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Background: The EQ VAS component of the EQ-5D questionnaire has been used to assess patients' valuation of their own health besides its use for self-reporting of overall health status. The objective of the present study was to identify patients' valuation of EQ-5D-3L health states using the EQ VAS in different patient groups over time and in comparison to the general population. Methods: Data were obtained from patients from nine National Quality Registers (n = 172,070 patients) at baseline and at 1-year follow-up and compared with data from the general population (n = 41,761 participants). The correlation between EQ VAS scores and EQ-5D-3L index based on the Swedish experience-based VAS value set was assessed. Ordinary least squares (OLS) regression models were used to determine the association between EQ-5D-3L dimensions and EQ VAS valuation. Results: EQ VAS scores showed consistency with severity of health states both at baseline and at 1-year follow-up in the nine selected EQ-5D-3L health states. The regression models showed mostly consistent decrements by severity levels in each dimension at both time points and similar to the general population. The dimension mainly associated with inconsistency was the self-care severity level three. Problems in the anxiety/depression dimension had the largest impact on overall health status in most of the patient groups and the general population. Conclusion: The study has demonstrated the important role EQ VAS can play in revealing patients' valuation of their health and showed the variation in valuation of EQ-5D-3L dimensions and levels of severity across different patient groups. [ABSTRACT FROM AUTHOR]

Background and purpose -- Strenuous efforts to minimize postoperative infection rates have been made, including the Swedish nationwide initiative Prosthesis Related Infections Shall be Stopped (PRISS). This study calculated the incidence rate of periprosthetic joint infection (PJI) following primary total knee arthroplasty (TKA) before and after PRISS. Patients and methods -- All 45,438 primary TKAs registered in the Swedish Knee Arthroplasty Register (SKAR) during 2007--2008 and 2012--2013 were included. Matched data on antibiotic prescriptions were obtained from the Swedish Prescribed Drug Register (SPDR). All patients with ≥ 28 days of continuous antibiotic treatment within 2 years of primary surgery had their medical charts reviewed to identify cases of PJI. The incidence rate was calculated by dividing the number of PJIs by the total time at risk during each time period and presented as percentages with 95% confidence interval (CI). Results -- 644 PJIs were identified, equaling a 2-year incidence rate of 1.45% (CI 1.34--1.57). The incidence rate was 1.44% (CI 1.27--1.61) before PRISS and 1.46% (CI 1.31--1.61) after. Diagnosis was made within 30 days of primary TKA in 52%, and within 90 days in 73% of cases. 603 cases were reoperated on or revised. Median time from operation to diagnosis was 29 days (1--716), for both time periods. Debridement with exchange of the insert was performed in 32% and 63% of cases before and after PRISS, respectively. Interpretation -- We found similar incidence rates before and after the PRISS initiative without any statistically significant difference. Time to diagnosis was similar during both time periods. The project may have contributed to increased compliance with treatment protocols. [ABSTRACT FROM AUTHOR]

Background and purpose -- Total knee replacement (TKR) studies usually analyze all-cause revision when considering relationships with patient and prosthesis factors. We studied how these factors impact different revision diagnoses. Patients and methods -- We used data from 2003 to 2019 of TKR for osteoarthritis from the arthroplasty registries of Sweden, Australia, and Kaiser Permanente, USA to study patient and prosthesis characteristics for specific revision diagnoses. There were 1,072,924 primary TKR included and 36,626 were revised. Factors studied included age, sex, prosthesis constraint, fixation method, bearing mobility, polyethylene type, and patellar component use. Revision diagnoses were arthrofibrosis, fracture, infection, instability, loosening, pain, patellar reasons, and wear. Odds ratios (ORs) for revision were estimated and summary effects were calculated using a meta-analytic approach. Results -- We found between-registry consistency in 15 factor/reason analyses. Risk factors for revision for arthro- fibrosis were age < 65 years (OR 2.0; 95% CI 1.4--2.7) and mobile bearing designs (MB) (OR 1.7; CI 1.1--2.5), for fracture were female sex (OR 3.2; CI 2.2--4.8), age ≥ 65 years (OR 2.8; CI 1.9--4) and posterior stabilized prostheses (PS) (OR 2.1; CI 1.3--3.5), for infection were male sex (OR 1.9; CI 1.7--2.0) and PS (OR 1.5; CI 1.2--1.8), for instability were age < 65 years (OR 1.5; CI 1.3--1.8) and MB (OR 1.5; CI 1.1--2.2), for loosening were PS (OR 1.5; CI 1.4--1.6), MB (OR 2.2; CI 1.6--3.0) and use of ultra-high molecular weight polyethylene (OR 2.3; CI 1.8--2.9), for patellar reasons were not resurfacing the patella (OR 13.6; CI 2.1--87.2) and MB (OR 2.0; CI 1.2--3.3) and for wear was cementless fixation (OR 4.9; CI 4.3--5.5). Interpretation -- Patients could be counselled regarding specific age and sex risks. Use of minimally stabilized, fixed bearing, cemented prostheses, and patellar components is encouraged to minimize revision risk. [ABSTRACT FROM AUTHOR]

