Participation in a digital self-management intervention for osteoarthritis and socioeconomic inequalities in patient-related outcomes.

OBJECTIVE: To investigate changes in socioeconomic inequalities in patient-related outcomes and pain medication use, following participation in a digital self-management intervention for osteoarthritis (OA) in Sweden. METHOD: Participants with hip/knee OA enrolled in the digital intervention were included. Self-reported outcomes collected were the numerical rating scale (NRS) pain, activity impairment, general health, Knee/Hip injury and Osteoarthritis Outcome Score (KOOS-12, HOOS-12) Pain, Function, and Quality of Life subscales, 5-level EuroQol 5 Dimensions (EQ-5D-5L), Patient Acceptable Symptom State (PASS) for function, walking difficulties, fear of movement, wish for surgery, pain medication use, physical function measured by the 30s chair-stand test, and level of physical activity. Educational attainment was used as a socioeconomic measure and the concentration index was used to assess the magnitude of inequalities at baseline and 3 month follow-up. RESULTS: The study included 21,688 participants (mean ± sd age 64.1 ± 9.1 years, 74.4% females). All outcomes except for PASS demonstrated inequalities in favour of highly educated participants at both time-points, with highly educated participants reporting better outcomes. At 3 month follow-up, the magnitude of inequality widened for activity impairment, but narrowed for NRS pain, EQ-5D-5L, KOOS-12/HOOS-12 Pain and Function, physical function, and wish for surgery. There were no statistically conclusive changes in the magnitude of inequalities for the remaining outcomes. CONCLUSIONS: There were inequalities in patient-related outcomes in favour of those with higher education among participants of a digital self-management intervention for OA, although the magnitude of these pre-existing inequalities generally narrowed after the 3 month intervention.

Bariatric surgery, osteoarthritis and arthroplasty of the hip and knee in Swedish Obese Subjects - up to 31 years follow-up of a controlled intervention study.

OBJECTIVE: To study the long-term effect of obesity and bariatric surgery on incidences of osteoarthritis and arthroplasty of hip and knee. DESIGN: Hazard ratios (HR) and incidence rates (IR) of osteoarthritis and arthroplasty of hip and knee were studied in the prospective, controlled, non-randomized Swedish Obese Subjects (SOS) study (bariatric surgery group, n = 2007; matched controls given usual obesity care, n = 2040) and the SOS reference cohort (n = 1135, general population). Osteoarthritis diagnosis and arthroplasty for osteoarthritis were captured from the National Swedish Patient Register. Median follow-up time was 21.2 (IQR 16.4-24.8), 22.9 (IQR 19.1-25.7), and 20.1 years (IQR 18.7-20.9) for the control group, surgery group and reference cohort, respectively. RESULTS: The surgery group displayed lower incidence of hip osteoarthritis (IR 5.3, 95% CI 4.7-6.1) compared to controls (IR 6.6, 95% CI 5.9-7.5, adjHR 0.83, 95% CI 0.69-1.00) but similar incidence of hip arthroplasty. Similar incidence of knee osteoarthritis was observed in the surgery group and controls, but knee arthroplasty was more common in the surgery group (IR 7.4, 95% CI 6.6-8.2 and 5.6, 95% CI 4.9-6.4, adjHR 1.45, 95% CI 1.22-1.74). The reference cohort displayed lower incidences of osteoarthritis and arthroplasty of hip and knee compared with the surgery group and controls. CONCLUSION: Bariatric surgery did not normalize the increased risk of knee and hip osteoarthritis in patients with obesity but was associated with an increased incidence of knee arthroplasty compared to the control group. With the limitations inherent to the present data, additional studies are needed to confirm these results. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01479452.

Is meniscal status in the anterior cruciate ligament injured knee associated with change in bone surface area? An exploratory analysis of the KANON trial.

