Search

Abstract Osteoarthritis is one of the most common musculoskeletal diseases and increases the risk of severe cardiovascular disease, like heart attack and stroke. In some individuals, osteoarthritis and cardiovascular disease will co-occur. This co-occurrence might be due to shared risk factors, for example high age, lifestyle factors and/or a shared genetic liability for the two diseases. Here, we show that the correlation between osteoarthritis and cardiovascular disease can be explained by shared genetic factors, independent of high age and body weight, and also likely independent of lifestyle factors, like smoking and physical activity level. Findings suggest that genetic factors that are shared for osteoarthritis and cardiovascular disease may contribute to both diseases. Thus, the prevailing idea that osteoarthritis is predominantly a risk factor for cardiovascular disease is challenged. Our findings imply that the current diagnostic boundaries between these diseases may need to be re-evaluated.

BackgroundCardiovascular, respiratory, and musculoskeletal disease are among the leading causes of disability in middle-aged and older people. Health and lifestyle factors in youth have known associations with cardiovascular or respiratory disease in adulthood, but largely unknown associations with musculoskeletal disease.Methods and findingsWe included approximately 40,000 18-year-old Swedish males, who completed their conscription examination in 1969 to 1970, followed up until age of 60 years. Exposures of interest were physical health: body mass and height, blood pressure, pulse at rest, muscle strength, cardiorespiratory fitness, and hematocrit; self-reported lifestyle: smoking, alcohol, and drug use; self-reported health: overall, headache and gastrointestinal. We followed the participants through the Swedish National Patient Register for incidence of common musculoskeletal (osteoarthritis, back pain, shoulder lesions, joint pain, myalgia), cardiovascular (ischemic heart disease, atrial fibrillation), and respiratory diseases (asthma, chronic obstructive pulmonary disease, bronchitis). We analyzed the associations using general estimating equations Poisson regression with all exposures included in one model and adjusted for parental education and occupation. We found that higher body mass was associated with higher risk of musculoskeletal (risk ratio [RR] per 1 standard deviation [SD] 1.12 [95% confidence interval, CI 1.09, 1.16]), cardiovascular (RR 1.22 [95% CI 1.17, 1.27] per 1 SD) and respiratory diseases (RR 1.14 [95% CI 1.05, 1.23] per 1 SD). Notably, higher muscle strength and cardiorespiratory fitness were associated with higher risk of musculoskeletal disease (RRs 1.08 [95% CI 1.05, 1.11] and 1.06 [95% CI 1.01, 1.12] per 1 SD difference in exposure), while higher cardiorespiratory fitness was protective against both cardiovascular and respiratory diseases (RRs 0.91 [95% CI 0.85, 0.98] and 0.85 [95% CI 0.73, 0.97] per 1 SD exposure, respectively). We confirmed the adverse effects of smoking, with risk ratios when comparing 11+ cigarettes per day to non-smoking of 1.14 (95% CI 1.06, 1.22) for musculoskeletal, 1.58 (95% CI 1.44, 1.74) for cardiovascular, and 1.93 (95% CI 1.60, 2.32) for respiratory diseases. Self-reported headache (category "often" compared to "never") was associated with musculoskeletal diseases (RR 1.38 [95% CI 1.21, 1.58]) and cardiovascular diseases (RR 1.29 [95% CI 1.07, 1.56]), but had an inconclusive association with respiratory diseases (RR 1.13 [95% CI 0.79, 1.60]). No large consistent associations were found for other exposures. The most notable associations with specific musculoskeletal conditions were for cardiorespiratory fitness and osteoarthritis (RR 1.23 [95% CI 1.15, 1.32] per 1 SD) and for muscle strength and back pain (RR 1.18 [95% CI 1.12, 1.24] per 1 SD) or shoulder diseases (RR 1.27 [95% CI 1.19, 1.36] per 1 SD). The main limitations include lack of adjustment for genetic factors and environmental exposures from childhood, and that the register data were available for males only.ConclusionsWhile high body mass was a risk factor for all 3 studied groups of diseases, high cardiorespiratory fitness and high muscle strength in youth were associated with increased risk of musculoskeletal disease in middle age. We speculate that these associations are mediated by chronic overload or acute trauma.

Objective To investigate the associations between rheumatic and musculoskeletal diseases (RMDs) and incident dementia using population register‐based data. Methods This nested case‐control study was conducted based on a cohort of residents in the Skåne region, Sweden, aged 50 years and older in 2009 without doctor‐diagnosed dementia during 1998 to 2009 (n = 402,825). Individuals with a new main diagnosis of dementia during 2010 to 2019 were identified as incident patients with dementia (n = 22,131). Controls without diagnosed dementia were randomly matched 1:1 by sex, age, and Elixhauser comorbidity index using incidence density sampling. Separate conditional logistic regression analyses adjusted for confounders were fitted for the following RMDs, diagnosed at least 2 years before dementia diagnosis as exposure: gout, osteoarthritis, rheumatoid arthritis, spondyloarthropathies (SpA), and systemic connective tissue disorders. Subgroup analyses by dementia subtype, sex, age, comorbidity, and RMDs/dementia identification were conducted. Results Although gout (adjusted rate ratio 0.88; 95% confidence interval 0.79–0.97), osteoarthritis (0.92; 0.88–0.96), and systemic connective tissue disorders (0.91; 0.83–0.99) were associated with decreased risk of dementia, the associations for rheumatoid arthritis (1.05; 0.92–1.19) and SpA (1.17; 0.94–1.45) were inconclusive. The associations between RMDs and incident dementia were similar across sex, age, and comorbidity subgroups with a few exceptions (eg, an adjusted rate ratio of 0.99 [95% confidence interval 0.71–1.39] in males vs 1.31 [0.99–1.74] in female patients for SpA). Conclusion Persons with diagnosed RMDs seem to have comparable or slightly lower risks of developing dementia compared with those without known RMD.

Objective: To describe the SHIELD cohort in terms of symptoms indicative of early knee osteoarthritis (OA) and to investigate associations between patient characteristics (demographics, activity/injury-related) and these symptoms at 1 (cross-sectional) and 3 years (longitudinal) post anterior cruciate ligament reconstruction (ACLR). Method: 106 participants (50 ​% women, mean [SD] age 25 [5] years) were included. Symptoms indicative of early knee OA were evaluated by the Knee injury and Osteoarthritis Outcome Score (KOOS) subscale pain, KOOS subscale pain ≤72 (KOOSpain ≤72), and ≤85 on two out of four KOOS subscales (pain, symptoms, activity of daily living, quality of life) (modified Luyten). Results: Mean (SD) KOOS pain scores were 83.2 (15.7) and 87.3 (12.7) at 1 and 3 years, respectively. At 1 year and 3 years post ACLR, 18/101 (18 ​%) and 14/86 (16 ​%) participants met the KOOSpain ≤72 criterion, whereas 83/101 (82 ​%) and 67/86 (78 ​%) met the modified Luyten criterion. 7/15 (47 ​%) (KOOSpain ≤72) and 59/70 (84 ​%) (modified Luyten) classified as having knee OA symptoms 1 year post ACLR were still classified as having OA symptoms after 3 years. Lower activity level at 1 year was the sole variable consistently associated with all three outcomes 3 years post ACLR. Conclusion: The proportion of participants fulfilling existing classification criteria for symptoms indicative of early OA after ACLR is highly dependent on the criteria applied and different criteria seem to capture varying aspects of early OA symptoms. Future studies will reveal if these symptoms will persist long-term or just reflect more transient issues.

Objective: The global impact of osteoarthritis is growing. Currently no disease modifying osteoarthritis drugs/therapies exist, increasing the need for preventative strategies. Knee injuries have a high prevalence, distinct onset, and strong independent association with post-traumatic osteoarthritis (PTOA). Numerous groups are embarking upon research that will culminate in clinical trials to assess the effect of interventions to prevent knee PTOA despite challenges and lack of consensus about trial design in this population. Our objectives were to improve awareness of knee PTOA prevention trial design and discuss state-of-the art methods to address the unique opportunities and challenges of these studies. Design: An international interdisciplinary group developed a workshop, hosted at the 2023 Osteoarthritis Research Society International Congress. Here we summarize the workshop content and outputs, with the goal of moving the field of PTOA prevention trial design forward. Results: Workshop highlights included discussions about target population (considering risk, homogeneity, and possibility of modifying osteoarthritis outcome); target treatment (considering delivery, timing, feasibility and effectiveness); comparators (usual care, placebo), and primary symptomatic outcomes considering surrogates and the importance of knee function and symptoms other than pain to this population. Conclusions: Opportunities to test multimodal PTOA prevention interventions across preclinical models and clinical trials exist. As improving symptomatic outcomes aligns with patient and regulator priorities, co-primary symptomatic (single or aggregate/multidimensional outcome considering function and symptoms beyond pain) and structural/physiological outcomes may be appropriate for these trials. To ensure PTOA prevention trials are relevant and acceptable to all stakeholders, future research should address critical knowledge gaps and challenges.

