| 1. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Loza, M. J., et al.
(författare)
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Validated and longitudinally stable asthma phenotypes based on cluster analysis of the ADEPT study
- 2016
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Ingår i: Respiratory Research. - : Springer Nature. - 1465-9921 .- 1465-993X. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Asthma is a disease of varying severity and differing disease mechanisms. To date, studies aimed at stratifying asthma into clinically useful phenotypes have produced a number of phenotypes that have yet to be assessed for stability and to be validated in independent cohorts. The aim of this study was to define and validate, for the first time ever, clinically driven asthma phenotypes using two independent, severe asthma cohorts: ADEPT and U-BIOPRED. Methods: Fuzzy partition-around-medoid clustering was performed on pre-specified data from the ADEPT participants (n = 156) and independently on data from a subset of U-BIOPRED asthma participants (n = 82) for whom the same variables were available. Models for cluster classification probabilities were derived and applied to the 12-month longitudinal ADEPT data and to a larger subset of the U-BIOPRED asthma dataset (n = 397). High and low type-2 inflammation phenotypes were defined as high or low Th2 activity, indicated by endobronchial biopsies gene expression changes downstream of IL-4 or IL-13. Results: Four phenotypes were identified in the ADEPT (training) cohort, with distinct clinical and biomarker profiles. Phenotype 1 was "mild, good lung function, early onset", with a low-inflammatory, predominantly Type-2, phenotype. Phenotype 2 had a "moderate, hyper-responsive, eosinophilic" phenotype, with moderate asthma control, mild airflow obstruction and predominant Type-2 inflammation. Phenotype 3 had a "mixed severity, predominantly fixed obstructive, non-eosinophilic and neutrophilic" phenotype, with moderate asthma control and low Type-2 inflammation. Phenotype 4 had a "severe uncontrolled, severe reversible obstruction, mixed granulocytic" phenotype, with moderate Type-2 inflammation. These phenotypes had good longitudinal stability in the ADEPT cohort. They were reproduced and demonstrated high classification probability in two subsets of the U-BIOPRED asthma cohort. Conclusions: Focusing on the biology of the four clinical independently-validated easy-to-assess ADEPT asthma phenotypes will help understanding the unmet need and will aid in developing tailored therapies. Trial registration:NCT01274507(ADEPT), registered October 28, 2010 and NCT01982162(U-BIOPRED), registered October 30, 2013.
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| 6. |
- Callary, Stuart A, et al.
(författare)
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The 6-Year Migration Characteristics of a Hydroxyapatite-Coated Femoral Stem A Radiostereometric Analysis Study
- 2012
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Ingår i: The Journal of Arthroplasty. - : Elsevier. - 0883-5403 .- 1532-8406. ; 27:7, s. 1344-1348
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Tidskriftsartikel (refereegranskat)abstract
- A prospective cohort of 30 patients undergoing primary total hip arthroplasty for treatment of osteoarthritis was enrolled in a study to characterize the migration behavior of a clinically successful cementless stem. At 6 years, the mean subsidence of the stem was 0.63 mm (range, -0.33 to 3.68 mm); the mean rotation into retroversion was 1.41° (range, -1.33° to 7.48°). No stems had additional subsidence of more than 0.25 mm between 6 months and 6 years. The resultant mean subsidence between 2 and 6 years was 0.03 mm, which is below the limit measurable by radiostereometric analysis. The data demonstrate that subsidence of this cementless stem occurs within the first 6 months, after which there is persistent stabilization.
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| 7. |
- Callary, Stuart A., et al.
(författare)
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Wear of a 5 Megarad Cross-linked Polyethylene Liner : A 6-year RSA Study
- 2013
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Ingår i: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 471:7, s. 2238-2244
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Tidskriftsartikel (refereegranskat)abstract
- One cross-linked polyethylene (XLPE) liner is manufactured using a lower dose of radiation, 5 Mrad, which may result in less cross-linking. The reported in vivo wear rate of this XLPE liner in patients undergoing THA has varied, and has included some patients in each reported cohort who had greater than 0.1 mm/year of wear, which is an historical threshold for osteolysis. Previous studies have measured wear on plain radiographs, an approach that has limited sensitivity. We therefore measured the amount and direction of wear at 6 years using Radiostereometric analysis (RSA) in patients who had THAs that included a cross-linked polyethylene liner manufactured using 5 Mrad radiation. We prospectively reviewed wear in 30 patients who underwent primary THAs with the same design of cross-linked acetabular liner and a 28-mm articulation. Tantalum markers were inserted during surgery and all patients had RSA radiographic examinations at 1 week, 6 months, 1, 2, and 6 years postoperatively. The mean proximal, two-dimensional (2-D) and three-dimensional (3-D) wear rates calculated between 1 year and 6 years were 0.014, 0.014, and 0.018 mm/per year, respectively. The direction of the head penetration recorded between 1 week and 6 years was in a proximal direction for all patients, proximolateral for 16 of 24 patients, and proximomedial for eight of 24 patients. The proximal, 2-D and 3-D wear of a XLPE liner produced using 5 Mrad of radiation was low but measurable by RSA after 6 years. No patients had proximal 2-D or 3-D wear rates exceeding 0.1 mm/year. Further followup is needed to evaluate the effect of XLPE wear particles on the development of long-term osteolysis.
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| 8. |
- Culina, Antica, et al.
(författare)
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Connecting the data landscape of long-term ecological studies : The SPI-Birds data hub
- 2021
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Ingår i: Journal of Animal Ecology. - : John Wiley & Sons. - 0021-8790 .- 1365-2656. ; 90:9, s. 2147-2160
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Tidskriftsartikel (refereegranskat)abstract
- The integration and synthesis of the data in different areas of science is drastically slowed and hindered by a lack of standards and networking programmes. Long-term studies of individually marked animals are not an exception. These studies are especially important as instrumental for understanding evolutionary and ecological processes in the wild. Furthermore, their number and global distribution provides a unique opportunity to assess the generality of patterns and to address broad-scale global issues (e.g. climate change). To solve data integration issues and enable a new scale of ecological and evolutionary research based on long-term studies of birds, we have created the SPI-Birds Network and Database ()-a large-scale initiative that connects data from, and researchers working on, studies of wild populations of individually recognizable (usually ringed) birds. Within year and a half since the establishment, SPI-Birds has recruited over 120 members, and currently hosts data on almost 1.5 million individual birds collected in 80 populations over 2,000 cumulative years, and counting. SPI-Birds acts as a data hub and a catalogue of studied populations. It prevents data loss, secures easy data finding, use and integration and thus facilitates collaboration and synthesis. We provide community-derived data and meta-data standards and improve data integrity guided by the principles of Findable, Accessible, Interoperable and Reusable (FAIR), and aligned with the existing metadata languages (e.g. ecological meta-data language). The encouraging community involvement stems from SPI-Bird's decentralized approach: research groups retain full control over data use and their way of data management, while SPI-Birds creates tailored pipelines to convert each unique data format into a standard format. We outline the lessons learned, so that other communities (e.g. those working on other taxa) can adapt our successful model. Creating community-specific hubs (such as ours, COMADRE for animal demography, etc.) will aid much-needed large-scale ecological data integration.
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| 9. |
- Grip, Helena, et al.
