scholarly journals Novel method for evaluation of hindfoot alignment in weight-bearing position using laser beam

2018 ◽  
Vol 30 (3) ◽  
pp. 474-478 ◽  
Author(s):  
Tadasuke Ohnishi ◽  
Mitsumasa Hida ◽  
Yukio Nakamura ◽  
Chikamune Wada
Keyword(s):  
Laser Beam ◽  
Weight Bearing ◽  
Hindfoot Alignment ◽  
Novel Method

Novel method for evaluation of subtalar joint alignment under weight-bearing conditions using laser beam

Physiotherapy ◽  
2015 ◽  
Vol 101 ◽  
pp. e1144-e1145
Author(s):  
T. Onishi ◽  
M. Hida ◽  
Y. Nakamura ◽  
T. Honda ◽  
C. Wada
Keyword(s):  
Laser Beam ◽  
Subtalar Joint ◽  
Weight Bearing ◽  
Novel Method

A novel method to reduce dross in laser beam cutting of Ti-6Al-4 V alloy sheet

2021 ◽  
Vol 64 ◽  
pp. 95-112
Author(s):  
Anitesh Kumar Singh ◽  
Kalinga Simant Bal ◽  
Abhishek Rudra Pal ◽  
Dipanjan Dey ◽  
Asimava Roy Choudhury
Keyword(s):  
Laser Beam ◽  
Alloy Sheet ◽  
Novel Method

Radiographic Comparison of the Mechanical Axis Including Calcaneus to the Conventional Mechanical Axis in Medial Unicompartmental Knee Arthroplasty

2019 ◽  
Author(s):  
Yuichi Kuroda ◽  
Koji Takayama ◽  
Kazunari Ishida ◽  
Shinya Hayashi ◽  
Shingo Hashimoto ◽  
...  
Keyword(s):  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Tibial Component ◽  
Mechanical Axis ◽  
Weight Bearing ◽  
Postoperative Outcome ◽  
Diagnostic Study ◽  
Hindfoot Alignment ◽  
Unicompartmental Knee ◽  
The Mean

AbstractSince a hindfoot alignment is not included in the conventional mechanical axis (hip–ankle [HA] line), a mechanical axis including the calcaneus (hip–calcaneus [HC] line) has recently attracted attention as an alternative weight-bearing line. However, there are few reports on unicompartmental knee arthroplasty (UKA) regarding the HC line. Therefore, this study aimed to compare postoperative alignments after UKA between the HA line and the HC line. Postoperatively, HC radiographs were taken in 88 consecutive patients who underwent medial UKA. The hip–knee–ankle (HKA) and hip–knee–calcaneus (HKC) angles were compared in the same patient. Regarding tibial inclination, the conventional tibial component–ankle (TCA) angle was compared with reference to the HC line (tibial component–calcaneus [TCC] angle). The mean postoperative HKA and HKC angles were 2.8 ± 2.7 and 2.0 ± 2.5 degree, respectively. The mean postoperative TCA and TCC angles were 87.7 ± 2.1 and 88.5 ± 2.1 degree, respectively. There were significant differences between the two groups in both lower limb alignment and tibial component angle. The present study indicated that the HKC and the TCC angles significantly decreased the varus alignment by approximately 1 degree compared with the HKA and TCA angles. Neutral in the HA line corresponds to valgus in reference to the HC line, which may result in overcorrection. Surgeons should consider evaluating the HC line in place of the HA line, which may affect preoperative planning and postoperative outcome during UKA. This is a Level II, diagnostic study.

scholarly journals 2019 IFFAS Award for Excellence Winner: Peri-Prosthetic Cysts and Alignment in Total Ankle Replacement: A 3-D, Weight Bearing Topographical Study

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0004
Author(s):  
Francois Lintz ◽  
Jef Mast ◽  
Nazim Mehdi ◽  
Alessio Bernasconi ◽  
Cesar de Cesar Netto ◽  
...  
Keyword(s):  
Weight Bearing ◽  
Total Ankle Replacement ◽  
Coronal Plane ◽  
Unequal Distribution ◽  
Hindfoot Alignment ◽  
Cyst Volume ◽  
Ankle Replacement ◽  
The Mean ◽  
The Difference