Objective: To examine changes in prevalence and socioeconomic inequalities in knee and hip OA outcomes, in more specific surgery and non-surgery specialist care visits, from 2001 to 2011 in Sweden and to what extent sociodemographic factors can explain the changes. Design: We included all individuals aged ≥35 years resident in Sweden from 2001 to 2011. Individual-level data was retrieved from the Swedish Interdisciplinary Panel. Highest educational attainment was used as socioeconomic measure and the concentration index was used to assess relative and absolute educational inequalities. We used decomposition method to examine changes in prevalence and relative educational inequalities. Results: A total of 4,794,693 and 5,359,186 people were included for the years 2001 and 2011, respectively. The crude prevalence of surgery and specialist visits for knee and hip OA was 36–83% higher in 2011 than in 2001. The increase in hip OA outcomes was largely explained by changes in the sociodemographic composition of the population, whereas for knee OA outcomes, changes in the strength of the associations with sociodemographic factors appeared more important. All outcomes were concentrated among people with lower education in all study years. The relative inequalities declined over the study period, while the absolute inequalities increased for knee OA outcomes and remained stable for hip OA. Conclusion: Our findings show an increasing burden of all studied OA outcomes. Moreover, our findings suggest persistent educational inequalities with more surgeries and specialist visits among lower-educated individuals. Future research should incorporate additional variables to better understand and address these inequalities.

Objectives To identify multimorbidity trajectories over 20 years among incident osteoarthritis (OA) individuals and OA-free matched references.Methods Cohort study using prospectively collected healthcare data from the Skåne region, Sweden (~1.4 million residents). We extracted diagnoses for OA and 67 common chronic conditions. We included individuals aged 40+ years on 31 December 2007, with incident OA between 2008 and 2009. We selected references without OA, matched on birth year, sex, and year of death or moving outside the region. We employed group-based trajectory modelling to capture morbidity count trajectories from 1998 to 2019. Individuals without any comorbidity were included as a reference group but were not included in the model.Results We identified 9846 OA cases (mean age: 65.9 (SD 11.7), female: 58%) and 9846 matched references. Among both cases and references, 1296 individuals did not develop chronic conditions (no-chronic-condition class). We identified four classes. At the study outset, all classes exhibited a low average number of chronic conditions (≤1). Class 1 had the slowest progression towards multimorbidity, which increased progressively in each class. Class 1 had the lowest count of chronic conditions at the end of the follow-up (mean: 2.9 (SD 1.7)), while class 4 had the highest (9.6 (2.6)). The presence of OA was associated with a 1.29 (1.12, 1.48) adjusted relative risk of belonging to class 1 up to 2.45 (2.12, 2.83) for class 4.Conclusions Our findings suggest that individuals with OA face an almost threefold higher risk of developing severe multimorbidity.

Objectives To determine the incidence rate (IR) of myocardial infarction (MI), relative risk of MI, and impact of incident MI on mortality in individuals with biopsy-confirmed giant cell arteritis (GCA).Methods MIs in individuals diagnosed with GCA 1998–2016 in Skåne, Sweden were identified by searching the SWEDEHEART register, a record of all patients receiving care for MI in a coronary care unit (CCU). The regional diagnosis database, with subsequent case review, identified GCA patients receiving care for MI outside of a CCU. A cohort of 10 reference subjects for each GCA case, matched for age, sex and area of residence, was used to calculate the incidence rate ratio (IRR) of MI in GCA to that in the general population.Results The GCA cohort comprised 1134 individuals. During 7958 person-years of follow-up, 102 were diagnosed with incident MI, yielding an IR of 12.8 per 1000 person-years (95% CI 10.3 to 15.3). The IR was highest in the 30 days following GCA diagnosis and declined thereafter. The IRR of MI in GCA to that of the background population was 1.29 (95% CI 1.05 to 1.59). Mortality was higher in GCA patients who experienced incident MI than in those without MI (HR 2.8; 95% CI 2.2 to 3.6).Conclusions The highest incidence of MI occurs within the 30 days following diagnosis of GCA. Individuals with GCA have a moderately increased risk of MI compared with a reference population. Incident MI has a major impact on mortality in GCA.

Abstract Background Comorbidities are common in patients with osteoarthritis (OA). This study aimed to determine the association of a wide range of previously diagnosed comorbidities in adults with newly diagnosed OA compared with matched controls without OA. Methods A case–control study was conducted. The data were derived from an electronic health record database that contains the medical records of patients from general practices throughout the Netherlands. Incident OA cases were defined as patients with one or more diagnostic codes recorded in their medical records that correspond to knee, hip, or other/peripheral OA. Additionally, the first OA code had to be recorded between January 1, 2006, and December 31, 2019. The date of cases’ first OA diagnosis was defined as the index date. Cases were matched (by age, sex, and general practice) to up to 4 controls without a recorded OA diagnosis. Odds ratios were derived for each 58 comorbidities separately by dividing the comorbidity prevalence of cases by that of their matched controls at the index date. Results 80,099 incident OA patients were identified of whom 79,937 (99.8%) were successfully matched with 318,206 controls. OA cases had higher odds for 42 of the 58 studied comorbidities compared with matched controls. Musculoskeletal diseases and obesity showed large associations with incident OA. Conclusions Most of the comorbidities under study had higher odds in patients with incident OA at the index date. While previously known associations were confirmed in this study, some associations were not described earlier.

Objective: To gain new insight into the molecular changes of the meniscus by comparing the proteome profiles of healthy controls with mild degeneration and end-stage osteoarthritis (OA). Method: We obtained tissue plugs from lateral and medial menisci of 37 individuals (central part of the posterior horn) classified as healthy (n ​= ​12), mild signs of joint damage (n ​= ​13) and end-stage OA (n ​= ​12). The protein profile was analysed by nano-liquid chromatography-mass spectrometry using data-independent acquisition and quantified by Spectronaut. Linear-mixed effects modelling was applied to extract the between-group comparisons. Results: A similar protein profile was observed for the mild group as compared to healthy controls while the most different group was end-stage OA mainly for the medial compartment. When a pattern of gradual change in protein levels from healthy to end-stage OA was required, a 42-proteins panel was identified, suggesting a potential role in OA development. The levels of QSOX1 were lower and G6PD higher in the mild group following the proposed protein abundance pattern. Qualitative protein changes suggest lower levels of CYTL1 as a potential biomarker of early joint degradation. Conclusion: For future targeted proteomic approaches, we propose a candidate panel of 42 proteins based on gradually altered meniscal posterior horn protein abundance patterns associated with joint degradation.

Abstract Background Long-term consequences of posterior cruciate ligament (PCL) injury such as persistent posterior tibial translation and risk of osteoarthritis development are unclear. Additionally, little data is available describing the natural history of structural morphology of the ruptured PCL. The purpose of the study was to determine the long-term outcome after non-operatively treated PCL injury. Methods Over 6-years, all acute knee injuries were documented by subacute MRI (median 8 days [5–15, 25th − 75th percentile] from injury to MRI). Twenty-six patients with acute PCL injury were identified of whom 18 (69%) participated in the long-term follow-up after 11 years. Follow-up included radiographic posterior tibial translation (RPTT) determined using the Puddu axial radiograph. weight-bearing knee radiographs, MRI and KOOS (Knee injury and Osteoarthritis Outcome Score). Results On subacute MRI, 11 knees displayed total and 7 partial ruptures. At 11 (SD 1.9) years, the median RPTT was 3.7 mm (1.5–6.3, 25th − 75th percentile). Seven knees displayed radiographic osteoarthritis approximating Kellgren-Lawrence grade ≥ 2. All follow-up MRIs displayed continuity of the PCL. Patients with more severe RPTT (> 3.7 mm), had worse scores in the KOOS subscales for symptoms (mean difference 14.5, 95% CI 7–22), sport/recreation (30, 95% CI 0–65) and quality of life (25, 95% CI 13–57) than those with less severe RPTT (≤ 3.7 mm). This was also the case for the KOOS4 (22, 95% CI 9–34). Conclusion Acute PCL injuries treated non-surgically display a high degree of PCL continuity on MR images 11 years after injury. However, there is a large variation of posterior tibial translation with higher values being associated with poorer patient-reported outcomes.

