72 research outputs found
Prolongation of regional anesthesia. Determinants of peripheral nerve block duration
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161228.pdf (Publisher’s version ) (Open Access)Radboud University, 02 december 2016Promotor : Scheffer, G.J. Co-promotores : Stienstra, R., Heesterbeek, P.J.C
Optimizing Locoregional Anesthesia for Fast Track Orthopedic Surgery
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209501.pdf (Publisher’s version ) (Open Access)Radboud University, 15 november 2019Promotor : Scheffer, G.J. Co-promotores : Stienstra, R., Heesterbeek, P.J.C
Regional anesthesia and total knee arthroplasty: Anesthetic and pharmacological considerations
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209723.pdf (Publisher’s version ) (Open Access)Radboud University, 21 november 2019Promotor : Scheffer, G.J. Co-promotores : Stienstra, R., Heesterbeek, P.J.C
The unhappy patient after TKA. A paradigm shift in assessing outcome
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304146.pdf (Publisher’s version ) (Open Access)Radboud University, 25 april 2024Promotores : Kleuver, M. de, Ende, C.H.M. van den Co-promotores : Heesterbeek, P.J.C., Smolders, J.M.H.187 p
Optimising Clinical Outcome and Survival in Revision Knee Arthroplasty
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319756.pdf (Publisher’s version ) (Open Access)In order to properly inform and treat a patient correctly, it is important to make an accurate judgement of the treatment's effect and which treatment provides the best result. Moreover, the outcome of knee revision surgeries depends on many factors. This dissertation shows that patients with a malaligned knee implant demonstrate a clinical relevant functional improvement up to 5 years after realignment by revision surgery. Anther important aspect for the longevity of revision implants is the fixation to the surrounding bone. This is evident from one of the studies, which shows a relationship between the fixation of a revision implant on a radiograph just after surgery and the risk of later re-revision for loosening. Moreover, certain knee implants have superior survival when the stems of these implants are used with cement compared to implants with press-fit stems.Radboud University, 26 juni 2025Promotor : Schreurs, B.W. Co-promotores : Heesterbeek, P.J.C., Wymenga, A.B.152 p
Mind the gaps! Clinical and technical aspects of PCL-retaining total knee replacement with the balanced gap technique.
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83220.pdf (Publisher’s version ) (Open Access)Radboud Universiteit Nijmegen, 25 januari 2011Promotor : Verdonschot, N.J.J. Co-promotores : Wymenga, A.B., Keijsers, N.L.W.239 p
In vivo knee laxity in flexion and extension: a radiographic study in 30 older healthy subjects.
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69774.pdf (Publisher’s version ) (Open Access)In order to determine how "tight" a total knee prosthesis should be implanted, it is important to know the amount of laxity in a healthy knee. The objective of this study was to determine knee laxity in extension and flexion in healthy, non-arthritic knees of subjects similar in age to patients undergoing a total knee arthroplasty and to provide guidelines for the orthopaedic surgeon in his attempt to restore the stability of an osteoarthritic knee to normal. Thirty healthy subjects (15 male, 15 female), mean age 62 (SD 6.4) years, were included in the study. For each subject one, randomly selected, knee was stressed in extension and in 70 degrees flexion (15 Nm). Varus and valgus laxity were measured on radiographs. The passive range of motion and active flexion was assessed. Mean valgus laxity in extension was 2.3 degrees (SD 0.9, range 0.2 degrees -4.1 degrees ). In extension mean varus laxity was 2.8 degrees (SD 1.3, range 0.6 degrees -5.4 degrees ). In flexion, mean valgus laxity was 2.5 degrees (SD 1.5, range 0.0 degrees -6.0 degrees ) and mean varus laxity was 3.1 degrees (SD 2.0, range 0.1 degrees -7.0 degrees ). Varus and valgus knee laxity in extension and in flexion were comparable. This study shows that the normal knee in this age group has an inherent degree of varus-valgus laxity. Whether the results of the present study can be used to optimise the total knee arthroplasty implantation technique requires further investigation
Urban Climate at Street Scale: Analysis and Adaptation
No full textIt is well known that the urban environment changes local climate inside the city. This change of the local climate manifests itself mainly through di_erences in air temperature, where cities remain warmer than the rural environment during the night. This phenomenon is called the Urban Heat Island (UHI) e_ect, and is de_ned as di_erence in air temperature between the urban and rural environment. The UHI e_ect is found in many cities of di_erent sizes around the world, and ranges between 1 and 10oC during the night. The combination of the increasing urbanisation, global warming and the impact of increasing temperature on human health makes the urban heat island a topic that is gaining more and more attention. This thesis focusses on the urban micro-climate, which treats indivicual buildings and their