Category: Ankle, Ankle Arthritis Introduction/Purpose: Peri-prosthetic cysts (PPC) in Total Ankle Replacement (TAR) are a common failure cause but the mechanisms of their development remains unclear. One possible explanation could be hindfoot malalignment and subsequent unequal distribution of load inside the joint. However, how residual malalignment influences the evolution of PPC remains unclear. Computed tomography (CT) has demonstrated superiority on conventional radiography in the follow up of PPC. Weight Bearing CT (WBCT), by combining 3D imaging and weight bearing measurements seems a valid tool to investigate this further. The objective for this work was to study the effects of residual hindfoot deformity on the distribution of PPC in the coronal plane. We hypothesized that cysts would be found predominantly medially in varus configuration, and laterally in valgus configuration. Methods: Retrospective comparative study, ethics committee approved. Forty-eight cases of TAR were included, with relevant demographics. Inclusion criteria were cases of primary TAR with available WBCT imaging of their ankle as part of normal follow up. Exclusion criteria were subsequent implant revision or cyst grafting. In each case, the localization and size of PPC’s were documented and their volume calculated by approximation of the closest ellipsoid. Hindfoot alignment was evaluated by the percentage Foot Ankle Offset (FAO) (foot-length normalized 3D ratio between the midline of the foot and the center of the ankle) using a WBCT dedicated semi-automatic software. The mean FAO value with 95%CI for the population was calculated. The difference in medial and lateral cyst volume defined by their position relative to the median axis in the coronal plane was compared in varus and valgus cases by a Mann-Whitney non-parametric test for unpaired samples. Results: Demographic distributions of the series were 32% female, mean age 65 (45-85) years. Mean FAO value was 0.12% (95%CI -1.09 to 1.33). Mean follow up was 43 months (6 to 239). The mean total cyst volume per case was 1190,7 mm3. In varus cases (defined by FAO<-1.09%), the volume of medial cysts was greater than laterally by a mean 197 mm3, whereas in valgus cases (defined by FAO>1.33%), the volume of lateral cysts was greater than medially by a mean 332 mm3. The difference was statistically significant (p<0.05). There was a weak, significant positive correlation (r=0.25, p<0,001) between FAO and total cyst volume and a moderate, significant correlation (r=0,56, p<0,001) between time to follow up and total cyst volume. Conclusion: Our hypothesis was confirmed. Periprosthetic cysts volume in this series of primary TAR was found to be relatively greater medially in postoperative varus configurations and vice-versa laterally in valgus. This confirms a possible correlation between the direction of residual hindfoot malalignment and the coronal localization of PPC in TAR, although this is certainly not the only pathophysiologic factor involved in PPC onset. Weightbearing CT may be helpful in Total Ankle Replacement follow up, in order to early detect PPC development and possibly to identify situations at risk of a more rapid evolution.

scholarly journals Drift Reduction of a 4-DOF Measurement System Caused by Unstable Air Refractive Index

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6329
Author(s):  
Ruijun Li ◽  
Yongjun Wang ◽  
Pan Tao ◽  
Rongjun Cheng ◽  
Zhenying Cheng ◽  
...  
Keyword(s):  
Refractive Index ◽  
Laser Beam ◽  
Measurement System ◽  
Degrees Of Freedom ◽  
Cost Effective ◽  
Control Mode ◽  
Detection Accuracy ◽  
Long Distance ◽  
Cost Effective Method ◽  
Novel Method

Laser beam drift greatly influences the accuracy of a four degrees of freedom (4-DOF) measurement system during the detection of machine tool errors, especially for long-distance measurement. A novel method was proposed using bellows to serve as a laser beam shield and air pumps to stabilize the refractive index of air. The inner diameter of the bellows and the control mode of the pumps were optimized through theoretical analysis and simulation. An experimental setup was established to verify the feasibility of the method under the temperature interference condition. The results indicated that the position stability of the laser beam spot can be improved by more than 79% under the action of pumping and inflating. The proposed scheme provides a cost-effective method to reduce the laser beam drift, which can be applied to improve the detection accuracy of a 4-DOF measurement system.

scholarly journals Three-Dimensional Displacement after a Medializing Calcaneal Osteotomy in Relation to the Hindfoot Alignment and Osteotomy Angle