Abstract We studied the prevalence and patterns of typical long COVID complaints in ~ 2.3 million individuals aged 18–70 years with and without confirmed COVID-19 in a Nation-wide population-based prospective cohort study in Norway. Our main outcome measures were the period prevalence of single-occurring or different combinations of complaints based on medical records: (1) Pulmonary (dyspnea and/or cough), (2) Neurological (concentration problems, memory loss), and/or (3) General complaints (fatigue). In persons testing positive (n = 75 979), 64 (95% confidence interval: 54 to 73) and 122 (111 to 113) more persons per 10 000 persons had pulmonary complaints 5–6 months after the test compared to 10 000 persons testing negative (n = 1 167 582) or untested (n = 1 084 578), respectively. The corresponding difference in prevalence of general complaints (fatigue) was 181 (168 to 195) and 224 (211 to 238) per 10 000, and of neurological complaints 5 (2 to 8) and 9 (6–13) per 10 000. Overlap between complaints was rare. Long COVID complaints were only slightly more prevalent in persons with than without confirmed COVID-19. Still, long COVID may pose a substantial burden to healthcare systems in the future given the lasting high incidence of symptomatic COVID-19 in both vaccinated and unvaccinated individuals.

Abstract Background Previous studies have reported an inverse association between educational attainment and different osteoarthritis (OA) outcomes. However, none of the previous studies have accounted for potential confounding by early-life environment and genetics. Thus, we aimed to examine the association between educational attainment and knee and hip OA surgery using twin data. Methods From the Swedish Twin Registry (STR), we identified dizygotic (DZ) and monozygotic (MZ) twins. All twins in the STR aged 35 to 64 years were followed from January the 1st 1987 or the date they turned 35 years until OA surgery, relocation outside Sweden, death or the end of 2016 (18,784 DZ and 8,657 MZ complete twin pairs). Associations between educational attainment and knee and hip OA surgery were estimated in models matched on twin pairs, using Weibull within-between (WB) shared frailty model. Results For knee OA surgery, the analysis matched on MZ twins yielded a within-estimate hazard ratio (HR) per 3 years of education, of 1.06 (95% CI: 0.81, 1.32), suggesting no association between the outcome and the individual´s education. Rather, there seemed to be a so called familial effect of education, with a between-pair estimate of HR = 0.71 (95% CI: 0.41, 1.01). For hip OA surgery, the within- and between-pair estimates for MZ twins were 0.92 (95% CI: 0.69, 1.14) and 1.15 (95% CI: 0.87, 1.42), respectively. Conclusions Our results suggest that the inverse associations between education and knee/hip OA surgery observed in cohort studies are potentially confounded by unobserved familial factors like genetics and/or early life exposures.

Background and purpose: Concerns exist regarding the generalizability of results from randomized controlled trials (RCTs) evaluating arthroscopic partial meniscectomy (APM) to treat degenerative meniscus tears. It has been suggested that study populations are not representative of subjects selected for surgery in daily clinical practice. Therefore, we aimed to compare patients included in trials and prospective cohort studies that received APM for a degenerative meniscus tear. Patients and methods: Individual participant data from 4 RCTs and 2 cohort studies undergoing APM were collected. 1,970 patients were analyzed: 605 patients included in RCTs and 1,365 included in the cohorts. We compared patient and disease characteristics, knee pain, overall knee function, and health-related quality of life at baseline between the RCT and cohort groups using standardized differences, ratios comparing the variance of continuous covariates, and graphical methods such as quantile–quantile plots, side-by-side boxplots, and non-parametric density plots. Results: Differences between RCT and the cohort were observed primarily in age (younger patients in the cohort; standardized difference: 0.32) and disease severity, with the RCT group having more severe symptoms (standardized difference: 0.38). While knee pain, overall knee function, and quality of life generally showed minimal differences between the 2 groups, it is noteworthy that the largest observed difference was in knee pain, where the cohort group scored 7 points worse (95% confidence interval 5–9, standardized difference: 0.29). Conclusion: Patients in RCTs were largely representative of those in cohort studies regarding baseline scores, though variations in age and disease severity were observed. Younger patients with less severe osteoarthritis were more common in the cohort; however, trial participants still appear to be broadly representative of the target population.

The SARS-CoV-2 Omicron variant is associated with less severe disease but less is known about variant-specific risk of long-term complaints. Monitoring 1.3 million individuals from Norway for post-acute COVID-19 complaints up to 126 days shows that the burden is similar for Omicron and Delta for most complaints except for musculoskeletal pain.

Aim To investigate temporal trends in primary care visits, physiotherapy visits, dispensed non-steroidal anti-inflammatory drugs (NSAIDs) and opioids in knee osteoarthritis (OA) patients who have and have not undergone knee replacement.Methods We analysed 5665 OA patients from the Skåne Healthcare Register, Sweden, who underwent knee replacement between 2015 and 2019. Controls were OA patients without knee replacement, matched 1:1 by sex, age, time and healthcare level of initial OA diagnosis, and assigned a pseudo-index date corresponding to their case’s knee replacement date. Annual prevalence and prevalence ratio of primary care and physiotherapy visits, dispensed NSAIDs and opioids (all for any cause) in the 10 years before knee replacement were estimated using Poisson regression.Results The annual prevalence of all-cause primary care visits, physiotherapy visits and opioid use was similar between cases and controls until 3 years before the index date when it started to increase among the cases. The year before the index date, the prevalence ratio (cases vs controls) for physiotherapy use was 1.8 (95% CI 1.7, 1.8), while for opioid use 1.6 (1.5, 1.7). NSAID use was consistently higher among cases, even 10 years before the index date when the prevalence ratio versus controls was 1.3 (1.2, 1.3), increasing to 1.8 (1.7, 1.9) in the year preceding the index date.Conclusions Management of OA patients who have and have not undergone knee replacement appears largely similar except for higher use of NSAIDs in knee replacement cases. Symptomatic treatments start to increase a few years before the surgery in knee replacement cases.

Abstract Introduction Despite the publication of clinical practice guidelines, the quality of the care process as experienced by patients with osteoarthritis (OA) appears suboptimal. Hence, this study investigates how patients with OA experience their disease and care process, highlighting potential elements that can enhance or spoil it, to optimise their quality of care. Methods A qualitative study based on semi‐structured interviews. Patients with hip and knee OA in Italy were interviewed. The interview guide was created by a pool of health professionals and patients. The interviews were analysed through a theme‐based analysis following a philosophy of descriptive phenomenological research. Results Our analysis revealed seven main themes: (1) Experiencing a sense of uncertainty, as interviewees perceived treatment choices not to be based on medical evidence; (2) Establishing challenging relationships with the self and the other, as they did not feel understood and felt ashamed or hopeless about their condition; (3) Being stuck in one's own or the health professionals' beliefs about the disease management, as a common thought was the perception of movement as something dangerous together with a frequent prescription of passive therapies; (4) Dealing with one's own attitudes towards the disease; Understanding (5) the barriers to and (6) the facilitators of the adherence to therapeutic exercise, which revolve around the therapy cost, the time needed and the patients' willingness to change their life habits and (7) Developing an uneasy relationship with food since the diet was considered as something that “you force yourself to follow” and overeating as a way “to eat your feelings”. Conclusion The lack of clear explanations and a negative attitude towards first‐line nonsurgical treatments (mainly physical exercise), which are considered as a way to fill the time while waiting for surgery, underlines the importance of providing patients with adequate information about OA treatments and to better explain the role of first‐line intervention in the care of OA. This will enhance patient‐centred and shared decision‐making treatments. Patient Contribution Patients with hip and knee OA participated in creating the interview and contributed with their experience of their care process.