OBJECTIVES: To study bone shape changes as a potential early feature of post-traumatic structural knee OA development, we estimated the association between meniscal status in the anterior cruciate ligament (ACL) injured knee and longitudinal condyle changes in bone surface area. DESIGN: We used data from the KANON trial, including 121 young ACL-injured adults. We obtained baseline and 2-year follow-up knee MRIs. Our outcome was change in the bone surface areas (mean mm2, log-transformed) in 4 locations (femur, tibia, patella, and trochlea femur) in the medial and lateral compartment from baseline to 2 years. Meniscal pathology was defined as both present at baseline and newly developed (i.e., incident or progressed) using ACLOAS. We used multilevel linear regression adjusted for baseline bone area, age, sex, body mass index, treatment arm (i.e., early or optional delayed ACL reconstruction), and location. We analyzed medial and lateral compartment separately. We present results as percentage (%) bone area change difference with 95% confidence intervals (CI). RESULTS: We analyzed 109 subjects (median 27 (18-36) years, 83% men) due to missing MRI information. The bone surface area increased on average by ∼2% over 2 years. The differences between knees with and without baseline meniscal pathology were 1.1% (95%CI 0.0-2.3%) and 1.4% (95%CI 0.6-2.2%) in the medial and lateral compartment, respectively, and 1.2% (95%CI 0.3-2.0%) and 1.3% (95%CI 0.6-2.0%) for medial and lateral newly developed pathology, respectively. CONCLUSION: Our finding of ∼1% increase bone area in compartment with meniscal pathology suggests a potentially important association between meniscal integrity and early bone surface area changes after ACL injury. Trial registration number ISRCTN 84752559.

Importance of patellofemoral and tibiofemoral cartilage lesions on trajectory of self-reported outcomes in patients at high risk of knee OA: 4-6 years follow-up of patients undergoing meniscal surgery.

OBJECTIVE: We evaluated whether patient-reported outcome trajectories (i.e., changes over time) differed by intraoperative compartmental cartilage lesion pattern over 4-6 years following arthroscopic meniscal surgery. METHODS: In this ancillary study of the Knee Arthroscopy Cohort Southern Denmark cohort, we intraoperatively categorized cartilage lesions as isolated patellofemoral, isolated tibiofemoral, or combined patellofemoral/tibiofemoral. Participants completed the Knee injury and Osteoarthritis Outcome Score (KOOS) pre-operatively, at 3 and 12 months, and at 4-6 years post-operatively and reported overall satisfaction at final follow-up. Our main outcome was KOOS4 (grand mean of four subscale means). We evaluated whether KOOS4 scores changed over time according to cartilage lesion patterns using adjusted mixed linear regression. We also estimated probability of treatment satisfaction using logistic regression. RESULTS: Of 630 participants with complete cartilage scores, 280 (44%) were women, mean (standard deviation) age was 49 (13) years, and BMI was 27.3 (4.4) kg/m2. KOOS4 scores at baseline were slightly lower in all lesion groups compared to the no lesion group, yet only the combined group was statistically significantly lower. KOOS4 trajectories were similar across cartilage lesion patterns, but by final follow-up, adjusted mean KOOS4 scores were 6.8 (95% CI 2.2, 11.4) to 9.8 (1.1, 18.5) points lower in groups with cartilage lesions compared to the no lesion group. Probability of patient-reported satisfaction did not differ statistically by group. CONCLUSIONS: Though KOOS4 scores were slightly lower in groups with arthroscopically assessed cartilage lesions compared to the no lesion group, trajectories were similar across all groups.

Fracture risk after three bariatric surgery procedures in Swedish obese subjects: up to 26 years follow-up of a controlled intervention study.

