Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 12) Show all publications
Stenlund, P., Kulbacka-Ortiz, K., Jönsson, S. & Brånemark, R. (2019). Loads on Transhumeral Amputees Using Osseointegrated Prostheses. Annals of Biomedical Engineering, 47(6), 1369-1377
Open this publication in new window or tab >>Loads on Transhumeral Amputees Using Osseointegrated Prostheses
2019 (English)In: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1573-9686, Vol. 47, no 6, p. 1369-1377Article in journal (Refereed) Published
Abstract [en]

The treatment of the upper extremities is not as prevalent as that of the lower limbs, but it is nonetheless equally important. Today, there are no load data relating to upper extremity bone-anchored prosthesis users in the literature, but they are important in order to improve the rehabilitation protocol, design aspects and confidence of the user when it comes to loading the prosthesis in daily life. The aim of the present study was to investigate, in a population of eleven transhumeral amputees with osseointegrated implants, the load levels reached during specific prosthetic movements at maximum voluntary effort and during daily activities. The data showed a wide range of maximum load levels throughout the different activities. Furthermore, the data indicate that some test subjects felt apprehensive about loading the prosthesis, resulting in relatively low loads compared with the group as a whole. Within the limits of the present study, it was concluded that loading the implant system was subject specific, which resulted in large subject-to-subject variability. Moreover, some subjects exhibited uncertainty about the levels that could damage the fixation or the implant system. The study illustrates the diversity and uncertainty that exist in a population of transhumeral amputees treated with bone-anchored prostheses in terms of loading in daily life.

Keywords
Amputee, Bone-anchored, Load, OPRA, Osseointegration, Prosthesis, Transhumeral, Upper extremity, Bone, Loading, Prosthetics, Artificial limbs
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38234 (URN)10.1007/s10439-019-02244-x (DOI)2-s2.0-85062774259 (Scopus ID)
Available from: 2019-03-27 Created: 2019-03-27 Last updated: 2019-06-28Bibliographically approved
Flys, O., Jarlemark, P., Petronis, S., Stenlund, P. & Rosen, B.-G. -. (2018). Applicability of characterization techniques on fine scale surfaces. Surface Topography: Metrology and Properties, 6(3), Article ID 034015.
Open this publication in new window or tab >>Applicability of characterization techniques on fine scale surfaces
Show others...
2018 (English)In: Surface Topography: Metrology and Properties, ISSN 2051-672X, Vol. 6, no 3, article id 034015Article in journal (Refereed) Published
Abstract [en]

In this study, several surface topographies typical for dental implants were evaluated by different measurement techniques. The samples were prepared by machine turning, wet chemical etching and electrochemical polishing of titanium discs. The measurement techniques included an atomic force microscope (AFM), coherence scanning interferometer (CSI) and a 3D stereo scanning electron microscope (SEM). The aim was to demonstrate and discuss similarities and differences in the results provided by these techniques when analyzing submicron surface topographies. The estimated surface roughness parameters were not directly comparable since the techniques had different surface spatial wavelength band limits. However, the comparison was made possible by applying a 2D power spectral density (PSD) function. Furthermore, to simplify the comparison, all measurements were characterized using the ISO 25178 standard parameters. Additionally, a Fourier transform was applied to calculate the instrument transfer function in order to investigate the behavior of CSI at different wavelength ranges. The study showed that 3D stereo SEM results agreed well with AFM measurements for the studied surfaces. Analyzed surface parameter values were in general higher when measured by CSI in comparison to both AFM and 3D stereo SEM results. In addition, the PSD analysis showed a higher power spectrum density in the lower frequency range 10-2-10-1 μm-1 for the CSI compared with the other techniques.