Background and purpose -- Characteristics of patients receiving total knee arthroplasty (TKA) and prostheses used vary between regions and change with time. How these practice variations influence revision remains unclear. We combined registry data for better understanding of the impact of variation, which could potentially improve revision rates. Patients and methods -- We used data from 2003 to 2019 for primary TKA from arthroplasty registries of Sweden (SKAR), Australia (AOANJRR), and Kaiser Permanente (KPJRR). We included 1,072,924 TKA procedures for osteoarthritis. Factors studied included age, sex, ASA class, BMI category, prosthesis constraint, fixation, bearing mobility, patellar resurfacing, and polyethylene type. Cumulative percentage revision (CPR) was calculated using Kaplan-- Meier estimates, and unadjusted Cox hazard ratios were used for comparisons. Random-effects generic inverse-variance meta-analytic methods were used to determine summary effects. Results -- We found similarities in age and sex, but between-registry differences occurred in the other 7 factors studied. Patients from Sweden had lower BMI and ASA scores compared with other registries. Use of cement fixation was similar in the SKAR and KPJRR, but there were marked differences in patellar resurfacing and posterior stabilized component use. Meta-analysis results regarding survivorship favored patients aged ≥ 65 years and minimally stabilized components. There were inconsistent results with time for sex, fixation, and bearing mobility, and no differences for the patellar resurfacing or polyethylene type comparisons. Interpretation -- Marked practice variation was found. Use of minimally stabilized and possibly also cemented and fixed bearing prostheses is supported. [ABSTRACT FROM AUTHOR]

Background: The microbiology and the susceptibility patterns of infected total knee arthroplasties (TKAs) vary depending on demographic, local antimicrobial stewardship, and surgical factors. We wanted to compare the recent microbial profile and antimicrobial resistance pattern in revisions due to infections after primary TKAs in Sweden and Lithuania. Our hypothesis was that there is a difference in bacteriology and resistance pattern based on patient related, societal and local hospital factors as almost similar praxis have been applied for TKA surgery, short term systemic prophylaxis and routine use of local gentamicin containing bone cement.Methods: Primary TKAs revised for the first time due to verified or suspected infection were collected nationwide in Sweden during 2018, and in Lithuania between 2011 and 2020 from a single major TKA revision centre in Kaunas. We identified 202 TKAs in Sweden from the Swedish Knee Arthroplasty Register and 84 from Kaunas revised due to infection. We collected available culture reports and evaluated the type of microorganisms with antimicrobial resistance pattern at revision.Results: The majority of the infected cases in Sweden were early-type prosthetic joint infection (PJI) (44%), whereas late-type PJI (52%) were more common in the Kaunas cases. Gram-positive bacteria prevailed in both Sweden (55%) and Lithuania (80%). Staphylococcus aureus was the most frequent organism identified in both countries (33% in Sweden and 34% in Lithuania). More polymicrobial infections were observed in Sweden than in Lithuania (16 and 6% respectively). Methicillin resistance in Staphylococcus aureus and coagulase-negative staphylococci were higher in Lithuania (4/28 and 19/29) than in Sweden (1/42 and 9/41).Conclusions: The type of infections, microbial profile, and drug resistance pattern differed between Sweden and Lithuania. Societal and local hospitals factors with emerging resistance in Lithuania are the most plausible explanation for the difference. Lack of complete data on a national level in Lithuania underlines the importance of adding microbiology of PJIs in implant registers for national aggregation and allow cross country comparisons. [ABSTRACT FROM AUTHOR]

Background and purpose — Total knee arthroplasty (TKA) has increased substantially in Sweden. We quantified the relative risk for TKA in the Swedish population for different BMI categories and age groups to investigate whether the continued increase in TKA is attributable to increased prevalence of obesity and elderly people in the population, and to put forward model predictions for coming needs for TKA. Patients and methods — We used the Swedish Nationwide Health Survey (SNHS) and the Swedish Knee Arthroplasty Register (SKAR) 2009–2015 to calculate the relative risk (RR) of TKA by age (middle-aged 45–64 years and elderly 65–84 years) and BMI (BMI 18.5–24.9 normal weight; BMI 25.0–29.9 overweight; BMI > 30 obese). The RR for TKA was applied to the demographic forecasts for the Swedish population as a forecasting model. Results — Population size increased 5.2% from 2009 to 2015 to 40,000 middle-aged and 250,000 elderly, and the prevalence of obesity increased from 16% to 18% in these 2 age categories. Compared with those of normal weight, the RR for TKA was 2.7 (95% CI 2.5–3.0) higher for the overweight and 7.3 (6.7–8.0) higher for the obese, aged 45–64. The corresponding figures for individuals aged 65–84 were 2.1 (2.0–2.2) and 4.0 (3.8–4.3) higher, respectively. The changes in the prevalence of obesity and an increase in the elderly population accounted for an estimated increase of 1,700 TKAs over the 7 years. Interpretation — The increase in obesity frequency and the rise in the population of middle-aged and elderly may, to some extent, explain the rise in TKA utilization in Sweden. [ABSTRACT FROM AUTHOR]