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0006
Author(s):  
Matthias Peiffer ◽  
C. Belvedere ◽  
S. Clockaerts ◽  
T. Leenders ◽  
Alexej Barg ◽  
...  
Keyword(s):  
Weight Bearing ◽  
Three Dimensional ◽  
Valgus Deformity ◽  
Flat Foot ◽  
Hindfoot Alignment ◽  
Calcaneal Osteotomy ◽  
Bony Landmarks ◽  
Operative Planning ◽  
Osteotomy Plane ◽  
Computer Based

Category: Hindfoot Introduction/Purpose: An adult-acquired flatfoot deformity is a three-dimensional (3D) condition characterized by a loss of the medial longitudinal arch, valgus alignment of the hindfoot, and abduction of the midfoot. When conservative measures are not sufficient, a medializing calcaneal osteotomy (MCO) is frequently performed to correct the deformity, but there is lack of data on the associated three-dimensional variables defining the final correction. A possible reason for this shortcoming could be the current image-based analyses, mainly performed on bi-dimensional radiographs. These are hampered by errors in 3D rotations and superimposition of bony structures. The aim of this study was therefore to assess the correlation between the preoperative hindfoot valgus deformity and calcaneal osteotomy angle and the postoperative calcaneal displacement by use of weightbearing CT (WBCT). Methods: Weight-bearing CT scans obtained pre- and post-operatively were analyzed for sixteen patients with a mean age of 49.4 years (range: 18-66 years). Indication for surgery was adult-acquired flat foot deformity stage II. Based on the WBCT images, pre- and post-operative 3D bone morphological models of the tibia, talus, calcaneus, and the second metatarsal were created, on which anatomical bony landmarks were computationally identified to define a Foot Anatomical reference Frame (FAF). This FAF was used to measure valgus deformity pre- and post-operatively, inclination of the osteotomy plane, and displacement of the calcaneus (Fig. 1). Linear regression was conducted to assess the relationship between these measurements. Results: On average, the hindfoot valgus changed from 13.1° (±4.6) preoperatively to 5.7° (±4.3) postoperatively. A mean inferior displacement of 3.2 mm (±1.3) was observed along the osteotomy with a mean inclination angle of 54.6° (±5.6), 80.5° (±10.7), - 13.7° (±15.7) in the axial, sagittal and coronal planes, respectively. A statistically significant positive relationship (P < .05, R2 = 0.6) was found between the preoperative valgus, the axial osteotomy inclination, and the inferior displacement. Conclusion: This study shows that the degree of preoperative valgus of the hindfoot and the axial osteotomy angle are predictive factors for the amount of postoperative plantar displacement of the calcaneus. These findings contrast the general recommendation of performing a 90° calcaneal osteotomy angle, i.e. perpendicular to the lateral calcaneal wall in every patient. The obtained factors should be taken into account when performing a MCO and could be integrated in a computer-based pre- operative planning.

scholarly journals 3D Imaging for Hindfoot Alignment: A Comparative Study between MRI and Weight Bearing CT

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0024
Author(s):  
Anil Haldar ◽  
Alessio Bernasconi ◽  
Syed E. Junaid ◽  
Matthew J. Welck ◽  
Asif Saifuddin
Keyword(s):  
Comparative Study ◽  
Negative Correlation ◽  
Pearson Correlation ◽  
Statistical Significance ◽  
Weight Bearing ◽  
Significant Negative Correlation ◽  
Common Finding ◽  
Foot And Ankle ◽  
Calcaneofibular Ligament ◽  
Hindfoot Alignment

