scholarly journals The effect of an infra-acetabular screw for anatomically shaped three-dimensional plate or standard plate designs in acetabulum fractures: a biomechanical analysis

2021 ◽  
Author(s):  
I. Graul ◽  
I. Marintschev ◽  
A. Pizanis ◽  
S. C. Herath ◽  
T. Pohlemann ◽  
...  
Keyword(s):  
Tracking System ◽  
Optical Tracking ◽  
Biomechanical Analysis ◽  
Anterior Column ◽  
Fracture Model ◽  
Biomechanical Stability ◽  
Level Of Evidence ◽  
Anatomic Reduction ◽  
Single Leg Stance ◽  
Acetabulum Fractures

Abstract Background Various plate shapes and implant configurations are used for stabilization of acetabulum fractures via anterior approaches. Little is known about the biomechanical stability of a two-dimensionally shaped “conventional” plate (“J-Plate”—JP) in comparison to three-dimensionally shaped plate configurations (3DP). In addition, the augmentary effect of an infra-acetabular lag-screw (IACS) fixation for anterior column and posterior hemi-transverse acetabulum fractures has not been clarified in comparison of JP and 3DP constructs. This study analyzed the difference between the biomechanical stability of JP compared to 3DP and the role of an IACS in a standardized acetabular fracture model in a single-leg stance loading configuration. Methods In an artificial bone substitute pelvis model (Synbone© Malans, Switzerland), a typical and standardized fracture pattern (anterior column and posterior hemi-transverse) was created with osteotomy jigs. After anatomic reduction the stabilization was performed using JP or 3DP. Eight pelvises per group were axially loaded in a single-leg stance model up to 400 N. After the load cycle, an additional infra-acetabular screw was placed and the measurement repeated. Fragment displacement was recorded by an optical tracking system (Optitrack Prime 13®, Corvallis, USA). Results In the pure placement, 3DP provided significantly superior stability when compared to JP. Augmentation of JP by IACS increased the stability significantly, up to the level of 3DP alone, whereas augmentation of the 3DP did not result in further increase of overall stability. Conclusion The anatomically shaped plate alone provides a superior biomechanical stability in fixation of an anterior column and posterior hemi-transverse fracture model. In a JP fixation the augmentation by IACS provides similar strength as the anatomically shaped 3DP. By use of the anatomically shaped 3DP the need of a clinically risky application of IACS might be avoidable. Level of evidence IV, Experimental study.

Factors Predicting the Outcome After Arthroscopically Assisted Stabilization of Acute High-Grade Acromioclavicular Joint Dislocations

2019 ◽  
Vol 47 (11) ◽  
pp. 2670-2677 ◽  
Author(s):  
Nina Maziak ◽  
Laurent Audige ◽  
Carmen Hann ◽  
Marvin Minkus ◽  
Markus Scheibel
Keyword(s):  
Clinical Outcome ◽  
Acromioclavicular Joint ◽  
High Grade ◽  
Radiological Outcome ◽  
Ac Joint ◽  
Level Of Evidence ◽  
Outcome Parameters ◽  
Joint Dislocations ◽  
Anatomic Reduction ◽  
Arthroscopically Assisted

Background: Factors influencing the outcome after arthroscopically assisted stabilization of acute high-grade acromioclavicular (AC) joint dislocations remain poorly investigated. Purpose: To identify determinants of the radiological outcome and investigate associations between radiological and clinical outcome parameters. Study Design: Cohort study; Level of evidence, 3. Methods: The authors performed a retrospective analysis of patients who underwent arthroscopically assisted stabilization for acute high-grade AC joint dislocations. The following potential determinants of the radiological outcome were examined using univariable and multivariable regression analyses: timing of surgery, initial AC joint reduction, isolated coracoclavicular (CC) versus combined CC and AC stabilization, ossification of the CC ligaments, age, and overweight status. In addition, associations between radiological (ie, CC difference, dynamic posterior translation [DPT]) and clinical outcome parameters (Subjective Shoulder Value, Taft score [TS] subjective subcategory, and Acromioclavicular Joint Instability Score [ACJI] pain subitem) were evaluated using univariable analysis. Results: One hundred four patients with a mean (±SD) age of 38.1 ± 11.5 years were included in this study. The mean postoperative follow-up was 2.2 ± 0.9 years. Compared with patients with an overreduced AC joint after surgery, the CC difference was 4.3 mm (95% CI, 1.3-7.3; P = .006) higher in patients with incomplete reduction. Patients with anatomic reduction were 3.1 times (95% CI, 1.2-7.9; P = .017) more likely to develop DPT than those with an overreduced AC joint. An incompletely reduced AC joint was 5.3 times (95% CI, 2.1-13.4; P < .001) more likely to develop DPT versus an overreduced AC joint. Patients who underwent isolated CC stabilization were 4.8 times (95% CI, 1.1-21.0; P = .039) more likely to develop complete DPT than patients with additional AC stabilization. Significantly higher CC difference values were noted for patients who reported pain on the subjective TS ( P = .025). Pain was encountered more commonly in patients with DPT ( PTS = .049; PACJI = .038). Conclusion: Clinicians should consider overreduction of the AC joint because it may lead to favorable radiological results. Because of its association with superior radiographic outcomes, consideration should also be given to the use of additional AC cerclage.

