Accurate Restoration Research Articles

Arthroscopic-assisted plate fixation for displaced large-sized comminuted greater tuberosity fractures of proximal humerus: a novel surgical technique.

The purpose of the present study was to describe the use of a novel hybrid surgical technique-arthroscopic-assisted plate fixation-and evaluate its clinical and anatomical outcomes in the management of large, displaced greater tuberosity (GT) fractures with comminution. From 2009 to 2011, this novel technique was performed in 11 patients [2 men and 9 women; median age, 64years (range 41-83years)] with large, comminuted GT fractures, with fragment displacements of >5mm. The preoperative mean posterior and superior migration of the fractured fragment, as measured on computed tomography (CT), was 19.5 and 5.5mm, respectively. Two patients had shoulder fracture-dislocation, and three had associated undisplaced surgical neck fracture. The mean duration between injury and surgery was 4days. The mean follow-up duration was 26months. At the final follow-up, the mean postoperative ASES, UCLA and SST scores were 84, 29, and 8, respectively. The mean range of motion was as follows: forward flexion, 138°; abduction, 135°; external rotation at the side, 19°; and internal rotation, up to the L2 level. The mean posterior and superior displacements of fracture fragments on postoperative CT scan [0.7±0.8mm (range 0-2.1mm) and 2.8±0.5mm (range 3.4-5.3mm), respectively] were significantly improved (p<0.05). On arthroscopy, a partial articular-side supraspinatus tendon avulsion lesion was identified in 10 of 11 patients (91%), and 1 of these patients had a partial tear of the biceps and 1 had a partial subscapularis tear, respectively (9%). Intraoperatively, 1 anchor pullout and 1 anchor protrusion through the humeral head were noted and corrected. Postoperatively, the loss of reduction in the fracture fragment was noted in 1 patient at 4weeks, after corrective reduction and fixation surgery. The novel arthroscopic-assisted anatomical plate fixation technique was found to be effective in reducing large-sized, displaced, comminuted GT fractures and in allowing concurrent management of intra-articular pathologies and early functional rehabilitation. Compared with the conventional plate fixation or arthroscopic suture anchor fixation technique, arthroscopic-assisted plate fixation enabled accurate restoration of the medial footprint of the GT fracture and provided an effective buttress to the large-sized GT fracture fragments. Retrospective clinical study, Level IV.

Primary and secondary reconstruction of complex craniofacial defects using polyetheretherketone custom-made implants.

The aim of this study was to evaluate the surgical outcomes using polyetheretherketone (PEEK) patient-specific prostheses produced by computer-aided design and manufacturing for primary and secondary reconstruction in patients with craniofacial defects. The study included 13 patients who underwent reconstruction for craniofacial defects using PEEK patient-specific implants (PSI). Eight patients underwent single-step primary reconstruction using individual custom-made surgical guides and custom-made prostheses during the same surgery; five patients underwent delayed reconstruction. The material used to manufacture the implants was PEEK in 13 cases. All patients underwent esthetic examination, ophthalmological examination, and radiological evaluation during the preoperative and follow-up periods. The operation duration and short- and long-term complications were recorded. The shape and global position of the implants were satisfactory in each case. Fitting of the implant during surgery required extensive adaptation in 1 case and minor in 11 cases. Of 13 implants, 11 adequately restored a morphological complex area with satisfactory cosmetic results. No complications related to the implants were reported. Reconstruction for cranio-facial defects using PEEK computer-aided designed and manufactured implants is a promising new technique that allows for accurate restoration of the complex 3D anatomy of the craniofacial region.

A method of Trajectory Restoration at Intersection

Floating car data (FCD) is vechiel’s position trace that is comes from Global Positioning System receivers.collected at the discrete time. FCD contains much information of traffic and road-network. But there are different level of trajectory shape damages because of the affection of sample frequency and running speed. So before the FCD mining, the first thing should be done is to restore track to make up for the loss. This paper analyzes the spatial-temporal characteristics of floating car trajectory at intersection, and build an error recognition model and a adjust algorithm. Experiments showed that this method can improve accuracy of trajectory restoration, and set a solid foundation for further data mining.