(författare)
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Does the Femoral Head Size in Hip Arthroplasty Influence Lower Body Movements during Squats, Gait and Stair Walking? : A Clinical Pilot Study Based on Wearable Motion Sensors
- 2019
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 19:14
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Tidskriftsartikel (refereegranskat)abstract
- A hip prosthesis design with larger femoral head size may improve functional outcomes compared to the conventional total hip arthroplasty (THA) design. Our aim was to compare the range of motion (RoM) in lower body joints during squats, gait and stair walking using a wearable movement analysis system based on inertial measurement units (IMUs) in three age-matched male groups: 6 males with a conventional THA (THAC), 9 with a large femoral head (LFH) design, and 8 hip- and knee-asymptomatic controls (CTRL). We hypothesized that the LFH design would allow a greater hip RoM, providing movement patterns more like CTRL, and a larger side difference in hip RoM in THAC when compared to LFH and controls. IMUs were attached to the pelvis, thighs and shanks during five trials of squats, gait, and stair ascending/descending performed at self-selected speed. THAC and LFH participants completed the Hip dysfunction and Osteoarthritis Outcome Score (HOOS). The results showed a larger hip RoM during squats in LFH compared to THAC. Side differences in LFH and THAC groups (operated vs. non-operated side) indicated that movement function was not fully recovered in either group, further corroborated by non-maximal mean HOOS scores (LFH: 83 +/- 13, THAC: 84 +/- 19 groups, vs. normal function 100). The IMU system may have the potential to enhance clinical movement evaluations as an adjunct to clinical scales.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Roselli, Carolina, et al.
(författare)
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Multi-ethnic genome-wide association study for atrial fibrillation
- 2018
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 50:9, s. 1225-1233
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Tidskriftsartikel (refereegranskat)abstract
- Atrial fibrillation (AF) affects more than 33 million individuals worldwide(1) and has a complex heritability(2). We conducted the largest meta-analysis of genome-wide association studies (GWAS) for AF to date, consisting of more than half a million individuals, including 65,446 with AF. In total, we identified 97 loci significantly associated with AF, including 67 that were novel in a combined-ancestry analysis, and 3 that were novel in a European-specific analysis. We sought to identify AF-associated genes at the GWAS loci by performing RNA-sequencing and expression quantitative trait locus analyses in 101 left atrial samples, the most relevant tissue for AF. We also performed transcriptome-wide analyses that identified 57 AF-associated genes, 42 of which overlap with GWAS loci. The identified loci implicate genes enriched within cardiac developmental, electrophysiological, contractile and structural pathways. These results extend our understanding of the biological pathways underlying AF and may facilitate the development of therapeutics for AF.
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| 14. |
- van Hamersveld, Koen T., et al.
(författare)
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Risk Factors for Tibial Component Loosening : A Meta-Analysis of Long-Term Follow-up Radiostereometric Analysis Data
- 2021
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Ingår i: Journal of Bone and Joint Surgery. American volume. - : NLM. - 0021-9355 .- 1535-1386. ; 103:12, s. 1115-1124
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Radiostereometric analysis (RSA) is a highly accurate tool to detect implant migration and predict loosening following total knee arthroplasty (TKA). However, little is known about the predisposing risk factors for implant migration, nor which migration profile should be considered physiological (i.e., merely part of an implant-settling phase) and which should be considered pathological (i.e., having a high probability for implant loosening). By pooling individual participant data from long-term follow-up RSA studies, we aimed to identify predisposing risk factors for tibial component loosening.METHODS: Individual data were collected for 630 patients from 11 RSA studies. The repeated measurements were analyzed with use of a linear mixed-effects model, determining the effect of age, sex, body mass index, diagnosis, preoperative and postoperative limb alignment, and prosthesis characteristics on tibial component migration over time, taking into account the clustering of patients within studies.RESULTS: High initial migration was found to result in early mechanical loosening in 18 cases (2.9%) and septic loosening in 2 cases (0.3%), whereas stabilization of high initial migration occurred in 17 cases (2.7%). Late loosening occurred in 13 cases (2.1%). All other 580 cases (92.1%) showed early stabilization and remained stable over time. Mixed-effects model analyses showed that for cemented prostheses, sex, diagnosis, and posterior cruciate ligament type had an effect on migration, but these differences were nonsignificant when analyzing migration from 3 months onwards. Uncemented prostheses aligned in varus showed more migration than neutrally and valgus-aligned TKAs (p = 0.031), and this difference increased over time (p < 0.001). Significantly higher migration was observed following uncemented TKA without an osseointegration-promoting surface (p < 0.001).CONCLUSIONS: For cemented prostheses, increased migration during the first 3 postoperative months was observed for female patients, patients with rheumatoid arthritis, and patients who underwent a posterior-stabilized TKA. For uncemented prostheses, both postoperative varus alignment of the lower limb and the absence of an osseointegration-promoting surface significantly increased postoperative tibial component migration.LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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| 15. |
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| 16. |
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| 17. |
- Aguiar Borges, Luciane, et al.
(författare)
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White Paper on Nordic Sustainable Cities
- 2017
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Rapport (populärvet., debatt m.m.)abstract
- Rapid urbanisation is one of today’s biggest global challenges. Nordic Sustainable Cities is a flagship project under the Nordic Prime Ministers’ initiative Nordic Solutions to Global Challenges that seeks to shed light on this challenge from a Nordic perspective.The White Paper on Nordic Sustainable Cities develops a narrative to describe the “Nordic Sustainable City”. It forms a basis for the knowledge sharing effort that will be carried out by Nordic Innovation, Nordregio’s sister institution under the Nordic Council of Ministers in 2018. This work aims to export Nordic stories as a means of branding the Nordic Region and contributing to global efforts towards urban sustainability.
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| 18. |
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| 19. |
- Andersson, Eva, 1955, et al.
(författare)
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A case-referent study of cancer mortality among sulfate mill workers in Sweden.
- 2001
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Ingår i: Occupational and environmental medicine. - 1351-0711. ; 58:5, s. 321-4
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To investigate whether workers in Swedish sulfate mills have an increased risk of death from certain malignancies that have previously been linked to the pulping process. METHODS: Subjects of the study (n=2480) were men aged 40-75 at death during 1960-89 in the parishes surrounding four sulfate mills. Exposure assessment was based on information from the personnel files in the mills- 35% of the subjects were recognised there, and work categories were created. RESULTS: Among all sulfate mill workers, the odds ratio (OR) (90% confidence interval (90% CI)) for death from lung cancer was 1.6 (1.1 to 2.3), pleural mesotheliomas 9.5 (1.9 to 48), brain tumours 2.6 (1.2 to 5.3), and liver or biliary tract cancer 2.3 (1.0 to 5.2). There was an increased mortality from leukaemia among workers in the soda recovery plant (5.9 (2.6 to 13)) and bleaching plant and digester house (2.8 (1.0 to 7.5)). CONCLUSIONS: Sulfate mill workers were at increased risk of dying from lung cancer and pleural mesotheliomas, probably due to exposure to asbestos. Increased risks of brain tumours and cancers of the liver or biliary tract were also found but the aetiology is not obvious.
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| 20. |
- Andersson, Eva, 1955, et al.
(författare)
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Mortality from asthma and cancer among sulfite mill workers.
