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AIMS: The aim of this study was to use national registry database information to estimate cumulative rates and relative risk of revision due to infection after reverse shoulder arthroplasty. PATIENTS AND METHODS: We included 17 730 primary shoulder arthroplasties recorded between 2004 and 2013 in The Nordic Arthroplasty Register Association (NARA) data set. With the Kaplan-Meier method, we illustrated the ten-year cumulative rates of revision due to infection and with the Cox regression model, we reported the hazard ratios as a measure of the relative risk of revision due to infection. RESULTS: In all, 188 revisions were reported due to infection during a mean follow-up of three years and nine months. The ten-year cumulative rate of revision due to infection was 1.4% overall, but 3.1% for reverse shoulder arthroplasties and 8.0% for reverse shoulder arthroplasties in men. Reverse shoulder arthroplasties were associated with an increased risk of revision due to infection also when adjusted for sex, age, primary diagnosis, and year of surgery (relative risk 2.41 (95% confidence interval 1.26 to 5.59); p = 0.001). CONCLUSION: The overall incidence of revision due to infection was low. The increased risk in reverse shoulder arthroplasty must be borne in mind, especially when offering it to men. Cite this article: Bone Joint J 2019;101-B:702-707.

Objective: To report the10-year survival rates of different shoulder arthroplasty types used for glenohumeral osteoarthritis. Design: Data from 2004 to 2013 was prospectively collected by the national shoulder arthroplasty registers in Denmark, Norway and Sweden and merged into a harmonized dataset under the umbrella of the Nordic Arthroplasty Register Association. The common dataset included data that all three registers could deliver and where consensus regarding definitions could be made. Revision was defined as removal or exchange of any component or the addition of a glenoid component. Results: The cumulative survival rates at 10 years after resurfacing hemiarthroplasty (RHA) (n = 1,923), stemmed hemiarthroplasty (SHA) (n = 1,587) and anatomical total shoulder arthroplasty (TSA) (n = 2,340) were 0.85, 0.93 and 0.96 respectively (P < 0.001, Log rank test). RHA (HR: 2.5; CI 1.9–3.4, P < 0.001) and SHA (HR: 1.4; CI 1.0–2.0, P < 0.04) had an increased risk of revision compared to TSA. Gender, age and period of surgery were included in the Cox regression model. For patients below 55 years, the 10-year cumulative survival rates were 0.75 (RHA, n = 354), 0.81 (SHA, n = 146), and 0.87 (TSA, n = 201). Conclusions: Anatomical TSA had the highest implant-survival rate. Young patients had, independently of the arthroplasty type, lower implant-survival rates. The treatment of young patients with end-stage osteoarthritis remains a challenge.

AIMS: Lifestyle risk factors are thought to increase the risk of infection after acute orthopaedic surgery but the evidence is scarce. We aimed to investigate whether smoking, obesity and alcohol overuse are risk factors for the development of infections after surgery for a fracture of the ankle.PATIENTS AND METHODS: We retrospectively reviewed all patients who underwent internal fixation of a fracture of the ankle between 2008 and 2013. The primary outcome was the rate of deep infection and the secondary outcome was any surgical site infection (SSI). Associations with the risk factors and possible confounding variables were analysed univariably and multivariably with backwards elimination.RESULTS: A total of 1043 patients were included; 64 (6.1%) had a deep infection and 146 (14.0%) had SSI. Obesity was strongly associated with both outcomes (odds ratio (OR) 2.21, p = 0.017 and OR 1.68, p = 0.032) in all analyses. Alcohol overuse was similarly associated, though significant only in unadjusted analyses. Surprisingly, smoking did not yield statistically significant associations with infections.CONCLUSION: These findings suggest that obesity and possibly alcohol overuse are independent risk factors for the development of infection following surgery for a fracture of the ankle. This large study brings new evidence concerning these common risk factors; although prospective studies are needed to confirm causality. Cite this article: Bone Joint J 2017;99-B:225-30.