Background and purpose — Rates of knee replacement (KR) are increasing worldwide. Based on population and practice changes, there are forecasts of a further exponential increase in primary knee replacement through to 2030, and a corresponding increase in revision knee replacement. We used registry data to document changes in KR over the past 15 years, comparing practice changes across Sweden, Australia, and the United States. This may improve accuracy of future predictions. Patients and methods — Aggregated data from the Swedish Knee Arthroplasty Register (SKAR), the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), and the Kaiser Permanente Joint Replacement Registry (KPJRR) were used to compare surgical volume of primary and revision KR from 2003 to 2017. Incidence was calculated using population census statistics from Statistics Sweden and the Australian Bureau of Statistics, as well as the yearly active membership numbers from Kaiser Permanente. Further analysis of KR by age < 65 and ≥ 65 years was carried out. Results — All registries recorded an increase in primary and revision KR, with a greater increase seen in the KPJRR. The rate of increase slowed during the study period. In Sweden and Australia, there was a smaller increase in revision surgery compared with primary procedures. There was consistency in the mean age at surgery, with a steady small decrease in the proportion of women having primary KR. The incidence of KR in the younger age group remained low in all 3 registries, but the proportional increases were greater than those seen in the ≥ 65 years of age group. Interpretation — There has been a generalized deceleration in the rate of increase of primary and revision KR. While there are regional differences in KR incidence, and rates of change, the rate of increase does not seem to be as great as previously predicted. [ABSTRACT FROM AUTHOR]

Background and purpose — Fast-track care programs have been broadly introduced at Swedish hospitals in elective total hip and knee replacement (THR/TKR). We studied the influence of fast-track programs on patient-reported outcomes (PROs) 1 year after surgery, by exploring outcome measures registered in the Swedish arthroplasty registers. Patients and methods — Data were obtained from the Swedish Knee and Hip Arthroplasty Registers and included TKR and THR operations 2011–2015 on patients with osteoarthritis. Based on questionnaires concerning the clinical pathway and care programs at Swedish hospitals, the patients were divided in 2 groups depending on whether they had been operated in a fast-track program or not. PROs of the fast-track group were compared with not fast-track using regression analysis. EQ-5D, EQ VAS, Pain VAS, and Satisfaction VAS were analyzed for both THR and TKR operations. The PROMs for TKR also included KOOS. Results — The differences of EQ-5D, EQ VAS, Pain VAS, and Satisfaction VAS 1 year after surgery were small but all in favor of fast-track for both THR and TKR, also in subscales of KOOS for TKR except KOOS QoL. However, the effect sizes as measured by Cohens' d formula were < 0.2 for all PROs, in both THR and TKR. Interpretation — Our results indicate that the fast-track programs may be at least as good as conventional care from the perspective of PROs 1-year postoperatively. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background and purpose — The incidence of manipulation under anesthesia (MUA) after knee arthroplasty surgery has been reported to vary between 0.5% and 10%. We evaluated the incidence of MUA after primary knee arthroplasty in Sweden, the demographics of the patients and the risk of revision. Patients and methods — Between 2009 and 2013, 64,840 primary total and unicompartmental knee arthroplasties (TKA and UKA) were registered in the Swedish Knee Arthroplasty Register (SKAR). MUAs performed between 2009 and 2014 were identified through the in- and outpatient registers of the Swedish National Board of Health and Welfare. Pertinent data were verified through medical records and patient demographics and revisions were obtained from the SKAR. Results — 1,258 MUAs were identified. Of these, 1,078 were 1st-time MUAs, performed within 1 year after the primary knee arthroplasty. The incidence of MUA was 1.7% and the incidence varied between hospitals from 0% to 5%. The majority were performed after TKA (98%), in younger patients (65% < 65 years), women (64%), and relatively healthy persons (88% had ASA ≤ 2). The cumulative risk of revision at 10 years was 10% (95% CI 8.6–12), similar for men and women. Interpretation — In Sweden, MUA is a rather uncommon measure after knee arthroplasty, especially after UKA. The CRR at 10 years was doubled compared to the general knee arthroplasty population. The frequency of the procedure varies between hospitals but in general it is performed more frequently in healthier and younger patients. [ABSTRACT FROM AUTHOR]