Load Response of the Tarsal Bones in Patients with Flatfoot Deformity: In Vivo 3D Study

2011 ◽  
Vol 32 (11) ◽  
pp. 1017-1022 ◽  
Author(s):  
Masamitsu Kido ◽  
Kazuya Ikoma ◽  
Kan Imai ◽  
Masahiro Maki ◽  
Ryota Takatori ◽  
...  
Keyword(s):  
Load Condition ◽  
Clinical Analysis ◽  
Biomechanical Analysis ◽  
Talonavicular Joint ◽  
Level Of Evidence ◽  
Tibiotalar Joint ◽  
Talocalcaneal Joint ◽  
Load Response ◽  
Tarsal Bones

Background: The objective of this study was to evaluate the bone rotation of each joint in the hindfoot and compare the load response in healthy feet with that in flatfeet by analyzing the reconstructive three-dimensional (3D) CT image data during weightbearing. Methods: CT scans of 21 healthy feet and 21 feet with flatfoot deformity were taken in non-load condition followed by full-body weightbearing load condition. The images of the hindfoot bones were reconstructed into 3D models. The volume merge method in three planes was used to calculate the position of the talus relative to the tibia in the tibiotalar joint, the navicular relative to the talus in talonavicular joint, and the calcaneus relative to the talus in the talocalcaneal joint. Results: The talar position difference to the load response relative to the tibia in the tibiotalar joint in a flatfoot was 1.7 degrees more plantarflexed in comparison to that in a healthy foot ( p = 0.031). The navicular position difference to the load response relative to the talus in the talonavicular joint was 2.3 degrees more everted ( p = 0.0034). The calcaneal position difference to the load response relative to the talus in the talocalcaneal joint was 1.1 degrees more dorsiflexed ( p = 0.0060) and 1.7 degrees more everted ( p = 0.0018). Conclusion: Referring to previous cadaver study, regarding not only the cadaveric foot, but also the live foot, joint instability occurred in the hindfoot with load in patients with flatfoot. Clinical Relevance: The method used in this study might be applied to clinical analysis of foot diseases such as the staging of flatfoot and to biomechanical analysis to evaluate the effects of foot surgery in the future. Level of Evidence: III

scholarly journals In Vitro and In Vivo Assessment of a New Workflow for the Acquisition of Mandibular Kinematics Based on Portable Tracking System with Passive Optical Reflective Markers

2021 ◽  
Vol 11 (9) ◽  
pp. 3947
Author(s):  
Marco Farronato ◽  
Gianluca M. Tartaglia ◽  
Cinzia Maspero ◽  
Luigi M. Gallo ◽  
Vera Colombo
Keyword(s):  
Measurement Error ◽  
Tracking System ◽  
Intraclass Correlation ◽  
Optical Tracking ◽  
Optical Tracking System ◽  
Rater Reliability ◽  
Tracking Device ◽  
Mandibular Kinematics

Clinical use of portable optical tracking system in dentistry could improve the analysis of mandibular movements for diagnostic and therapeutic purposes. A new workflow for the acquisition of mandibular kinematics was developed. Reproducibility of measurements was tested in vitro and intra- and inter-rater repeatability were assessed in vivo in healthy volunteers. Prescribed repeated movements (n = 10) in three perpendicular directions of the tracking-device coordinate system were performed. Measurement error and coefficient of variation (CV) among repetitions were determined. Mandibular kinematics of maximum opening, left and right laterality, protrusion and retrusion of five healthy subjects were recorded in separate sessions by three different operators. Obtained records were blindly examined by three observers. Intraclass correlation coefficient (ICC) was calculated to estimate inter-rater and intra-rater reliability. Maximum in vitro measurement error was 0.54 mm and CV = 0.02. Overall, excellent intra-rater reliability (ICC > 0.90) for each variable, general excellent intra-rater reliability (ICC = 1.00) for all variables, and good reliability (ICC > 0.75) for inter-rater tests were obtained. A lower score was obtained for retrusion with “moderate reliability” (ICC = 0.557) in the inter-rater tests. Excellent repeatability and reliability in optical tracking of primary movements were observed using the tested portable tracking device and the developed workflow.

