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

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

scholarly journals Supracondylar rotation osteotomy of the femur influences the coronal alignment of the ankle

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Christian Konrads ◽  
Marc-Daniel Ahrend ◽  
Myriam R. Beyer ◽  
Ulrich Stöckle ◽  
Sufian S. Ahmad
Keyword(s):  
Subtalar Joint ◽  
Distal Femur ◽  
External Rotation ◽  
Weight Bearing ◽  
Orientation Angle ◽  
Osteotomy Site ◽  
Limb Alignment ◽  
Coronal Alignment ◽  
Rotational Osteotomy ◽  
Rotation Osteotomy

Abstract Purpose Osteotomies represent well-established treatment-options for the redistribution of loads and forces within and around the knee-joint. Effects of these osteotomies on the remaining planes and adjacent joints are not fully understood. The aim of this study was to determine the influence of a distal-femoral-rotation-osteotomy on the coronal alignment of the ankle. It was hypothesized that supracondylar-external-rotation-osteotomy of the distal femur leads to a change in the coronal orientation of the ankle joint. Methods Long-leg standing radiographs and CT-based torsional measurements of 27 patients undergoing supracondylar-rotational-osteotomy of the femur between 2012 and 2019 were obtained and utilized for the purpose of this study. Postoperative radiographs were obtained after union at the osteotomy-site. The hip-knee-ankle-angle (HKA), the mechanical-lateral-distal-femur-angle (mLDFA), and Tibia-Plafond-Horizontal-Orientation-Angle (TPHA) around the ankle were measured. Comparison between means was performed using the Wilcoxon-Mann–Whitney test. Results Twenty-seven patients with high femoral antetorsion (31.3° ± 4.0°) underwent supracondylar-external-rotation-osteotomy. The osteotomy led to a reduced antetorsion (17.4 ± 5.1; p < 0.001) and to a valgisation of the overall limb-alignment. The HKA decreased by 2.4° ± 1.4° (p < 0.001). The TPHA decreased by 2.6° (p < 0.001). Conclusions Supracondylar external rotation osteotomy of the femur leads to lateralization of the weight bearing line at the knee and ankle due to valgisation of the coronal limb alignment. The mobile subtalar joint has to compensate (inversion) for the resulting valgus orientation of the ankle to ensure contact between the foot and the floor. When planning a rotational osteotomy of the lower limb, this should be appreciated – especially in patients with a preexisting valgus alignment of the lower extremities or restricted mobility in the subtalar joint.

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

scholarly journals Talar process fractures

2018 ◽  
Vol 3 (3) ◽  
pp. 85-92 ◽  
Author(s):  
Haroon Majeed ◽  
Donald J. McBride
Keyword(s):  
Subtalar Joint ◽  
Avulsion Fracture ◽  
Weight Bearing ◽  
Cartilage Damage ◽  
Flexor Hallucis Longus ◽  
High Clinical Suspicion ◽  
Significant Disability ◽  
Missed Diagnosis ◽  
And Inversion

Fractures of the lateral and the posterior processes of the talus are uncommon and frequently missed because of a low level of suspicion and difficulty in interpretation on plain radiographs. Missed fractures can lead to persistent pain and reduced function. Lateral process fractures are usually a consequence of forced dorsiflexion and inversion of fixed pronated foot. These are also commonly known as snowboarder’s fractures. The posterior process of the talus is composed of medial and lateral tubercles, separated by the groove for the flexor hallucis longus tendon. The usual mechanism of injury is forced hyperplantarflexion and inversion causing direct compression of the posterior talus, or an avulsion fracture caused by the posterior talofibular ligament. CT scans are helpful in cases of high clinical suspicion. There is a lack of consensus regarding optimal management of these fractures; however, management depends on the size, location and displacement of the fragment, the degree of cartilage damage and instability of the subtalar joint. Non-operative treatment includes immobilization and protected weight-bearing for six weeks. Surgical treatment includes open reduction and internal fixation or excision of the fragments, depending on the size. Fractures of the lateral and the posterior processes of the talus are uncommon but important injuries that may result in significant disability in cases of missed diagnosis or delayed or inadequate treatment. Early diagnosis and timely management of these fractures help to avoid long-term complications, including malunion, nonunion or severe subtalar joint osteoarthritis. Cite this article: EFORT Open Rev 2018;3:85-92. DOI: 10.1302/2058-5241.3.170040

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 The Role of Calcaneofibular Ligament (CFL) Injury in Ankle Instability

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0002
Author(s):  
Kenneth Hunt ◽  
Richard Fuld ◽  
Judas Kelley ◽  
Nicholas Anderson ◽  
Todd Baldini
Keyword(s):  
Contact Mechanics ◽  
Ankle Joint ◽  
Motion Capture ◽  
Contact Area ◽  
Subtalar Joint ◽  
Ankle Instability ◽  
Weight Bearing ◽  
Calcaneofibular Ligament ◽  
Tibiotalar Joint ◽  
Ankle Stability

