Patient specific instrumentation in ACL reconstruction:a proof-of-concept cadaver experiment assessing drilling accuracy when using 3D printed guides

Introduction: Accurate positioning of the femoral tunnel in ACL reconstruction is of the utmost importance to reduce the risk of graft failure. Limited visibility during arthroscopy and a wide anatomical variance attribute to femoral tunnel malposition using conventional surgical techniques. The purpose of this study was to determine whether a patient specific 3D printed surgical guide allows for in vitro femoral tunnel positioning within 2 mm of the planned tunnel position. Materials and Methods: A patient specific guide for femoral tunnel positioning in ACL reconstruction was created for four human cadaveric knee specimens based on routine clinical MRI data. Fitting properties were judged by two orthopedic surgeons. MRI scanning was performed both pre- and post-procedure. The planned tunnel endpoint was compared to the actual drilled femoral tunnel. Results: This patient specific 3D printed guide showed a mean deviation of 5.0 mm from the center of the planned femoral ACL origin. Conclusion: In search to improve accuracy and consistency of femoral tunnel positioning in ACL reconstruction, the use of a patient specific 3D printed surgical guide is a viable option to explore further. The results are comparable to those of conventional techniques; however, further design improvements are necessary to improve accuracy and enhance reproducibility.</p

Anterolateral proximal tibial opening wedge osteotomy for biplanar correction in genu valgum recurvatum using patient specific instrumentation (PSI):A technical note

BACKGROUND: Biplanar anterolateral proximal tibial opening wedge osteotomy has been described as successful for patients with combined recurvatum and valgus alignment. As it is a correction in two planes, it is a technically demanding procedure. We report the use of a novel technique with patient specific instrumentation (PSI) guides for different steps, aiming to reduce the complexity of this procedure. METHODS: One patient was treated for genu valgum recurvatum. A virtual surgical plan was made. A two-step PSI approach was used, consisting of an osteotomy guide and a repositioning guide and a custom trial wedges. RESULTS: Follow-up showed full function and improved VAS and KOOS scores. A neutral alignment was achieved. There was 2.76 degrees less varus compared to pre-operative planning, 1.24 degrees of excess slope and a rotational difference of 0.10 degrees. Saw plane accuracy was within 1 mm. CONCLUSIONS: PSI is a recent technical addition to HTOs as a modality to improve accuracy and reduce surgical complexity. Pre-planning and PSI use in an anterolateral opening wedge PTO allowed for an accurate and reproducible biplanar correction in genu valgum recurvatum. Accuracy was comparable to PSI use in lateral open wedge high tibial osteotomies

First Test of Lorentz Invariance in the Weak Decay of Polarized Nuclei

A new test of Lorentz invariance in the weak interactions has been made by searching for variations in the decay rate of spin-polarized 20Na nuclei. This test is unique to Gamow-Teller transitions, as was shown in the framework of a recently developed theory that assumes a Lorentz symmetry breaking background field of tensor nature. The nuclear spins were polarized in the up and down direction, putting a limit on the amplitude of sidereal variations of the form |(\Gamma_{up} - \Gamma_{down})| / (\Gamma_{up} + \Gamma_{down}) < 3 * 10^{-3}. This measurement shows a possible route toward a more detailed testing of Lorentz symmetry in weak interactions.Comment: 11 pages, 6 figure

Understanding educational care farms as outdoor learning interventions for children who have dropped out of school in the Netherlands

When children drop out of school, either temporarily or permanently, this poses a significant problem for both children and society. In the Netherlands, care farms offering care-education programs for school dropouts are emerging. While there is evidence for their effectiveness, models explaining how such outdoor interventions may facilitate positive developments of children and their return to school are lacking. Using the generic Context-Intervention-Mechanisms-Outcome Model as an overarching deductive frame, this study inductively examines how care-educational programs facilitate the positive development of children who have dropped out of school

Are torso asymmetry and torso displacements in a computer brace model associated with initial in-brace correction in adolescent idiopathic scoliosis?

