440 research outputs found

    10-year survival of total ankle arthroplasties: A report on 780 cases from the Swedish Ankle Register

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    Background and purpose There is an ongoing need to review large series of total ankle replacements (TARs) for monitoring of changes in practice and their outcome. 4 national registries, including the Swedish Ankle Register, have previously reported their 5-year results. We now present an extended series with a longer follow-up, and with a 10-year survival analysis. Patients and methods Records of uncemented 3-component TARs were retrospectively reviewed, determining risk factors such as age, sex, and diagnosis. Prosthetic survival rates were calculated with exchange or removal of components as endpoint-excluding incidental exchange of the polyethylene meniscus. Results Of the 780 prostheses implanted since 1993, 168 (22%) had been revised by June 15, 2010. The overall survival rate fell from 0.81 (95% CI: 0.79-0.83) at 5 years to 0.69 (95% CI: 0.67-0.71) at 10 years. The survival rate was higher, although not statistically significantly so, during the latter part of the period investigated. Excluding the STAR prosthesis, the survival rate for all the remaining designs was 0.78 at 10 years. Women below the age of 60 with osteoarthritis were at a higher risk of revision, but age did not influence the outcome in men or women with rheumatoid arthritis. Revisions due to technical mistakes at the index surgery and instability were undertaken earlier than revisions for other reasons. Interpretation The results have slowly improved during the 18-year period investigated. However, we do not believe that the survival rates of ankle replacements in the near future will approach those of hip and knee replacements-even though improved instrumentation and design of the prostheses, together with better patient selection, will presumably give better results

    Variation in reproductive investment increases body temperature amplitude in a temperate passerine

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    Many birds and mammals show substantial circadian variation in body temperature, which has been attributed to fluctuations in ambient temperature and energy reserves. However, to fully understand the variation in body temperature over the course of the day, we also need to consider effects of variation in work rate. We made use of a dataset on body temperature during the resting and active periods in female marsh tits (Poecile palustris) that bred in a temperate area and were subjected to experimental changes in reproductive investment through brood size manipulations. Furthermore, the amplitude increased with daytime, but were unaffected by nighttime, ambient temperature. Amplitudes in females with manipulated broods were 44% above predictions based on inter-specific allometric relationships. In extreme cases, amplitudes were > 100% above predicted values. However, no individual female realised the maximum potential amplitude (8.5 °C, i.e. the difference between the highest and lowest body temperature within the population) but seemed to prioritise either a reduction in body temperature at night or an increase in body temperature in the day. This suggests that body temperature amplitude might be constrained by costs that preclude extensive use of both low nighttime and high daytime body temperatures within the same individual. Amplitudes in the range found here (0.5–6.7 °C) have previously mostly been reported from sub-tropical and/or arid habitats. We show that comparable values can also be found amongst birds in relatively cool, temperate regions, partly due to a pronounced increase in body temperature during periods with high work rate

    Age differences in night-time metabolic rate and body temperature in a small passerine

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    Spending the winter in northern climes with short days and cold ambient temperatures (Ta) can be energetically challenging for small birds that have high metabolic and heat loss rates. Hence, maintaining body temperature (Tb) in Ta below thermoneutrality can be energetically costly for a small bird. We still know little about how increased heat production below thermoneutrality affects the level at which Tb is maintained, and if these patterns are age specific. To test this, we measured subcutaneous body temperature (Ts) and resting metabolic rate (RMR) simultaneously in blue tits (Cyanistes caeruleus) during winter nights in Ta’s ranging from 25 to − 15 °C. RMR increased below the lower critical temperature (LCT, estimated at 14 °C) and was 6% higher in young (birds in their first winter) compared to old birds (birds in their second winter or older). The higher RMR was also mirrored in higher Ts and thermal conductance (C) in young birds, which we suggest could be caused by age differences in plumage quality, likely driven by time constraints during moult. Reduction in nightly predicted Tb was modest and increased again at the coldest ambient temperatures, suggesting that either heat retention or heat production (or both) improved when Ta reached levels which are cold by the standards of birds in our population. Our results show that levels of heat production and Tb can be age specific. Further studies should address age-specific differences on quality, structure, and thermal conductivity of plumage more explicitly, to investigate the role of variation in insulation in age-linked metabolic phenotypes

    Experimental facilitation of heat loss affects work rate and innate immune function in a breeding passerine bird

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    The capacity to get rid of excess heat produced during hard work is a possible constraint on parental effort during reproduction [heat dissipation limit (HDL) theory]. We released hard-working blue tits (Cyanistes caeruleus) from this constraint by experimentally removing ventral plumage. We then assessed whether this changed their reproductive effort (feeding rate and nestling size) and levels of self-maintenance (change in body mass and innate immune function). Feather-clipped females reduced the number of feeding visits and increased levels of constitutive innate immunity compared with unclipped females but did not fledge smaller nestlings. Thus, they increased self-maintenance without compromising current reproductive output. In contrast, feather clipping did not affect the number of feeding visits or innate immune function in males, despite increased heat loss rate. Our results show that analyses of physiological parameters, such as constitutive innate immune function, can be important when trying to understand sources of variation in investment in self-maintenance versus reproductive effort and that risk of overheating can influence innate immune function during reproduction

    Former Male Elite Athletes Have a Higher Prevalence of Osteoarthritis and Arthroplasty in the Hip and Knee Than Expected.