Keywords
3D-stereo SEM, AFM, Coherence scanning interferometer, power spectral density, surface topography, transfer function, Atomic force microscopy, Chemical polishing, Dental prostheses, Interferometers, Scanning, Scanning electron microscopy, Spectral density, Surface roughness, Topography, Transfer functions, Wet etching, 3d stereos, Characterization techniques, Measurement techniques, Power spectrum density, Scanning interferometers, Spatial wavelengths, Surface roughness parameters, Wavelength ranges, Parameter estimation
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-35683 (URN)10.1088/2051-672X/aacf5e (DOI)2-s2.0-85055559461 (Scopus ID)
Available from: 2018-11-06 Created: 2018-11-06 Last updated: 2018-11-06Bibliographically approved
Granskog, V., García-Gallego, S., von Kieseritzky, J., Rosendahl, J., Stenlund, P., Zhang, Y., . . . Malkoch, M. (2018). High-Performance Thiol–Ene Composites Unveil a New Era of Adhesives Suited for Bone Repair. Advanced Functional Materials, 28(26), Article ID 1800372.
Open this publication in new window or tab >>High-Performance Thiol–Ene Composites Unveil a New Era of Adhesives Suited for Bone Repair
Show others...
2018 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, no 26, article id 1800372Article in journal (Refereed) Published
Abstract [en]

The use of adhesives for fracture fixation can revolutionize the surgical procedures toward more personalized bone repairs. However, there are still no commercially available adhesive solutions mainly due to the lack of biocompatibility, poor adhesive strength, or inadequate fixation protocols. Here, a surgically realizable adhesive system capitalizing on visible light thiol–ene coupling chemistry is presented. The adhesives are carefully designed and formulated from a novel class of chemical constituents influenced by dental resin composites and self-etch primers. Validation of the adhesive strength is conducted on wet bone substrates and accomplished via fiber-reinforced adhesive patch (FRAP) methodology. The results unravel, for the first time, on the promise of a thiol–ene adhesive with an unprecedented shear bond strength of 9.0 MPa and that surpasses, by 55%, the commercially available acrylate dental adhesive system Clearfil SE Bond of 5.8 MPa. Preclinical validation of FRAPs on rat femur fracture models details good adhesion to the bone throughout the healing process, and are found biocompatible not giving rise to any inflammatory response. Remarkably, the FRAPs are found to withstand loads up to 70 N for 1000 cycles on porcine metacarpal fractures outperforming clinically used K-wires and match metal plates and screw implants.

Keywords
adhesives, biomedical applications, composites, photochemistry, polymeric materials, Biocompatibility, Composite materials, Dental composites, Dental materials, Fracture, Fracture fixation, Functional polymers, Medical applications, Photochemical reactions, Polymeric implants, Polymers, Chemical constituents, Coupling chemistry, Dental adhesive system, Dental resin composites, Inflammatory response, Shear bond strengths, Surgical procedures, Bone
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33958 (URN)10.1002/adfm.201800372 (DOI)2-s2.0-85048981911 (Scopus ID)
Note

Funding details: KI, Karolinska Institutet; Funding details: MSCA-IF-2014-655649, MSCA, H2020 Marie Skłodowska-Curie Actions; Funding details: 2010-435; Funding details: 2014-03777; Funding details: 2012-0196, Knut och Alice Wallenbergs Stiftelse; 

Available from: 2018-07-03 Created: 2018-07-03 Last updated: 2019-08-19Bibliographically approved
Murase, K., Stenlund, P., Thomsen, P., Lausmaa, J. & Palmquist, A. (2018). Three-dimensional modeling of removal torque and fracture progression around implants.. Journal of materials science. Materials in medicine, 29(7), Article ID 104.
Open this publication in new window or tab >>Three-dimensional modeling of removal torque and fracture progression around implants.
Show others...
2018 (English)In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 29, no 7, article id 104Article in journal (Refereed) Published
Abstract [en]

