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Migration behaviour of 2 clinically excellent cementless stems with different design rationales: 5-year follow-up of a randomised RSA-study

van der Voort, Paul (author), van Delft, Danny (author), Valstar, E.R. (author), Kaptein, B.L. (author), Fiocco, Marta (author), Nelissen, R.G.H.H. (author)

Introduction: Excellent long-term survival has been reported for both the Taperloc and the Mallory-Head cementless stems. However, little is known about the migration behaviour of these stems which have different design rationales. The purpose of this randomised clinical trial was to compare the migration and clinical outcomes of these stems...

journal article 2021

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Long-term migration of a cementless stem with different bioactive coatings. Data from a “prime” RSA study: lessons learned

Van Der Voort, Paul (author), D Klein Nulent, Martijn L. (author), Valstar, E.R. (author), Kaptein, B.L. (author), Fiocco, Marta (author), Nelissen, R.G.H.H. (author)

Background and purpose — Little is known about the long-term migration pattern of cementless stems in total hip arthroplasty (THA). Furthermore, the role of bioactive coatings in fixation, and thus migration, remains uncertain. Hydroxyapatite (HA) is the most commonly used bioactive coating. However, delamination of the coating might induce...

journal article 2020

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Water Jet Applicator for Interface Tissue Removal in Minimally Invasive Hip Refixation: Testing the Principle and Design of Prototype

Kraaij, G. (author), Loeve, A.J. (author), Dankelman, J. (author), Nelissen, R.G.H.H. (author), Valstar, E.R. (author)

Mechanical loosening of implants is in the majority accompanied with a periprosthetic interface membrane, which has to be removed during revision surgery. The same is true if a minimal invasive (percutaneous) refixation of a loose implant is done. We describe the requirements for a waterjet applicator for interface tissue removal for this...

journal article 2019

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Migration and clinical outcome of mobile-bearing versus fixed-bearing single-radius total knee arthroplasty: A randomized controlled trial

Van Hamersveld, Koen T. (author), Marang-van de Mheen, P.J. (author), Van Der Heide, Huub J.L. (author), Van Der Linden-Van Der Zwaag, Henrica M.J. (author), Valstar, E.R. (author), Nelissen, R.G.H.H. (author)

Background and purpose — Mobile-bearing total knee prostheses (TKPs) were developed in the 1970s in an attempt to increase function and improve implant longevity. However, modern fixed-bearing designs like the single-radius TKP may provide similar advantages. We compared tibial component migration measured with radiostereometric analysis (RSA)...

journal article 2018

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Peri-prosthetic tissue cells show osteogenic capacity to differentiate into the osteoblastic lineage

Schoeman, Monique A.E. (author), Oostlander, Angela E. (author), Rooij, Karien Ede (author), Valstar, E.R. (author), Nelissen, R.G.H.H. (author)

During the process of aseptic loosening of prostheses, particulate wear debris induces a continuous inflammatory-like response resulting in the formation of a layer of fibrous peri-prosthetic tissue at the bone-prosthesis interface. The current treatment for loosening is revision surgery which is associated with a high-morbidity rate,...

journal article 2017

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Palacos compared to Palamed bone cement in total hip replacement: a randomized controlled trial: RSA migration similar at 10-year follow-up

Meinardi, J.E. (author), Valstar, E.R. (author), van der Voort, P (author), Kaptein, B.L. (author), Fiocco, M. (author), Nelissen, R.G.H.H. (author)

Background and purpose — Stability and survival of cemented total hip prostheses is dependent on a multitude of factors, including the type of cement that is used. Bone cements vary in viscosity, from low to medium and high. There have been few clinical RSA studies comparing the performance of low- and high-viscosity bone cements. We compared...

journal article 2016

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A fluoroscopy-based planning and guidance software tool for minimally invasive hip refixation by cement injection

Malan, D.F. (author), Van der Walt, S.J. (author), Raidou, R.G. (author), Van den Berg, B. (author), Stoel, B.C. (author), Botha, C.P. (author), Nelissen, R.G.H.H. (author), Valstar, E.R. (author)

Purpose In orthopaedics, minimally invasive injection of bone cement is an established technique. We present HipRFX, a software tool for planning and guiding a cement injection procedure for stabilizing a loosening hip prosthesis. HipRFX works by analysing a pre-operative CT and intraoperative C-arm fluoroscopic images. Methods HipRFX simulates...

journal article 2015

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Numerical optimization of alignment reproducibility for customizable surgical guides

Kroes, T. (author), Valstar, E.R. (author), Eisemann, E. (author)

Purpose Computer-assisted orthopedic surgery aims at minimizing invasiveness, postoperative pain, and morbidity with computer-assisted preoperative planning and intra-operative guidance techniques, of which camera-based navigation and patient-specific templates (PST) are the most common. PSTs are one-time templates that guide the surgeon...

journal article 2015

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Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

Bsat, S. (author), Yavari, S. (author), Munsch, M. (author), Valstar, E.R. (author), Zadpoor, A.A. (author)

Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the...

journal article 2015

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Early subsidence of shape-closed hip arthroplasty stems is associated with late revision

Van der Voort, P. (author), Pijls, B.G. (author), Nieuwenhuijse, M.J. (author), Jasper, J. (author), Fiocco, M. (author), Plevier, J.W.M. (author), Middeldorp, S. (author), Valstar, E.R. (author), Nelissen, R.G.H.H. (author)