BACKGROUND: Previous studies have reported an increased fracture risk after bariatric surgery. OBJECTIVE: To investigate the association between different bariatric surgery procedures and fracture risk. METHODS: Incidence rates and hazard ratios for fracture events were analysed in the Swedish Obese Subjects study; an ongoing, nonrandomized, prospective, controlled intervention study. Hazard ratios were adjusted for risk factors for osteoporosis and year of inclusion. Information on fracture events were captured from the Swedish National Patient Register. The current analysis includes 2007 patients treated with bariatric surgery (13.3% gastric bypass, 18.7% gastric banding, and 68.0% vertical banded gastroplasty) and 2040 control patients with obesity matched on group level based on 18 variables. Median follow-up was between 15.1 and 17.9 years for the different treatment groups. RESULTS: During follow-up, the highest incidence rate for first-time fracture was observed in the gastric bypass group (22.9 per 1000 person-years). The corresponding incidence rates were 10.4, 10.7 and 9.3 per 1000 person-years for the vertical banded gastroplasty, gastric banding and control groups, respectively. The risk of fracture was increased in the gastric bypass group compared with the control group (adjusted hazard ratio [adjHR] 2.58; 95% confidence interval [CI] 2.02-3.31; P < 0.001), the gastric banding group (adjHR 1.99; 95%CI 1.41-2.82; P < 0.001), and the vertical banded gastroplasty group (adjHR 2.15; 95% CI 1.66-2.79; P < 0.001). CONCLUSIONS: The risk of fracture is increased after gastric bypass surgery. Our findings highlight the need for long-term follow-up of bone health for patients undergoing this treatment.

Molecular and imaging biomarkers of local inflammation at 2 years after anterior cruciate ligament injury do not associate with patient reported outcomes at 5 years.

OBJECTIVE: To estimate the association between molecular or imaging inflammatory biomarkers at 2 years after anterior cruciate ligament (ACL) injury and patient-reported outcomes at 5 years. METHODS: For 116 ACL-injured patients, molecular biomarkers of inflammation (synovial fluid and serum cytokines) and Hoffa- and effusion-synovitis as visualized on magnetic resonance imaging (MRI) were assessed 2 years post-injury. Knee injury and Osteoarthritis Outcome Score (KOOS) and SF-36 were assessed at 2 and 5 years. We used multiple imputation to handle biomarker values that were below the level of detection or missing, and linear regression for statistical analyses. RESULTS: None of the synovial fluid cytokines or imaging biomarkers of inflammation at 2 years were associated with any of the patient-reported outcomes at 5 years. With each log10 unit higher of serum tumor necrosis factor concentration the knee-related quality of life of KOOS was increased (i.e., better outcome) by 35 (95% confidence interval 7 to 63) points. No other serum biomarker measured at 2 years was associated with patient-reported outcome at 5 years. CONCLUSION: Local joint inflammation assessed by biomarkers in synovial fluid and Hoffa- and effusion-synovitis on MRI at 2 years after an ACL injury did not associate with patient-reported outcomes at 5 years. Thus, chronic inflammation in the ACL-injured knee, as reflected by the biomarkers studied here, seems not to be a key determinant for the long-term patient-reported outcomes.

Marked and rapid change of bone shape in acutely ACL injured knees - an exploratory analysis of the Kanon trial.

BACKGROUND: To investigate changes in knee 3D bone shape over the first 5 years after acute anterior cruciate ligament (ACL) injury in participants of the randomized controlled KANON-trial. METHODS: Serial MR images over 5 years from 121 young (32 women, mean age 26.1 years) adults with an acute ACL tear in a previously un-injured knee were analyzed using statistical shape models for bone. A matched reference cohort of 176 individuals was selected from the Osteoarthritis Initiative (OAI). Primary endpoint was change in bone area of the medial femoral condyle; exploratory analyses compared results by treatment and examined other knee regions. Comparisons were made using repeated measures mixed model ANOVA with adjustment for age, sex and body mass index (BMI). RESULTS: Mean medial femur bone area increased 3.2% (78.0 [95% CI 70.2 to 86.4] mm2) over 5 years after ACL injury and most prominently in knees treated with ACL reconstruction (ACLR). A higher rate of increase occurred over the first 2 years compared to the latter 3-years (66.2 [59.3 to 73.2] vs 17.6 [12.2 to 23.0] mm2) and was 6.7 times faster than in the reference cohort. The pattern and location of shape change in the extrapolated KANON data was very similar to that observed in another knee-osteoarthritis cohort. CONCLUSION: 3D shape modelling after acute ACL injury revealed rapid bone shape changes, already evident at 3 months. The bone-change pattern after ACL injury demonstrated flattening and bone growth on the outer margins of the condyles similar to that reported in established knee osteoarthritis.