Objective: To investigate the associations between incipient dementia (ID) and hospitalization for ambulatory care sensitive conditions (ACSCs) among people with osteoarthritis (OA) of the peripheral joints. Methods: Among individuals aged 51–99 years residing in Skåne, Sweden, in 2009, we identified those with a doctor-diagnosed OA and no dementia during 1998–2009 (n ​= ​57,733). Treating ID as a time-varying exposure, we followed people from January 1, 2010 or their 60th birthday (whichever occurred last) until hospitalization for ACSCs, death, 100th birthday, relocation outside Skåne, or December 31, 2019 (whichever occurred first). Using age as time scale, we applied flexible parametric survival models, adjusted for confounders, to assess the associations between ID and hospitalization for ACSCs. Results: There were 58 and 33 hospitalizations for ACSCs per 1000 person-years among OA people with and without ID, respectively. The association between ID and hospitalization for any ACSCs was age-dependent with higher risk in ages

Objective: To evaluate sick leave after meniscal repair vs arthroscopic partial meniscectomy (APM) and, for comparison, vs the general population. Method: Using Swedish register data we included all employed persons aged 19–49 years in the general population of Skåne region and identified those having had meniscus repair or APM in the period of 2005–2012. We retrieved data on sick leave during 1 year before until 2 years after surgery. We used logistic regression to estimate the risk differences of being on sick leave and negative binomial model to analyze differences in the number of days on sick leave. Results: We included 192 persons with meniscus repair, 2481 with APM, and 376 ​345 references without meniscus surgery. Of these, 55% of meniscus repair group, 43% of APM group had any sick leave in the 2-year period following the surgery, while 17% of the references were on sick leave in the corresponding period. The mean (SD) number of days of sick leave after meniscus repair was 55 (77) days and for APM 37 (86) days. Meniscus repair was associated with higher probability of sick leave compared to APM with an adjusted risk difference of 0.13 (95% CI 0.07–0.19). Conclusion: Persons undergoing meniscus repair have more frequent and 37% longer periods of sick leave in the short term than persons undergoing APM. However, sick leave in the long-term warrant further attention as successful repair may be associated with less knee osteoarthritis development than APM.

Objective To update the epidemiology of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) in a defined geographical area of southern Sweden.Methods The study area comprised 14 municipalities with a combined adult population (≥18 years) of 623 872 in 2019. All cases diagnosed with AAV in 1997–2019 in the study area were included in the estimate of incidence. Diagnosis of AAV was verified by case record review, and cases were classified using the European Medicines Agency algorithm. Point prevalence was estimated on 01 January 2020.Results Three hundred and seventy-four patients (median age 67.5 years, 47% female) were diagnosed with new-onset AAV during the study period. One hundred and ninety-two were classified as granulomatosis with polyangiitis (GPA), 159 as microscopic polyangiitis (MPA) and 23 as EGPA. The average annual incidence/million adults was 30.1 (95% CI 27.0 to 33.1) for AAV: 15.4 (95% CI 13.3 to 17.6) for GPA, 12.8 (95% CI 10.8 to 14.8) for MPA and 1.8 (95% CI 1.1 to 2.6) for eosinophilic GPA (EGPA). Incidence was stable during the study period, 30.3/million 1997–2003, 30.4/million 2004–2011 and 29.5/million 2012–2019. The incidence increased with age and was highest in age group 70–84 years (96/million adults). On 1 January 2020, the prevalence was 428/million adults and was higher in males than in females (480 vs 378/million).Conclusions The incidence of AAV in southern Sweden was found stable over the course of 23 years; while the prevalence has increased, which might indicate better management and treatment of AAV resulting in improved survival.

Objective: To investigate the value of ultrasonographic data in predicting total knee replacement (TKR). Design: Data from the Musculoskeletal Pain in Ullensaker study (MUST) was linked to the Norwegian Arthroplasty Register to form a 5–7 year prospective cohort study of 630 persons (69% women, mean (SD) age 64 (8.7) years). We examined the predictive power of ultrasound (US) features, i.e. osteophytes, meniscal extrusion, synovitis in the suprapatellar recess, femoral cartilage thickness, and quality for future knee osteoarthritis (OA) surgery. We investigated 4 main settings for multivariate predictive modeling: 1) clinical predictors (age, sex, body mass index, knee injury, familial OA and workload), 2) radiographic data (assessed by the Kellgren Lawrence grade, KL) with clinical predictors, 3) US features and clinical predictors. Finally, we also considered an ensemble of models 2) and 3) and used it as our fifth model. All models were compared using the Average Precision (AP) and the Area Under Receiver Operating Characteristic Curve (AUC) metrics. Results: Clinical predictors yielded AP of 0.11 (95% confidence interval [CI] 0.05–0.23) and AUC of 0.69 (0.58–0.79). Clinical predictors with KL grade yielded AP of 0.20 (0.12–0.33) and AUC of 0.81 (0.67–0.90). The clinical variables with ultrasound yielded AP of 0.17 (0.08–0.30) and AUC of 0.79 (0.69–0.86). Conclusion: Ultrasonographic examination of the knee may provide added value to basic clinical and demographic descriptors when predicting TKR. While it does not achieve the same predictive performance as radiography, it can provide additional value to the radiographic examination.

Background and purpose — Meniscal repair may reduce long-term risk of knee osteoarthritis compared with arthroscopic partial meniscectomy (APM), whereas patient-reported outcomes may be poorer at short term than for APM. We compared patient-reported outcomes in young adults undergoing meniscal repair or APM up to ∼5 years after surgery. Patients and methods — We included 150 patients aged 18–40 years from the Knee Arthroscopy Cohort Southern Denmark (KACS) undergoing meniscal repair or APM. Between-group differences in change in a composite of 4 of 5 Knee injury and Osteoarthritis Outcome Score (KOOS) subscales (pain, symptoms, sport and recreation, and quality of life—KOOS4) from baseline, 12, and 52 weeks, and a median of 5 years (range 4–6 years) were analyzed using adjusted mixed linear models, with 52 weeks being the primary endpoint. Results — 32 patients had meniscal repair (mean age 26 [SD 6]), and 118 patients underwent APM (mean age 32 [SD 7]). The repair and APM groups improved in KOOS4 from before to 52 weeks after surgery (least square means 7 and 19, respectively; adjusted mean difference –12, [95% CI –19 to –4] in favor of APM). Both groups improved further from 52 weeks to 5 years after surgery with the difference in KOOS4 scores between the groups remaining similar. Interpretation — Patients having meniscal repair experienced less improvements in patient-reported outcomes from baseline to 52 weeks and 5 years post-surgery. The findings highlight the need for randomized trials comparing these interventions in terms of patient-reported outcomes and knee OA development.

Abstract Carpal tunnel syndrome (CTS) is a common cause of work disability. The association with occupational load and education level has not been established in general-population studies. The purpose of this study was to investigate the association of clinically relevant CTS with work and education. From the Healthcare Register of Skane region (population 1.2 million) in southern Sweden we identified all individuals, aged 17–57 years, with first-time physician-made CTS diagnosis during 2004–2008. For each case we randomly sampled 4 referents, without a CTS diagnosis, from the general population matched by sex, age, and residence. We retrieved data about work and education from the national database. The study comprised 5456 individuals (73% women) with CTS and 21,667 referents. We found a significant association between physician-diagnosed CTS and type of work and level of education in both women and men. Compared with white-collar workers, the odds ratio (OR) for CTS among blue-collar workers was 1.67 (95% CI 1.54–1.81) and compared with light work, OR in light-moderate work was 1.37 (1.26–1.50), moderate work 1.70 (1.51–1.91), and heavy manual labor 1.96 (1.75–2.20). Compared with low-level education, OR for CTS in intermediate level was 0.82 (0.76–0.89) and high-level 0.48 (0.44–0.53). In women and men there is significant association with a dose–response pattern between clinically relevant CTS and increasing manual work load and lower education level. These findings could be important in design and implementation of preventive measures.

Objective: To investigate whether the first wave of the COVID-19 pandemic impacted healthcare consultations (HCC) and hospitalization among people with and without osteoarthritis (OA). Methods: Using register data, we included individuals aged ≥35 years residing in Skåne region, Sweden, during 2009–2019 with (n ​= ​123,523) and without (n ​= ​552,412) a diagnosis of OA during January 1, 2009–December 31, 2019. We collected bi-weekly individual data on HCC/hospitalization between January and May for years 2017–2020. Treating the year 2020 as intervention and 2017–2019 as control as well as dividing data to pre– (January–February) and post–pandemic (March–May), we applied event study design to measure the dynamic effects of the COVID-19 pandemic on HCC/hospitalization. We used fixed-effect Poisson regressions for estimation and subgroup analyses by sex, age, and comorbidity were conducted among OA patients. Results: The impact of the pandemic on healthcare use was evident from mid-March 2020 (34–45%/12–25% reductions in in-person HCC/hospitalization) among people with OA relative to 2017–2019. Smaller reductions were seen in those without OA with 25–34%/8–16% reductions in in-person HCC/hospitalization. On contrary, there were increases in remote HCC following the pandemic (5–25% and 11–31% in people with and without OA, respectively). Among persons with OA, there were variations in the pandemic's effects by sex, age and comorbidity. Conclusion: Despite no lockdown in Sweden there were substantial reductions in in-person healthcare use during the first wave of COVID-19 pandemic with greater reductions among people with than without OA.