In the present study, a model for simulations of removal torque experiments was developed using finite element method. The interfacial retention and fracturing of the surrounding material caused by the surface features during torque was analyzed. It was hypothesized that the progression of removal torque and the phases identified in the torque response plot represents sequential fractures at the interface. The 3-dimensional finite element model fairly accurately predicts the torque required to break the fixation of acid-etched implants, and also provides insight to how sequential fractures progress downwards along the implant side.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33991 (URN)10.1007/s10856-018-6108-7 (DOI)29961132 (PubMedID)2-s2.0-85049241234 (Scopus ID)
Available from: 2018-07-03 Created: 2018-07-03 Last updated: 2019-01-02Bibliographically approved
Stenlund, P., Trobos, M., Lausmaa, J., Brånemark, R., Thomsen, P. & Palmquist, A. (2017). Effect of load on the bone around bone-anchored amputation prostheses. Journal of Orthopaedic Research, 35(5), 1113-1122
Open this publication in new window or tab >>Effect of load on the bone around bone-anchored amputation prostheses
Show others...
2017 (English)In: Journal of Orthopaedic Research, ISSN 0736-0266, E-ISSN 1554-527X, Vol. 35, no 5, p. 1113-1122Article in journal (Refereed) Published
Abstract [en]

Osseointegrated transfemoral amputation prostheses have proven successful as an alternative method to the conventional socket-type prostheses. The method improves prosthetic use and thus increases the demands imposed on the bone-implant system. The hypothesis of the present study was that the loads applied to the bone-anchored implant system of amputees would result in locations of high stress and strain transfer to the bone tissue and thus contribute to complications such as unfavourable bone remodeling and/or elevated inflammatory response and/or compromised sealing function at the tissue-abutment interface. In the study, site-specific loading measurements were made on amputees and used as input data in finite element analyses to predict the stress and strain distribution in the bone tissue. Furthermore, a tissue sample retrieved from a patient undergoing implant revision was characterized in order to evaluate the long-term tissue response around the abutment. Within the limit of the evaluated bone properties in the present experiments, it is concluded that the loads applied to the implant system may compromise the sealing function between the bone and the abutment, contributing to resorption of the bone in direct contact with the abutment at the most distal end. This was supported by observations in the retrieved clinical sample of bone resorption and the formation of a soft tissue lining along the abutment interface. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1113–1122, 2017.

Keywords
biomechanics, finite element analysis, interface, osseointegration, titanium implant, adult, aged, amputee, Article, bone remodeling, bone stress, bone tissue, clinical article, female, femur prosthesis, human, inflammation, male, micro-computed tomography, middle aged, musculoskeletal function, musculoskeletal system parameters, osseointegrated transfemoral amputation prosthesis, osteolysis, postoperative complication, priority journal, tissue reaction, trabecular bone, walking, diagnostic imaging, femur, leg, limb prosthesis, physiology, weight bearing, Artificial Limbs, Humans, Weight-Bearing, X-Ray Microtomography
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33175 (URN)10.1002/jor.23352 (DOI)2-s2.0-84978929528 (Scopus ID)
Available from: 2018-01-23 Created: 2018-01-23 Last updated: 2018-08-14Bibliographically approved
Shah, F. A., Stenlund, P., Martinelli, A., Thomsen, P. & Palmquist, A. (2016). Direct communication between osteocytes and acid-etched titanium implants with a sub-micron topography. Journal of materials science. Materials in medicine, 27(11), Article ID 167.
Open this publication in new window or tab >>Direct communication between osteocytes and acid-etched titanium implants with a sub-micron topography
Show others...
2016 (English)In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 27, no 11, article id 167Article in journal (Refereed) Published
Abstract [en]