Towards prevention of post-traumatic osteoarthritis: report from an international expert working group on considerations for the design and conduct of interventional studies following acute knee injury.

OBJECTIVE: There are few guidelines for clinical trials of interventions for prevention of post-traumatic osteoarthritis (PTOA), reflecting challenges in this area. An international multi-disciplinary expert group including patients was convened to generate points to consider for the design and conduct of interventional studies following acute knee injury. DESIGN: An evidence review on acute knee injury interventional studies to prevent PTOA was presented to the group, alongside overviews of challenges in this area, including potential targets, biomarkers and imaging. Working groups considered pre-identified key areas: eligibility criteria and outcomes, biomarkers, injury definition and intervention timing including multi-modality interventions. Consensus agreement within the group on points to consider was generated and is reported here after iterative review by all contributors. RESULTS: The evidence review identified 37 studies. Study duration and outcomes varied widely and 70% examined surgical interventions. Considerations were grouped into three areas: justification of inclusion criteria including the classification of injury and participant age (as people over 35 may have pre-existing OA); careful consideration in the selection and timing of outcomes or biomarkers; definition of the intervention(s)/comparator(s) and the appropriate time-window for intervention (considerations may be particular to intervention type). Areas for further research included demonstrating the utility of patient-reported outcomes, biomarkers and imaging outcomes from ancillary/cohort studies in this area, and development of surrogate clinical trial endpoints that shorten the duration of clinical trials and are acceptable to regulatory agencies. CONCLUSIONS: These considerations represent the first international consensus on the conduct of interventional studies following acute knee joint trauma.

OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis.

OBJECTIVE: To update and expand upon prior Osteoarthritis Research Society International (OARSI) guidelines by developing patient-focused treatment recommendations for individuals with Knee, Hip, and Polyarticular osteoarthritis (OA) that are derived from expert consensus and based on objective review of high-quality meta-analytic data. METHODS: We sought evidence for 60 unique interventions. A systematic search of all relevant databases was conducted from inception through July 2018. After abstract and full-text screening by two independent reviewers, eligible studies were matched to PICO questions. Data were extracted and meta-analyses were conducted using RevMan software. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Evidence Profiles were compiled using the GRADEpro web application. Voting for Core Treatments took place first. Four subsequent voting sessions took place via anonymous online survey, during which Panel members were tasked with voting to produce recommendations for all joint locations and comorbidity classes. We designated non-Core treatments to Level 1A, 1B, 2, 3, 4A, 4B, or 5, based on the percentage of votes in favor, in addition to the strength of the recommendation. RESULTS: Core Treatments for Knee OA included arthritis education and structured land-based exercise programs with or without dietary weight management. Core Treatments for Hip and Polyarticular OA included arthritis education and structured land-based exercise programs. Topical non-steroidal anti-inflammatory drugs (NSAIDs) were strongly recommended for individuals with Knee OA (Level 1A). For individuals with gastrointestinal comorbidities, COX-2 inhibitors were Level 1B and NSAIDs with proton pump inhibitors Level 2. For individuals with cardiovascular comorbidities or frailty, use of any oral NSAID was not recommended. Intra-articular (IA) corticosteroids, IA hyaluronic acid, and aquatic exercise were Level 1B/Level 2 treatments for Knee OA, dependent upon comorbidity status, but were not recommended for individuals with Hip or Polyarticular OA. The use of Acetaminophen/Paracetamol (APAP) was conditionally not recommended (Level 4A and 4B), and the use of oral and transdermal opioids was strongly not recommended (Level 5). A treatment algorithm was constructed in order to guide clinical decision-making for a variety of patient profiles, using recommended treatments as input for each decision node. CONCLUSION: These guidelines offer comprehensive and patient-centered treatment profiles for individuals with Knee, Hip, and Polyarticular OA. The treatment algorithm will facilitate individualized treatment decisions regarding the management of OA.

Change in patient-reported outcomes in patients with and without mechanical symptoms undergoing arthroscopic meniscal surgery: A prospective cohort study.