Aim: To study the risk of receiving a new (incident) osteoarthritis (OA) diagnosis in different joint sites based on conditions diagnosed in the 20 years prior the OA diagnosis. Methods: We used register data for the entire population of the Skåne region (Sweden) to perform a nested case-control study. The outcome was newly diagnosed (incident) OA in peripheral joints, i.e. knee (ICD-10 code M17), hip (M16) and other joints (M15, M18, M19), diagnosed in 2018 or 2019 in persons aged 45+ years with 20 years of register coverage. For each OA case, we sampled 1 control matched on age (1-year strata), sex and residential area in the year of index date using incidence density sampling. The exposures of interest comprised 50 comorbidities. We used adjusted conditional logistic regression for analysis. Results: Between January 1st, 2018 and December 31st, 2019, we identified 7 201, 2 895, and 7863 persons, respectively, with newly diagnosed knee, hip and other OA. Hypertension, back pain, gout, allergy, depression, anxiety and migraine were all associated with increased risk of knee OA diagnosis, while only gastroesophageal reflux disease and back pain were associated with newly diagnosed hip OA. Interestingly, many of the analysed conditions were associated with increased risk of OA diagnosis in other peripheral joints, including diagnosed generalised OA. Conclusions: The risk of being diagnosed with OA increases with the presence of multimorbidity earlier in life, but the associations seem to differ between weight-bearing and non-weight-bearing joints.

Objectives: To investigate the role of osteoarthritis (OA) in the incidence of musculoskeletal, metabolic, cardiovascular, digestive, neuro-psychological, kidney and other comorbidities/adverse events after (i) incident non-steroidal anti-inflammatory drug (NSAID) initiation and (ii) NSAID discontinuation. Methods: We used register data for the population of Skåne, Sweden. For (i), we analysed the association between starting NSAIDs and the risk of incident outcome events in the 6 years following NSAID dispensation among people with prevalent OA vs no OA. For (ii) we studied the effect of discontinuing NSAIDs among people with and without OA up to 120 days. We used flexible parametric models to estimate adjusted differences in cumulative incidence with NSAIDs as time-varying exposure in the presence of non-proportional hazards. Results: For (i) we included between 243,832 and 409,749 persons. In the whole cohort, over the 6 years of follow-up, NSAID initiation was associated with a 3% (metabolic) to 16% (musculoskeletal) higher cumulative incidence of outcomes compared to non-users. The difference between those initiating NSAIDs vs non-users was similar in those with and without OA for most outcomes, but in those with OA the increase was lower for neuro-psychological (95%CI: 3.7%–4.6% vs 7.1%–7.9%) and musculoskeletal comorbidities (12%–14.5% vs 16.2%–17.2%).In (ii), we found no interaction between OA and NSAID discontinuation. NSAID discontinuation was associated with decreased risks for most of the outcomes, from −1.3% for musculoskeletal to −0.4% for cardiovascular comorbidities. Conclusions: OA appears to have little influence on the increased risk of comorbidities observed after NSAID initiation or decrease after discontinuation.

Objective: To characterize the trend of opioid use (number of users, dispensations and oral morphine milligram equivalents) in Catalonia (Spain).Design, setting, and participants: This population-based cohort study included all individuals aged 18 years or older, registered in the Information System for Research in Primary Care (SIDIAP), which covers >75% of the population in Catalonia, Spain, from 1 January 2007, to 31 December 2019.Main exposure and outcomes: The exposures were all commercialized opioids and their combinations (ATC-codes): codeine, tramadol, oxycodone, tapentadol, fentanyl, morphine, and other opioids (dihydrocodeine, hydromorphone, dextropropoxyphene, buprenorphine, pethidine, pentazocine). The main outcomes were the annual figures per 1,000 individuals of 1) opioid users, 2) dispensations, and 3) oral morphine milligram equivalents (MME). Results were stratified separately by opioid types, age (5-year age groups), sex (male or female), living area (rural or urban), and socioeconomic status (from least, U1, to most deprived, U5). The overall trends were quantified using the percentage change (PC) between 2007 and 2019.Results: Among 4,656,197 and 4,798,114 residents from 2007 to 2019, the number of opioid users, dispensations and morphine milligram equivalents per 1,000 individuals increased 12% (percentage change: 95% confidence interval (CI) 11.9–12.3%), 105% (95% confidence interval 83%–126%) and 339% (95% CI 289%–390%) respectively. Tramadol represented the majority of opioid use in 2019 (61, 59, and 54% of opioid users, dispensations, and total MME, respectively). Individuals aged 80 years or over reported the sharpest increase regarding opioid users (PC: 162%), dispensations (PC: 424%), and MME (PC: 830%). Strong opioids were increasingly prescribed for non-cancer pains over the years.Conclusion: Despite the modest increase of opioid users, opioid dispensations and MME increased substantially, particularly in the older population. In addition, strong opioids were incrementally indicated for non-cancer pains over the years. These findings suggest a transition of opioid prescriptions from intermittent to chronic and weak to strong and call for more rigorous opioid stewardship.

Because of generally small log piles, loading forwarders during thinning is time consuming. The Assortment Grapple, an innovative grapple with an extra pair of claws which facilitates the handling of two assortments during one loading crane cycle, has been designed to decrease forwarders' loading time consumption. A standardized experiment was performed in a virtual thinning stand using a machine simulator with the objectives to form guidelines for working with the Assortment Grapple and to analyse its development potential. Four experienced operators participated in the study. According to the results, the Assortment Grapple's accumulating function is beneficial only when there are no remaining trees between piles loaded during the same crane cycle. In such cases, none of participating operators lost time, and 3 of 4 operators saved time notably. The problem with the remaining trees is the extra time required to steer the crane tip around them. Therefore, a harvester should place those log piles that are later to be forwarded together in the same space with no remaining trees between the piles. Furthermore, we recommend that the Assortment Grapple's usability will be improved by adding an own rocker switch on the forwarder's controls to command the extra claws.

Introduction Osteoarthritis (OA) is one of the leading chronic conditions in the older population. People with OA are more likely to have one or more other chronic conditions than those without. However, the temporal associations, clusters of the comorbidities, role of analgesics and the causality and variation between populations are yet to be investigated. This paper describes the protocol of a multinational study in four European countries (UK, Netherlands, Sweden and Spain) exploring comorbidities in people with OA.Methods and analysis This multinational study will investigate (1) the temporal associations of 61 identified comorbidities with OA, (2) the clusters and trajectories of comorbidities in people with OA, (3) the role of analgesics on incidence of comorbidities in people with OA, (4) the potential biomarkers and causality between OA and the comorbidities, and (5) variations between countries.A combined case–control and cohort study will be conducted to find the temporal association of OA with the comorbidities using the national or regional health databases. Latent class analysis will be performed to identify the clusters at baseline and joint latent class analysis will be used to examine trajectories during the follow-up. A cohort study will be undertaken to evaluate the role of non-steroidal anti-inflammatory drugs (NSAIDs), opioids and paracetamol on the incidence of comorbidities. Mendelian randomisation will be performed to investigate the potential biomarkers for causality between OA and the comorbidities using the UK Biobank and the Rotterdam Study databases. Finally, a meta-analyses will be used to examine the variations and pool the results from different countries.Ethics and dissemination Research ethics was obtained according to each database requirement. Results will be disseminated through the FOREUM website, scientific meetings, publications and in partnership with patient organisations.