In this study, we evaluated patient-reported outcomes, the rate of revision and the indications for revision following resurfacing hemiarthroplasty of the shoulder in patients with osteoarthritis. All patients with osteoarthritis who underwent primary resurfacing hemiarthroplasty and reported to the Danish Shoulder Arthroplasty Registry (DSR), between January 2006 and December 2010 were included. There were 772 patients (837 arthroplasties) in the study. The Western Ontario Osteoarthritis of the Shoulder (WOOS) index was used to evaluate patient-reported outcome 12 months (10 to 14) post-operatively. The rates of revision were calculated from the revisions reported to the DSR up to December 2011 and by checking deaths with the Danish National Register of Persons. A complete questionnaire was returned by 688 patients (82.2%). The mean WOOS was 67 (0 to 100). A total of 63 hemiarthroplasties (7.5%) required revision; the cumulative five-year rate of revision was 9.9%. Patients aged < 55 years had a statistically significant inferior WOOS score, which exceeded the minimal clinically important difference, compared with older patients (mean difference 14.2 (8.8; 95% CI 19.6; p < 0.001), but with no increased risk of revision. There was no significant difference in the mean WOOS or the risk of revision between designs of resurfacing hemiarthroplasty.

In this study, we evaluated patient-reported outcomes, the rate of revision and the indications for revision following resurfacing hemiarthroplasty of the shoulder in patients with osteoarthritis. All patients with osteoarthritis who underwent primary resurfacing hemiarthroplasty and reported to the Danish Shoulder Arthroplasty Registry (DSR), between January 2006 and December 2010 were included. There were 772 patients (837 arthroplasties) in the study. The Western Ontario Osteoarthritis of the Shoulder (WOOS) index was used to evaluate patient-reported outcome 12 months (10 to 14) post-operatively. The rates of revision were calculated from the revisions reported to the DSR up to December 2011 and by checking deaths with the Danish National Register of Persons. A complete questionnaire was returned by 688 patients (82.2%). The mean WOOS was 67 (0 to 100). A total of 63 hemiarthroplasties (7.5%) required revision; the cumulative five-year rate of revision was 9.9%. Patients aged < 55 years had a statistically significant inferior WOOS score, which exceeded the minimal clinically important difference, compared with older patients (mean difference 14.2 (8.8; 95% CI 19.6; p < 0.001), but with no increased risk of revision. There was no significant difference in the mean WOOS or the risk of revision between designs of resurfacing hemiarthroplasty.

The diagnosis and management of complex fractures of the proximal humerus have challenged surgical practitioners and medical writers since the earliest recorded surgical texts. Current knowledge of fractures of the proximal humerus has been obtained through pathoanatomical and biomechanical studies within the last two centuries. However, the historical preconditions for this development have not been studied. This paper reviews written sources from the fall of the Roman Empire to the late eighteenth century. Medieval and early modern writers mainly rely on the Hippocratic writings De Fracturis and De Articulationes. The Hippocratic account of the normal anatomy of the shoulder reveals some biomechanical insights. However, knowledge of bone and joint anatomy of the shoulder useful for surgical purposes is not found in medieval sources. Even in fourteenth century illustrations based on human dissections 'naturalistic' observations are rarely found. In Renaissance sources, knowledge of the musculoskeletal system useful for the understanding of shoulder pathology appears. The anatomical drawings by Leonardo da Vinci (1452-1519) demonstrate knowledge of the biomechanical properties of the shoulder, and Vesalius (1514-1564) gives a systematic account for the osteology and myology of the shoulder. In early eighteenth century, the Hippocratic approach is challenged and more gentle modes of reduction and bandaging are proposed. Desault (1744-1795) gives an account of the muscle traction responsible for displacement in fractures of the proximal humerus. Reports on open surgery for fractures of the proximal humerus appear in the scientific literature.

The diagnosis and management of complex fractures of the proximal humerus have challenged surgical practitioners and medical writers since the earliest recorded surgical texts. Current knowledge of fractures of the proximal humerus has been obtained through pathoanatomical and biomechanical studies within the last two centuries. However, the historical preconditions for this development have not been studied. This paper reviews written sources from the fall of the Roman Empire to the late eighteenth century. Medieval and early modern writers mainly rely on the Hippocratic writings De Fracturis and De Articulationes. The Hippocratic account of the normal anatomy of the shoulder reveals some biomechanical insights. However, knowledge of bone and joint anatomy of the shoulder useful for surgical purposes is not found in medieval sources. Even in fourteenth century illustrations based on human dissections 'naturalistic' observations are rarely found. In Renaissance sources, knowledge of the musculoskeletal system useful for the understanding of shoulder pathology appears. The anatomical drawings by Leonardo da Vinci (1452-1519) demonstrate knowledge of the biomechanical properties of the shoulder, and Vesalius (1514-1564) gives a systematic account for the osteology and myology of the shoulder. In early eighteenth century, the Hippocratic approach is challenged and more gentle modes of reduction and bandaging are proposed. Desault (1744-1795) gives an account of the muscle traction responsible for displacement in fractures of the proximal humerus. Reports on open surgery for fractures of the proximal humerus appear in the scientific literature.