Percutaneous Arthroscopic Calcaneal Osteosynthesis: A Minimally Invasive Technique for Displaced Intra-Articular Calcaneal Fractures

The management of calcaneal fracture remains challenging. Open surgery has been fraught with high infection rates and soft tissue complications. More minimally invasive procedures have reduced this risk, but the patient outcomes after treatment of displaced calcaneal fractures have remained relatively unsatisfactory. We present a method for the management of Sanders grade II and III calcaneal fractures: percutaneous arthroscopic calcaneal osteosynthesis. Thirty-three fractures in 30 patients who had presented to our tertiary foot and ankle trauma center in central London were treated with percutaneous arthroscopic calcaneal osteosynthesis for calcaneal fractures, and the data were prospectively collected. The mean patient age at injury was 39 years. The mean follow-up period was 24 months. Of our patients, 58% were smokers at injury. Of the 33 fractures, 46% were classified as grade II and 54% as grade III. The mean length of stay was 1.92 days. At the final follow-up visit, the mean Böhler angle had increased from 11.10° (range 2° to 24°) to 23.41° (range 15° to 35°). The modified American Orthopaedic Foot and Ankle Society scale score was 72.18 (range 18 to 100), the calcaneal fracture scoring system score was 79.34 (range 42 to 100), and the visual analog scale score was 29.50 (range 0 to 100). We had a single case of a superficial port site infection and 2 cases of prominent screws, which were removed. No cases of deep infection developed, and no conversion to subtalar fusion was required. This technique significantly reduced the incidence of postoperative wound complications. Direct visualization of the fracture site allowed accurate restoration of the articular surface and correction of heel varus. Furthermore, it was associated with a high self-reported functional outcome and a return to preinjury employment levels. Also, the results did not appear to be influenced by tobacco consumption.

Single image fog removal based on local extrema

Atmospheric conditions induced by suspended particles, such as fog and haze, severely alter the scene appearance. In this paper, we propose a novel defogging method based on the local extrema, aiming at improving the image visibility under foggy or hazy weather condition. The proposed method utilizes atmospheric scattering model to realize the fog removal. It applies the local extrema method to figure out three pyramid levels to estimate atmospheric veil, and manipulates the tone and contrast of details at different scales through multi-scale tone manipulation algorithm. The results on the experiments of comparison with traditional methods demonstrate that the proposed method can achieve more accurate restoration for the color and details, resulting in a great improvement in image visibility.

Adaptive image fog removal based on multi-scale WLS filter

Atmospheric conditions induced by suspended particles, such as fog and haze, severely alter the scene appearance. In this paper, we proposed a novel adaptive defogging method based on the weighted least squares WLS framework, aiming at improving the image visibility under foggy or hazy weather condition. Through the inference of halo intensity and smooth degree, our method adopts image fusion technology based on multi-scale WLS filter to estimate atmospheric veil, and restores the foggy image by inverting the atmospheric scattering model. The results on the experiments of comparison with traditional algorithms demonstrate that the proposed method can achieve more accurate restoration, resulting in a great improvement in image visibility.

Tooth preparation for full-coverage restorations-a literature review.

The objective of this review was to assess the current knowledge about tooth preparation for full-coverage restorations regarding the following aspects: biological parameters, preparation geometry, and technical conditions. A systematic literature search was conducted using three electronic databases (MEDLINE, DIMDI, and Cochrane databases) in order to identify relevant citations; additionally, the process was augmented by a hand search. A number of 117 citations were relevant; 11 of these were reviews, 23 were clinical studies, 82 were in vitro investigations, and one was animal research. The basic form of a preparation has not changed substantially over the years, although new materials like all-ceramic systems have their own demands with regard to the details of the preparation's geometry. Estimating how much of the tooth structure can be removed without harming the tooth remains one of the biggest problems, if not the main difficulty, during tooth preparation. As the periodontal tissues may be affected by the restoration margin, a supragingival position of the margin should be preferred whenever possible. No finish line design has yet proven to be superior with regard to the marginal accuracy of the subsequent restoration. Instead, good detectability of the margin for the dental technician or intraoral scanning devices appears to be of primary importance in order to achieve a good fitting restoration. A detailed look at the covered aspects regarding tooth preparations can help to improve clinical outcomes in daily practice.