OBJECTIVE: Patients with degenerative or traumatic meniscal tears are at high risk of developing knee osteoarthritis. We investigated if younger (≤40 years) and older (>40 years) patients with preoperative mechanical symptoms (MS) improved more in patient-reported outcomes after meniscal surgery than those without MS. DESIGN: Patients from Knee Arthroscopy Cohort Southern Denmark (KACS) undergoing arthroscopic surgery for a meniscal tear completed online questionnaires before surgery, and at 12 and 52 weeks follow-up. Questionnaires included self-reported presence of MS (i.e., sensation of catching and/or locking) and the Knee injury and Osteoarthritis Outcome Score (KOOS). We analyzed between-group differences in change in KOOS4 from baseline to 52 weeks, using an adjusted mixed linear model. RESULTS: 150 younger patients (mean age 31 (SD 7), 67% men) and 491 older patients (mean age 54 (SD 9), 53% men) constituted the baseline cohorts. Patients with MS generally had worse self-reported outcomes before surgery. At 52 weeks follow-up, younger patients with preoperative MS had improved more in KOOS4 scores than younger patients without preoperative MS (adjusted mean difference 10.5, 95% CI: 4.3, 16.6), but did not exceed the absolute postoperative KOOS4 scores observed for those without MS. No difference in improvement was observed between older patients with or without MS (adjusted mean difference 0.7, 95% CI: -2.6, 3.9). CONCLUSIONS: Younger patients (≤40 years) with preoperative MS experienced greater improvements after arthroscopic surgery compared to younger patients without MS. Our observational study result needs to be confirmed in randomized trials.

Factors associated with the orthopaedic surgeon's decision to recommend total joint replacement in hip and knee osteoarthritis: an international cross-sectional study of 1905 patients.

OBJECTIVE: To determine factors associated with orthopaedic surgeons' decision to recommend total joint replacement (TJR) in people with knee and hip osteoarthritis (OA). DESIGN: Cross-sectional study in eleven countries. For consecutive outpatients with definite hip or knee OA consulting an orthopaedic surgeon, the surgeon's indication of TJR was collected, as well as patients' characteristics including comorbidities and social situation, OA symptom duration, pain, stiffness and function (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), joint-specific quality of life, Osteoarthritis Research Society International (OARSI) joint space narrowing (JSN) radiographic grade (0-4), and surgeons' characteristics. Univariable and multivariable logistic regressions were performed to identify factors associated with the indication of TJR, adjusted by country. RESULTS: In total, 1905 patients were included: mean age was 66.5 (standard deviation [SD], 10.8) years, 1082 (58.0%) were women, mean OA symptom duration was 5.0 (SD 7.0) years. TJR was recommended in 561/1127 (49.8%) knee OA and 542/778 (69.7%) hip OA patients. In multivariable analysis on 516 patients with complete data, the variables associated with TJR indication were radiographic grade (Odds Ratio, OR for one grade increase, for knee and hip OA, respectively: 2.90, 95% confidence interval [1.69-4.97] and 3.30 [2.17-5.03]) and WOMAC total score (OR for 10 points increase: 1.65 [1.32-2.06] and 1.38 [1.15-1.66], respectively). After excluding radiographic grade from the analyses, on 1265 patients, greater WOMAC total score was the main predictor for knee and hip OA; older age was also significant for knee OA. CONCLUSION: Radiographic severity and patient-reported pain and function play a major role in surgeons' recommendation for TJR.

Harmonising measures of knee and hip osteoarthritis in population-based cohort studies: an international study.