The osteocyte network, through the numerous dendritic processes of osteocytes, is responsible for sensing mechanical loading and orchestrates adaptive bone remodelling by communicating with both the osteoclasts and the osteoblasts. The osteocyte network in the vicinity of implant surfaces provides insight into the bone healing process around metallic implants. Here, we investigate whether osteocytes are able to make an intimate contact with topologically modified, but micrometre smooth (Sa < 0.5 µm) implant surfaces, and if sub-micron topography alters the composition of the interfacial tissue. Screw shaped, commercially pure (cp-Ti) titanium implants with (i) machined (Sa = ~0.2 µm), and (ii) two-step acid-etched (HF/HNO3 and H2SO4/HCl; Sa = ~0.5 µm) surfaces were inserted in Sprague Dawley rat tibia and followed for 28 days. Both surfaces showed similar bone area, while the bone-implant contact was 73 % higher for the acid-etched surface. By resin cast etching, osteocytes were observed to maintain a direct intimate contact with the acid-etched surface. Although well mineralised, the interfacial tissue showed lower Ca/P and apatite-to-collagen ratios at the acid-etched surface, while mineral crystallinity and the carbonate-to-phosphate ratios were comparable for both implant surfaces. The interfacial tissue composition may therefore vary with changes in implant surface topography, independently of the amount of bone formed. Implant surfaces that influence bone to have higher amounts of organic matrix without affecting the crystallinity or the carbonate content of the mineral phase presumably result in a more resilient interfacial tissue, better able to resist crack development during functional loading than densely mineralised bone.

Keywords
Phosphate minerals, Surface topography, Tissue, Titanium, Topography, Bone healing process, Direct communications, Functional loadings, Interfacial tissues, Mechanical loading, Metallic implants, Osteocyte networks, Titanium implants, Bone
National Category
Biomaterials Science Medical Materials
Identifiers
urn:nbn:se:ri:diva-27592 (URN)10.1007/s10856-016-5779-1 (DOI)2-s2.0-84989897825 (Scopus ID)
Available from: 2016-12-19 Created: 2016-12-19 Last updated: 2019-06-13Bibliographically approved
Stenlund, P., Omar, O., Brohede, U., Norgren, S., Norlindh, B., Johansson, A., . . . Palmquist, A. (2015). Bone response to a novel Ti-Ta-Nb-Zr alloy (ed.). Acta Biomaterialia, 20, 165-175
Open this publication in new window or tab >>Bone response to a novel Ti-Ta-Nb-Zr alloy
Show others...
2015 (English)In: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 20, p. 165-175Article in journal (Refereed) Published
Abstract [en]

Commercially pure titanium (cp-Ti) is regarded as the state-of-the-art material for bone-anchored dental devices, whereas the mechanically stronger alloy (Ti–6Al–4V), made of titanium, aluminum (Al) and vanadium (V), is regarded as the material of choice for high-load applications. There is a call for the development of new alloys, not only to eliminate the potential toxic effect of Al and V but also to meet the challenges imposed on dental and maxillofacial reconstructive devices, for example. The present work evaluates a novel, dual-stage, acid-etched, Ti–Ta–Nb–Zr alloy implant, consisting of elements that create low toxicity, with the potential to promote osseointegration in vivo. The alloy implants (denoted Ti–Ta–Nb–Zr) were evaluated after 7 days and 28 days in a rat tibia model, with reference to commercially pure titanium grade 4 (denoted Ti). Analyses were performed with respect to removal torque, histomorphometry and gene expression. The Ti–Ta–Nb–Zr showed a significant increase in implant stability over time in contrast to the Ti. Further, the histological and gene expression analyses suggested faster healing around the Ti–Ta–Nb–Zr, as judged by the enhanced remodeling, and mineralization, of the early-formed woven bone and the multiple positive correlations between genes denoting inflammation, bone formation and remodeling. Based on the present experiments, it is concluded that the Ti–Ta–Nb–Zr alloy becomes osseointegrated to at least a similar degree to that of pure titanium implants. This alloy is therefore emerging as a novel implant material for clinical evaluation.