Fast algorithm for estimating power frequency phasors under power system transients

Power frequency phasors are widely used in the measurement, analysis, control and protection of power systems. When disturbances occur in such systems, power frequency phasors must be estimated quickly to ensure an accurate restoration to normal operation. Hence, a fast and accurate estimation algorithm would be a significantly useful tool. In consideration of the composition of transient signals in power systems, a novel algorithm for power frequency phasor estimation is proposed. Based on the double matrix pencil method, a unitary reference matrix of complex-valued exponential signals is formed. The power frequency phasor estimation is then transformed to a brief multiplication of matrices. Thus, the QR decomposition, generalised eigenvalue calculation, and secondary estimation can be avoided and no complex multiplication is introduced. Therefore, the computational efficiency of the proposed method is improved compared with previous estimation techniques. Analytical and experimental investigations show that the proposed algorithm can extract power frequency phasors accurately, stably and quickly under power system transients.

Geometric correction of atmospheric turbulence-degraded video containing moving objects.

Long-distance surveillance is a challenging task because of atmospheric turbulence that causes time-varying image shifts and blurs in images. These distortions become more significant as the imaging distance increases. This paper presents a new method for compensating image shifting in a video sequence while keeping real moving objects in the video unharmed. In this approach, firstly, a highly accurate and fast optical flow technique is applied to estimate the motion vector maps of the input frames and a centroid algorithm is employed to generate a geometrically correct frame in which there is no moving object. The second step involves applying an algorithm for detecting real moving objects in the video sequence and then restoring it with those objects unaffected. The performance of the proposed method is verified by comparing it with that of a state-of-the-art approach. Simulation experiments using both synthetic and real-life surveillance videos demonstrate that this method significantly improves the accuracy of image restoration while preserving moving objects.

An in vitro study to evaluate the accuracy of dies obtained from dual-arch impression trays using addition silicone impression material and tray combinations

Objectives: This study aims to evaluate and compare the accuracy of dies obtained from dual-arch impression trays using vinyl polysiloxane impression material and tray combinations. Materials and Methods: Typodont teeth were embedded in the maxillary and mandibular Dentoform model bases and mounted in an articulator using maximum intercuspation. Impressions were made with vinyl polysiloxane materials (Reprosil Putty, Aquasil Ultra Heavy, Aquasil Ultra LV [Dentsply International]) using one-step simultaneous dual viscosity technique in dual-arch plastic trays and metal trays as well as in full arch acrylic resin custom trays. These were compared for the dimensional accuracy with the dies prepared from typodont tooth as a control. Results obtained were statistically analyzed. Results: The results indicated that dies obtained from all the impression combinations showed increased dimension (acrylic resin custom trays 9.4 ± 0.048 mm, dual-arch plastic trays 9.5 ± 0.035 mm, and dual-arch metal trays 9.41 ± 0.017 mm) as compared to the dimension of control (9.39 ± 0.007 mm). Conclusion: All the tray impression material combinations showed variable accuracies. Full arch acrylic resin trays exhibited the greatest accuracy whereas dual-arch plastic trays showed the least accuracy. CLINICAL RELEVANCE TO INTERDISCIPLINARY DENTISTRY In fixed prosthodontics, a lower incidence of errors can be obtained using a combination of PVS impression material with metal or custom tray, thereby improving the accuracy of the subsequent restoration. Interdisciplinary dentistry necessitates good prosthodontics and as such prosthodontics is an integral part of good interdisciplinary dentistry.

