A New 4-DOF Robot for Rehabilitation of Knee and Ankle-Foot Complex: Simulation and Experiment

Stationary robotic trainers are lower limb rehab robots which often incorporate an exoskeleton attached to a stationary base. The issue observed in the stationery trainers for simultaneous knee and ankle-foot complex joints is that they restrict the natural motion of ankle-foot in the rehab trainings due to the insufficient Degrees of Freedom (DOFs) of these trainers. A new stationary knee-ankle-foot rehab robot with all necessary DOFs is developed here. A typical rehab training is first implemented in simulation, and then tested on a healthy subject. Results show that the proposed system functions naturally and meets the requirements of the desired rehab training.Comment: 23 pages, 14 figure

Assessment of axial bone rigidity in rats with metabolic diseases using CT-based structural rigidity analysis

Objectives: This study aims to assess the correlation of CT-based structural rigidity analysis with mechanically determined axial rigidity in normal and metabolically diseased rat bone. Methods: A total of 30 rats were divided equally into normal, ovariectomized, and partially nephrectomized groups. Cortical and trabecular bone segments from each animal underwent micro-CT to assess their average and minimum axial rigidities using structural rigidity analysis. Following imaging, all specimens were subjected to uniaxial compression and assessment of mechanically-derived axial rigidity. Results: The average structural rigidity-based axial rigidity was well correlated with the average mechanically-derived axial rigidity results (R$^2$ = 0.74). This correlation improved significantly (p < 0.0001) when the CT-based Structural Rigidity Analysis (CTRA) minimum axial rigidity was correlated to the mechanically-derived minimum axial rigidity results (R$^2$ = 0.84). Tests of slopes in the mixed model regression analysis indicated a significantly steeper slope for the average axial rigidity compared with the minimum axial rigidity (p = 0.028) and a significant difference in the intercepts (p = 0.022). The CTRA average and minimum axial rigidities were correlated with the mechanically-derived average and minimum axial rigidities using paired t-test analysis (p = 0.37 and p = 0.18, respectively). Conclusions: In summary, the results of this study suggest that structural rigidity analysis of micro-CT data can be used to accurately and quantitatively measure the axial rigidity of bones with metabolic pathologies in an experimental rat model. It appears that minimum axial rigidity is a better model for measuring bone rigidity than average axial rigidity

Microstructural, Densitometric and Metabolic Variations in Bones from Rats with Normal or Altered Skeletal States

Background: High resolution μCT, and combined μPET/CT have emerged as non-invasive techniques to enhance or even replace dual energy X-ray absorptiometry (DXA) as the current preferred approach for fragility fracture risk assessment. The aim of this study was to assess the ability of µPET/CT imaging to differentiate changes in rat bone tissue density and microstructure induced by metabolic bone diseases more accurately than current available methods. Methods: Thirty three rats were divided into three groups of control, ovariectomy and vitamin-D deficiency. At the conclusion of the study, animals were subjected to glucose (18FDG) and sodium fluoride (Na18F) PET/CT scanning. Then, specimens were subjected to µCT imaging and tensile mechanical testing. Results: Compared to control, those allocated to ovariectomy and vitamin D deficiency groups showed 4% and 22% (significant) increase in 18FDG uptake values, respectively. DXA-based bone mineral density was higher in the vitamin D deficiency group when compared to the other groups (cortical bone), yet μCT-based apparent and mineral density results were not different between groups. DXA-based bone mineral density was lower in the ovariectomy group when compared to the other groups (cancellous bone); yet μCT-based mineral density results were not different between groups, and the μCT-based apparent density results were lower in the ovariectomy group compared to the other groups. Conclusion: PET and micro-CT provide an accurate three-dimensional measurement of the changes in bone tissue mineral density, as well as microstructure for cortical and cancellous bone and metabolic activity. As osteomalacia is characterized by impaired bone mineralization, the use of densitometric analyses may lead to misinterpretation of the condition as osteoporosis. In contrast, µCT alone and in combination with the PET component certainly provides an accurate three-dimensional measurement of the changes in both bone tissue mineral density, as well as microstructure for cortical and cancellous bone and metabolic activity