Udgivelsesdato: 2009-Apr, Displaced four-part fractures comprise 2-10 % of all proximal humeral fractures. The optimal treatment is unclear and randomised trials are needed. The conduct and interpretation of such trials is facilitated by a reproducible fracture classification. We aimed at quantifying observer agreement on the classification of displaced four-part fractures according to the Neer system. Published and unpublished data from five observer studies were reviewed. Observers agreed less on displaced four-part fractures than on the overall Neer classification. Mean kappa values for interobserver agreement ranged from 0.16 to 0.48. Specialists agreed slightly more than fellows and residents. Advanced imaging modalities (CT and 3D CT) seemed to contribute more to classification of displaced four-part patterns than in less complex fracture patterns. Low observer agreement may challenge the clinical approach to displaced four-part fractures and poses a problem for the interpretation and generalisation of results from future randomised trials.

Blinding can reduce bias in randomized clinical trials, but blinding procedures may be unsuccessful. Our aim was to assess how often randomized clinical trials test the success of blinding, the methods involved and how often blinding is reported as being successful.

Blinding can reduce bias in randomized clinical trials, but blinding procedures may be unsuccessful. Our aim was to assess how often randomized clinical trials test the success of blinding, the methods involved and how often blinding is reported as being successful.

Blinding can reduce bias in randomized clinical trials, but blinding procedures may be unsuccessful. Our aim was to assess how often randomized clinical trials test the success of blinding, the methods involved and how often blinding is reported as being successful.

Blinding can reduce bias in randomized clinical trials, but blinding procedures may be unsuccessful. Our aim was to assess how often randomized clinical trials test the success of blinding, the methods involved and how often blinding is reported as being successful.

Udgivelsesdato: 2007

Udgivelsesdato: 2007

Twenty-four orthopaedic surgeons classified 42 pairs of radiographs according to the Neer system for proximal humeral fractures. Mean kappa value for inter-observer agreement was 0.27 (95% CI 0.26-0.28) with no clinically significant difference between orthopaedic residents ( n=9), fellows ( n=6) and specialists ( n=9). Mean kappa for agreement of displacement versus non-displacement was 0.41 (95% CI 0.39-0.43) overall, and 0.50 (95% CI 0.45-0.56) within the specialist group. The agreement found in our study is unsatisfactory from a clinical perspective.

We investigated whether training doctors to classify proximal fractures of the humerus according to the Neer system could improve interobserver agreement. Fourteen doctors were randomised to two training sessions, or to no training, and asked to categorise 42 unselected pairs of plain radiographs of fractures of the proximal humerus according to the Neer system. The mean kappa difference between the training and control groups was 0.30 (95% CI 0.10 to 0.50, p = 0.006). In the training group the mean kappa value for interobserver variation improved from 0.27 (95% CI 0.24 to 0.31) to 0.62 (95% CI 0.57 to 0.67). The improvement was particularly notable for specialists in whom kappa increased from 0.30 (95% CI 0.23 to 0.37) to 0.79 (95% CI 0.70 to 0.88). These results suggest that formal training in the Neer system is a prerequisite for its use in clinical practice and research.

Twenty-four orthopaedic surgeons classified 42 pairs of radiographs according to the Neer system for proximal humeral fractures. Mean kappa value for inter-observer agreement was 0.27 (95% CI 0.26-0.28) with no clinically significant difference between orthopaedic residents ( n=9), fellows ( n=6) and specialists ( n=9). Mean kappa for agreement of displacement versus non-displacement was 0.41 (95% CI 0.39-0.43) overall, and 0.50 (95% CI 0.45-0.56) within the specialist group. The agreement found in our study is unsatisfactory from a clinical perspective.