Super-Resolution Definition of Coordinates of Single Semiconductor Nanocrystal (Quantum Dot): Luminescence Intensity Dependence

In this research a relation between the accuracy of restoration of the single quantum dots (QD) CdSe/CdS/ZnS cross-cut coordinates and luminescence intensity was investigated. It was shown that the limit of the accuracy of determining the coordinates of a single QD for a considerable total amount of registered photons approaches its limiting value that is comparable to the size of the QD. It also means that the installation used in the research is mechanically stable enough to reach the limiting values of determination accuracy of point emitters coordinates.

Factors affecting the functional results of open reduction and internal fixation for fracture-dislocations of the proximal interphalangeal joint.

To clarify the factors affecting functional results of fracture-dislocations of the proximal interphalangeal (PIP) joint treated by open reduction and internal fixation (ORIF), 60 patients, including 38 patients with a dorsal fracture-dislocation and 22 with a pilon fracture, were analysed. The mean ratio of articular surface involvement was 48.5% and a depressed central fragment existed in 75.3% of the cases. ORIF was performed in 47 patients through a lateral approach using Kirschner wires and in 13 through a palmar approach using a plate or screws. The mean flexion, extension and range of motion (ROM) of the PIP joint was 89.5°, 11.5° and 78.0°, respectively. Stepwise regression analysis revealed that a delayed start of active motion exercise after surgery, elderly age and ulnar ray digit were factors affecting functional outcomes. Although ORIF allows accurate restoration of the articular surfaces, an early start of motion exercise is essential for good results.

Recent improvements in photometric stereo for rock art 3D imaging

Recent improvements in photometric stereo (PS) are shown to remove the major limitations of this low-cost 3D recording technique. In particular, there are significant improvements in lighting constraints, processing time and presence of deformation in reconstructed surfaces, allowing for fast and accurate restoration of shape and color information. The shooting technique is sufficiently easy to make PS ideal for ancient rock art, which is generally encountered in difficult to access sites, where many of the rock engravings to survey are often placed in a narrow space. This paper focuses on the Sardinia neolithic tombs known as Domus de Janas, as they offer an opportunity to demonstrate the applicability of PS to general rock art.

Arthroscopic 4-Point Suture Fixation of Anterior Cruciate Ligament Tibial Avulsion Fractures

Tibial eminence avulsion fractures are rare injuries occurring mainly in adolescents and young adults. When necessary, regardless of patient age, anatomic reduction and stable internal fixation are mandatory for fracture healing and accurate restoration of normal knee biomechanics. Various arthroscopically assisted fixation methods with sutures, anchors, wires, or screws have been described but can be technically demanding, thus elongating operative times. The purpose of this article is to present a technical variation of arthroscopic suture fixation of anterior cruciate ligament avulsion fractures. Using thoracic drain needles over 2.4-mm anterior cruciate ligament tibial guidewires, we recommend the safe and easy creation of four 2.9-mm tibial tunnels at different angles and at specific points. This technique uses thoracic drain needles as suture passage cannulas and offers 4-point fixation stability, avoiding potential complications of bony bridge fracture and tunnel connection.

Limited Femoral Navigation Versus Conventional Intramedullary Femoral Jig Based Instrumentation for Achieving Optimal Restoration of Mechanical Axis Post Total Knee Arthroplasty: A Prospective Comparative Study of 200 Knees

A prospective comparative study was conducted to compare the mechanical axis post total knee arthroplasty (TKA) between two groups: In the first group of 100 knees (ASM group) Articular Surface Mounted navigation system was used to guide the distal femoral cut. In the second group of 100 knees (JIG group) conventional intramedullary femoral jig was used. The postoperative mechanical axis of the leg was within 3° of neutral alignment in 90% of the TKA in the ASM group (mean 178.12°) as compared to 74% in the JIG group (mean 177.02°). This difference was statistically significant (P<0.05). The data presented show that the use of limited femoral navigation leads to more accurate restoration of mechanical axis alignment when compared to conventional intramedullary femoral jigs.

Patient-specific instrumentation improved mechanical alignment, while early clinical outcome was comparable to conventional instrumentation in TKA.