OBJECTIVE: Population-based osteoarthritis (OA) cohorts provide vital data on risk factors and outcomes of OA, however the methods to define OA vary between cohorts. We aimed to provide recommendations for combining knee and hip OA data in extant and future population cohort studies, in order to facilitate informative individual participant level analyses. METHOD: International OA experts met to make recommendations on: 1) defining OA by X-ray and/or pain; 2) compare The National Health and Nutrition Examination Survey (NHANES)-type OA pain questions; 3) the comparability of the Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) scale to NHANES-type OA pain questions; 4) the best radiographic scoring method; 5) the usefulness of other OA outcome measures. Key issues were explored using new analyses in two population-based OA cohorts (Multicenter Osteoarthritis Study; MOST and Osteoarthritis Initiative OAI). RESULTS: OA should be defined by both symptoms and radiographs, with symptoms alone as a secondary definition. Kellgren and Lawrence (K/L) grade ≥2 should be used to define radiographic OA (ROA). The variable wording of pain questions can result in varying prevalence between 41.0% and 75.4%, however questions where the time anchor is similar have high sensitivity and specificity (91.2% and 89.9% respectively). A threshold of 3 on a 0-20 scale (95% CI 2.1, 3.9) in the WOMAC pain subscale demonstrated equivalence with the preferred NHANES-type question. CONCLUSION: This research provides recommendations, based on expert agreement, for harmonising and combining OA data in existing and future population-based cohorts.

Hip complaints differ across age and sex: a population-based reference data for the Hip disability and Osteoarthritis Outcome Score (HOOS).

BACKGROUND: The Hip disability and Osteoarthritis Outcome Score (HOOS) is a self-administered hip-specific questionnaire intended to evaluate symptoms and functional limitations, and it is commonly used to evaluate interventions in individuals with hip dysfunction or hip osteoarthritis. The HOOS consists of 43 questions in five subscales: Pain, Symptoms, Function in daily living, Function in sport and recreation and Hip-Related Quality of Life. This study aimed to establish population-based reference values for the HOOS and to describe the variation of hip-related symptoms in an adult population. METHODS: The HOOS questionnaire was mailed to 840 individuals aged 18-84 years randomly retrieved from a national population record for the Skåne region of Southern Sweden. RESULTS: The overall response rate was 67%. Older women and men consistently reported more hip-related complaints than those younger. There were significant differences between the oldest and the youngest age groups in all five subscales in women and men. CONCLUSIONS: Hip-related pain, symptoms, activity of daily life and quality of life varied with age and sex in this population-based cohort. Our findings show the importance of using age- and sex-matched reference values for evaluation of outcomes after interventions due to hip-related problems.

Surgical reconstruction of ruptured anterior cruciate ligament prolongs trauma-induced increase of inflammatory cytokines in synovial fluid: an exploratory analysis in the KANON trial.

OBJECTIVE: Prospectively monitor how treatment of acutely ruptured anterior cruciate ligament (ACL) affects biomarkers of inflammation and proteolytic degradation over 5 years. DESIGN: We studied 119 subjects with acute ACL injury from the randomized controlled knee anterior cruciate ligament, non-surgical versus surgical treatment (KANON)-trial (Clinical trial ISRCTN 84752559) who had synovial fluid, serum and urine samples available from at least two out of six visits over 5 years after acute ACL rupture. All subjects followed a similar rehabilitation protocol where, according to randomization, 60 also had early ACL reconstruction and 59 had the option to undergo a delayed ACL reconstruction if needed. Interleukin (IL)-6, IL-8, IL-10, interferon-gamma (IFNγ), tumor necrosis factor (TNF), amino acids alanine, arginine, glycine, serine (ARGS)-aggrecan, C-terminal crosslinking telopeptide type II collagen (CTX-II) and N-terminal crosslinking telopeptide type I collagen (NTX-I) were quantified by enzyme-linked immunosorbent assays (ELISA). RESULTS: Subjects randomized to early ACL reconstruction had higher cytokine concentrations in index knee synovial fluid at 4 months (IL-6, IL-8, IL-10, TNF), 8 months (IL-6 and TNF) and at 5 years (IFNγ) compared to those randomized to optional delayed reconstruction. Those that underwent delayed ACL reconstruction within 5 years (30 subjects), had higher synovial fluid concentrations of IL-6 at 5 years compared to those treated with rehabilitation alone. No differences between groups were noted for ARGS-aggrecan in synovial fluid and serum or CTX-II and NTX-I in urine over 5 years, neither as randomized nor as treated. CONCLUSIONS: Surgical ACL reconstruction constitutes a second trauma to the acutely injured joint resulting in a prolonged elevation of already high synovial fluid levels of inflammatory cytokines.