Background and purpose — Patient-reported outcome (PRO) in total knee arthroplasty (TKA) patients with high body mass index (BMI) is controversial. We compared pain, function, quality of life, general health, and satisfaction among different BMI categories preoperatively and 1 year after primary TKA. Patients and methods — 4,318 patients were operated with a TKA for knee osteoarthritis in the Region of Skane in 2013–2015. In all, 3,327 patients (77%) had complete PRO data and information on BMI and were included. Preoperatively the patients filled in the Knee injury and Osteoarthritis Outcome Score (KOOS) and EQ-VAS (general health). 1 year postoperatively the same questionnaires were filled in together with a question asking whether they were satisfied with the surgery. Information on age, sex, BMI, and ASA grade were obtained from the Swedish Knee Arthroplasty Register. Each patient was classified as Outcome Measures in Rheumatology– Osteoarthritis Research Society International (OMERACT–OARSI) responder or not based on a combination of absolute and relative changes in scores. Welch's t-test and a chi-square test were used in the statistical analysis. Results — Both preoperatively and 1 year postoperatively the obese patients reported somewhat worse scores than the normal weight and overweight. The differences were small with 1 exception, the KOOS sport- and recreation function postoperatively, where normal-weight and overweight patients reported fewer problems than obese patients with a BMI over 35 (40 and 39 points vs. 31 points, p < 0.001). Similar proportions of patients were satisfied and categorized as OMERACT–OARSI responders in the different BMI categories. Interpretation — The degree of improvement in PROs 1 year after TKA surgery does not seem to be affected by BMI. [ABSTRACT FROM AUTHOR]

Background and purpose — The nonagenarian (those aged 90 years and older) population is expected to double in the next 20 years. This demographic age quake may have a significant impact on the incidence of total knee arthroplasty (TKA), although current literature provides limited data. We examined death and revision rates, patient-reported outcomes (PROs) and bias on patient selection of nonagenarian patients operated on with TKA for osteoarthritis (OA) between 2000 and 2016. Patients and methods — The Swedish national knee arthroplasty register was used to identify 329 nonagenarians (mean age, 92 years). Each patient was followed-up until death or the end of 2017. PRO data of 22 of these patients were compared with 65- to 74-year-old patients operated in 2015, from the same register. Results — 5 patients (1.5%) died within 90 days and 23 (7%) patients died within 365 days after TKA. 8 patients (2.4%) developed knee complications that needed revision. For patients followed for 5 and 10 years, more than 50% and 10%, respectively, lived without being revised. The patients had statistically significant improvements in PROs, not significantly different from the younger SKAR cohort. However, the material is small and this statistical finding does not preclude that there may be clinically relevant differences. TKA incidence was different amongst the 21 counties in the country (range, 0-5.1/10,000). Interpretation — Our study suggests that nonagenarians with knee OA qualify for TKA, having similar outcomes to younger patients. The data presented may help surgeons and patients assessing the risks and outcome associated with the procedure. [ABSTRACT FROM AUTHOR]

Background and purpose — Clindamycin has not been compared with other antibiotics for prophylaxis in arthroplasty. Since 2009, the Swedish Knee Arthroplasty Register (SKAR) has been collecting information on the prophylactic antibiotic regime used at every individual operation. In Sweden, when there is allergy to penicillin, clindamycin has been the recommended alternative. We examined whether there were differences in the rate of revision due to infection depending on which antibiotic was used as systemic prophylaxis. Patients and methods — Patients who had a total knee arthroplasty (TKA) performed due to osteoarthritis (OA) during the years 2009–2015 were included in the study. Information on which antibiotic was used was available for 80,018 operations (55,530 patients). Survival statistics were used to calculate the rate of revision due to infection until the end of 2015, comparing the group of patients who received cloxacillin with those who received clindamycin as systemic prophylaxis. Results — Cloxacillin was used in 90% of the cases, clindamycin in 7%, and cephalosporins in 2%. The risk of being revised due to infection was higher when clindamycin was used than when cloxacillin was used (RR =1.5, 95% CI: 1.2–2.0; p = 0.001). There was no significant difference in the revision rate for other causes (p = 0.2). Interpretation — We advise that patients reporting allergic reaction to penicillin should have their allergic history explored. In the absence of a clear history of type-I allergic reaction (e.g. urticaria, anaphylaxis, or bronchospasm), we suggest the use of a third-generation cephalosporin instead of clindamycin as perioperative prophylaxis when undergoing a TKR. No recommendation can be given regarding patients with type-1 allergy. [ABSTRACT FROM AUTHOR]