- 1998
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Ingår i: Scandinavian journal of work, environment & health. - 0355-3140. ; 24:1, s. 12-7
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The aims of the present case-referent study were to investigate whether sulfite workers show increased mortality from asthma, chronic obstructive pulmonary disease or certain malignancies of interest in relation to sulfite mill work. The main exposure from the pulping processes is from sulfur dioxide, wood dust and terpenes. METHODS: The subjects of the study were all the men who died between 1960 and 1989 and who were aged 40 to 75 years at death (N = 780) in the parishes surrounding 3 sulfite mills. The men who died from asthma (N = 13), COPD (N = 20), lung cancer (N = 33), stomach cancer (N = 35), or brain tumor (N = 10) formed the case group. All the subjects, except the cases in question, were used as referents. As a proxy variable of exposure, job titles from the registers of deaths and burials were used, and 24% of the subjects were classified as exposed. RESULTS: There was an increased mortality from asthma [odds ratio(OR) 2.8, 90% confidence interval (90% CI) 1.1-6.8] and brain tumors (OR 3.3, 90% CI 1.2-8.9) among the sulfite workers. The mortality due to lung cancer was not significantly increased (OR 1.4, 90% CI 0.7-2.6), and there was a reduced mortality from stomach cancer (OR 0.4, 90% CI 0.2-0.9). CONCLUSIONS: The increased asthma mortality may be due to accidental exposure to irritating gases, such as sulfur dioxide. The increased risk for brain tumors has no obvious explanation.
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| 21. |
- Aspenberg, Per, 1949-, et al.
(författare)
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Fixed or loose? Dichotomy in RSA data for cemented cups
- 2008
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Ingår i: Acta Orthopaedica. - Basingstoke : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 79:4, s. 467-473
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Roentgen stereometric analysis (RSA) cannot discern whether a single prosthesis is fixed or migrating below the detection level. Samples of patients usually show migration values that appear to be continuously distributed. Is there such continuity, or is there a dichotomy between stable and migrating prostheses? The hypothesis of a dichotomy has, to our knowledge, not been tested. We present an exploratory evaluation of such a dichotomy using a mixture distribution algorithm. METHODS: We analyzed the migration (as determined by RSA) of 147 cemented acetabular cups of 7 different designs by using a new set of algorithms for frequency distribution analysis called Rmix. RESULTS: We first analyzed a migration vector, regardless of direction. After 2 years there was a significant dichotomy between 2 lognormal subgroups within the sample. Although some types of cups were over-represented in one of the subgroups, neither cup design, sex, nor operating department could explain the dichotomy into two groups, which appears to reflect the existence of two basically different types of behavior of the cups. We next analyzed the migration along the 3 axes in space, and found a similar dichotomy. During the second year, around 80% of the patients belonged to a distinct, normally distributed subgroup with a mean not different from 0 mm and a small variation. The remainder differed significantly from this subgroup and showed migration. INTERPRETATION: There is a dichotomy in migration pattern. During the second postoperative year, most cups belonged to a subpopulation that appeared stable. The remainder is probably at risk of loosening. For a single type of prosthesis, the relative size of the stable subgroup may be a good index of the expected performance. The possibility of detecting subgroups within a seemingly continuous sample might be useful in many fields of medicine.
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| 22. |
- Beecham, Ashley H, et al.
(författare)
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Analysis of immune-related loci identifies 48 new susceptibility variants for multiple sclerosis.
- 2013
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Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 45:11, s. 1353-60
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Tidskriftsartikel (refereegranskat)abstract
- Using the ImmunoChip custom genotyping array, we analyzed 14,498 subjects with multiple sclerosis and 24,091 healthy controls for 161,311 autosomal variants and identified 135 potentially associated regions (P < 1.0 × 10(-4)). In a replication phase, we combined these data with previous genome-wide association study (GWAS) data from an independent 14,802 subjects with multiple sclerosis and 26,703 healthy controls. In these 80,094 individuals of European ancestry, we identified 48 new susceptibility variants (P < 5.0 × 10(-8)), 3 of which we found after conditioning on previously identified variants. Thus, there are now 110 established multiple sclerosis risk variants at 103 discrete loci outside of the major histocompatibility complex. With high-resolution Bayesian fine mapping, we identified five regions where one variant accounted for more than 50% of the posterior probability of association. This study enhances the catalog of multiple sclerosis risk variants and illustrates the value of fine mapping in the resolution of GWAS signals.
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| 23. |
- Bjerke, Joakim, et al.
(författare)
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Compensatory strategies for muscle weakness during stair ascent in subjects with total knee arthroplasty
- 2014
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Ingår i: The Journal of Arthroplasty. - : Elsevier. - 0883-5403 .- 1532-8406. ; 29:7, s. 1499-1502
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Tidskriftsartikel (refereegranskat)abstract
- Subjects with total knee arthroplasty (TKA) exhibit decreased quadriceps and hamstring strength. This may bring about greater relative effort or compensatory strategies to reduce knee joint moments in daily activities. To study gait and map out the resource capacity, knee muscle strength was assessed by maximal voluntary concentric contractions, and whole body kinematics and root mean square (RMS) electromyography (EMG) of vastus lateralis and semitendinosus were recorded during stair ascent in 23 unilateral TKA-subjects ~19months post-operation, and in 23 healthy controls. Muscle strength and gait velocity were lower in the TKA group, but no significant group differences were found in RMS EMG or forward trunk lean. The results suggest that reduced walking velocity sufficiently compensated for reduced knee muscle strength.
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| 24. |
- Bjerke, Joakim, et al.
(författare)
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Gait on soft versus hard surface after total knee arthroplasty
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Asymmetric gait patterns are common following total knee arthroplasty (TKA). Gait on even and hard surface is primarily characterized by reduced peak knee flexion in the prosthetic knee, increased contralateral knee adduction angle, and decreased walking speed compared to controls. Natural conditions may however lead to different strategies. Therefore, the objective of the present study was to explore how gait patterns may differ when walking on a soft surface. Methods: 3D kinematics during gait on hard and soft surface were assessed in 23 unilateral TKA-subjects ~19 months post-operative, and in 23 controls. Results: Gait characteristics in TKA-subjects that differed from controls observed on hard surface were amplified on soft surface. Flexion in the prosthetic knee was further decreased and a tendency towards reduced flexion in the contralateral knee was observed. Knee and hip adduction were not affected by surface conditions nevertheless there was a difference between groups, in particular with regard to the prosthetic side. In addition, step width increased on soft surface in TKA-subjects. Conclusion: Gait on an even and soft surface did not amplify asymmetries in TKA-subjects, but decreased knee flexion and increased step-width, albeit with similar gait speed as the control group suggests that the soft surface provided a small but significant challenge making the TKA-subjects precautious.
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| 25. |
- Bjerke, Joakim, et al.