The aim of this prospective study was to compare early clinical outcome, radiological limb alignment, and three-dimensional (3D)-component positioning between conventional and computed tomography (CT)-based patient-specific instrumentation (PSI) in primary mobile-bearing total knee arthroplasty (TKA). Two hundred ninety consecutive patients (300 knees) with severe, debilitating osteoarthritis scheduled for TKA were included in this study using either conventional instrumentation (CVI, n = 150) or PSI (n = 150). Patients were clinically assessed before and 2 years after surgery according to the Knee-Society-Score (KSS) and the visual-analog-scale for pain (VAS). Additionally, the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and the Oxford-Knee-Score (OKS) were collected at follow-up. To evaluate accuracy of CVI and PSI, hip-knee-ankle angle (HKA) and 3D-component positioning were assessed on postoperative radiographs and CT. Data of 222 knees (CVI: n = 108, PSI: n = 114) were available for analysis after a mean follow-up of 28.6 ± 5.2 months. At the early follow-up, clinical outcome (KSS, VAS, WOMAC, OKS) was comparable between the two groups. Mean HKA-deviation from the targeted neutral mechanical axis (CVI: 2.2° ± 1.7°; PSI: 1.5° ± 1.4°; p < 0.001), rates of outliers (CVI: 22.2%; PSI: 9.6%; p = 0.016), and 3D-component positioning outliers were significantly lower in the PSI group. Non-outliers (HKA: 180° ± 3°) showed better clinical results than outliers at the 2-year follow-up. CT-based PSI compared with CVI improves accuracy of mechanical alignment restoration and 3D-component positioning in primary TKA. While clinical outcome was comparable between the two instrumentation groups at early follow-up, significantly inferior outcome was detected in the subgroup of HKA-outliers. Prospective comparative study, Level II.

Bristol index of patellar width to thickness (BIPWiT): A reproducible measure of patellar thickness from adult MRI

The restoration of an adequate patellar thickness is a key to the successful outcome of knee arthroplasty. This study investigated the relationship between the thickness of the native patellar and medial-lateral patellar width using magnetic resonance imaging (MRI). 75 MRI scans of young adults, with an average age of 27 (range 16-40) were studied. Exclusion criteria included a diagnosis of degenerative joint disease, patello-femoral pathology or age under 16/over 40 (170 patients). The bony thickness of the patellar, the chondral thickness and patellar width were measured, as was the location of maximal patellar thickness. Inter/intraobserver variability was calculated and correlation analysis was performed. We found a strong correlation between patellar width and thickness (bone plus cartilage) (Pearson 0.75, P<0.001). The mean width to thickness ratio was 1.8:1 (standard deviation 0.1, 95% confidence interval 1.78-1.83). Without cartilage the ratio was 2.16:1 (SD 0.15, 95% CI 2.11-2.21), correlation was moderate (Pearson 0.59, P<0.001). The average maximal patellar cartilage thickness was 4.1mm (SD 1.3). The strong correlation and narrow confidence intervals for the ratio of patellar width to thickness, suggest that patellar width might be used as a guide for accurate restoration of patellar thickness during total knee or patello-femoral replacement. After removing osteophytes we would recommend a ratio of 1.8:1. Further work is required to establish whether there is a relationship between anterior knee pain post total knee arthroplasty and an abnormal patellar width:thickness ratio. Level III.

Fluoroscopy and imageless navigation enable an equivalent reconstruction of leg length and global and femoral offset in THA.