Background and purpose — The annual number of total knee arthroplasties (TKAs) has increased worldwide in recent years. To make projections regarding future needs for primaries and revisions, additional knowledge is important. We analyzed and compared the incidences among 4 Nordic countries Patients and methods — Using Nordic Arthroplasty Register Association (NARA) data from 4 countries, we analyzed differences between age and sex groups. We included patients over 30 years of age who were operated with TKA or unicompartmental knee arthroplasty (UKA) during the period 1997–2012. The negative binomial regression model was used to analyze changes in general trends and in sex and age groups. Results — The average annual increase in the incidence of TKA was statistically significant in all countries. The incidence of TKA was higher in women than in men in all 4 countries. It was highest in Finland in patients aged 65 years or more. At the end of the study period in 2012, Finland’s total incidence was double that of Norway, 1.3 times that of Sweden and 1.4 times that of Denmark. The incidence was lowest in the youngest age groups (< 65 years) in all 4 countries. The proportional increase in incidence was highest in patients who were younger than 65 years. Interpretation — The incidence of knee arthroplasty steadily increased in the 4 countries over the study period. The differences between the countries were considerable, with the highest incidence in Finland. Patients aged 65 years or more contributed to most of the total incidence of knee arthroplasty. [ABSTRACT FROM AUTHOR]

Background and purpose - The incidence of knee osteoarthritis will most likely increase. We analyzed historical trends in the incidence of knee arthroplasty in Sweden between 1975 and 2013, in order to be able to provide projections of future demand. Patients and methods - We obtained information on all knee arthroplasties in Sweden in the period 1975-2013 from the Swedish Knee Arthroplasty Register, and used public domain data from Statistics Sweden on the evolution of and forecasts for the Swedish population. We forecast the incidence, presuming the existence of a maximum incidence. Results - We found that the incidence of knee arthroplasty will continue to increase until a projected upper incidence level of about 469 total knee replacements per 105 Swedish residents aged 40 years and older is reached around the year 2130. In 2020, the estimated incidence of total knee arthroplasties per 105 Swedish residents aged 40 years and older will be 334 (95% prediction interval (PI): 281-374) and in 2030 it will be 382 (PI: 308-441). Using officially forecast population growth data, around 17,500 operations would be expected to be performed in 2020 and around 21,700 would be expected to be performed in 2030. Interpretation - Today's levels of knee arthroplasty are well below the expected maximum incidence, and we expect a continued annual increase in the total number of knee arthroplasties performed. [ABSTRACT FROM AUTHOR]

Background: Currently, the use of metal-backed tibial components is more common than the use of all-polyethylene components in total knee arthroplasty. However, the available literature indicates that all-polyethylene tibial components are not inferior to the metal-backed design. We hypothesized that there would be no difference in the ten-year survival rate between all-polyethylene and metal-backed tibial components of a specific design in a large nationwide cohort.Methods: In the Swedish Knee Arthroplasty Register, we identified 27,733 cruciate-retaining total knee replacements using the press-fit condylar prosthesis with either metal-backed or all-polyethylene tibial components inserted from 1999 to 2011. Unadjusted survival functions were calculated with the end points of revision for any reason, revision due to infection, and revision due to reasons other than infection, and the differences between the groups were investigated with the log-rank test. Cox proportional hazard models were fitted to analyze the influence of various covariates on the adjusted relative risk of revision.Results: The median duration of follow-up was 4.5 years (range, zero to 12.9 years). Of all total knee replacements, 16,896 (60.9%) were in women and 10,837 (39.1%) were in men. Metal-backed components were used in 16,011 total knee arthroplasties (57.7%) and all-polyethylene in 11,722 total knee arthroplasties (42.3%). With revision for any reason as the end point, the all-polyethylene tibial component had slightly superior, unadjusted ten-year survival compared with the metal-backed component: 97.2% (95% confidence interval [CI], 96.7% to 97.7%) compared with 96.6% (95% CI, 96.2% to 96.9%; p = 0.002). Cox multiple regression analysis adjusting for age group, sex, and patellar resurfacing showed that all-polyethylene components had a reduced risk of revision for any reason (relative risk = 0.75; 95% CI, 0.64 to 0.89) and a reduced risk of revision due to infection (relative risk = 0.63; 95% CI, 0.46 to 0.86). Patellar resurfacing and male sex increased the risk of revision due to infection (relative risk = 2.22 [95% CI, 1.37 to 3.62] and 2.21 [95% CI, 1.66 to 2.94], respectively).Conclusions: These all-polyethylene tibial components were at least as good as or superior to metal-backed tibial components with respect to implant survivorship at ten years in cruciate-retaining total knee replacements. We concluded that these less expensive all-polyethylene tibial components can be safely and effectively used in total knee arthroplasty.Level Of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background and purpose Prosthetic joint infections can be caused by bacteria derived from the patient's skin. The aim of the study was: (1) to determine which bacteria colonize the nose and groin in patients planned for primary hip or knee arthroplasty, (2) to determine the antimicrobial resistance patterns, and (3) to monitor changes in bacterial colonization and resistance patterns connected to surgery. Patients and methods 2 weeks before scheduled primary hip or knee arthroplasty, culture samples were taken from the anterior nares and from the groin of 133 consecutive patients. At surgery, cloxacillin was given prophylactically and cement with gentamicin was used. 2 weeks after surgery, another set of samples were taken from 120 of these patients. Bacterial findings and resistance patterns were analyzed. Results Preoperatively, 95% of the patients had coagulase-negative staphylococci (CNS) in the groin and 77% in the nose. The proportion of patients with a methicillin-resistant CNS in the groin increased from 20% preoperatively to 50% postoperatively (p < 0.001), and the proportion of patients with a gentamicin-resistant CNS in the groin increased from 5% to 45% (p < 0.001). 28% of the patients had Staphylococcus aureus in the nose preoperatively, and 7% in the groin. Methicillin-resistant Staphylococcus aureus (MRSA) was found in the nose of 1 patient. Interpretation In southern Sweden, beta-lactams were effective against 99% of the Staphylococcus aureus strains and 80% of the CNS strains colonizing the patients undergoing primary hip or knee arthroplasty. Gentamicin protects against most CNS strains in cemented primary joint replacements. [ABSTRACT FROM AUTHOR]