Objective To examine the experience of the COVID-19 pandemic as lived by people with hip and knee osteoarthritis (OA), in Italy.Design A qualitative study based on semi-structured interviews.Setting Urban and suburban areas in northern Italy.Participants A total of 11 people with OA were enrolled through a purposeful sampling and completed the study.Primary outcome measure The experience of Italian people with OA during the COVID-19 pandemic.Results Four themes were brought to the forefront from the analysis of the interviews. (1) Being Stressed for the Limited Social Interactions and for the Family Members at High Risk of Infection, as the interviewees were frustrated because they could not see their loved ones or felt a sense of apprehension for their relatives. (2) Recurring Strategies to Cope with the Pandemic such as an active acceptance towards the situation. (3) Being Limited in the Possibility of Undergoing OA Complementary Treatments and Other Routine Medical Visits. (4) Being Unaware of the Importance of Physical Activity as First-Line Interventions which was an attitude already present before the pandemic.Conclusion The COVID-19 pandemic and related restrictions impacted the quality of life and the care of individuals with hip and knee OA. The social sphere seemed to be the most hindered. However, the interviewees developed a good level of acceptance to deal with the pandemic. When it came to their care, they faced a delay of routine medical visits not related to OA and of other complementary treatments (eg, physical therapies) to manage OA. Finally, a controversial result that emerged from these interviews was that first-line interventions for OA (ie, therapeutic exercise) was not sought by the interviewees, regardless of the restrictions dictated by the pandemic. Policy-making strategies are thus necessary to support the awareness of the importance of such interventions.

Abstract Background The research objectives of the 5-year and 10-year assessments in the Finnish degenerative meniscal lesion study (FIDELITY) are twofold: (1) to assess the long-term efficacy of arthroscopic partial meniscectomy (APM) in adults (age 35 to 65 years) with a degenerative meniscus tear and (2) to determine the respective effects of APM and degenerative meniscus tear on the development of radiographic and clinical knee osteoarthritis (OA). Methods and design FIDELITY is an ongoing multi-center, randomized, participant and outcome assessor blinded, placebo-surgery-controlled trial in 146 patients. This statistical analysis plan (SAP) article describes the overall principles for analysis of long-term outcomes (5-year and 10-year follow up), including how participants will be included in each analysis, the primary and secondary outcomes and their respective analyses, adjustments for covariates, and the presentation of the results. In addition, we will present the planned sensitivity and subgroup analyses. Discussion To assess the long-term efficacy of APM on knee symptoms and function we are carrying out a long-term (5-year and 10-year) follow up of our placebo-surgery-controlled FIDELITY trial according to statistical principles outlined in detail in this document. As our second primary objective, whether APM (resection of torn meniscus tear) accelerates or delays the development of knee osteoarthritis in patients with an arthroscopically verified degenerative tear of the medial meniscus, a pre-registered follow-up is also carried out. Trial registration ClinicalTrials.gov, NCT00549172 (Arthroscopy in the Treatment of Degenerative Medial Meniscus Tear). Registered on 25 October 2007 (NCT00549172). ClinicalTrials.gov, NCT01052233 (Development of Knee Osteoarthritis After Arthroscopic Partial Resection of Degenerative Meniscus Tear). Registered on 20 January 2010.

Abstract Objective To estimate the prevalence and incidence of non-gout crystal arthropathy in relation to socioeconomic factors in southern Sweden. Methods All patients (age ≥ 18 years) with at least one visit to a physician with the diagnosis of interest in the Skåne region (population of 1.3 million) in 1998–2014 were identified. Non-gout crystal arthropathy (ICD-10 codes M11.0–M11.9) was subclassified in four different groups: calcium pyrophosphate crystal deposition related arthropathy (CPPD), unspecified non-gout arthropathies, chondrocalcinosis, and hydroxyapatite crystal deposition disease. The crude and age-adjusted point prevalence on December 31, 2014, and the cumulative incidence during 2014 were calculated for all non-gout crystal arthropathies, CPPD, and other unspecified non-gout arthropathies overall and in relation to occupation, income, and level of education. Results The crude 2014 point prevalence (95% CI) and 2014 cumulative incidence (95% CI) of all non-gout crystal arthropathies were 0.23% (0.23–0.24) and 21.5 (19–25) cases/100,000 persons. Mean age (range) among all prevalent cases in 2014 was 71 (20–102) years and 56% were males. The point prevalence and cumulative incidence of CPPD were 0.09% (0.08–0.09) and 8 (7–10)/100,000 persons, respectively. The corresponding data for unspecified non-gout crystal deposition disease was 0.16% (0.16–0.17) and 15.6 (13–18)/100,000 persons, respectively. The prevalence and incidence of CPPD and unspecified non-gout crystal arthropathies were slightly higher in men and increased with age irrespective of gender. Unspecified non-gout crystal arthropathy but not CPPD was less prevalent in persons with ≥ 15 years of education, whereas there were no clear associations with occupation and income. Conclusion The prevalence of all diagnosed non-gout crystal arthropathies was 0.23%, thus considerably less prevalent than gout in southern Sweden. CPPD and other unspecified non-gout crystal arthropathies are the predominant diagnoses, increasing with age and in men. With the exception for unspecified non-gout crystal arthropathies being inversely correlated to a higher level of education, no convincing association with the socioeconomic factors was found.

Abstract Background Gout is the most common inflammatory arthritis with a rising prevalence around the globe. While educational inequalities in incidence and prevalence of gout have been reported, no previous study investigated educational inequality in mortality among people with gout. The aim of this study was to assess absolute and relative educational inequalities in all-cause and cause-specific mortality among people with gout in comparison with an age- and sex-matched cohort free of gout in southern Sweden. Methods We identified all residents aged ≥30 years of Skåne region with doctor-diagnosed gout (ICD-10 code M10, n = 24,877) during 1998–2013 and up to 4 randomly selected age- and sex-matched comparators free of gout (reference cohort, n = 99,504). These were followed until death, emigration, or end of 2014. We used additive hazards models and Cox regression adjusted for age, sex, marital status, and country of birth to estimate slope and relative indices of inequality (SII/RII). Three cause-of-death attribution approaches were considered for RII estimation: “underlying cause”, “any mention”, and “weighted multiple-cause”. Results Gout patients with the lowest education had 1547 (95% CI: 1001, 2092) more deaths per 100,000 person-years compared with those with the highest education. These absolute inequalities were larger than in the reference population (1255, 95% CI: 1038, 1472). While the contribution of cardiovascular (cancer) mortality to these absolute inequalities was greater (smaller) in men with gout than those without, the opposite was seen among women. Relative inequality in all-cause mortality was smaller in gout (RII 1.29 [1.18, 1.41]) than in the reference population (1.46 [1.38, 1.53]). The weighted multiple-cause approach generally led to larger RIIs than the underlying cause approach. Conclusions Our register-based matched cohort study showed that low level of education was associated with increased mortality among gout patients. Although the magnitude of relative inequality was smaller in people with gout compared with those without, the absolute inequalities were greater reflecting a major mortality burden among those with lower education.

Abstract Background It has been suggested that smoking is associated with reduced risk of knee osteoarthritis (OA). However, supplementary studies are needed to further investigate any such potential association. Thus, our aim was to examine the relationship between smoking and early or more established knee OA in a cohort of relatively young patients with meniscal tears. Methods This cross-sectional study included 620 participants from the Knee Arthroscopy Cohort Southern Denmark (KACS) undergoing knee arthroscopy for a meniscal tear (mean age 49.2 (18.0–76.8) years). Recruitment of patients was performed between February 1, 2013, and January 31, 2015, at four different hospitals in Denmark. We defined early or more established knee OA as the combination of patient-reported frequent knee pain, degenerative meniscal tissue and presence of cartilage defects assessed by the operating surgeons. The relationship between smoking status and knee OA was examined by risk ratio (RR) with a 95% confidence interval (CI), estimated from logistic regression adjusted for age, sex, BMI, education, work status and level of physical activity. Results The prevalence of early or more established knee OA was 37.7% in current smokers and 45.0% in non-smokers. We found no statistically significant association between current smoking and knee OA (adjusted RR 1.09, 95% CI 0.91–1.30). Conclusions This study found no relationship between current smoking and early or more established knee OA in a cohort of patients undergoing arthroscopic meniscal surgery. Thus, the inverse association between smoking and knee OA that has been suggested by previous studies was not confirmed.

En recension av Håkan Blomqvists bok Socialism på jiddisch: judiska Arbeter Bund i Sverige (Carlssons, 2020).

Abstract Purpose To investigate the impact of COVID‐19 in Sweden on rates of knee and hip surgeries. Methods We used healthcare data for the population of the southernmost region in Sweden (1.4 million inhabitants). We did an interrupted time‐series analysis to estimate changes in rates and trends of joint replacements (JR), arthroscopies, and fracture surgeries for knee or hip in April–December 2020 compared to pre‐COVID‐19 levels adjusting for seasonal variations. Results We found a drop of 54% (95% CI 42%; 68%) and 42% (95% CI 32%; 52%), respectively, in the rate of JRs and arthroscopies in April 2020 when compared to the counterfactual scenario. This was followed by an increase that brought the rates of JRs and arthroscopies back to their predicted levels also during the beginning of the second wave (November–December 2020). Acute fracture surgeries were largely unaffected, i.e. did not show any decrease as observed for the other surgeries. Conclusions In southern Sweden, we observed a marked decrease in elective knee and hip surgeries following the first wave of Covid‐19. The rates remained close to normal during the beginning of the second wave suggesting that important elective surgeries for patients with end‐stage osteoarthritis can still be offered despite an ongoing pandemic provided adequate routines and hospital resources.