The effect of gentamycin in the irrigating solution to prevent joint infection after anterior cruciate ligament (ACL) reconstruction

Background: Arthroscopic reconstruction of ACL is an effective method to restore knee stability after ACL rupture. Postoperative septic arthritis (SA) is very uncommon while the incidence of serious complications range between 0.14 and 1.8. Some of the devastating consequences of septic arthritis can encompass hyaline cartilage damage, arthrofibrosis, and in rare cases amputation. The purpose of this study was to evaluate the effect of gentamicin irrigation solutions as a process to restrain septic arthritis following arthroscopic ACL reconstruction. Methods: In this retrospective cohort study, 1464 patients who underwent ACL reconstruction with hamstring tendon autograft in our institution over 7 years (February 2008 to January 2015) were included. The patients were divided into two groups based on the type of intra-articular irrigation solution used during the surgery. Patients in Group 1 (Saline) received intra-articular irrigation with normal saline (0.9 sodium chloride) solution, while those in Group 2 (Gentamycin) received intra-articular irrigation with gentamicin (80 mg/L) added to the normal saline solution. Data about postoperative infection, its course, management, and outcome were obtained from patients' records. Results: Seven patients developed SA, four of whom were from SALINE group (2.2) and three from Gentamycin group (0.23). The incidence rate of SA after arthroscopic ACL reconstruction was significantly lower (P <0.05) when irrigated with gentamicin solution than merely with saline solution. Conclusion: Gentamicin irrigation solution has a preservative and protective effect against SA development following arthroscopic ACL reconstruction. We recommend evaluating this technique as a way in order to depreciate the prevalence of SA after ACL reconstruction. © 2019 BY THE ARCHIVES OF BONE AND JOINT SURGERY

Preliminary evaluation of a robotic apparatus for the analysis of passive glenohumeral joint kinematics

Background: The shoulder has the greatest range of motion of any joint in the human body. This is due, in part, to the complex interplay between the glenohumeral (GH) joint and the scapulothoracic (ST) articulation. Currently, our ability to study shoulder kinematics is limited, because existing models isolate the GH joint and rely on manual manipulation to create motion, and have low reproducibility. Similarly, most established techniques track shoulder motion discontinuously with limited accuracy. Methods: To overcome these problems, we have designed a novel system in which the shoulder girdle is studied intact, incorporating both GH and ST motions. In this system, highly reproducible trajectories are created using a robotic actuator to control the intact shoulder girdle. High-speed cameras are employed to track retroreflective bone markers continuously. Results: We evaluated this automated system’s capacity to reproducibly capture GH translation in intact and pathologic shoulder conditions. A pair of shoulders (left and right) were tested during forward elevation at baseline, with a winged scapula, and after creation of a full thickness supraspinatus tear. Discussion The system detected differences in GH translations as small as 0.5 mm between different conditions. For each, three consecutive trials were performed and demonstrated high reproducibility and high precision

Design and manufacture of a novel system to simulate the biomechanics of basic and pitching shoulder motion

Objectives: Cadaveric models of the shoulder evaluate discrete motion segments using the glenohumeral joint in isolation over a defined trajectory. The aim of this study was to design, manufacture and validate a robotic system to accurately create three-dimensional movement of the upper body and capture it using high-speed motion cameras. Methods: In particular, we intended to use the robotic system to simulate the normal throwing motion in an intact cadaver. The robotic system consists of a lower frame (to move the torso) and an upper frame (to move an arm) using seven actuators. The actuators accurately reproduced planned trajectories. The marker setup used for motion capture was able to determine the six degrees of freedom of all involved joints during the planned motion of the end effector. Results: The testing system demonstrated high precision and accuracy based on the expected versus observed displacements of individual axes. The maximum coefficient of variation for displacement of unloaded axes was less than 0.5% for all axes. The expected and observed actual displacements had a high level of correlation with coefficients of determination of 1.0 for all axes. Conclusions: Given that this system can accurately simulate and track simple and complex motion, there is a new opportunity to study kinematics of the shoulder under normal and pathological conditions in a cadaveric shoulder model