Background and purpose Most studies on high tibial osteotomies (HTOs) have been hospital-based and have included a limited number of patients. We evaluated the use and outcome-expressed as rate of revision to knee arthroplasty-of HTO performed in Sweden with 9 million inhabitants, 1998-2007. Patients and methods 3, 161 HTO procedures on patients 30 years or older (69% men) who were operated on for knee osteoarthritis in Sweden, 1998-2007, were identified through the inpatient and outpatient care registers of the Swedish National Board of Health and Welfare. Pertinent data were verified through surgical records. Conversions of HTO to knee arthroplasty before 2010 were identified through the Swedish Knee Arthroplasty Register (SKAR). The 10-year survival was determined using revision to an arthroplasty as the endpoint. Results The number of HTOs decreased by one third between 1998 and 2007, from 388 operations a year to 257 a year. Most of the HTOs were performed with open wedge osteotomy using external fixation. The cumulative revision rate at 10 years was 30% (95% CI: 28-32). The risk of revision increased with increasing age and was higher in women than in men (RR = 1.3, CI: 1.1-1.5). Interpretation If being without an artificial joint implant is considered to be beneficial, then HTO is an excellent alternative to knee arthroplasty in younger and/or physically active patients suffering from knee osteoarthritis. [ABSTRACT FROM AUTHOR]

Background and purpose In Sweden, surgery for knee osteoarthritis (OA) in patients younger than 55 years of age has doubled during the last 10 years. We evaluated the use of 3 surgical alternatives: high tibial osteotomy (HTO), unicompartmental arthroplasty (UKA), and total knee arthroplasty (TKA). We also examined the outcome, expressed by rate of revision. Methods The numbers of all procedures during 1998–2007 were obtained from the Swedish Knee Arthroplasty Register (SKAR) (UKA < 55 years: n = 1,050; UKA ≥ 55 years: n = 7,743; TKA < 55 years: n = 2,832; TKA ≥ 55 years: n = 62,829) and the National Board of Health and Welfare (NHW) (HTO 25–55 years: n = 2,266). The revision rate (presented as life tables) was based on the SKAR material for arthroplasties. For HTOs, a single institutional series of 450 patients aged 30–64 years was used to calculate the revision rate and to compare it to that for UKAs (n = 4,799; age 30–64 years). Results During the 10 years, the use of TKA in patients younger than 55 years increased fivefold. While UKA increased threefold, its use diminished in the last 2 years. Although the use of HTO halved during the period, it is still used more often than UKA. The risk of revision increased in patients younger than 55 years and was lower for TKA (9%) than for UKA (24%). The revision rate was similar for HTO (17%) and for UKA (17%) in patients aged 30–64 years. Interpretation TKA is the preferred method for young OA patients in Sweden today. The use of HTO and UKA has diminished, and as the few operations are spread over many hospitals, there is a risk of gradual loss of experience with respect to patient selection and surgical routine—with a negative effect on outcome. Thus, there is a risk that these treatment alternatives for younger patients will eventually be abandoned. [ABSTRACT FROM AUTHOR]

Hip and knee arthroplasties are mostly successful procedures; however, patient injuries may occur and should be reported to Löf, the Swedish patient insurance. This study investigated the incidence of patient injuries after primary total hip and knee arthroplasty in the Swedish regions, differences in incidence depending on annual surgical volume, and types of approved injuries. Approved patient injuries were related to the total number of hip and knee arthroplasties registered in the Swedish Arthroplasty Register 2012-2021. The national incidence was 11.4 and 8.1 per 1,000 hip and knee arthroplasties respectively and varied in the regions from 30.4 to 4.9 and 15.4 to 5.4 per 1,000 hip and knee arthroplasties respectively. Orthopedic departments with higher annual volumes of performed arthroplasties had a lower proportion of patient injuries. Infection was the most common patient injury, followed by nerve lesions and mechanical complications. The differences may be due to underreporting and varying quality of care in the regions. A centralization of hip and knee arthroplasties may be beneficial.

