◽  
Ct Reconstruction ◽  
Knee Prostheses ◽  
Uptake Quantification ◽  
Ct Data ◽  
Joint Prostheses ◽  
Painful Hip ◽  
Xspect Bone

Abstract Background There is a need for better diagnostic tools that identify loose total hip and knee arthroplasties. Here, we present the accuracy of different 99mTc-dicarboxypropandiphosphate ([99mTc]Tc-DPD) SPECT/CT quantification tools for the detection of loose prostheses in patients with painful hip and knee arthroplasties. Methods Quantitative reconstruction of mineral phase SPECT data was performed using Siemens xSPECT-Quant and xSPECT-Bone, with and without metal artefact reduction (iMAR) of CT-data. Quantitative data (SUVmax values) were compared to intraoperative diagnosis or clinical outcome after at least 1 year as standard of comparison. Cut-off values and accuracies were calculated using receiver operator characteristics. Accuracy of uptake quantification was compared to the accuracy of visual SPECT/CT readings, blinded for the quantitative data and clinical outcome. Results In this prospective study, 30 consecutive patients with 33 symptomatic hip and knee prostheses underwent [99mTc]Tc-DPD SPECT/CT. Ten arthroplasties were diagnosed loose and 23 stable. Mean-SUVmax was significantly higher around loose prostheses compared to stable prostheses, regardless of the quantification method (P = 0.0025–0.0001). Quantification with xSPECT-Bone-iMAR showed the highest accuracy (93.9% [95% CI 79.6–100%]) which was significantly higher compared to xSPECT-Quant-iMAR (81.8% [67.5–96.1%], P = 0.04) and xSPECT-Quant without iMAR (77.4% [62.4–92.4%], P = 0.02). Accuracies of clinical reading were non-significantly lower compared to quantitative measures (84.8% [70.6–99.1%] (senior) and 81.5% [67.5–96.1%] (trainee)). Conclusion Quantification with [99mTc]Tc-DPD xSPECT-Bone-iMAR discriminates best between loose and stable prostheses of all evaluated methods. The overall high accuracy of different quantitative measures underlines the potential of [99mTc]Tc-DPD-quantification as a biomarker and demands further prospective evaluation in a larger number of prosthesis.

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