Category: Ankle Introduction/Purpose: Acute inversion ankle sprains are among the most common musculoskeletal injuries. Higher grade sprains, which include anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) injury, can be particularly problematic and often require surgical repair. The implications of CFL injury on ankle instability are unclear. We aim to evaluate the impact of CFL injury on ankle stability and subtalar joint biomechanics. We hypothesized that CFL injury will result in decreased stiffness and torque, and alteration of ankle contact mechanics compared to the uninjured ankle in a cadaveric model. Methods: Twenty matched cadaveric ankles dissected of skin and subcutaneous tissue were mounted to an Instron with 20° of ankle plantar flexion and 15° of internal rotation. Intact specimens were axially loaded to body weight, then underwent inversion stress along the anatomic axis of the ankle from 0 to 20° (simulating inversion injury) for three cycles. ATFL and CFL were sequentially sectioned, and inversion testing repeated for each condition. Stiffness and change in torque were recorded using an Instron, and pressure and contact area were recorded using a calibrated Tekscan sensor system. Inversion angle of the talus and calcaneus relative to the ankle mortise were recorded using a three-dimensional motion capture system. Paired t tests were performed for inter and intra-group comparisons. Results: Stiffness and torque did not significantly decrease after sectioning of the ATFL, but did decreased significantly after sectioning of CFL. Peak pressures in the tibiotalar joint decreased significantly following CFL release compared to both the uninjured ankle and ATFL-only release. Mean contact area significantly increased following CFL release compared to both the uninjured ankle and ATFL release. There was a concentration of force in the anteromedial ankle joint during weight-bearing inversion. However, the center-of-force shifts 1.22 mm posteromedial after CFL release relative to an intact ankle. Motion capture showed a significant and sequential increase in inversion angle of both the calcaneus and talus, after release of each ligament. There was significantly more inversion in the subtalar joint than the tibiotalar joint with weight-bearing inversion. Conclusion: There is significantly lower stiffness and torque with weight-bearing inversion of the ankle joint complex following injury to both ATFL and CFL, and sequentially greater inversion of the talus and calcaneus with progressive ligament injury. This corresponds to a significant shift in the center of force in the tibiotalar joint. CFL contributes considerably to lateral ankle stability, and sprains that include CFL injury result in substantial alteration of contact mechanics at the ankle and subtalar joints. Repair of CFL may be beneficial during lateral ligament reconstruction, potentially mitigating long-term consequences (e.g., articular damage) of a loose or incompetent CFL.

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 Centre of Rotation of the Human Subtalar Joint Using Weight-Bearing Clinical Computed Tomography

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marta Peña Fernández ◽  
Dorela Hoxha ◽  
Oliver Chan ◽  
Simon Mordecai ◽  
Gordon W. Blunn ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Subtalar Joint ◽  
Weight Bearing ◽  
Centre Of Rotation

scholarly journals Tibiotalocalcaneal Arthrodesis Using a Straight Intramedullary Nail

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0026
Author(s):  
Lucky Jeyaseelan ◽  
Nicholas Cullen ◽  
Andrew Goldberg ◽  
Matthew Welck
Keyword(s):  
Clinical Practice ◽  
Intramedullary Nail ◽  
Subtalar Joint ◽  
Weight Bearing ◽  
Ct Imaging ◽  
Wound Complications ◽  
Union Rate ◽  
Reliable Technique ◽  
Hindfoot Alignment ◽  
Clinical Series

Category: Hindfoot Introduction/Purpose: Tibiotalocalcaneal (TTC) arthrodesis using a hindfoot intramedullary nail has been shown to be a safe and reliable technique in patients with severe ankle and hindfoot disease. There is debate about the use of straight nails versus curved nails. Proponents of the curved nail argue that straight nails predispose to greater risk of lateral plantar nerve injury, poor calcaneal bone purchase and inability to maintain satisfactory hindfoot valgus alignment. However, the subtalar joint is a condyloid joint enabling rotation of the talus on the calcaneum to create varus/valgus position of the calcaneal tuberosity. We present a clinical series of patients undergoing TTC fusion using a straight nail assessed by clinical and radiological outcomes to establish whether theoretical risks of straight nails are reflected in clinical practice. Methods: This single centre, retrospective study of prospectively collected data on a sequential series of patients to undergo TTC fusion, with pre and post-operative weight bearing CT imaging. Data was collected on indication for procedure, co-morbidities, post-operative complications, union rate as well as clinical scores, EQ5D and MOXFQ. Weight bearing CT imaging was analysed using the validated TALUS™ (torque ankle lever arm system) method on weight bearing CT, providing calcaneal offset, hindfoot angle and hindfoot alignment. These were used as markers of hindfoot alignment. Results: 65 patients (37 males, 28 females) were included in the study, with an average age of 57 years. Average follow-up was 20 months. Indications for TTC fusion included Charcot arthropathy, talar avascular necrosis, post traumatic arthritis and non-union of previous arthrodeses. Union rate was 91% (59/65). Overall complication rate was 11% (7/65) and most were minor wound complications. There were no plantar nerve injuries noted. There were no nail cut outs from the calcaneum. On all markers of hindfoot alignment, cases showed a more physiological degree of hindfoot valgus compared to pre-operative measures. There were significant improvement in both EQ5D and MOXFQ scores (p<0.05). Conclusion: We present the largest series of TTC fusion using a straight intramedullary nail and the first series to analyse hindfoot alignment using weight bearing 3D CT imaging. Our data regarding correction of hindfoot alignment is supported by biomechanical theories of subtalar varus/valgus, being related to rotatory changes at the subtalar joint, questioning the perceived need for a curved nail. This is particularly at the level of the entry point of the nail. The principles of valgus hindfoot nails are based on biomechanical laboratory studies and cadaveric studies, neither of which reflect our findings in clinical practice.

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