(författare)
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Peak knee flexion angles during stair descent in TKA patients
- 2014
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Ingår i: The Journal of Arthroplasty. - : Elsevier. - 0883-5403 .- 1532-8406. ; 29:4, s. 707-711
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Tidskriftsartikel (refereegranskat)abstract
- Reduced peak knee flexion during stair descent (PKSD) is demonstrated in subjects with total knee arthroplasty (TKA), but the underlying factors are not well studied. 3D gait patterns during stair descent, peak passive knee flexion (PPKF), quadriceps strength, pain, proprioception, demographics, and anthropometrics were assessed in 23 unilateral TKA-subjects ~ 19 months post-operatively, and in 23 controls. PKSD, PPKF and quadriceps strength were reduced in the TKA-side, but also in the contralateral side. A multiple regression analysis identified PPKF as the only predictor (57%) to explain the relationship with PKSD. PPKF was, however sufficient for normal PKSD. Deficits in quadriceps strength in TKA-group suggest that strength is also contributing to smaller PKSD. Increased hip adduction at PKSD may indicate both compensatory strategy and reduced hip strength.
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| 26. |
- Bjerke, Joakim, et al.
(författare)
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Walking on a compliant surface does not enhance kinematic gait asymmetries after unilateral total knee arthroplasty
- 2016
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Ingår i: Knee Surgery, Sports Traumatology, Arthroscopy. - : Springer. - 0942-2056 .- 1433-7347. ; 24:8, s. 2606-2613
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate gait asymmetries and the effect of walking on compliant surfaces in individuals with unilateral total knee arthroplasty (TKA), hypothesizing that asymmetries would increase as an effect of the compliant surface.METHODS: Individuals with unilateral TKA ~19 months post-operative (n = 23, median age 59 years) recruited from one orthopaedic clinic and age- and gender-matched healthy individuals without knee complaints (n = 23, median age 56 years) walked at comfortable speed on a hard surface and on a compliant surface. 3D kinematic analyses were made for knee and hip angles in sagittal and frontal planes, stance time, step length, and gait velocity.RESULTS: Shorter stance time (p < 0.01) and less peak knee flexion (p < 0.001) at weight bearing acceptance was found in the prosthetic side compared with the contralateral side. Larger knee (p < 0.01) and hip (p < 0.001) adduction was found compared with healthy controls. Neither asymmetries between the prosthetic and the contralateral side nor differences compared with healthy controls were enhanced when walking on compliant surfaces compared with hard surfaces.CONCLUSION: The TKA group adapted their gait to compliant surfaces similarly to healthy controls. Gait asymmetries in the TKA group observed on hard surface were not enhanced, and adduction in hip and knee joints did not increase further as an effect of walking on compliant surfaces. Thus, unfavourable knee joint loading did not increase when walking on a compliant surface. This implies that recommendations for walking on soft surfaces to reduce knee joint loading are not counteracted by increased gait asymmetries and unfavourable joint loading configurations.LEVEL OF EVIDENCE: III.
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| 27. |
- Campbell, David, et al.
(författare)
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All-polyethylene tibial components in young patients have stable fixation; a comparison RSA study
- 2019
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Ingår i: Knee (Oxford). - : Elsevier. - 0968-0160 .- 1873-5800. ; 26:2, s. 392-399
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: All-polyethylene (AP) tibial components in patients aged greater than 60 years have stable tibial migration patterns and favorable survival rates when compared to identical Metal-backed (MB) designs. Tibial component migration in younger patients has not been reported. The aim of this study was to examine the migration characteristics of patients aged less than 60 years compared to a previous cohort of AP and MB tibial components of identical design in older patients.METHODS: A prospective consecutive study examined tibial component migration in 21 patients aged less than 60 years undergoing a cemented total knee arthroplasty with an AP tibial component by radiostereometric analysis (RSA) to 24 months. Results were compared to the authors' previous series of 21 patients aged greater than 60 years that were randomized to either an AP or MB tibial component.RESULTS: Both age groups of patients implanted with an AP component had stable migration patterns with no patient having greater than 0.2° rotation or 0.2 mm maximum total point motion. Five of 11 MB tibial components displayed continued migration between one and two years. Subsidence was similar in all groups, whilst maximum total point motion was greater for the MB cohort (0.34 mm, 0.33 mm, 0.61 mm; AP <60, AP >60, MB).CONCLUSIONS: Young patients implanted with an AP tibial component had stable tibial migration patterns comparable to older patients with the same AP implant. Regardless of age, AP tibial components were at least as stable as MB tibial components.LEVEL OF EVIDENCE: Level II, Prospective comparative study.
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| 28. |
- Campbell, David, et al.
(författare)
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Early migration characteristics of a hydroxyapatite-coated femoral stem : an RSA study.
- 2011
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Ingår i: International Orthopaedics. - : Springer. - 0341-2695 .- 1432-5195. ; 35:4, s. 483-488
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Tidskriftsartikel (refereegranskat)abstract
- Measurement of early stem subsidence can be used to predict the likelihood of long-term femoral component loosening and clinical failure. Data that examines the early migration pattern of clinically proven stems will provide clinicians with useful baseline data with which to compare new stem designs. This study was performed to evaluate the early migration pattern of a hydroxyapatite-coated press-fit femoral component that has been in use for over ten years. We enrolled 30 patients who underwent THA for osteoarthritis. The median age was 70 years (range, 55-80 years). Patients were clinically assessed using the Harris hip score. Radiostereometric analysis was used to evaluate stem migration at three to four days, six months, one year and two years. We observed a mean subsidence of 0.73 mm at six months, 0.62 mm at one year and 0.58 mm at two years and a mean retroversion of 1.82° at six months, 1.90° at one year and 1.59° at two years. This data suggests that subsidence is confined to the first six months after which there was no further subsidence. The results from this study can be compared with those from novel cementless stem designs to help predict the long-term outcome one may expect from new cementless stem designs.
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| 29. |
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| 30. |
- Cronskär, Marie, et al.
(författare)
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Patient-Specific Clavicle Reconstruction Using Digital Design and Additive Manufacturing
- 2015
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Ingår i: Journal of mechanical design (1990). - : ASME Press. - 1050-0472 .- 1528-9001. ; 137:11
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Tidskriftsartikel (refereegranskat)abstract
- There is a trend toward operative treatment for certain types of clavicle fractures and these are usually treated with plate osteosynthesis. The subcutaneous location of the clavicle makes the plate fit important, but the clavicle has a complex shape, which varies greatly between individuals and hence standard plates often have a poor fit. Using computed tomography (CT) based design, the plate contour and screw positioning can be optimized to the actual case. A method for patient-specific plating using design based on CT-data, additive manufacturing (AM), and postprocessing was initially evaluated through three case studies, and the plate fit on the reduced fracture was tested during surgery (then replaced by commercial plates). In all three cases, the plates had an adequate fit on the reduced fracture. The time span from CT scan of the fracture to final implant was two days. An approach to achieve functional design and screw-hole positioning was initiated. These initial trials of patient-specific clavicle plating using AM indicate the potential for a smoother plate with optimized screw positioning. Further, the approach facilitates the surgeon's work and operating time can be saved.
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| 31. |
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| 32. |
- Ekström, Magnus, et al.