Summary: Introduction: Knee injury history and increased joint load, respectively, are major risk factors for the development of knee osteoarthritis (OA). Lower extremity muscle function, such as knee muscle strength, influence joint load and may be important for the onset of knee OA. However, the role of muscle function as a possible modifiable protective mechanism for the development of OA after anterior cruciate ligament reconstruction (ACLR) is not clear. Methods and analysis: In this prospective cohort study, 100 patients (50% women, 18–35 years) with ACLR will be recruited from Skåne University Hospital, Sweden and Oslo University Hospital, Norway. They will be assessed with a comprehensive test battery of muscle function including muscle strength, muscle activation, hop performance, and postural orientation as well as patient-reported outcomes, one year (baseline) and three years (follow-up) after ACLR. Primary predictor will be knee extension strength, primary outcome will be patient-reported knee pain (Knee injury and Osteoarthritis Outcome Score, subscale pain) and secondary outcomes include compositional MRI (T2 mapping) and turnover of cartilage and bone biomarkers. Separate linear regression model will be used to elucidate the influence of each baseline muscle function variable on the outcomes at follow-up, adjusted for baseline values. Twenty non-injured individuals will also be assessed with MRI. This study is approved by The Regional Ethical Review Board in Lund (Sweden) and Oslo (Norway). Discussion: This study may have important clinical implications for using muscle function to screen for risk of early-onset knee OA and for optimizing exercise therapy after knee injury.

Summary: Objective: There is limited knowledge on sick leave associated with arthroscopic partial meniscectomy (APM) due to traumatic meniscal tear and its potential gender differences. Thus, our aim was to determine gender-specific sick leave before and after APM. Method: In Skåne region, Sweden, we identified patients, aged 18–59 years diagnosed with traumatic meniscal tear without ligament injury, who had APM during 2004–2012. For each patient, we randomly sampled four age- and sex-matched reference subjects from the general population. We retrieved social insurance register data of all-cause sick leave exceeding two weeks. We analyzed the proportions and duration of sick leave with respect to days of sick leave, age, and gender. Results: The cohort comprised 604 patients (29% women), mean (SD) age 40 (11) years, and 2254 reference subjects. Thirty-nine percent of women and 27% of men had a sick leave period longer than 14 days after APM. Still, we found that a new period of sick leave longer than 14 days, initiated on the day of APM (and not before), was relatively uncommon and equally distributed (15%) between women and men. Conclusion: About one-third of the patients have more than 2 weeks of sick leave after APM for a traumatic meniscal tear and women are overrepresented in this category. Prolonged sick leave initiated on the day of APM was relatively uncommon. Other factors than surgery seem to explain the prolonged sick leave.

Summary: Background: Quantitative magnetic resonance imaging (MRI), e.g. relaxation parameter mapping, may be sensitive to structural and compositional tissue changes, and could potentially be used to non-invasively detect and monitor early meniscus degeneration related to knee osteoarthritis. Objective: To investigate MR relaxation times as potential biomarkers for meniscus degeneration through comparisons with histopathology. Methods: We measured MR relaxation parameters in the posterior horn of 40 menisci (medial and lateral) at a wide range of degenerative stages. T1, T2 and T2∗ were mapped using standard and ultrashort echo time sequences at 9.4 T and compared to gold standard histology using Pauli's histopathological scoring system, including assessment of surface integrity, collagen organization, cellularity and Safranin-O staining. Results: All three relaxation times increased with total Pauli score (mean difference per score (95% CI) for T2∗: 0.62 (0.37, 0.86), T2: 0.83 (0.53, 1.1) and T1: 24.7 (16.5, 32.8) ms/score). Clear associations were seen with scores of surface integrity (mean difference per score for T2∗: 3.0 (1.8, 4.2), T2: 4.0 (2.5, 5.5) and T1: 116 (75.6, 156) ms/score) and collagen organization (mean difference between highest and lowest score for T2∗: 5.3 (1.6, 8.9), T2: 6.1 (1.7, 11) and T1: 204 (75.9, 332) ms). The results were less clear for the remaining histopathological measures. Conclusions: MR relaxation times T1, T2 and T2∗ of ex vivo human menisci are associated with histologically verified degenerative processes, in particular related to surface integrity and collagen organization. If confirmed in vivo, MR relaxation times may thus be potential biomarkers for meniscus degeneration.

Abstract Background Musculoskeletal (MSK) disorders are less likely to be reported as an underlying cause of death (UCD) and since cause of death studies are generally limited to the UCD, little is known about socioeconomic inequalities in MSK disorders as cause of death in the general population. Using multiple-cause-of-death data, we aimed to quantify and compare educational inequalities in musculoskeletal (MSK) disorders- with non-MSK disorders-related mortality. Methods All residents aged 30–99 years in the Skåne region, Sweden, during 1998–2013 (n = 999,148) were followed until their 100th birthday, death, relocation outside Skåne, or end of 2014. We identified any mention of rheumatoid arthritis (RA) or other MSK disorders on death certificates using multiple-cause-of-death data. We retrieved and linked individual-level data from Statistics Sweden on highest level of education. We used Cox regression and additive hazards models with age as time-scale adjusted for sex, marital status, and country of birth to calculate slope and relative indices of inequality (SII/RII). Results During a mean follow-up of 12.2 years, there were 1407 (0.8% of all deaths) and 3725 (2.1% of all deaths) death certificates with mention of RA and other MSK disorders, respectively, and 171,798 death certificates without any mention of a MSK disorder. Age-standardized RA mortality rate was 2.2 (95% confidence interval [CI]: 2.0–2.8) times greater in people with 0–9 years of education compared with those with > 12 years of education. Corresponding figure for other MSK disorders was 1.5 (95% CI: 1.4–1.6). Both RIIs and SIIs revealed statistically significant educational inequalities in RA/other MSK disorders mortality favouring high-educated people. The RIIs of MSK disorders-related deaths were generally greater than non-MSK disorders-related deaths. Conclusion We found substantial educational inequality in mortality from MSK disorders. Further research is needed to investigate underlying pathways driving these inequalities.

Introduction Arthroscopic partial meniscectomy (APM) after degenerative meniscus tears is one of the most frequently performed surgeries in orthopaedics. Although several randomised controlled trials (RCTs) have been published that showed no clear benefit compared with sham treatment or non-surgical treatment, the incidence of APM remains high. The common perception by most orthopaedic surgeons is that there are subgroups of patients that do need APM to improve, and they argue that each study sample of the existing trials is not representative for the day-to-day patients in the clinic. Therefore, the objective of this individual participant data meta-analysis (IPDMA) is to assess whether there are subgroups of patients with degenerative meniscus lesions who benefit from APM in comparison with non-surgical or sham treatment.Methods and analysis An existing systematic review will be updated to identify all RCTs worldwide that evaluated APM compared with sham treatment or non-surgical treatment in patients with knee symptoms and degenerative meniscus tears. Time and effort will be spent in contacting principal investigators of the original trials and encourage them to collaborate in this project by sharing their trial data. All individual participant data will be validated for missing data, internal data consistency, randomisation integrity and censoring patterns. After validation, all datasets will be combined and analysed using a one-staged and two-staged approach. The RCTs’ characteristics will be used for the assessment of clinical homogeneity and generalisability of the findings. The most important outcome will be the difference between APM and control groups in knee pain, function and quality of life 2 years after the intervention. Other outcomes of interest will include the difference in adverse events and mental health.Ethics and dissemination All trial data will be anonymised before it is shared with the authors. The data will be encrypted and stored on a secure server located in the Netherlands. No major ethical concerns remain. This IPDMA will provide the evidence base to update and tailor diagnostic and treatment protocols as well as (international) guidelines for patients for whom orthopaedic surgeons consider APM. The results will be submitted for publication in a peer-reviewed journal.PROSPERO registration number CRD42017067240.