Keywords
Osseointegration, Removal torque, Gene expression, Titanium alloy, Tantalum (Ta)
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6838 (URN)10.1016/j.actbio.2015.03.038 (DOI)2-s2.0-84929518669 (Scopus ID)23658 (Local ID)23658 (Archive number)23658 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2020-01-20Bibliographically approved
Stenlund, P., Kurosu, S., Koizumi, Y., Suska, F., Matsumoto, H., Chiba, A. & Palmquist, A. (2015). Osseointegration Enhancement by Zr doping of Co-Cr-Mo Implants Fabricated by Electron Beam Melting (ed.). Additive Manufacturing, 6, 6-15
Open this publication in new window or tab >>Osseointegration Enhancement by Zr doping of Co-Cr-Mo Implants Fabricated by Electron Beam Melting
Show others...
2015 (English)In: Additive Manufacturing, ISSN 2214-8604, Vol. 6, p. 6-15Article in journal (Refereed) Published
Abstract [en]

Direct osseous healing to prosthetic components is a prerequisite for the clinical success of uncemented treatment in total hip replacements (THR). The demands imposed on the material properties are constantly being stepped up to withstand the impact of an active lifestyle and ensure lifelong integration. Cobalt–chromium–molybdenum (Co-Cr-Mo) materials are interesting for their excellent mechanical stability, corrosion resistance and possibility to be produced by additive manufacturing into complex designs with modifiable stiffness. The bone response to Co-Cr-Mo is regarded as inferior to that of titanium and are usually cemented in THR. The hypothesis in the present study was that a low amount of Zr in the Co-Cr-Mo alloy would improve the bone response and biomechanical anchorage. The results showed significantly higher implant stability for the Co-Cr-Mo alloy with an addition of 0.04% Zr after eight weeks of healing in rabbits, while no major differences were observed in the amount of bone formed around the implants. Further, bone tissue grew into surface irregularities and in direct contact with the implant surfaces. It is concluded that additively manufactured Co-Cr-Mo alloy implants osseointegrate and that the addition of a low amount of Zr to the bulk Co-Cr-Mo further improves the bone anchorage.

Keywords
Cobalt–chromium–molybdenum alloy, Zirconium, Additive manufacturing, Bone anchorage, In vivo
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6797 (URN)10.1016/j.addma.2015.02.002 (DOI)2-s2.0-84924087090 (Scopus ID)23584 (Local ID)23584 (Archive number)23584 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2020-01-31Bibliographically approved
Lausmaa, J. & Stenlund, P. (2014). Understanding mechanisms and factors related to implant fixation; a model study of removal torque (ed.). Journal of The Mechanical Behavior of Biomedical Materials, 34(Jun), 83-92
Open this publication in new window or tab >>Understanding mechanisms and factors related to implant fixation; a model study of removal torque
2014 (English)In: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 34, no Jun, p. 83-92Article in journal (Refereed) Published
Abstract [en]

Osseointegration is a prerequisite for achieving a stable long-term fixation and load-bearing capacity of bone anchored implants. Removal torque measurements are often used experimentally to evaluate the fixation of osseointegrated screw-shaped implants. However, a detailed understanding of the way different factors influence the result of removal torque measurements is lacking. The present study aims to identify the main factors contributing to anchorage. Individual factors important for implant fixation were identified using a model system with an experimental design in which cylindrical or screw-shaped samples were embedded in thermosetting polymers, in order to eliminate biological variation. Within the limits of the present study, it is concluded that surface topography and the mechanical properties of the medium surrounding the implant affect the maximum removal torque. In addition to displaying effects individually, these factorsdemonstrate interplay between them. The rotational speed was found not to influence the removal torque measurements within the investigated range.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6679 (URN)10.1016/j.jmbbm.2014.02.006 (DOI)2-s2.0-84894333338 (Scopus ID)23659 (Local ID)23659 (Archive number)23659 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2019-08-08Bibliographically approved
Stenlund, P. (2012). Healing of complement activating Ti implants compared with non-activating Ti in rat tibia (ed.). Acta Biomaterialia, 8(9), 3532-3540
Open this publication in new window or tab >>Healing of complement activating Ti implants compared with non-activating Ti in rat tibia
2012 (English)In: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 8, no 9, p. 3532-3540Article in journal (Refereed) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6423 (URN)23966 (Local ID)23966 (Archive number)23966 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2018-08-14Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9442-7245

Search in DiVA

Show all publications
v. 2.35.10