(författare)
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Effects of smoking, gender and occupational exposure on the risk of severe pulmonary fibrosis: A population-based case-control study
- 2014
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Ingår i: BMJ Open. - : BMJ. - 2044-6055. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To estimate the effects of smoking, gender and occupational exposure on the risk of developing severe pulmonary fibrosis (PF), including dose-response and interaction effects. Methods: National case.control study of 171 patients (cases) who had started a long-term oxygen therapy for PF in Sweden between February 1997 and April 2000, and 719 random control participants from the general population. Of these cases, 137 had probable idiopathic PF (IPF). The ORs for smoking, gender and occupational exposure were estimated using Mantel-Haenszel analysis and conditional logistic regression, controlling for age and year of diagnosis. Results: The adverse effect of smoking was amplified by male gender and occupational exposure, OR 4.6 (95% CI 2.1 to 10.3) for PF, and OR 3.0 (1.3 to 6.5) for IPF, compared with in non-exposed women. Higher cumulative smoking exposure was linearly associated with increased risks. Compared with smoking less than 10 pack-years, smoking ≥20 pack-years was associated with increased risk of PF and IPF, OR 2.6 (1.4 to 4.9) and OR 2.5 (1.3 to 5.0), respectively. Conclusions: Smoking has a dose-related association with increased risk of severe PF. Men with a history of smoking and occupational exposure is a particular risk group for developing severe PF.
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| 33. |
- Feldmann, Daneil C., et al.
(författare)
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Investigation of multiple populations highlight VEGFA polymorphisms to modulate anterior cruciate ligament injury
- 2022
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Ingår i: Journal of Orthopaedic Research. - : John Wiley & Sons. - 0736-0266 .- 1554-527X. ; 40:7, s. 1604-1612
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Tidskriftsartikel (refereegranskat)abstract
- Polymorphisms in VEGFA and KDR encoding proteins have been associated with anterior cruciate ligament (ACL) injury risk. We leveraged a collective sample from Sweden, Poland, and Australia to investigate the association of functional polymorphisms in VEGFA and KDR with susceptibility to ACL injury risk. Using a case–control genetic association approach, polymorphisms in VEGFA and KDR were genotyped and haplotypes inferred from 765 controls, and 912 cases clinically diagnosed with ACL rupture. For VEGFA, there was a significant overrepresentation of the rs2010963 CC genotype (p = 0.0001, false discovery rate [FDR]: p = 0.001, odds ratio [OR]: 2.16, 95% confidence interval [CI]: 1.47–3.19) in the combined ACL group (18%) compared to the combined control group (11%). The VEGFA (rs699947 C/A, rs1570360 G/A, rs2010963 G/C) A-A-G haplotype was significantly (p = 0.010, OR: 0.85, 95% CI: 0.69–1.05) underrepresented in the combined ACL group (23%) compared to the combined control group (28%). In addition, the A-G-G construct was significantly (p = 0.036, OR: 0.81, 95% CI: 0.64–1.02) underrepresented in the combined ACL group (12%) compared to the combined CON group (16%). Our findings support the association of the VEGFA rs2010963 CC genotype with increased risk and (ii) the VEGFA A-A-G haplotype with a reduced risk, and are in alignment with the a priori hypothesis. Collectively identifying a genetic interval within VEGFA to be implicated in ACL risk modulation and highlight further the importance of vascular regulation in ligament biology.
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| 34. |
- Fredrik, Öhberg, et al.
(författare)
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Gait analysis using a portable motion sensor system : measurements in subjects with hip implant as compared with healthy controls
- 2013
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Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 38:suppl 1, s. 99-100
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: There is an increase of age related diseases such as hip joint arthritis, something that is often treated with hip replacement surgery. The aim of this study was to quantify movement function and its effect on quality of life in persons treated with hip implant, in comparison to matched asymptomatic controls.Patients/Materials and Methods: This is an ongoing study, and so far, 2 asymptomatic subjects (CTRL, age 50 ± 13 years, BMI 23 ± 2), and 4 subjects with hip implant (HIP, age 51 ± 15 years, BMI 25 ± 3), have been analyzed. The HIP group received their implant 2.6 ± 1.1 years ago and finished their rehabilitation 1.6 ± 1.1 years ago. Hip dysfunction and Osteoarthritis Outcome Score (HOOS) was used to assess the subject's hip function and its associated problems. A functional calibration (flexion/abduction movements) was done and each subject then performed 5 repetitions of gait (approx. 25 left/right gait cycles). Movement was registered with a custom-developed portable motion sensor system, where each sensor consisted of a tri-axial accelerometer and gyroscope. Sensors were placed on pelvis and each thigh and shank. Further calculations were done in MATLAB (v7.12 R2011a, Mathworks). Cosine rotation matrices were extracted by functional sensor-to- segment-calibration and sensor fusion [1], and hip and knee angles were obtained as Euler angles.Results: Preliminary results indicated larger range in hip rotation and smaller range of knee flexion during gait in HIP group than in the CTRL group (Fig. 1). HOOS profile (Fig. 2) indicated that hip function during sports (SP) and the general quality of life (QOL) were lower in the HIP group.Fig. 1. Mean and SD of hip and knee angle over 15 gait cycles in one HIP subject (blue) as compared with the CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)Figure optionsFig. 2. HOOS profiles in HIP (blue square) and CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)Figure optionsDiscussion and conclusions: Motion patterns during gait seemed to be negatively affected in subjects with hip implant, even after the rehabilitation program was completed and even though the HOOS profiles indicated a relative good hip function.Reference[1]J. Favre, B.M. Jolles, O. Siegrist, K. AminianQuaternion-based fusion of gyroscopes and accelerometers to improve 3D angle measurement
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| 35. |
- Gao, Feng, et al.
(författare)
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Cemented versus uncemented fixation of the femoral component of the NexGeb CR total knee replacement in patients younger than 60 years : A Prospective Randomised Controlled RSA Study
- 2009
-
Ingår i: The Knee. - : Elsevier BV. - 0968-0160. ; 16:3, s. 200-206
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Tidskriftsartikel (refereegranskat)abstract
- The optimal mode of femoral fixation in total knee arthroplasty (TKA) remains controversial, especially for the young patient. In a prospective randomised study we compared the magnitude and pattern of the fixation of cemented versus uncemented femoral components during 2 years in patients younger than 60 years. Forty-one knees in 41 patients were randomised to receive a NexGen (Zimmer, Warsaw, USA) cruciate-retaining TKA with either a cemented or an uncemented non HA-coated femoral component. The patients were examined by radiostereometric analysis (RSA), as well as clinical and radiological evaluation. The magnitude and pattern of migration as measured by RSA did not differ significantly between the cemented and uncemented fixation during the 2-year follow-up, nor were there any differences between the groups in clinical parameters. These findings suggest that an uncemented and non HA-coated femoral component may behave equally as well as a cemented one in the long-term.
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| 36. |
- Guigas, R., et al.
(författare)
-
Strong interaction effects in antiprotonic 6Li/7Li atoms
- 1984
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 137:56, s. 323-328
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Tidskriftsartikel (refereegranskat)abstract
- The effects of strong interaction on the 3 –> 2 X-ray transition in antiprotonic 6Li/7Li atoms have been measured at the low energy -beam at CERN. For the shifts and widths of the levels the values [epsilon]2p = (-230 ï¿œ 72) eV, [Gamma]2p = (443 ï¿œ 210) eV, and [Gamma]3d = (0.130 ï¿œ 0.045) eV for 6Li, and [epsilon]2p = (-336 ï¿œ 60) eV, [Gamma]2p = (456 ï¿œ 190) eV, and [Gamma]3d = (0.210 ï¿œ 0.062) eV for 7Li were found. The data are compared with optical model predictions.