scholarly journals High Precision Optical Tracking System Based on near Infrared Trinocular Stereo Vision

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2528
Author(s):  
Songlin Bi ◽  
Yonggang Gu ◽  
Jiaqi Zou ◽  
Lianpo Wang ◽  
Chao Zhai ◽  
...  
Keyword(s):  
High Precision ◽  
Stereo Vision ◽  
Near Infrared ◽  
Nearest Neighbor ◽  
Tracking System ◽  
Optical Tracking ◽  
Tracking Accuracy ◽  
Optical Tracking System ◽  
Dynamic Tracking ◽  
Trinocular Stereo

A high precision optical tracking system (OTS) based on near infrared (NIR) trinocular stereo vision (TSV) is presented in this paper. Compared with the traditional OTS on the basis of binocular stereo vision (BSV), hardware and software are improved. In the hardware aspect, a NIR TSV platform is built, and a new active tool is designed. Imaging markers of the tool are uniform and complete with large measurement angle (>60°). In the software aspect, the deployment of extra camera brings high computational complexity. To reduce the computational burden, a fast nearest neighbor feature point extraction algorithm (FNNF) is proposed. The proposed method increases the speed of feature points extraction by hundreds of times over the traditional pixel-by-pixel searching method. The modified NIR multi-camera calibration method and 3D reconstruction algorithm further improve the tracking accuracy. Experimental results show that the calibration accuracy of the NIR camera can reach 0.02%, positioning accuracy of markers can reach 0.0240 mm, and dynamic tracking accuracy can reach 0.0938 mm. OTS can be adopted in high-precision dynamic tracking.

scholarly journals Skill Transference of a Probe-Tube Placement Training Simulator

2020 ◽  
Vol 31 (01) ◽  
pp. 040-049 ◽  
Author(s):  
Robert W. Koch ◽  
Hasan Saleh ◽  
Paula Folkeard ◽  
Sheila Moodie ◽  
Conner Janeteas ◽  
...  
Keyword(s):  
Mixed Model ◽  
Tracking System ◽  
Optical Tracking ◽  
Tube Placement ◽  
Control Group ◽  
Educational Settings ◽  
Training Simulator ◽  
Nonlinear Mixed Model ◽  
Optical Tracking System ◽  
Clinical Scenarios

AbstractProbe-tube placement is a necessary step in hearing aid verification which needs ample hands-on experience and confidence before performing in clinic. To improve the methods of training in probe-tube placement, a manikin-based training simulator was developed consisting of a 3D-printed head, a flexible silicone ear, and a mounted optical tracking system. The system is designed to provide feedback to the user on the depth and orientation of the probe tube, and the time required to finish the task. Although a previous validation study was performed to determine its realism and teachability with experts, further validation is required before implementation into educational settings.This study aimed to examine the skill transference of a newly updated probe-tube placement training simulator to determine if skills learned on this simulator successfully translate to clinical scenarios.All participants underwent a pretest in which they were evaluated while performing a probe-tube placement and real-ear-to-coupler difference (RECD) measurement on a volunteer. Participants were randomized into one of two groups: the simulator group or the control group. During a two-week training period, all participants practiced their probe-tube placement according to their randomly assigned group. After two weeks, each participant completed a probe-tube placement on the same volunteer as a posttest scenario.Twenty-five novice graduate-level student clinicians.Participants completed a self-efficacy questionnaire and an expert observer completed a questionnaire evaluating each participant’s performance during the pre- and posttest sessions. RECD measurements were taken after placing the probe tube and foam tip in the volunteer’s ear. Questionnaire results were analyzed through nonparametric t-tests and analysis of variance, whereas RECD results were analyzed using a nonlinear mixed model method.Results suggested students in the simulator group were less likely to contact the tympanic membrane when placing a probe tube, appeared more confident, and had better use of the occluding foam tip, resulting in more improved RECD measurements.The improved outcomes for trainees in the simulator group suggest that supplementing traditional training with the simulator provides useful benefits for the trainees, thereby encouraging its usage and implementation in educational settings.

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