Background and purpose — Few studies have addressed the association between early migration of femoral stems and late aseptic revision in total hip arthroplasty. We performed a meta-regression analysis on 2 parallel systematic reviews and meta-analyses to determine the association between early migration and late aseptic revision of femoral...

journal article 2015

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Validation of the in vivo volumetric wear measurement for total knee prostheses in model-based RSA

Van IJsseldijk, E.A. (author), Lebel, B. (author), Stoel, B.C. (author), Valstar, E.R. (author), Gouzy, S. (author), Vielpeau, C. (author), Kaptein, B.L. (author)

Implant failure related to polyethylene wear remains an important issue in total knee arthroplasty. Polyethylene wear is usually assessed in vivo by measuring the remaining insert thickness on X-ray images of the knee. To reflect the amount of wear debris more accurately, a 3-dimensional overlap measurement has been suggested, which is based on...

journal article 2014

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Grip op loslating

Valstar, E.R. (author)

public lecture 2013

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Kinematics and early migration in single-radius mobile- and fixed-bearing total knee prostheses

Wolterbeek, N. (author), Garling, E.H. (author), Mertens, B.J. (author), Nelissen, R.G.H.H. (author), Valstar, E.R. (author)

Background The mobile-bearing variant of a single-radius design is assumed to provide more freedom of motion compared to the fixed-bearing variant because the insert does not restrict the natural movements of the femoral component. This would reduce the contact stresses and wear which in turn may have a positive effect on the fixation of the...

journal article 2012

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Voxel classification and graph cuts for automated segmentation of pathological periprosthetic hip anatomy

Malan, D.F. (author), Botha, C.P. (author), Valstar, E.R. (author)

Purpose Automated patient-specific image-based segmentation of tissues surrounding aseptically loose hip prostheses is desired. For this we present an automated segmentation pipeline that labels periprosthetic tissues in computed tomography (CT). The intended application of this pipeline is in pre-operative planning. Methods Individual voxels...

journal article 2012

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AQUILA: Assessment of quality in lower limb arthroplasty. An expert Delphi consensus for total knee and total hip arthroplasty

Pijls, B.G. (author), Dekkers, O.M. (author), Middeldorp, S. (author), Valstar, E.R. (author), Van der Heide, H.J.L. (author), Van der Linden-Van der Zwaag, H.M.J. (author), Nelissen, R.G.H.H. (author)

Background: In the light of both the importance and large numbers of case series and cohort studies (observational studies) in orthopaedic literature, it is remarkable that there is currently no validated measurement tool to appraise their quality. A Delphi approach was used to develop a checklist for reporting quality, methodological quality...

journal article 2011

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No differences in in vivo kinematics between six different types of knee prostheses

Wolterbeek, N. (author), Nelissen, R.G.H.H. (author), Valstar, E.R. (author)

Purpose: The aim of this study was to compare a broad range of total knee prostheses with different design parameters to determine whether in vivo kinematics was consistently related to design. The hypothesis was that there are no clear recognizable differences in in vivo kinematics between different design parameters or prostheses. Methods: At...

journal article 2011

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Measuring femoral lesions despite CT metal artefacts: A cadaveric study

Malan, D.F. (author), Botha, C.P. (author), Kraaij, G. (author), Joemai, R.M.S. (author), Van der Heide, H.J.L. (author), Nelissen, R.G.H.H. (author), Valstar, E.R. (author)

Objective Computed tomography is the modality of choice for measuring osteolysis but suffers from metal-induced artefacts obscuring periprosthetic tissues. Previous papers on metal artefact reduction (MAR) show qualitative improvements, but their algorithms have not found acceptance for clinical applications. We investigated to what extent metal...

journal article 2011

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Co-contraction in RA patients with a mobile bearing total knee prosthesis during a step-up task

Garling, E.H. (author), Wolterbeek, N. (author), Velzeboer, S. (author), Nelissen, R.G.H.H. (author), Valstar, E.R. (author), Doorenbosch, C.A.M. (author), Harlaar, J. (author)

It was hypothesized that rheumatoid arthritis (RA) patients with a total knee prosthesis that allows axial rotation of the bearing (MB) will show more co-contraction to stabilize the knee joint during a step-up task than RA patients with a fixed bearing total knee prosthesis (FB) where this rotational freedom is absent while having the same...

journal article 2008

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Inverse modeling of groundwater flow using model reduction

Vermeulen, P.T.M. (author), Heemink, A.W. (author), Valstar, J.R. (author)

Numerical groundwater flow models often have a very high number of model cells (greater than a million). Such models are computationally very demanding, which is disadvantageous for inverse modeling. This paper describes a low?dimensional formulation for groundwater flow that reduces the computational burden necessary for inverse modeling. The...

journal article 2005

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NA-Interface: Natural Attenuation of oxidisable organic contaminants at the Interface between groundwater and surface water

Middeldorp, P. (author), Staps, S. (author), Rijnaarts, H. (author), van Dokkum, H. (author), Smits, J. (author), Valstar, J. (author), de Rooij, N. (author), Roelofsen, F. (author), v.d. Hoek, E. (author)

report 2003