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| 37. |
- Gustafson, T., et al.
(författare)
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Occupational exposure and severe pulmonary fibrosis
- 2007
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Ingår i: Respir Med. - : Elsevier BV. - 0954-6111 .- 1532-3064. ; 101:10, s. 2207-12
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: External agents, especially metal and wood dust, are believed to be risk factors for development of idiopathic pulmonary fibrosis (IPF). The aim of this case-control study was to investigate which occupational exposure types are associated with development of severe pulmonary fibrosis (PF), and especially IPF. METHODS: An extensive postal questionnaire including 30 specific items regarding occupational exposure was completed by 181 patients with severe PF and respiratory failure reported to the Swedish Oxygen Register, among whom 140 were judged as having IPF. The questionnaire was also completed by 757 control subjects. We stratified data for age, sex and smoking and calculated odds ratios (ORs). RESULTS: We found increased risk for IPF in men with exposure to birch dust (OR 2.7, 95% confidence interval (95% CI) 1.30-5.65) and hardwood dust (OR 2.7, 95% CI 1.14-6.52). Men also had slightly increased ORs associated with birds. We did not find any increased risk in association with metal dust exposure. CONCLUSION: Exposure for birch and hardwood dust may contribute to the risk for IPF in men.
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| 38. |
- Heijbel, Siri, et al.
(författare)
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Substantial clinical benefit and patient acceptable symptom states of the Forgotten Joint Score 12 after primary knee arthroplasty
- 2022
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Ingår i: Acta Orthopaedica. - : Taylor & Francis Group. - 1745-3674 .- 1745-3682. ; 93, s. 158-163
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose - Knowing how to interpret values obtained with patient reported outcome measures (PROMs) is essential. We estimated the substantial clinical benefit (SCB) and patient acceptable symptom state (PASS) for Forgotten Joint Score 12 (FJS) and explored differences depending on methods used for the estimates. Patients and methods - The study was based on 195 knee arthroplasties (KA) performed at a university hospital. We used 1 item from the Knee injury and Osteoarthritis Outcome Score domain quality of life and satisfaction with surgery, obtained 1-year postoperatively, to assess SCB and PASS thresholds of the FJS with anchor-based methods. We used different combinations of anchor questions for SCB and PASS (satisfied, satisfied with no or mild knee difficulties, and satisfied with no knee difficulties). A novel predictive approach and receiver-operating characteristics curve were applied for the estimates.Results - 70 and 113 KAs were available for the SCB and PASS estimates, respectively. Depending on method, SCB of the FJS (range 0-100) was 28 (95% CI 21-35) and 22 (12-45) respectively. PASS was 31 (2-39) and 20 (10-29) for satisfied patients, 40 (31-47) and 38 (32-43) for satisfied patients with no/mild difficulties, and 76 (39-80) and 64 (55-74) for satisfied patients with no difficulties. The areas under the curve ranged from 0.82 to 0.88.Interpretation - Both the SCB and PASS thresholds varied depending on methodology. This may indicate a problem using meaningful values from other studies defining outcomes after KA. This study supports the premise of the FJS as a PROM with good discriminatory ability in patients undergoing KA.
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| 39. |
- Heijbel, Siri, et al.
(författare)
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The Forgotten Joint Score-12 in Swedish patients undergoing knee arthroplasty : a validation study with the Knee Injury and Osteoarthritis Outcome Score (KOOS) as comparator
- 2020
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 91:1, s. 88-93
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose — Having patients self-evaluate the outcome is an important part of the follow-up after knee arthroplasty. The Forgotten Joint Score-12 (FJS-12) introduced joint awareness as a new approach, suggested to be sensitive enough to differentiate well-functioning patients. This study evaluated the Swedish translation of the FJS-12 and investigated the validity, reliability, and interpretability in patients undergoing knee arthroplasty.Patients and methods — We included 109 consecutive patients 1 year after primary knee arthroplasty to assess construct validity (Pearson’s correlation coefficient, r), internal consistency (Cronbach’s alpha [CA]), floor and ceiling effects, and score distribution. The Knee injury and Osteoarthritis Outcome Score (KOOS) was the comparator instrument for the analyses. Further, 31 patients preoperatively and 22 patients postoperatively were included to assess test–retest reliability (intraclass correlation coefficient [ICC]). Results — Construct validity was moderate to excellent (r = 0.62–0.84). The FJS-12 showed a high degree of internal consistency (CA = 0.96). The ICC was good preoperatively (0.76) and postoperatively (0.87). Ceiling effects were 2.8% in the FJS-12 and ranging between 0.9% and 10% in the KOOS. Interpretation — The Swedish translation of the FJS-12 showed good validity and reliability and can be used to assess outcome after knee arthroplasty. Moreover, the FJS-12 shows promising results in its ability to differentiate well-functioning patients. Future studies on unidimensionality, scale validity, interpretability, and responsiveness are needed for a more explicit analysis of the psychometric properties.
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| 40. |
- Henricson, Anders, 1944-, et al.
(författare)
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A trabecular metal tibial component in total knee replacement in patients younger than 60 years
- 2008
-
Ingår i: Journal of Bone and Joint Surgery. - 0301-620X .- 2044-5377. ; 90-B:12, s. 1585-1593
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Tidskriftsartikel (refereegranskat)abstract
- We compared the performance of uncemented trabecular metal tibial components in total knee replacement with that of cemented tibial components in patients younger than 60 years over two years using radiostereophotogrammetric analysis (RSA). A total of 22 consecutive patients (mean age 53 years, 33 to 59, 26 knees) received an uncemented NexGen trabecular metal cruciate-retaining monobloc tibial component and 19 (mean 53 years, 44 to 59, 21 knees) a cemented NexGen Option cruciate-retaining modular tibial component. All the trabecular metal components migrated during the initial three months and then stabilised. The exception was external rotation, which did not stabilise until 12 months. Unlike conventional metal-backed implants which displayed a tilting migration comprising subsidence and lift-off from the tibial tray, most of the trabecular metal components showed subsidence only, probably due to the elasticity of the implant. This pattern of subsidence is regarded as being beneficial for uncemented fixation.
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| 41. |
- Henricson, Anders, 1944-, et al.
(författare)
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Mobile bearings do not improve fixation in cemented total knee arthroplasty
- 2006
-
Ingår i: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 448, s. 114-121
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Tidskriftsartikel (refereegranskat)abstract
- Mobile bearings were introduced to improve wear and knee kinematics. By uncoupling the forces generated at the articulation from the implant-bone interface this would, theoretically, also improve the fixation of the implant to bone. We did this study to evaluate whether mobile bearings improve the fixation of the tibial component to bone. Fifty-two consecutive knees in 47 patients (average age, 72 years; range, 62-84 years) with primary osteoarthrosis were randomized into two groups to receive a cemented total knee arthroplasty with either a fixed-bearing or mobile-bearing tibial component. The quality of fixation was analyzed with radiostereometric analysis for up to 2 years. Mobile bearings did not improve fixation. Both magnitudes and directions of component rotations were similar, and the number of implants with continuous migration was almost identical. Both implant types had a combination of subsidence and lift-off, but where the mobile bearing implants displayed more of subsidence, the fixed bearing knees showed more lift-off. It might be that the somewhat stiffer cobalt-chromium baseplate or the different joint conformity used in the mobile-bearing knees counteracts any potential effects of the mobile bearing.