Abstract Background Lack of initial in-brace correction is strongly predictive for brace treatment failure in adolescent idiopathic scoliosis (AIS) patients. Computer-aided design (CAD) technology could be useful in quantifying the trunk in 3D and brace characteristics in order to further investigate the effect of brace modifications on initial in-brace correction and subsequently long-term brace treatment success. The purpose of this pilot study was to identify parameters obtained from 3D surface scans which influence the initial in-brace correction (IBC) in a Boston brace in patients with AIS. Methods Twenty-five AIS patients receiving a CAD-based Boston brace were included in this pilot study consisting of 11 patients with Lenke classification type 1 and 14 with type 5 curves. The degree of torso asymmetry and segmental peak positive and negative torso displacements were analyzed with the use of patients’ 3D surface scans and brace models for potential correlations with IBC. Results The mean IBC of the major curve on AP view was 15.9% (SD = 9.1%) for the Lenke type 1 curves, and 20.1% (SD = 13.9%) for the type 5 curves. The degree of torso asymmetry was weakly correlated with patient’s pre-brace major curve Cobb angle and negligible correlated with major curve IBC. Mostly weak or negligible correlations were observed between IBC and the twelve segmental peak displacements for both Lenke type 1 and 5 curves. Conclusion Based on the results of this pilot study, the degree of torso asymmetry and segmental peak torso displacements in the brace model alone are not clearly associated with IBC

Socioeconomic status and mental health during the COVID-19 crisis: Are sense of coherence, sense of community coherence and sense of national coherence predictors for mental health?

Evidence about the impact of the COVID-19 pandemic on existing health inequalities is emerging. This study explored differences in mental health, sense of coherence (SOC), sense of community coherence (SOCC), sense of national coherence (SONC), and social support betweenlow and high socioeconomic (SES) groups, and the predictive value of these predictors for mental health. participants and procedureA cross-sectional study was conducted using an online survey in the Netherlands in October 2021, comprising a total of 91 respondents (n = 41, low SES; n = 50, high SES).resultsThere were no differences in mental health, SOC, SOCC, SONC, and social support between the groups. SOC was a predictor for mental health in both groups and SOCC for the low SES group. conclusionsWe found that both SOC and SOCC predict mental health during the pandemic. In the article we reflect on possible pathways for strengthening these resources for mental health

The Care Farming Sector in The Netherlands: A Reflection on Its Developments and Promising Innovations

This paper describes the development of care farming in the Netherlands, one of the pioneering countries in this sector, where care farming has developed into a very diverse sector, with some farmers focussing primarily on agricultural production and others more specifically on providing care services. Care farms are increasingly open to a diversity of participants. The sector has become professionalised with the establishment of strong regional organisations and a steady growth increase in revenues, providing employment opportunities and boosting the economy of rural areas. In this paper, we highlight two promising innovations in care farming: education for school dropouts and the establishment of social farming activities in cities. These innovations face the challenge of connecting not only the agricultural and care sectors, but also the educational sector and the urban context. Initiators face a number of challenges, like trying to embed their activities in the educational sector, a mismatch in regulations and a lack of legitimacy in the case of education on care farms, as well as problems gaining access to land and a lack of recognition in the case of social farming in urban areas. However, the prospects are promising in both cases, because they match the changing demands in Dutch society and are able to integrate social, ecological and economic benefits. View Full-Tex

The Care Farming Sector in The Netherlands: A Reflection on Its Developments and Promising Innovations

This paper describes the development of care farming in the Netherlands, one of the pioneering countries in this sector, where care farming has developed into a very diverse sector, with some farmers focussing primarily on agricultural production and others more specifically on providing care services. Care farms are increasingly open to a diversity of participants. The sector has become professionalised with the establishment of strong regional organisations and a steady growth increase in revenues, providing employment opportunities and boosting the economy of rural areas. In this paper, we highlight two promising innovations in care farming: education for school dropouts and the establishment of social farming activities in cities. These innovations face the challenge of connecting not only the agricultural and care sectors, but also the educational sector and the urban context. Initiators face a number of challenges, like trying to embed their activities in the educational sector, a mismatch in regulations and a lack of legitimacy in the case of education on care farms, as well as problems gaining access to land and a lack of recognition in the case of social farming in urban areas. However, the prospects are promising in both cases, because they match the changing demands in Dutch society and are able to integrate social, ecological and economic benefits. View Full-Tex