Category: Hindfoot; Other Introduction/Purpose: Hindfoot malalignment is a common finding in multiple foot and ankle pathologies. In clinical practice, it is usually quantified through traditional weight bearing radiographs or, more recently, through cone beam weight bearing CT (CB- WBCT), which overcomes issues related to two-dimensional imaging. Interestingly, a few studies have suggested that hindfoot alignment can also be accurately assessed using non-weight bearing magnetic resonance imaging (MRI). The purpose of this study was to compare measurements of hindfoot alignment on non-weight bearing ankle MRI and CB-WBCT and to establish if there was any correlation. Methods: In this Level III retrospective comparative study, a database review identified 51 feet in 47 patients (27 males, 20 females; mean age of 45 (range 13-79)) which had both CB-WBCT and MRI scans on the same day as part of standard care at our specialist tertiary referral Foot and Ankle Unit. Hindfoot alignment was assessed by independent Consultant Musculoskeletal specialists. The foot ankle offset (FAO), calcaneal offset (CO) and hindfoot alignment angle (HA) were assessed on CB-WBCT using dedicated software. The tibiocalcaneal angle (TCA) and calcaneofibular ligament angle (CFLA) were assessed on non-weight bearing MRI. Pearson correlation was used to evaluate the correlation between these measurements. Results: We found a statistically significant positive correlation between TCA on non-weight bearing MRI and each measurement on CB-WBCT (Pearson correlation for TCA and FAO: 0.42, p=0.003; for TCA and CO: 0.46, p=0.001; and for TCA and HA: 0.40, p=0.005).We also demonstrated a moderate-to-low negative but significant correlation between CFLA and CO (Pearson correlation: -0.35; p=0.03). Conversely, the negative correlation between CFL and FAO (Pearson correlation: -0.29; p=0.07) and CFL with HA (Pearson correlation: -0.26; p=0.11) did not reach statistical significance. Conclusion: Weight bearing three-dimensional imaging has shown high degrees of accuracy and reproducibility for hindfoot alignment. The significant correlation between TCA on non-weight bearing MRI and hindfoot alignment measurements on CB- WBCT suggests that TCA should be reported during routine ankle MRI in order to put into context some of the soft-tissue findings. The CFLA shows a less significant negative correlation.

Laser-Beam-Triggered Microcavitation: A Novel Method for Selective Cell Destruction

2001 ◽  
Vol 156 (4) ◽  
pp. 399-407 ◽  
Author(s):  
Dariusz Leszczynski ◽  
Costas M. Pitsillides ◽  
Riikka K. Pastila ◽  
R. Rox Anderson ◽  
Charles P. Lin
Keyword(s):  
Laser Beam ◽  
Cell Destruction ◽  
Novel Method

scholarly journals Association between changes in hip-knee-ankle angle and hindfoot alignment after total knee arthroplasty for varus knee osteoarthritis

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Naicheng Diao ◽  
Fei Yu ◽  
Bo Yang ◽  
Lifeng Ma ◽  
Heyong Yin ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Osteoarthritis ◽  
Knee Arthroplasty ◽  
Weight Bearing ◽  
Linear Regression Analysis ◽  
Varus Knee ◽  
Hindfoot Alignment ◽  
Total Knee ◽  
American Orthopaedic ◽  
The Relationship

Abstract Background The change in hip-knee-ankle (HKA) angle after total knee arthroplasty (TKA) may cause an adjustment in hindfoot alignment (HFA). However, the relationship between the changes in HKA angle and HFA is still not well studied. This study aimed to investigate the association between HKA angle and hindfoot alignment changes after TKA for varus knee osteoarthritis. Methods A prospective study was carried out in which 108 patients with varus knee deformities were radiographically and clinically evaluated before and 3 months after TKA. The relationship of change in HFA with correction in HKA angle was investigated. Results The results showed that the HFA was adjusted significantly by 3 months after TKA (p < 0.001), along with improved American Orthopaedic Foot and Ankle Society (AOFAS) ankle hindfoot score (p < 0.001). Next, a univariate correlation and linear regression analysis showed that the change in HFA was weakly correlated with the change in HKA angle (r=-0.262, β=-0.14, 95 % CI: -0.23 to -0.04, P = 0.006). Further stratified analysis and interaction tests revealed that age has a distinct effect on the correlation between the changes in HFA and HKA angle. The correlation was dramatically greater in the group under 65 years (r=-0.474, β=-0.26, 95 % CI: -0.41 to -0.12, P = 0.001), whilst, no correlation was observed in those above 65 years old (r=-0.036, β=-0.02, 95 % CI: -0.14 to 0.11, P = 0.779). Conclusions Our findings indicated that correction of HKA after TKA tend to promote adjustment in the hindfoot alignment toward re-balance of the whole lower limb weight-bearing axis. However, this mechanism obviously weakens in elderly patients. Therefore, if apparent hindfoot deformity exists in these patients before TKA, more perioperative intervention is required for hindfoot adjustment, and even HKA undercorrection may be considered.

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