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    BACKGROUND: Intense exercise has been reported as one risk factor for hip and knee osteoarthritis (OA). PURPOSE: This study aimed to evaluate (1) whether this is true for both former impact and nonimpact athletes, (2) if the risk of a hip or knee arthroplasty due to OA is higher than expected, and (3) if joint deterioration is associated with knee injuries. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: The prevalence of OA and arthroplasty in the hip and knee were registered in 709 former male elite athletes with a median age of 70 years (range, 50-93 years), retired from sports for a median 35 years (range, 1-63 years), and compared with 1368 matched controls. Odds ratios (ORs) are presented as means with 95% confidence intervals (95% CIs). RESULTS: The risk of hip or knee OA was higher in former athletes (OR, 1.9; 95% CI, 1.5-2.3), as was arthroplasty based on OA in either of these joints (OR, 2.2; 95% CI, 1.6-3.1). The risk of hip OA was doubled (OR, 2.0; 95% CI, 1.5-2.8) and hip arthroplasty was 2.5 times higher (OR, 2.5; 95% CI, 1.6-3.7) in former athletes than in controls, predominantly driven by a higher risk in former impact athletes. Also, the risk of knee OA was higher (OR, 1.6; 95% CI, 1.3-2.1), as was knee arthroplasty (OR, 1.6; 95% CI, 0.9-2.7), driven by a higher risk in both former impact and nonimpact athletes. Knee OA in impact athletes was associated with knee injury. CONCLUSION: Hip and knee OA and hip and knee arthroplasty are more commonly found in former male elite athletes than expected. A previous knee injury is associated with knee OA in former impact athletes but not in nonimpact athletes

    Impact of concomitant DMARD therapy on adherence to treatment with etanercept and infliximab in rheumatoid arthritis. Results from a six-year observational study in southern Sweden

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    The objective of this work is to compare the adherence to therapy of patients receiving etanercept and infliximab during first tumour necrosis factor (TNF)-blocking treatment course in rheumatoid arthritis. Special emphasis is placed on potential predictors for treatment termination and the impact of concomitant methotrexate (MTX) or other disease-modifying antirheumatic drugs (DMARDs). Patients (n = 1,161) with active rheumatoid arthritis, not responding to at least two DMARDs including MTX starting etanercept or infliximab therapy for the first time, were included in a structured clinical follow-up protocol. Information on diagnosis, disease duration, previous and ongoing DMARDs, treatment start and termination, as well as cause of withdrawal was prospectively collected during the period of March 1999 through December 2004. Patients were divided into six groups according to TNF-blocking drugs and concomitant DMARDs. Five-year level (one-year) of adherence to therapy was 36% (69%) for patients receiving infliximab in combination with MTX compared with 65% (89%) for patients treated with etanercept and MTX (p < 0.001). Cox regression models showed that the risk for premature treatment termination of patients treated with infliximab was threefold higher than for etanercept (p < 0.001). Also, the regression analysis showed that patients receiving concomitant MTX had better treatment continuation than patients treated solely with TNF blockers (p < 0.001). Moreover, patients receiving concomitant MTX had superior drug survival than patients receiving other concomitant DMARDs (p < 0.010). The superior effect of MTX was associated primarily with fewer treatment terminations because of adverse events. In addition, the study identifies low C-reactive protein level, high age, elevated health assessment questionnaire score, and higher previous number of DMARDs as predictors of premature treatment termination. In summary, treatment with etanercept has higher adherence to therapy than treatment with infliximab. Concomitant MTX is associated with improved treatment continuation of biologics when compared with both TNF blockers as monotherapy and TNF blockers combined with other DMARDs

    Poor prosthesis survival and function after component exchange of total ankle prostheses

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    BACKGROUND AND PURPOSE: In failed total ankle replacements (TARs), fusion is often the procedure of preference; the outcome after exchanging prosthetic components is debated. We analyzed prosthetic survival, self-reported function, and patient satisfaction after component exchange. Patients and methods We identified patients in the Swedish Ankle Registry who underwent exchange of a tibial and/or talar component between January 1, 1993 and July 1, 2013 and estimated prosthetic survival by Kaplan-Meier analysis. We evaluated the patient-reported outcome measures (PROMs) SEFAS, EQ-5D, EQ-VAS, SF-36, and patient satisfaction by direct questions.RESULTS: 69 patients underwent revision TAR median 22 (0-110) months after the primary procedure. 24 of these failed again after median 26 (1-110) months. Survival analysis of revision TAR showed a 5-year survival rate of 76% and a 10-year survival of 55%. 29 patients with first revision TAR in situ answered the PROMs at mean 8 (1-17) years after revision and had the following mean scores: SEFAS 22, SF-36 physical 37 and mental 49, EQ-5D index 0.6, and EQ-VAS 64. 15 of the patients were satisfied, 5 were neither satisfied nor dissatisfied, and 9 were dissatisfied.INTERPRETATION: Revision TAR had a 10-year survival of 55%, which is lower than the 10-year survival of 74% for primary TAR reported from the same registry. Only half of the patients were satisfied. Future studies should show which, if any, patients benefit from revision TAR and which patients should rather be fused directly

    Changes and sex differences in patient reported outcomes in rheumatoid factor positive RA-results from a community based study.

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    Patient reported outcomes (PROs) are important measures in rheumatoid arthritis (RA). A register of patients with RA from all rheumatology care providers in Malmö, Sweden, was established in 1997 and has been continually updated. This register includes virtually all the RA patients in the area. The aim of this study was to analyse PROs in surveys of this population conducted between 1997 and 2009, and to assess differences in treatment and outcome in male and female patients
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