Association between statin use and consultation or surgery for osteoarthritis of the hip or knee: a pooled analysis of four cohort studies.

OBJECTIVE: Experimental findings and previous observational data have suggested lower risk of osteoarthritis (OA) with statin use but results are inconsistent. Large-scale studies with a clinically important outcome are needed. Thus, we aimed to determine whether statin use is associated with a reduced risk of developing clinically-defined hip or knee OA. DESIGN: Pooled analysis based on time-to-event analysis of four population-based large cohorts, encompassing in total 132,607 persons aged 57-91 years resident in southern and central Sweden. We studied the association between statin use and time to consultation or surgery for OA of the hip or knee by time-dependent exposure analysis and Cox regression. RESULTS: During 7.5 years of follow-up, we identified 7468 out- or inpatient treated cases of hip or knee OA. Compared with never use, current use of statins conferred no overall reduction in the risk of OA with an adjusted pooled hazard ratio (HR) of 1.04 (95% confidence intervals [95% CI] 0.99-1.10). We found no dose-response relation between duration of current statin use and the risk of OA, with similar HRs among patients with less than 1 year of use (HR 1.09; 95% CI 0.92-1.32) as in patients with use for 3 years or more (HR 1.05; 0.93-1.16). Results were comparable in those with low, medium and high dose of current statin use, without indications of heterogeneity of study results. CONCLUSION: Statin use is not associated with reduced risk of consultation or surgery for OA of the hip or knee.

Variations in pain and function before and after total knee arthroplasty: a comparison between Swedish and Australian cohorts.

OBJECTIVE: Preoperative pain and function is viewed as an important predictor of total knee arthroplasty (TKA) outcomes. We examined whether variations in pain and function outcomes existed at 12 months between two centres in Sweden and Australia, and whether this was explained by variations in patient presentation for TKA. METHODS: This was a retrospective analysis of prospectively collected data. Patients from one centre in Australia (St. Vincent's Hospital (SVH), N = 516) and in Sweden (Trelleborg (TBG), N = 899) who underwent primary TKA between 2012 and 2013. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) was analysed pre- and 12 months' post TKA from which non-response to surgery was determined using the OMERACT-OARSI criteria. Multiple linear regression analysis was used to examine the relationship between change in pain and function and surgery centre, adjusting for preoperative patient characteristics and surgical technique. RESULTS: Despite worse preoperative outcomes in all subscales of the WOMAC for the SVH cohort, there were no clinically meaningful differences in 12-month WOMAC subscales nor change in WOMAC subscales between SVH and TBG. Almost identical proportions of patients were considered OMERACT-OARSI responders, 85.7% (SVH) and 85.9% (TBG), however for the SVH cohort 25 (4.9%) were moderate and 417 (80.8%) were high responders, compared to the TBG cohort of which 225 (25%) were moderate and 547 (60.9%) were high responders. CONCLUSION: Despite differences in preoperative presentation between 2 countries, improvements in pain and function and the proportion of individual who responded to TKA surgery at 1 year were similar. Factors related to poor response to TKA surgery require further elucidation.

Socioeconomic inequalities in knee pain, knee osteoarthritis, and health-related quality of life: a population-based cohort study in southern Sweden.

OBJECTIVES: To determine socioeconomic inequalities in frequent knee pain (FKP), knee osteoarthritis (OA), and associated health-related quality of life (HRQoL) in Sweden. METHOD: In 2007 a postal questionnaire about knee pain was sent to a random sample of 10 000 residents of Malmö, Sweden (7402 individuals responded). Subjects reporting pain with duration ≥ 4 weeks in one or both knees in the past 12 months were classified as having FKP. A random sample of 1527 subjects with and without FKP attended a clinical and radiographic knee examination and responded to generic and disease-specific HRQoL questionnaires. We used the individuals' level of education and occupation as socioeconomic status (SES) measures, and we calculated the relative index of inequality (RII) using Poisson regression with robust standard errors adjusted for age and gender. We applied weighting to account for a possible selection bias that might arise from non-responses in the study. RESULTS: With education, the RIIs for FKP and knee OA were 0.71 [95% confidence interval (CI) 0.61-0.84] and 0.56 (95% CI 0.34-0.93), respectively. With occupation, the corresponding figures were 0.70 (95% CI 0.60-0.82) and 0.59 (95% CI 0.37-0.94), respectively. There were socioeconomic gradients in HRQoL in favour of people with better SES. RIIs for FKP and HRQoL but not knee OA were essentially similar after additional adjustment for mediators. CONCLUSIONS: In Sweden there are socioeconomic gradients related to both FKP and knee OA as well as HRQoL in favour of people with better SES. SES should be taken into account in health resource allocation pertaining to knee-related disorders.