Restoration of biomechanics is a major goal in THA. Imageless navigation enables intraoperative control of leg length equalization and offset reconstruction. However, the effect of navigation compared with intraoperative fluoroscopy is unclear. We asked whether intraoperative use of imageless navigation (1) improves the relative accuracy of leg length and global and femoral offset restoration; (2) increases the absolute precision of leg length and global and femoral offset equalization; and (3) reduces outliers in a reconstruction zone of ± 5 mm for leg length and global and femoral offset restoration compared with intraoperative fluoroscopy during minimally invasive (MIS) THA with the patient in a lateral decubitus position. In this prospective study a consecutive series of 125 patients were randomized to either navigation-guided or fluoroscopy-controlled THA using sealed, opaque envelopes. All patients received the same cementless prosthetic components through an anterolateral MIS approach while they were in a lateral decubitus position. Leg length, global or total offset (representing the combination of femoral and acetabular offset), and femoral offset differences were restored using either navigation or fluoroscopy. Postoperatively, residual leg length and global and femoral offset discrepancies were analyzed on magnification-corrected radiographs of the pelvis by an independent and blinded examiner using digital planning software. Accuracy was defined as the relative postoperative difference between the surgically treated and the unaffected contralateral side for leg length and offset, respectively; precision was defined as the absolute postoperative deviation of leg length and global and femoral offset regardless of lengthening or shortening of leg length and offset throughout the THA. All analyses were performed per intention-to-treat. Analyzing the relative accuracy of leg length restoration we found a mean difference of 0.2 mm (95% CI, -1.0 to +1.4 mm; p = 0.729) between fluoroscopy and navigation, 0.2 mm (95 % CI, -0.9 to +1.3 mm; p = 0.740) for global offset and 1.7 mm (95 % CI, +0.4 to +2.9 mm; p = 0.008) for femoral offset. For the absolute precision of leg length and global and femoral offset equalization, there was a mean difference of 1.7 ± 0.3 mm (p < 0.001) between fluoroscopy and navigation. The biomechanical reconstruction with a residual leg length and global and femoral offset discrepancy less than 5 mm and less than 8 mm, respectively, succeeded in 93% and 98%, respectively, in the navigation group and in 54% and 95%, respectively, in the fluoroscopy group. Intraoperative fluoroscopy and imageless navigation seem equivalent in accuracy and precision to reconstruct leg length and global and femoral offset during MIS THA with the patient in the lateral decubitus position.

Statistical synthesis of radiometric imaging formation in scanning radiometers with signal weight processing by Kravchenko windows

Statistical optimization of the radiometric images (RMIs) algorithms formation in scanning radiometers with weight correction of the antenna amplitude-phase distribution and synchronous sliding strobing of the received noise-like signal by a function describing the antenna pattern corrected by temporal Kravchenko windows is performed for the first time. The ambiguity function (AF) of the scanning radiometer, which determines the RMI quality, is found. It is established that the AF shape substantially depends on the amplitude field distribution (AFD) in the antenna. It is shown that the use of the AFD in the antenna in the form of weight functions (classic and Kravchenko) makes it possible to correct the AF shape and to increase the RMI quality. A simulation of the RMI formation algorithm is performed. It follows from the analysis of simulation data that the use of the weight Kravchenko functions provides higher accuracy of the RMI restoration compared with classic weight functions.

Fast Space-Varying Convolution Using Matrix Source Coding With Applications to Camera Stray Light Reduction

Many imaging applications require the implementation of space-varying convolution for accurate restoration and reconstruction of images. Here, we use the term space-varying convolution to refer to linear operators whose impulse response has slow spatial variation. In addition, these space-varying convolution operators are often dense, so direct implementation of the convolution operator is typically computationally impractical. One such example is the problem of stray light reduction in digital cameras, which requires the implementation of a dense space-varying deconvolution operator. However, other inverse problems, such as iterative tomographic reconstruction, can also depend on the implementation of dense space-varying convolution. While space-invariant convolution can be efficiently implemented with the fast Fourier transform, this approach does not work for space-varying operators. So direct convolution is often the only option for implementing space-varying convolution. In this paper, we develop a general approach to the efficient implementation of space-varying convolution, and demonstrate its use in the application of stray light reduction. Our approach, which we call matrix source coding, is based on lossy source coding of the dense space-varying convolution matrix. Importantly, by coding the transformation matrix, we not only reduce the memory required to store it; we also dramatically reduce the computation required to implement matrix-vector products. Our algorithm is able to reduce computation by approximately factoring the dense space-varying convolution operator into a product of sparse transforms. Experimental results show that our method can dramatically reduce the computation required for stray light reduction while maintaining high accuracy.