direct surroundings. A numerical modelling approach is used in this thesis, such that the local urban climate can be investigated and perturbed in a systematic way. The developed 2D model, called URBSIM, combines computation of radiative transfer by a Monte-Carlo model, conduction of energy into the urban material and a Computational Fluid Dynamics (CFD) model to compute air ow and air temperature. With this model, it is shown that the main source of energy to the urban heat budget is due to radiative transfer. During the night, the long wave trapping e_ect (de_ned in this theses as radiation emitted by one surface and absorbed by an other) and absorbed long wave radiation emitted from the sky are of the same order of magnitude for a building height (H) over street width (W) ratio of H=W=0.5. With increasing building height, longwave trapping becomes the main source of energy to the urban energy budget. During the day time, absorbed shortwave radiation is the main source of energy, followed by the long wave trapping e_ect. The relative contribution of these radiative components is decreasing with increasing building height, vi Summary and the conductive heat ux becomes more important. The large impact of radiation sparked the question which high albedo adaptation measure (white surfaces) is best suited to reduce the Urban Heat Island e_ect. This thesis shows that there is a clear distinction between the atmospheric UHI (air temperature) and pedestrian heat stress. Lower air temperatures can be achieved by using high albedo materials, whereas thermal comfort at street level can be improved by using low albedo materials. By using a low albedo material, less radiation is reected back inside the canyon, thereby reducing the mean radiant temperature. The lowest pedestrian heat stress is found by using a vertical albedo gradient from high albedo at the bottom part to a low albedo at the top part of the wall for H=W=1.0. This study indicated that using a high albedo material can decrease the UHI e_ect, but increases pedestrian heat stress, which might not be the desired e_ect. The developed micro-scale model is also compared to a large-scale urban parametrisation scheme that is used in meso-scale models. In this parametrisation, a 2D geometry is used to compute the uxes of the 3D environment. Results indicate that radiative transfer is well captured in the parametrisation. Canyon wind speeds and the sensible heat ux showed much larger di_erences between the two models, which is most likely due to the 2D geometry that is used as a basis for the parametrisation. It is very likely that these parametrisations are adapted to better represent the 3D urban environment. The result of this thesis is an advanced numerical model that includes most processes relevant to the urban environment. Despite the fact that the model is limited to 2D cases, the studies presented in this thesis have aided the understanding of the elementary processes that control urban air temperature, the feedback processes and interactions between the di_erent mechanisms in the urban surface energyAtmospheric Remote Sensin
Stresses near a plate vertex due to a shear force on one of the edges
No full textCivil Engineering and Geoscience
Mechanical Stability of the Prodisc-C Vivo Cervical Disc Arthroplasty: A Preliminary, Observational Study Using Radiostereometric Analysis
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220943.pdf (Publisher’s version ) (Open Access)STUDY DESIGN: Prospective cohort study. OBJECTIVE: To investigate the primary stability of the Prodisc-C Vivo cervical disc arthroplasty with regard to the adjacent cervical vertebrae using radiostereometric analysis (RSA), and to monitor its clinical performance. METHODS: Sixteen patients with degenerative cervical disc disease were included. RSA radiographs were obtained at the first postoperative day, at 6 weeks, 3 months, and 6 months postoperatively. Migration (translation [mm]) of the superior and inferior implant components were measured with model-based RSA, expressed along the 3 orthogonal axes, and calculated as total translation. Clinical outcomes were Neck Disability Index, numeric rating scales for neck and arm pain, Likert-type scales for satisfaction, and adverse events. Range of motion was reported as C2-C7 flexion-extension mobility (ROM). RESULTS: At final follow-up, no significant increase over time in median total translation was found. One inferior and 3 superior components subsided but were asymptomatic. ROM remained stable and clinical outcomes improved over time. Although 3 patients were unsatisfied and 3 adverse events occurred, this was not related to translation of the components. CONCLUSIONS: On a group level, both components of the Prodisc-C Vivo cervical disc arthroplasty remained stable over time and below the clinical threshold of 1 mm. Individual outliers for translation were not clinically relevant and probably related to settling of the components into the vertebral endplates. RSA allowed us to perform a preliminary but accurate study on the micromotion of a new cervical disc replacement in a small sample size, without putting large numbers of patients at risk
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