Osteoarthritis of the knee after meniscal resection: long term radiographic evaluation of disease progression.

OBJECTIVE: To determine prevalence, incidence and progression of radiographic knee osteoarthritis (OA) in a cohort of subjects with previous meniscectomy. METHODS: We assessed 221 subjects (177 men and 44 women) with weight bearing knee radiography twice (assessment A and B) with a follow-up time ranging from 4 to 10 years. All subjects had undergone meniscectomy 15-22 years before assessment A. At assessment B the mean (SD) age was 60 (11) years. We assessed prevalence and incidence of OA, as well as progression of radiographic features over time. Radiographic OA was defined as approximating Kellgren and Lawrence grade 2 or worse. RESULTS: At assessment A, we found tibiofemoral radiographic OA in 107 subjects' index knee (48%) of which 41 subjects (38%) had bilateral tibiofemoral OA. At assessment B, the corresponding figures were 151 (68%) and 71 (32%). At assessment A, we found patellofemoral OA in 32 subjects' index knee (14%) of which 11 (34%) had bilateral patellofemoral OA. At assessment B, the corresponding figures were 51 (23%) and 19 (37%). There was an increase of the sum of joint space narrowing (JSN) and osteophyte grades in the tibiofemoral joint of 144 subjects' index knee (64%) and in the contralateral tibiofemoral joints of 79 subjects (36%). The corresponding progression in the patellofemoral joint was observed in 66 index knees (30%) and in 41 (19%) contralateral knees. CONCLUSIONS: Overall, some 20-30 years after meniscectomy nearly three out of four persons had developed radiographic tibiofemoral OA and one out of four had developed patellofemoral OA.

Changes in knee joint load indices from before to 12 months after arthroscopic partial meniscectomy: a prospective cohort study.

OBJECTIVE: Patients undergoing arthroscopic partial meniscectomy (APM) are at increased risk of knee osteoarthritis (OA). Meniscal damage and/or surgery may alter knee joint loading to increase OA risk. We investigated changes in knee joint loading following medial APM surgery, compared with the contra-lateral leg. METHODS: We estimated indices of knee joint loading (external peak knee adduction moment (KAM), KAM impulse and peak knee flexion moment (KFM)) normalized to body size (i.e., body mass (BM) and height (HT)) using 3D gait analysis in 23 patients (17 men, mean (SD) 46.2 (6.4) years, BMI 25.8 (3.4) kg/m(2)) without radiographic knee OA before and 12 months after medial APM. Static alignment was assessed by radiography and self-reported outcomes by Knee injury and Osteoarthritis Outcome Score (KOOS). RESULTS: Peak KAM and KAM impulse increased in the APM leg compared to the contra-lateral leg from before to 12 months after surgery (change difference: 0.38 Nm/BM*HT% 95% CI 0.01 to 0.76 (P = 0.049) and 0.20 Nm*s/BM*HT% 95% CI 0.10 to 0.30 (P < 0.001)). Patients self-reported improvements on all KOOS subscales (KOOS pain improvement: 22.8 95% CI 14.5 to 31.0 (P < 0.01)). CONCLUSIONS: A relative increase in indices of medial compartment loading was observed in the leg undergoing APM compared with the contra-lateral leg from before to 12 months after surgery. This increase may contribute to the elevated risk of knee OA in these patients. Randomized trials including a non-surgical control group are needed to determine if changes in joint loading following APM are caused by surgery or by changes in symptoms.