Background: In the past decades, the incidence of obesity has increased worldwide. This disease is often accompanied with several comorbidities and therefore, surgeons and anesthesiologists should be prepared to provide optimal management for these patients. The aim of this descriptive cross-sectional study was to map the criteria and routines that are used by Swedish knee arthroplasty surgeons today when considering patients with obesity for knee arthroplasty., Methods: A survey including 21 items was created and sent to all the Swedish centers performing knee arthroplasty. The survey included questions about the surgeons' experience, hospital routines of preoperative information given and the surgeons' individual assessment of patients with obesity that candidates for knee arthroplasty. Descriptive statistics were used to present the data., Results: A total of 203 (64%) knee surgeons responded to the questionnaire. Almost 90% of the surgeons claimed to inform their patients with obesity that obesity has been associated with an increased risk of complications after knee arthroplasty. Seventy-nine percent reported that they had an upper BMI limit to perform knee arthroplasty, a larger proportion of the private centers had a BMI limit compared to public centers. The majority of the centers had an upper BMI limit of 35., Conclusion: The majority of the knee arthroplasty surgeons in Sweden inform their patients with obesity regarding risks associated with knee arthroplasty. Most centers that perform knee arthroplasties in Sweden have an upper BMI limit., (© 2022. The Author(s).)

Background and purpose - Obesity is a considerable medical challenge in society. We investigated the risk of revision for any reasons and for infection in patients having total knee arthroplasty (TKA) for osteoarthritis (OA) within 2 years after bariatric surgery (BS) and compared them with TKAs without BS.Patients and methods - We used the Scandinavian Obesity Surgery Registry (SOReg) and the Swedish Knee Arthroplasty Register (SKAR) to identify patients operated on in 2009-2019 with BS who had had primary TKA for OA within 2 years after the BS (BS group) and compared them with TKAs without prior BS (noBS group). We determined adjusted hazard ratio (HR) for the BS group and noBS group using Cox proportional hazard regression for revision due to any reasons and for infection. Adjustments were made for sex, age groups, and BMI categories preoperatively.Results - 441 patients were included in the BS group. The risk of revision for infection was higher for the BS group with HR 2.2 (95% CI 1.1-4.7) adjusting for BMI before the TKA, while the risk of revision for any reasons was not statistically significant different for the BS group with HR 1.3 (CI 0.9-2.1). Corresponding figures when adjusting for BMI before the BS were HR 0.9 (CI 0.4-2) and HR 1.2 (CI 0.7-2).Interpretation - Our findings did not indicate that BS prior to TKA was associated with lower risk of revision.

Background and purpose - Obesity defined as increased BMI is commonly associated with higher revision rates following total knee arthroplasty (TKA). We examined the effect of BMI on the rate of revision after TKA, for both infection and other reasons, and analyzed weight and height separately to provide better understanding of the risk profile.Patients and methods - The Swedish national knee arthroplasty register was used to identify 107,228 patients operated with primary TKA for osteoarthritis between 2009 and 2017. Cox proportional hazards regression was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for BMI (categories: < 18.5, 18.5-24.9, 25-29.9, 30-34.9, 35-39.9, ≥ 40), weight (categories: < 65, 65-89, 90-114, ≥ 115 kg) and height (categories: < 160, 160-179, ≥ 180 cmResults - There were 2,503 revisions in the follow-up period; 1,036 for infection and 1,467 for other reasons. Higher BMI and weight categories were associated with a similar and statistically significantly increased risk of revision for all causes and for infection. The risk of revision for infection was almost twice in the highest BMI and highest weight group: HR = 3.4 (CI 2.3-4.7) and HR = 3.1 (CI 2.5-3.9) respectively. For BMI and weight categories there was no statistically significant association between revision for other reasons than infection, contrary to the tallest height category where it was statistically significant (HR = 1.3 [CI 1.1-1.5]).Interpretation - BMI, weight, and height may be associated with different types of risks for revision following TKA.

Background and Purpose: Prosthetic joint infection (PJI) is a leading cause of early revision after total knee arthroplasty (TKA). Open debridement with exchange of tibial insert allows treatment of infection with retention of fixed components. We investigated the success rate of this procedure in the treatment of knee PJIs in a nationwide material, and determined whether the results were affected by microbiology, antibiotic treatment, or timing of debridement., Patients and Methods: 145 primary TKAs revised for the first time, due to infection, with debridement and exchange of the tibial insert were identified in the Swedish Knee Arthroplasty Register (SKAR). Staphylococcus aureus was the most common pathogen (37%) followed by coagulase-negative staphylococci (CNS) (23%). Failure was defined as death before the end of antibiotic treatment, revision of major components due to infection, life-long antibiotic treatment, or chronic infection., Results: The overall healing rate was 75%. The type of infecting pathogen did not statistically significantly affect outcome. Staphylococcal infections treated without a combination of antibiotics including rifampin had a higher failure rate than those treated with rifampin (RR = 4, 95% CI: 2-10). In the 16 cases with more than 3 weeks of symptoms before treatment, the healing rate was 62%, as compared to 77% in the other cases (p = 0.2). The few patients with a revision model of prosthesis at primary operation had a high failure rate (5 of 8)., Interpretation: Good results can be achieved by open debridement with exchange of tibial insert. It is important to use an antibiotic combination including rifampin in staphylococcal infections.