Blended learning for teacher professional learning

Lärare behöver professionellt lärande för att skolresultaten ska förbättras. För att det ska göra skillnad för alla elever så behöver alla lärare delta i den. Samtidigt visas en brist på organiserat professionellt lärande för lärare (Skolverket, 2013). Digitaliseringen skapar nya möjligheter. Lärande online kännetecknas av att vara flexibel tids- och rumsmässigt. Något som kan möta det tidsmässiga hinder som skolledare uttrycker (Skolinspektionen, 2015). Forskning, av Means et al. (2009), visar att lärande med blended learning; där undervisning och lärande i det fysiska rummet kombineras med undervisning och lärande online, ger bättre effekt än lärande helt fysiskt respektive helt online. Denna studie har tittat på hur de olika undervisningsmiljöerna i blended learning; fysiskt respektive online, kan tillämpas för att skapa förutsättningar för ett framgångsrikt professionellt lärande. Metoden metasyntes har använts för att sätta samman resultat från olika studier i syfte att skapa en samling vetenskapligt grundade råd; en best practice att luta sig på vid framtida planering. Studien är teoretiskt influerad av ett sociokulturellt perspektiv på lärande. Metasyntesen visar att blended learning kan vara en god form att tillämpa. Det är tydligt att de båda undervisningsmiljöerna; fysiskt och online, är viktiga. Vid de fysiska träffarna vårdas och stärks sociala relationer, medan onlinemiljön erbjuder en betydelsefull tids- och rumsmässig flexibilitet. Förutsättningar för ett framgångsrikt professionellt lärande med blended learning är att strukturella resurser som god IT-miljö och avsatt tid för lärandet finns. Metasyntesen är tänkt som ett stöd för skolledare och andra beslutsfattare inför planering av framtida professionellt lärande för grundskollärare.Teachers need professional learning opportunities to improve school results. To have impact for all students, all teachers need to participate. However, there is currently an acknowledged lack of organized professional learning for teachers (Skolverket, 2013). Technology creates new possibilities. Online learning is known to be flexible in terms of time and space, a feature that can help meet the time-related obstacles that school leaders report (Skolinspektionen, 2015). Research, by Means et al. (2009), shows that blended learning, a method where teaching and learning face-to-face is combined with teaching and learning online, has a better effect then exclusively face-to-face or online approaches. This study has explored how the different teaching environments in a blended learning approach; face-to-face and online, can be used to create successful professional learning opportunities. The method used is research synthesis to combine results from different studies in order to create an overarching account of best practice to draw on during future planning. The study is theoretical influenced by a sociocultural view of learning. The research synthesis shows that blended learning can be a promising approach. It is clear that both the teaching environments; face-to-face and online, are important. It shows that social relationships are particularly strengthened by face-to-face meetings, while online solutions offer increased flexibility in terms of time and space. The results also show that necessary conditions for successful blended learning initiatives include structural resources such as good ICT and allocated time for learning. This research synthesis is intended to support school leaders and policymakers in the planning of future teacher professional learning

Hierarchical analysis and multi-scale modelling of rat cortical and trabecular bone

The aim of this study was to explore the hierarchical arrangement of structural properties in cortical and trabecular bone and to determine a mathematical model that accurately predicts the tissue's mechanical properties as a function of these indices. By using a variety of analytical techniques, we were able to characterize the structural and compositional properties of cortical and trabecular bones, as well as to determine the suitable mathematical model to predict the tissue's mechanical properties using a continuum micromechanics approach. Our hierarchical analysis demonstrated that the differences between cortical and trabecular bone reside mainly at the micro- and ultrastructural levels. By gaining a better appreciation of the similarities and differences between the two bone types, we would be able to provide a better assessment and understanding of their individual roles, as well as their contribution to bone health overall