Development of an Automated Mass-Customisation Pipeline for Knee Replacement Surgery Using Bi-Planar X-rays

2021 ◽  
pp. 1-23
Author(s):  
Thomas A Burge ◽  
Jonathan Jeffers ◽  
Connor Myant
Keyword(s):  
Knee Replacement ◽  
Mean Squared Error ◽  
Preoperative Assessment ◽  
Application Programming Interface ◽  
Anatomical Reconstruction ◽  
X Rays ◽  
X Ray ◽  
Mass Customisation ◽  
Replacement Surgery ◽  
Implant Selection

Abstract For standard ‘off-the-shelf’ knee replacement procedures surgeons use X-ray images to aid implant selection from a limited number of models and sizes. This can lead to complications and the need for implant revision due to poor implant fit. Customised solutions have been shown to improve results but require increased preoperative assessment (Computed Tomography or Magnetic Resonance Imaging), longer lead times and higher costs which have prevented widespread adoption. To attain the benefits of custom implants, whilst avoiding the limitations of currently available solutions, a fully automated mass-customisation pipeline, capable of developing customised implant designs for fabrication via additive manufacturing from calibrated X-rays, is proposed. The pipeline uses convolutional neural networks to extract information from bi-planar X-ray images, point depth and statistical shape models to reconstruct the anatomy, and application programming interface scripts to generate various customised implant designs. The pipeline was trained using data from the Korea Institute of Science and Technology Information. Thirty subjects were used to test the accuracy of the anatomical reconstruction, ten from this dataset and a further twenty independent subjects obtained from the Osteoarthritis Initiative. An average root mean squared error of 1.00 mm was found for the femur test cases and 1.07 mm for the tibia. 3D distance maps of the output components demonstrated these results corresponded to well-fitting components, verifying automatic customisation of knee replacement implants is feasible from 2D medical imaging.

159 The Need Of Six Monthly Follow Up X-Rays Post Total Knee Replacement(TKR)

2021 ◽  
Vol 108 (Supplement_6) ◽  
Author(s):  
N Baig ◽  
M Ferrari ◽  
A Lukaszewicz
Keyword(s):  
Total Knee Replacement ◽  
Knee Replacement ◽  
Trauma Centre ◽  
X Rays ◽  
Data Set ◽  
X Ray ◽  
Major Trauma Centre ◽  
Plain Films ◽  
Total Knee

Abstract Background There is a longstanding culture of repeat x-rays after total knee replacement (TKR) as part of follow up, often combined with a clinic review. This is to check that the prosthesis is in a satisfactory position. There are inherently a number of issues with this historic approach including exposure of patients to further radiation who may be asymptomatic, time delays in busy clinics or x-ray departments and costs. Objectives The aim of this audit was to assess whether follow up plain films after TKR are methodically undertaken and of benefit to confirm satisfactory appearance if immediate post -operative x-rays were unremarkable. The findings of a six month follow up x-ray was specifically evaluated. The secondary aim was to establish the timing of further follow up x-rays within the department. Method 200 patients were included within the analysis, they all received a TKR at a major trauma centre, over a one-year period between December 2017 and December 2018. Results It was found that 100% of those patients having a post-operative film had a satisfactory appearance. 78% of patients had at least one further follow op x-ray of which 99.4% were satisfactory. Up to five follow up x-rays were taken with 53.5% of patients having a follow up x-ray at 6 months. Conclusions From the above results there is minimal, if any, evidence within the data set to support routine, additional follow up imaging if initial post-operative films are satisfactory, and the patient is asymptomatic.

scholarly journals Shape Analysis of the Patellar Bone Surface and Cutting Plane for Knee Replacement Surgery

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
E. L. Rex ◽  
J. Werle ◽  
B. C. Burkart ◽  
J. R. MacKenzie ◽  
K. D. Johnston ◽  
...  
Keyword(s):  
Knee Replacement ◽  
Shape Analysis ◽  
Cutting Plane ◽  
X Rays ◽  
Anterior Surface ◽  
Knee Replacement Surgery ◽  
Replacement Surgery ◽  
Contact Points ◽  
Definition Of ◽  
Quantitative Definition