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| 42. |
- Henricson, Anders, 1944-
(författare)
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Total knee arthroplasty : aspects on improved fixation in the younger patient
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The results of total knee arthroplasty are inferior in younger patients. The challenge today is therefore to develop designs and concepts that will last at least 25 years. This thesis has evaluated the fixation to bone of modern designs of knee prostheses uring RSA analysis. Coating implant surfaces with hydroxy-apatite have proven to enhance fixation to bone. Addition of screws for fixation of the tibial component enhances the fixation, but has negative side effects such as osteolysis around the screws, in turn leading to a higher risk of component loosening. The magnitude and pattern of migration was studied in a randomized study of uncemented tibial implants coated with hydroxy-apatite with and without additional screw fixation in patients younger than 65 years. The uncemented implants migrated initially more than the cemented implants that constituted the control group. Both uncemented groups stabilized at 3 monthes with no further migration, while the cemented implants showed a continuous migration up to the 2 year follow-up, indicating continuous bone resorption at the implant-bone interface, a fact that might lead to an increased risk of late implant loosening. This may not be a problem in older patients, but may have consequences for long-term fixation in younger patients. There was no difference between the two uncemented groups indicating that screws do not improve fixation. Hydroxy-apatite coated knee implants might be well suited for younger patients. Mobile bearing total knee arthroplasty theoretically uncouples the forces at the implant-bone interface, thus improving fixation of the implant to bone. The magnitude and pattern of migration of a cemented mobile bearing knee arthroplasty and a fixed bearing total knee arthroplasty was compared in a randomized study. The results showed that mobile bearings did not improve fixation. Trabecular metal, a new material recently introduced for total knee arthroplasty, has several theoretical advantages. Trabecular metal tibial implants were evaluated in a randomized study in patients younger than 60 years. The implants displayed the typical migration pattern for uncemented implants with greater migration initially followed by early stabilization. The majority of the trabecular metal implants subsided into the bone with no lift-off. Lift-off has the potential of exposing the interface to joint fluid with the potential risk of bone resorption and late loosening, and is commonly seen in metal-backed implants. The finding of absence of lift-off is regarded beneficial for uncemented fixation. Trabecular metal tibial implants might be suited for younger patients. The optimal mode of fixation of the femoral component is yet to be established. Comparing cemented femoral components with uncemented femoral components in a randomized study in patients younger than 60 years revealed no differences of the magnitude or the pattern of migration. Uncemented femoral component seems equally as good as cemented components in younger patients.
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| 43. |
- Henricson, Anders, et al.
(författare)
-
Trabecular metal tibia still stable at 5 years : an RSA study of 36 patients aged less than 60 years
- 2013
-
Ingår i: Acta Orthopaedica. - : Medical Journals Sweden. - 1745-3674 .- 1745-3682. ; 84:4, s. 398-405
-
Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Clinical results of total knee replacement (TKR) are inferior in younger patients, mainly due to aseptic loosening. Coating of components with trabecular metal (TM) is a new way of enhancing fixation to bone. We have previously reported stabilization of TM tibial components at 2 years. We now report the 5-year follow-up of these patients, including RSA of their TM tibial components.Patients and methods: 22 patients (26 knees) received an uncemented TM cruciate-retaining tibial component and 19 patients (21 knees) a cemented NexGen Option cruciate-retaining tibial component. Follow-up with RSA, and clinical and radiographic examinations were done at 5 years. In bilaterally operated patients, the statistical analyses included only the first-operated knee.Results: Both groups had most migration within the first 3 months, the TM implants to a greater extent than the cemented implants. After 3 months, both groups stabilized and remained stable up to the 5-year follow-up.Interpretation: After a high initial degree of migration, the TM tibia stabilized. This stabilization lasted for at least 5 years, which suggests a good long-term performance regarding fixation. The cemented NexGen CR tibial components showed some migration in the first 3 months and then stabilized up to the 5-year follow-up. This has not been reported previously.
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| 44. |
- Henricson, Anders, et al.
(författare)
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Trabecular metal tibial knee component still stable at 10 years : An RSA study of 33 patients less than 60 years of age
- 2016
-
Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 87:5, s. 504-510
-
Tidskriftsartikel (refereegranskat)abstract
- Background and purpose - Total knee replacement (TKR) in younger patients using cemented components has shown inferior results, mainly due to aseptic loosening. Excellent clinical results have been reported with components made of trabecular metal (TM). In a previous report, we have shown stabilization of the TM tibial implants for up to 5 years. In this study, we compared the clinical and RSA results of these uncemented implants with those of cemented implants. Patients and methods - 41 patients (47 knees) aged 60 years underwent TKR. 22 patients (26 knees) received an uncemented monoblock cruciate-retaining (CR) tibial component (TM) and 19 patients (21 knees) received a cemented NexGen Option CR tibial component. Follow-up examination was done at 10 years, and 16 patients (19 knees) with TM tibial components and 17 patients (18 knees) with cemented tibial components remained for analysis. Results - 1 of 19 TM implants was revised for infection, 2 of 18 cemented components were revised for knee instability, and no revisions were done for loosening. Both types of tibial components migrated in the first 3 months, the TM group to a greater extent than the cemented group. After 3 months, both groups were stable during the next 10 years. Interpretation - The patterns of migration for uncemented TM implants and cemented tibial implants over the first 10 years indicate that they have a good long-term prognosis regarding fixation
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| 45. |
- Henricson, Anders, et al.
(författare)
-
Uncemented or cemented femoral components work equally well in total knee arthroplasty
- 2019
-
Ingår i: Knee Surgery, Sports Traumatology, Arthroscopy. - : Springer. - 0942-2056 .- 1433-7347. ; 27:4, s. 1251-1258
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To study the pattern of migration and clinical results up to 10 years of uncemented versus cemented fixation of the femoral component in total knee arthroplasty.METHODS: Randomized controlled trial was conducted of 41 patients (23 women, 18 men) under the age of 60 years using radiostereometric analysis.RESULTS: About two-thirds of the cemented implants and half of the uncemented implants stabilized between 2 and 10 years, while the remainder displayed a small annual increase of maximum total point motion of 0.09-0.10 mm/year. At 10 years there were no statistically significant differences in migration or clinical results between the groups.CONCLUSION: Uncemented fixation with titanium fiber mesh coating of the femoral component in total knee arthroplasty works equally as well as cemented fixation up to 10 years. An annual migration of 0.1 mm seems compatible with excellent long-term performance.LEVEL OF EVIDENCE: I.
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| 46. |
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| 47. |
- Nilsson, Kjell G, et al.