We investigated whether training doctors to classify proximal fractures of the humerus according to the Neer system could improve interobserver agreement. Fourteen doctors were randomised to two training sessions, or to no training, and asked to categorise 42 unselected pairs of plain radiographs of fractures of the proximal humerus according to the Neer system. The mean kappa difference between the training and control groups was 0.30 (95% CI 0.10 to 0.50, p = 0.006). In the training group the mean kappa value for interobserver variation improved from 0.27 (95% CI 0.24 to 0.31) to 0.62 (95% CI 0.57 to 0.67). The improvement was particularly notable for specialists in whom kappa increased from 0.30 (95% CI 0.23 to 0.37) to 0.79 (95% CI 0.70 to 0.88). These results suggest that formal training in the Neer system is a prerequisite for its use in clinical practice and research.

Twenty-four orthopaedic surgeons classified 42 pairs of radiographs according to the Neer system for proximal humeral fractures. Mean kappa value for inter-observer agreement was 0.27 (95% CI 0.26-0.28) with no clinically significant difference between orthopaedic residents ( n=9), fellows ( n=6) and specialists ( n=9). Mean kappa for agreement of displacement versus non-displacement was 0.41 (95% CI 0.39-0.43) overall, and 0.50 (95% CI 0.45-0.56) within the specialist group. The agreement found in our study is unsatisfactory from a clinical perspective.

Twenty-four orthopaedic surgeons classified 42 pairs of radiographs according to the Neer system for proximal humeral fractures. Mean kappa value for inter-observer agreement was 0.27 (95% CI 0.26-0.28) with no clinically significant difference between orthopaedic residents ( n=9), fellows ( n=6) and specialists ( n=9). Mean kappa for agreement of displacement versus non-displacement was 0.41 (95% CI 0.39-0.43) overall, and 0.50 (95% CI 0.45-0.56) within the specialist group. The agreement found in our study is unsatisfactory from a clinical perspective.

We investigated whether training doctors to classify proximal fractures of the humerus according to the Neer system could improve interobserver agreement. Fourteen doctors were randomised to two training sessions, or to no training, and asked to categorise 42 unselected pairs of plain radiographs of fractures of the proximal humerus according to the Neer system. The mean kappa difference between the training and control groups was 0.30 (95% CI 0.10 to 0.50, p = 0.006). In the training group the mean kappa value for interobserver variation improved from 0.27 (95% CI 0.24 to 0.31) to 0.62 (95% CI 0.57 to 0.67). The improvement was particularly notable for specialists in whom kappa increased from 0.30 (95% CI 0.23 to 0.37) to 0.79 (95% CI 0.70 to 0.88). These results suggest that formal training in the Neer system is a prerequisite for its use in clinical practice and research.

We investigated whether training doctors to classify proximal fractures of the humerus according to the Neer system could improve interobserver agreement. Fourteen doctors were randomised to two training sessions, or to no training, and asked to categorise 42 unselected pairs of plain radiographs of fractures of the proximal humerus according to the Neer system. The mean kappa difference between the training and control groups was 0.30 (95% CI 0.10 to 0.50, p = 0.006). In the training group the mean kappa value for interobserver variation improved from 0.27 (95% CI 0.24 to 0.31) to 0.62 (95% CI 0.57 to 0.67). The improvement was particularly notable for specialists in whom kappa increased from 0.30 (95% CI 0.23 to 0.37) to 0.79 (95% CI 0.70 to 0.88). These results suggest that formal training in the Neer system is a prerequisite for its use in clinical practice and research.

'Proto-idea' was a central concept in the thinking of the Polish microbiologist and philosopher of science Ludwik Fleck (1896-1961). Based on studies of the origin of the modern concept of syphilis, Fleck claimed that many established scientific facts are best understood as interpretations of prescientific, somewhat hazy 'proto-ideas' in the framework of a certain 'thought-style'. As an example, Fleck saw the modern knowledge of infection as an interpretation of the ancient proto-idea of diseases as caused by minute 'animalcules'. However, the epistemological aspects of the concept of proto-ideas have only been sparsely developed and discussed by Fleck and his critics. This paper attempts to bridge the gap. Firstly, I reconstruct the concept of proto-ideas in the context of Fleck's constructivist theory of knowledge. Secondly, I illustrate the relation between Fleck's concept of proto-ideas and his nominalist view on medical taxonomy. Finally, I discuss four philosophical problems implied by Fleck's concept of proto-ideas: (a) the problem of combining two conflicting perspectives on the history of science (b) the problem of accounting for the notion of 'continuity' within a nonrealist theory of knowledge (c) the problem of ascribing no truth-content to proto-ideas, and (d) the problem concerning the non-neutrality of the analyst's viewpoint.