Geometry of the patella (kneecap) remains poorly understood yet is highly relevant to performing the correct patellar cut to reduce pain and to improve function and satisfaction after knee replacement surgery. Although studies routinely refer to “parallel to the anterior surface” and “the patellar horizon,” a quantitative definition of these is lacking and significant variability exists between observers for this irregularly-shaped bone. A 2D-3D shape analysis technique was developed to determine the optimal device configuration for contacting the patellar surface. Axial and sagittal pseudo-X-rays were created from 18 computed tomography (CT) scans of cadaveric knees. Four expert surgeons reviewed three repetitions of the X-rays in randomized order, marking their desired cut plane and their estimate of the anterior surface. These 2D results were related back to the 3D model to create the desired plane. There was considerable variability in perceptions, with intra- and intersurgeon repeatability (standard deviations) ranging from 1.3° to 2.4°. The best configuration of contact points to achieve the desired cutting plane was three pegs centred on the patellar surface, two superior and one inferior, forming a 16 mm equilateral triangle. This configuration achieved predicted cut planes within 1° of the surgeon ranges on all 18 patellae. Implementing this, as was done in a subsequent prototype surgical device, should help improve the success and satisfaction of knee replacement surgery.

scholarly journals Clinical Impact of Pelvic Malrotation on X-ray based Preoperative Planning for Total Hip Arthroplasty: A Proof-of-concept and Prudent Prediction of Acceptable Rotation

2021 ◽  
Author(s):  
Ernest Christian Lourens ◽  
Andrew Kurmis ◽  
Wan Yin Lim
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Clinical Impact ◽  
Anatomical Reconstruction ◽  
Horizontal Distance ◽  
X Rays ◽  
Proof Of Concept ◽  
Pelvic Rotation ◽  
X Ray ◽  
Total Hip

Abstract IntroductionPelvic rotation (PR) on preoperative X-ray templating can affect various critical measured acetabular angles and potentially outcomes of successful total hip arthroplasty (THA). Optimising anatomical reconstruction of the joint is essential to achieve function, longevity and prevention of complications following surgery. There is limited literature that standardises the degree of acceptable PR on X-ray or its effects on the fitting of acetabular prostheses. ObjectiveThis study aimed to develop a proof-of-concept that quantifies how PR can affect various acetabular angles used in pre-operative THA templating and to formulate a practicable method of determining if the preoperative PR is acceptable. Materials and MethodsComputerised tomography (CT) models from three control and two THA patients were generated and manipulated in various degrees of PR. CT slices were thickened to simulate X-rays and acetabular angles measured. ResultsThe acetabular anteversion distance (AAD) and lateral opening angle (LOA) demonstrated a linear and quadratic relationship with good correlation (R2=0.923, R2=0.710 respectively, p<0.0001) in relation to PR. Change in area of prosthesis (AOP) demonstrated a good linear correlation (r2=0.774 and r2=0.875, p<0.0001) with PR. Two novel measurements were used to estimate the degree of PR from a pelvic X-ray; the horizontal distance between pubic symphysis and middle of sacrococcygeal joint (PSSC) and the simplified pelvic rotation ratio (SPRR). A strong correlation between PSSC and SPRR with change in PR was observed (R2=0.970, R2=0.953, p<0.001). ConclusionPreliminary results suggests that an SPRR >2.0 correlates to PR>20° with potential to have a clinical impact on preoperative measurements.

Features of preoperative planning for hip arthroplasty

2021 ◽  
Vol 2 (2) ◽  
pp. 59-64
Author(s):  
B.P. Buryachenko ◽  
◽  
D.I. Vartholomew ◽  
Keyword(s):  
Hip Arthroplasty ◽  
Hip Replacement ◽  
Preoperative Planning ◽  
X Rays ◽  
X Ray ◽  
Replacement Surgery ◽  
Hip Replacement Surgery ◽  
Digital Planning ◽  
Speed Up

Relevance. Preoperative planning is an integral stage of hip replacement surgery, which reduces the number of complications and improves the accuracy of the installation of endoprosthesis components. Goal. Assess the accuracy of digital preoperative planning using mediCAD® v.6. Material and methods. The study included data from 276 patients with idiopathic coxarthrosis who were treated at the orthopedic department of the Center of Traumatology and Orthopedics of the Main Military Clinical Hospital named after N.N. Burdenko in the period from 2018 to 2020.The patients had X-rays of the pelvis and hip joint in two projections. All patients underwent total hip arthroplasty with cementless endoprostheses. Before surgery, all patients underwent preoperative planning using the mediCAD® v.6 software. After the operation, a control X-ray was performed, followed by an assessment of the obtained images in the same software. The planning accuracy was evaluated by comparing the parameters that were calculated in the program before the operation with the parameters of the installed implants. The results. The conducted study demonstrated the high accuracy of digital preoperative planning. The coincidence of the planned sizes of the acetabular component of the endoprosthesis and a deviation within +/- one size was observed in 93% of patients, femoral — in 84% of patients. Conclusion. Preoperative planning is an integral stage of hip replacement surgery, which allows you to perform the necessary preparation for the intervention. Digital planning allows you to simplify and speed up the process of preparing for an operation and improve the quality of its execution.