(författare)
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Assessment of horizontal laminar air flow instrument table for additional ultraclean space during surgery
- 2010
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Ingår i: Journal of Hospital Infection. - : Elsevier. - 0195-6701 .- 1532-2939. ; 76:3, s. 243-246
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Tidskriftsartikel (refereegranskat)abstract
- The area in a vertical ultraclean laminar air flow (LAF) theatre is usually too small to accommodate all the equipment needed for major surgery. We investigated the addition of an instrument table supplied with fixed ultraclean LAF and placed alongside the existing main LAF unit, to determine its physical and bacteriological effect on the main unit. In phase 1, with two investigators but without a patient, smoke tests showed no intrusion of air from the table into the main unit and particle counts did not show any adverse effect on the main LAF unit. In phase 2, during patients undergoing two total knee replacements, the LAF table and a table without LAF were placed alongside the main LAF unit. The tables were subjected to the activity of an extra operating room (OR) nurse working from inside the main LAF vigorously simulating handling of instruments. During this activity, the >5 μm particle counts were 275/m3 at the instrument table with LAF and 8550/m3 at the table without LAF (P < 0.0001). Also, without the OR nurse activity, the particle counts, just inside the main unit and adjacent to the LAF table, were significantly reduced (P < 0.03–0.003). Sedimentation plates on the LAF table and in the main unit registered 22 and 25 cfu/m2/h respectively compared with 45 cfu/m2/h at the instrument table without LAF. In conclusion, the results from the smoke tests, particle counts and bacteriological evaluation showed that the additional instrument table supplied with LAF is efficient and can be safely used as an extension additional to a main OR LAF unit.
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| 48. |
- Nilsson, Kjell G., 1953-
(författare)
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Kinematics and fixation of total knee arthroplasties : a clinical, radiographic, scintimetric, and roentgen stereophotogrammetric evaluation
- 1992
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aseptic loosening of the tibial component is an important cause of failure after total knee arthroplasty. Bone destruction often claimed to be caused by the cement makes the revision difficult. In order to treat younger patients, uncemented fixation has been introduced, but the etiology to loosening is multifactorial and only partly known. Early detection of implant migration facilitates research in this field but is difficult using conventional techniques. In this study modified versions of roentgen stereophotogrammetric analysis (RSA) were developed to obtain accurate and standardized evaluations facilitating comparison between prosthetic designs. The method was used to record the efficacy of cemented and uncemented fixation of different designs of the tibial component, to determine the accuracy of scintimetry in the detection of early aseptic loosening, and to analyse the in vivo kinematics of knee arthroplasties with different design and stability between the joint surfaces.Forty-three arthroplasties with comparatively high inherent stability of the joint surfaces were randomized to cemented or uncemented fixation of the tibial component. In all groups micromovements were rather large, but with no differences between the cemented and uncemented components. The preoperative diagnosis (arthrosis OA, n=25; rheumatoid arthritis RA, n=18) did not influence the magnitude of micromotion.20 arthroplasties with the same design as above but equipped with an intramedullary stem, were randomized to cemented or uncemented fixation in patients with RA. Cement improved the fixation. Uncemented stemmed components displayed micromovements seemingly larger than unstemmed ones.34 arthroplasties with an unconstrained design of the joint area and fixed to the tibia with four pegs were randomized to cemented or uncemented fixation in patients with OA. When used uncemented 4 screws were added. Compared with previously investigated designs small micromotions were recorded, and especially in the cemented cases. Uncemented components with thin polyethylene inserts displayed larger initial micromotions. The preoperative deformity influenced the direction of the micromotion.33 knees were followed prospectively with RSA and scintimetry to evaluate any correlation between these methods. Low activity under the tibial component at 2 years implied prosthetic stability, whereas high activity indicated instability or high bone remodelling caused by the preoperative malalignment.The in vivo kinematics in three different designs of knee arthroplasties were analyzed during active flexion and extension without weight-bearing. Each type of prosthesis displayed design-specific abnormalities when compared with a normal material. Pronounced posterior tibial translations were recorded during flexion regardless whether the posterior cruciate ligament had been sacrificed or not. Data from the kinematic and the fixation studies suggest that movements restricted by the design of the joint area are transmitted to the bony interface with design-specific micromotions as the result.Analysis of knee joint kinematics during extension and weight-bearing revealed small alterations compared with non-weight-bearing. Evaluation of the three-dimensional movements in terms of helical axis rotations and translations confirmed the constrained or unconstrained in vivo behaviour of the designs under study. This analysis also facilitated the interpretation of the kinematic behaviour of the prosthetic knees and may be of value in the evaluation of new designs.
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| 49. |
- Nilsson, Kjell G., et al.
(författare)
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Mid-term migration of a cementless, porous acetabular cup : A 5 year Radiostereometric analysis
- 2017
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Ingår i: Journal of Orthopaedics. - : Elsevier. - 0972-978X .- 2589-9082. ; 14:4, s. 454-460
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of the study was to determine the 5 year migratory and wear patterns, adverse events and clinical outcomes of a cementless, porous acetabular cup. Methods: RSA imaging of a cohort of 11 patients was retrospective analysed at 5 years post Total Hip Arthroplasty (THA). Changes in pain, function and symptoms of the hip at 5 years post-THA were compared to preoperative and 2 year postoperative assessments on the Harris Hip Score (HHS) and Hip dysfunction and Osteoarthritis Outcome Score (HOOS). Results: The majority of cup migration occurred up to 6 months and stabilised thereafter (6 months to 5 years, p = 0.091-0.866, Wilcoxon Signed Rank test). The direction of rotation around the 3 axes was evenly distributed among the cups between anterior-posterior rotation, internal-external rotation and increased-decreased inclination. The majority of the cups translated proximally, at an average migration of 0.36 mm (+/- 95% CI 0.17) at 5-years post-THA. Following initial bedding in, up to 6 months, there was no detectable polyethylene wear between 6 months and 5 years. At 5 years postoperatively, a statistically significant difference was observed across all HOOS subscales in comparison to preoperative values, with higher means reported at 5 years (p < 0.001). The total mean HHS displayed a statistically significant improvement, increasing from 'poor' preoperatively to 'good' at 5 years post-THA. Conclusion: Following initial migration between discharge and 6 months, the cementless porous acetabular cup demonstrated a tendency for stabilisation from 6 months up to 5 years post-THA, suggesting good mid-term fixation. Additionally, improvements in clinical outcome measures of pain, function and quality-of-life remained high following THA at 5 years post-surgery.
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| 50. |
- Nilsson, Kjell G, 1953-, et al.
(författare)
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Uncemented HA-coated implant is the optimum for the TKA in the young patient
- 2006
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Ingår i: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 448, s. 129-139
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Tidskriftsartikel (refereegranskat)abstract
- Fixation of the tibial component in total knee arthroplasty in younger patients remains controversial. We evaluate the results of three different types of fixation of the Profix total knee arthroplasty in a randomized controlled trial of 97 consecutive knees (85 patients) with osteoarthrosis or inflammatory arthritis with 2-year followup of all patients. We randomized patients to three different types of fixation of the tibial component: cemented, uncemented (HA coated) with screws, or uncemented (HA coated) without screws. We performed clinical evaluations and radiostereometric analysis at 6 weeks, and 3, 6, 12 and 24 months postoperatively. The knees in the uncemented groups migrated more than those in the cemented group during the first 3 months, but at 2 years we observed no differences. The uncemented implants displayed all migration within the first 3 months. The cemented implants did not stabilize but had continuously increasing migration during the followup. Cementless implants without screws did not migrate more than implants with screws and displayed similar pattern of migration, indicating screws do not improve fixation. Uncemented fixation using hydroxyapatite-coated implants without screws seems to be the best solution for the younger patient.
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