Background: High tibial osteotomy (HTO) and unicompartmental arthroplasty (UKA) are reconstructive surgeries advocated for younger patients. In case of failure or progression of osteoarthritis, they can both be converted to a total knee arthroplasty (TKA)., Questions/purposes: We used registry data to answer if the risks of revision for TKAs after previous HTOs and UKAs differ and how these compare with that of de novo TKAs. Furthermore, we wanted to examine the extent of stemmed/revision implants being used for the conversions., Methods: We identified HTOs performed during 1998 to 2007 with the help of the inpatient and outpatient care registries of the Swedish National Board of Health and Welfare and gathered relevant information from hospital records. The Swedish Knee Arthroplasty Register was then examined to find all de novo TKAs, TKAs performed after HTO, and TKAs performed after UKA through the end of 2012., Results: For 920 TKAs after previous UKA and 356 TKAs after previous closed-wedge HTOs, we found the risk of revision significantly higher than for the 118,229 de novo TKAs (risk ratio, 2.8; confidence interval [CI], 2.2-3.5; p<0.001, and 1.7 CI, 1.1-2.6; p<0.001, respectively), whereas for the 482 open-wedge osteotomies, the difference was not significant (risk ratio, 1.2; CI, 0.8-1.8; p=0.44). Stemmed implants were used in 663 of the 117,566 primary de novo TKAs (0.6%), in 22 of the 809 HTO conversions (4%) and in 136 of the 920 UKA conversions (17%)., Conclusions: TKAs after previous reconstructive surgery carry an increased risk for revision. However, our findings do not mitigate against the use of UKA and HTO in selected cases., Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Introduction and Purpose: In recent years, there has been renewed interest in using unicompartmental knee arthroplasty (UKA). Several studies have reported increasing numbers of UKAs for osteoarthritis in patients who are less than 65 years of age, with low revision rates. To describe and compare the use and outcome of UKA in this age group, we have combined data from the Australian and Swedish knee registries., Patients and Methods: More than 34,000 UKA procedures carried out between 1998 and 2007 were analyzed, and we focused on over 16,000 patients younger than 65 years to determine usage and to determine differences in the revision rate. Survival analysis was used to determine outcomes of revision related to age and sex, using any reason for revision as the endpoint., Results: Both countries showed a decreasing use of UKA in recent years in terms of the proportion of knee replacements and absolute numbers undertaken per year. The 7-year cumulative risk of revision of UKA in patients younger than 65 years was similar in the two countries. Patients younger than 55 years had a statistically significantly higher cumulative risk of revision than patients aged 55 to 64 years (19% and 12%, respectively at 7 years). The risk of revision in patients less than 65 years of age was similar in both sexes., Interpretation: The results of the combined UKA data from the Australian and Swedish registries show a uniformity of outcome between countries with patients aged less than 65 having a higher rate of revision than patients who were 65 or older. Surgeons and patients should be aware of the higher risk of revision in this age group.

Background and Purpose: There are rising concerns about the frequency of infection after arthroplasty surgery. Prophylactic antibiotics are an important part of the preventive measures. As their effect is related to the timing of administration, it is important to follow how the routines with preoperative prophylactic antibiotics are working., Methods: In 114 consecutive cases treated at our own university clinic in Lund during 2008, the time of administration of preoperative prophylactic antibiotic in relation to the start of surgery was recorded from a computerized operation report. In 291 other cases of primary total knee arthroplasty (TKA), randomly selected from the Swedish Knee Arthroplasty Register (SKAR), the type and dose of prophylactic antibiotic as well as the time of administration in relation to the inflation of a tourniquet and to the start of surgery was recorded from anesthetic records., Results: 45% (95% CI: 36-54) of the patients operated in Lund and 57% (CI: 50-64) of the TKAs randomly selected from the SKAR received the preoperative antibiotic 15-45 min before the start of surgery. 53% (CI: 46-61) received antibiotics 15-45 min before inflation of a tourniquet., Interpretation: The inadequate timing of prophylactic antibiotics indicates that the standards of strict antiseptic and aseptic routines in arthroplasty surgery are falling. The use of a simple checklist to ensure the surgical safety may be one way of reducing infections in arthroplasty surgery.