scholarly journals Severe Heterotopic Ossification following Total Knee Replacement

2014 ◽  
Vol 2014 ◽  
pp. 1-3 ◽  
Author(s):  
Alexander L. Dodds ◽  
Gregory C. R. Keene
Keyword(s):  
Total Knee Replacement ◽  
Range Of Motion ◽  
Heterotopic Ossification ◽  
Knee Replacement ◽  
Rare Event ◽  
Nonoperative Treatment ◽  
X Rays ◽  
Rotating Platform ◽  
Replacement Surgery ◽  
Total Knee

Although the incidence of minor heterotopic ossification is probably higher than what is usually expected, severe heterotopic ossification (HO) is an extremely rare event following total knee replacement surgery. We present the case of a 66-year-old woman who initially had achieved an excellent range of motion following bilateral uncemented rotating platform total knee replacement, before presenting with pain and loss of range of motion at 2 months after surgery. Severe HO was diagnosed on X-rays. Treatment consisted of nonoperative measures only, including physiotherapy with hydrotherapy and anti-inflammatories. She eventually regained her range of motion when seen at 8 months after operation. This case illustrates that nonoperative treatment without the use of radiotherapy or surgery can be used to safely resolve stiffness caused by HO after total knee replacement.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

Chemical Species Identification in an SEM by Changes in Emitted X-Ray Energies

1974 ◽  
Vol 32 ◽  
pp. 570-571
Author(s):  
R. H. Duff
Keyword(s):  
Species Identification ◽  
Valence Electron ◽  
Chemical Species ◽  
X Rays ◽  
Chemical Bonds ◽  
Small Shift ◽  
X Ray ◽  
Electron Transitions ◽  
Peak Energy ◽  
Chemical Combination

A material irradiated with electrons emits x-rays having energies characteristic of the elements present. Chemical combination between elements results in a small shift of the peak energies of these characteristic x-rays because chemical bonds between different elements have different energies. The energy differences of the characteristic x-rays resulting from valence electron transitions can be used to identify the chemical species present and to obtain information about the chemical bond itself. Although these peak-energy shifts have been well known for a number of years, their use for chemical-species identification in small volumes of material was not realized until the development of the electron microprobe.

Influence of X-Ray Induced Fluorescence on Energy Dispersive X-Ray Analysis of Thin Foils

1977 ◽  
Vol 35 ◽  
pp. 328-329
Author(s):  
E. A. Kenik ◽  
J. Bentley
Keyword(s):  
Thin Foil ◽  
Electron Excitation ◽  
Simple Approach ◽  
Foil Thickness ◽  
X Rays ◽  
X Ray ◽  
Hole Spectrum ◽  
Illumination System ◽  
Thin Foils ◽  
Intensity Ratios

Cliff and Lorimer (1) have proposed a simple approach to thin foil x-ray analy sis based on the ratio of x-ray peak intensities. However, there are several experimental pitfalls which must be recognized in obtaining the desired x-ray intensities. Undesirable x-ray induced fluorescence of the specimen can result from various mechanisms and leads to x-ray intensities not characteristic of electron excitation and further results in incorrect intensity ratios.In measuring the x-ray intensity ratio for NiAl as a function of foil thickness, Zaluzec and Fraser (2) found the ratio was not constant for thicknesses where absorption could be neglected. They demonstrated that this effect originated from x-ray induced fluorescence by blocking the beam with lead foil. The primary x-rays arise in the illumination system and result in varying intensity ratios and a finite x-ray spectrum even when the specimen is not intercepting the electron beam, an ‘in-hole’ spectrum. We have developed a second technique for detecting x-ray induced fluorescence based on the magnitude of the ‘in-hole’ spectrum with different filament emission currents and condenser apertures.

X-ray micro tomography in the scanning electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 106-107 ◽  
Author(s):  
W. Brünger
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Target Surface ◽  
The Body ◽  
X Rays ◽  
Cross Sectional ◽  
X Ray ◽  
Micro Tomography ◽  
Scanning Electron

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

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