Abstract Background Proteomics is an emerging field in the study of joint disease. Our two aims with this pilot analysis were to compare healthy human knee articular cartilage with meniscus, two tissues both known to become affected in the osteoarthritic disease process, and to compare two mass spectrometry (MS)-based methods: data-dependent acquisition (DDA) and data-independent acquisition (DIA). Methods Healthy knee articular cartilage taken from the medial tibial condyle and medial meniscus samples taken from the body region were obtained from three adult forensic medicine cases. Proteins were extracted from tissue pieces and prepared for MS analysis. Each sample was subjected to liquid chromatography (LC)-MS/MS analysis using an Orbitrap mass spectrometer, and run in both DDA and DIA mode. Linear mixed effects models were used for statistical analysis. Results A total of 653 proteins were identified in the DDA analysis, of which the majority was present in both tissue types. Only proteins with quantitation information in both tissues (n = 90) were selected for more detailed analysis, of which the majority did not statistically significantly differ in abundance between the two tissue types, in either of the MS analyses. However, 21 proteins were statistically significantly different (p

Background and purpose — Few data are available regarding structural changes present in knees without radiographically evident osteoarthritis (OA). We evaluated the prevalence of findings suggestive of knee OA by magnetic resonance imaging (MRI) in middle-aged subjects without radiographic OA with or without OA risk factors. Patients and methods — 340 subjects from the Osteoarthritis Initiative, aged 45–55 years (51% women) with Kellgren–Lawrence grade 0 in both knees, who had 3T knee MR images were eligible. 294 subjects had risk factors and 46 were without risk factors. MR images were assessed using the MOAKS scoring system. Results — At least 1 MR-detected feature was found in 96% (283/294) of subjects with risk factors and in 87% (40/46) of those without. Cartilage damage (82%), bone marrow lesions (60%), osteophytes (45%), meniscal body extrusion (32%), and synovitis–effusion (29%) were the most common findings in subjects with risk factors, while cartilage damage (67%), osteophytes (46%), meniscal body extrusion (37%), and bone marrow lesions (35%) were most common in subjects without. The prevalence of any abnormality was higher in subjects with OA risk factors than in subjects without (prevalence ratio adjusted for age and sex 1.3 [95% CI 1.1–1.6]), so was prevalence of subchondral cysts and bone marrow lesions. MR-detected structural changes were more frequent in patellofemoral joints. Interpretation — Our findings highlight the great challenge in distinguishing pathological features of early knee OA from what could be considered part of “normal ageing.” Bone marrow lesions were more frequently found in subjects with multiple OA risk factors.

Abstract Background Hyperuricemia (HU) is in the causal pathway for developing clinical gout. There are few population-based assessments of the absolute and relative risk of clinically diagnosed incident gout in subjects with HU. We aimed to explore the long-term risk of developing incident gout among asymptomatic adults with different levels of serum urate (SU). Methods Malmö Preventive Project was a population-based screening program for cardiovascular risk factors, alcohol abuse, and breast cancer in Malmö, Sweden. The study population was screened between 1974 and 1992. At baseline, subjects were assessed with a questionnaire, physical examination, and laboratory tests. Follow-up ended at first gout diagnosis, death, moving from area, or December 31, 2014. Incident gout (using ICD10 codes) was diagnosed based on national registers for specialized inpatient and outpatient care, and from 1998 onward in the Skåne Healthcare Register including primary healthcare. Incidence rates, absolute risk, hazard ratios (HRs) and potentially associated factors were analyzed by baseline SU levels, i.e. normal levels (≤ 360 μmol/L); 361–405 (levels below tissue solubility of SU), and > 405 (HU), overall, and by sex. Results Overall, 1275 individuals [3.8%; 1014 men (4.5%) and 261 women (2.4%)] of the 33,346 study participants (mean age: 45.7 (SD: 7.4), 67% men), developed incident gout during follow-up (mean 28.2 years). Of those with HU, 14.7% of men and 19.5% of women developed gout. Compared to subjects in the lowest SU category, the age-adjusted HR in men increased from 2.7 to 6.4, and in women from 4.4 to 13.1 with increasing baseline SU category, and with a statistically significant interaction of sex (p

Abstract Background Knee arthroscopy is one of the most common surgical procedures worldwide and the number of arthroscopies has substantially increased in the last 30 years. Thus, our aim was to provide updated estimates on the risk of complications and compare it with the background risk in the general population. Methods We identified patients aged 15–84 years with knee arthroscopy in the years 2005–2016 in southern Sweden. We calculated the risk of pyogenic arthritis, venous thromboembolism, and other typical complications within 30 days. As a reference cohort we included the regional population in the corresponding age interval. We estimated the relative and absolute risks of complications compared to the reference cohort using logistic regression adjusted for age, sex, and level of education. We also estimated the proportion of complications in the population explained by knee arthroscopy (population attributable fraction). Results We identified 18,735 knee arthroscopy patients (mean age 39 years) and 1,171,084 reference subjects (mean age 46 years). The absolute risk of one or more complications was 1.1% after knee arthroscopy and 0.16% in references. The odds ratio of any complication after knee arthroscopy vs. the reference cohort was 9.4 (95% confidence interval [CI] 8.1, 10.9) with an absolute risk difference of 1.4% (1.1, 1.6%). The relative risk (95% CI) for pyogenic arthritis was 115 (75, 174), venous thromboembolism 6.8 (5.1, 9.1), and other complications 7.7 (6.3, 9.5). The population attributable fraction for pyogenic arthritis was 5%. Conclusions The absolute risks of complications associated with knee arthroscopy remain small at about 1%. Still, 5% of all pyogenic knee arthritis cases in adults are attributable to knee arthroscopy, thus risks with knee arthroscopy should be carefully considered in the choice of treatment.

Background and purpose — Osteoarthritis (OA) imposes a substantial burden on individuals and societies. We report on the burden of knee and hip OA in the Nordic region. Patients and methods — We used the findings from the 2015 Global Burden of Diseases Study to explore prevalence, years lived with disability (YLDs), and disability-adjusted life-years (DALYs) of OA in the 6 Nordic countries during 1990–2015 (population of about 27 million in 2015). Results — During 1990–2015, the number of prevalent OA cases increased by 43% to 1,507,587 (95% uncertainty interval [UI] 1,454,338–1,564,778) in the region. OA accounted for 1.3% (UI 1.0–1.7) of YLDs in 1990, increasing to 1.6% (UI 1.2–2.0) in 2015. Of 315 causes studied, OA was the 15th leading cause of YLDs, causing 52,661 (UI 34,056–77,499) YLDs in 2015; of these 23% were attributable to high body mass index. The highest relative importance of OA was reported for women aged 65–74 years (8th leading cause of YLDs in 2015). Among the top 30 leading causes of YLDs in the region, OA had the 5th greatest relative increase in total YLDs during 1990–2015. From 1990 to 2015, increase in age-standardized YLDs from OA in the region was slightly lower than increase at the global level (7.5% vs. 10.5%). OA was, however, responsible for a higher proportional burden of DALYs in the region compared with the global level. Interpretation — The OA burden is high and rising in the Nordic region. With population growth, aging, and the obesity epidemic, a substantial rise in the burden of OA is expected and should be addressed in health policies.

Abstract Background A distal forearm fracture is a very common injury causing both suffering and substantial health care costs. The incidence of this fracture type seemed to increase worldwide until the middle 1980’s, but thereafter most reports have shown stable or decreasing rates. As few large studies have been presented lately we aimed to describe recent epidemiology and time trends of distal forearm fractures in adults. We paid special attention to fractures in working ages as they present challenges in terms of treatment and costs for sick-leave, and have not previously been thoroughly investigated. Methods By use of population data from Statistics Sweden and official in- and out-patient register data of men and women (≥17 years) in Sweden (Skåne region), we ascertained distal forearm fractures and estimated age- and sex-specific rates and time-trends from year 1999 to 2010 (11.2 million person-years (py)). Results The total incidence rate was 278 per 100,000 py (31,233 fractures) with 23% higher annual numbers 2010 compared with 1999. An increase in the annual age standardized incidence was found in men, +0.7% per annum (95% confidence interval (CI) 0.1, 1.4), and women, +0.9% (95% CI 0.5, 1.3), driven mainly by an increasing incidence in working ages (17–64 years). Also, expected demographic changes including a 25% population increase may result in 38% more fractures until 2050, compared to 2017. Conclusions The incidence of distal forearm fractures in adults in southern Sweden is increasing, mainly driven by an increase in working ages. In combination with expected demographic changes these findings may present substantial challenges for the future.