'Proto-idea' was a central concept in the thinking of the Polish microbiologist and philosopher of science Ludwik Fleck (1896-1961). Based on studies of the origin of the modern concept of syphilis, Fleck claimed that many established scientific facts are best understood as interpretations of prescientific, somewhat hazy 'proto-ideas' in the framework of a certain 'thought-style'. As an example, Fleck saw the modern knowledge of infection as an interpretation of the ancient proto-idea of diseases as caused by minute 'animalcules'. However, the epistemological aspects of the concept of proto-ideas have only been sparsely developed and discussed by Fleck and his critics. This paper attempts to bridge the gap. Firstly, I reconstruct the concept of proto-ideas in the context of Fleck's constructivist theory of knowledge. Secondly, I illustrate the relation between Fleck's concept of proto-ideas and his nominalist view on medical taxonomy. Finally, I discuss four philosophical problems implied by Fleck's concept of proto-ideas: (a) the problem of combining two conflicting perspectives on the history of science (b) the problem of accounting for the notion of 'continuity' within a nonrealist theory of knowledge (c) the problem of ascribing no truth-content to proto-ideas, and (d) the problem concerning the non-neutrality of the analyst's viewpoint.

The large signal dynamics of passively colliding pulse mode-locked laser diodes is studied. We derive a model which explains modelocking via the interplay of gain and loss dynamics; no bandwidth limiting element is necessary for pulse formation. It is found necessary to have both fast and slow absorber dynamics to achieve mode-locking. Significant chirp is predicted for pulses emitted from long lasers, in agreement with experiment. The pulse width shows a strong dependence on both cavity and saturable absorber length. (C) 1995 American Institute of Physics.

Terahertz pulse emission from four different delta-doped molecular beam epitaxially grown GaAs samples is studied. We observe a decrease of the emitted THz pulse amplitude as the distance of the delta-doped layer from the surface is increased, and a change in polarity of the THz pulses as compared to bulk n-type doped GaAs reference samples. The electric fields in the region of the doping layer are investigated by photoreflectance spectroscopy. A careful analysis of Franz-Keldysh oscillations observed in the photoreflectance spectra provides information about the built-in fields on both sides of the delta-doped layer.

Terahertz pulse emission from four different delta-doped molecular beam epitaxially grown GaAs samples is studied. We observe a decrease of the emitted THz pulse amplitude as the distance of the delta-doped layer from the surface is increased, and a change in polarity of the THz pulses as compared to bulk n-type doped GaAs reference samples. The electric fields in the region of the doping layer are investigated by photoreflectance spectroscopy. A careful analysis of Franz-Keldysh oscillations observed in the photoreflectance spectra provides information about the built-in fields on both sides of the delta-doped layer.

Availability: Pub. in Applied Physics Letters v57 n26 p2814-2816, 24 Dec 90. Available only to DTIC users. No copies furnished by NTIS.

This report contains a discussion of the effect of the gate metal on the build up of interface states at the Si-Si02 interface. A method for reducing electron trapping in Si02 is described that significantly increases the cyclability of electrically-alterable read-only storage devices. A new low voltage electroluminescent device has been built that uses Si rich Si02 charge injectors. Photon-assisted-tunneling and internal photoemission measurements have been made on metal-oxide-semiconductor samples. A quantum mechanical image force theory has been used to explain the results. Studies of the temperature dependence of the oxidation rate of silicon indicate that there are two oxidant species responsible.

The papers enclosed with this report include: a new method for studying hot electron energy distributions in SiO2, plasma enhanced chemical vapor deposition of Si-rich SiO2, the use of Si-rich SiO2 to greatly reduce electron trapping effects, the use of Si-rich SiO2 to increase the yield of thin film capacitors, ellipsometry measurements of polycrystalline silicon films and the use of a delay time technique to measure the diffusion of the oxidant in SIO2 films., Sponsored in part by DARPA.