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Objective: To identify distinct trajectories of lack of knee confidence over an 8-year follow-up period and to examine baseline factors associated with poor trajectories in individuals with or at risk for knee osteoarthritis (OA)., Methods: The Osteoarthritis Initiative is a prospective cohort study of individuals with or at high risk for knee OA. Confidence in the knees was assessed within the Knee Injury and Osteoarthritis Outcome Score instrument querying how much the individual is troubled by lack of confidence in his/her knee(s), rated as not-at-all (score = 0), mildly (score = 1), moderately (score = 2), severely (score = 3), and extremely (score = 4) troubled, reported annually from baseline to 96 months. Lack of knee confidence was defined as a score of ≥2. We used latent class models to identify subgroups that share similar underlying knee confidence trajectories over an 8-year period and multivariable multinomial logistic regression models to examine baseline factors associated with poor trajectories., Results: Among 4,515 participants (mean ± SD age 61.2 ± 9.2 years, mean ± SD BMI 28.6 ± 4.8 kg/m 2 ; 2,640 [58.5%] women), 4 distinct knee confidence trajectories were identified: persistently good (65.6%); declining (9.1%); poor, improving (13.9%); and persistently poor (11.4%). Baseline predictors associated with persistently poor confidence (reference: persistently good) were younger age, male sex, higher body mass index (BMI), depressive symptoms, more advanced radiographic disease, worse knee pain, weaker knee extensors, history of knee injury and surgery, and reported hip and/or ankle pain., Conclusion: Findings suggest the dynamic nature of self-reported knee confidence and that addressing modifiable factors (e.g., BMI, knee strength, depressive symptoms, and lower extremity pain) may improve its long-term course., (© 2021 American College of Rheumatology.)

Objective: Manifestations of instability in knee osteoarthritis (OA) include low overall knee confidence, low confidence that the knees will not buckle, buckling, and excessive motion during gait. Confidence and buckling may particularly influence activity choices, contributing to events leading to disability. Buckling is more likely to affect advanced than basic functional tasks. In this prospective longitudinal study, we tested the hypothesis that overall knee confidence, buckling confidence, buckling, and frontal plane motion during gait are associated with advanced 2-year function outcomes in persons with knee OA., Methods: Persons with knee OA were queried about overall knee confidence (higher score = worse confidence), buckling confidence, and knee buckling, and underwent quantitative gait analysis to quantify varus-valgus excursion and angular velocity. Physical function was assessed using the Late-Life Function and Disability Instrument Basic and Advanced Lower Extremity Domain scores. Logistic regression was used to evaluate the relationship between baseline instability measures and baseline-to-2-year function outcome, adjusting for potential confounders., Results: The sample was comprised of 212 persons (mean age 64.6 years, 76.9% women). Buckling was significantly associated with poor advanced function outcome (adjusted odds ratio [OR] 2.08, 95% confidence interval [95% CI] 1.03-4.20) but not basic function outcome. Overall knee confidence was significantly associated with advanced outcome (adjusted OR 1.65, 95% CI 1.01-2.70), while associations between buckling confidence and both outcomes approached significance. Neither varus-valgus excursion nor angular velocity during gait was associated with either outcome., Conclusion: Knee buckling and low knee confidence were each associated with poor 2-year advanced function outcomes. Current treatment does not address these modifiable factors; interventions to address them may improve outcome in knee OA., (© 2015, American College of Rheumatology.)

Objective: Few strategies to improve pain outcome in knee osteoarthritis (OA) exist in part because how best to evaluate pain over the long term is unclear. Our objectives were to determine the frequency of a good pain experience outcome based on previously formulated OA pain stages and test the hypothesis that less depression and pain catastrophizing and greater self-efficacy and social support are each associated with greater likelihood of a good outcome., Methods: Study participants, all with knee OA, reported pain stage at baseline and 2 years. Baseline assessments utilized the Geriatric Depression Scale, Pain Catastrophizing Scale, Arthritis Self-Efficacy Scale, and Medical Outcomes Study social support survey. Using pain experience stages, good outcome was defined as persistence in or movement to no pain or stage 1 (predictable pain, known trigger) at 2 years. A multivariable logistic regression model was developed to identify independent predictors of a good outcome., Results: Of 212 participants, 136 (64%) had a good pain outcome and 76 (36%) a poor pain outcome. In multivariable analysis, higher self-efficacy was associated with a significantly higher likelihood of good outcome (adjusted odds ratio [OR] 1.14 [95% confidence interval (95% CI) 1.04-1.24]); higher pain catastrophizing was associated with a significantly lower likelihood of good outcome (adjusted OR 0.88 [95% CI 0.83-0.94])., Conclusion: This stage-based measure provides a meaningful and interpretable means to assess pain outcome in knee OA. The odds of a good 2-year outcome in knee OA were lower in persons with greater pain catastrophizing and higher in persons with greater self-efficacy. Targeting these factors may help to improve pain outcome in knee OA., (Copyright © 2014 by the American College of Rheumatology.)

Objective: We evaluated whether African Americans in the Osteoarthritis Initiative (OAI) have a greater risk (versus whites) of poor 4-year function outcome within strata defined by sex, body mass index (BMI), and waist circumference., Methods: Using Western Ontario and McMaster Universities Osteoarthritis Index function, 20-meter walk, and chair stand performance, poor outcome was defined as moving into a worse function group or remaining in the 2 worst groups over 4 years. Logistic regression was used to evaluate the relationship between racial group and outcome within each stratum, adjusting for age, education, and income, and then further adjusting for BMI, comorbidity, depressive symptoms, physical activity, knee pain, and osteoarthritis (OA) severity., Results: In 3,695 persons with or at higher risk for knee OA, higher BMI and large waist circumference were each associated with poor outcome. Among women with high BMI and among women with large waist circumference, African Americans were at greater risk for poor outcome by every measure, adjusting for age, education, and income. From fully adjusted models, potential explanatory factors included income, comorbidity, depressive symptoms, pain, and disease severity. Findings were less consistent for men, emerging only for the 20-meter walk or chair stand outcomes, and potentially explained by age and knee pain., Conclusion: Among OAI women with excess body weight, African Americans are at greater risk than whites for poor 4-year outcome. Modifiable factors that may help to explain these findings in the OAI include comorbidity, depressive symptoms, and knee pain. Targeting such factors, while supporting weight loss, may help to lessen the outcome disparity between African American and white women., (Copyright © 2013 by the American College of Rheumatology.)

Objective: Bone marrow lesions are believed to increase risk of knee osteoarthritis (OA) progression. Whether their effect is local and whether it can be explained by other types of bone lesions concomitantly present in the same subregion is unclear. We evaluated bone lesion frequency in subregions without cartilage lesions and cartilage lesion frequency in subregions without bone lesions, and investigated the within-subregion bone marrow lesion/subsequent cartilage loss relationship after adjusting for other types of bone lesions at baseline., Methods: Individuals with knee OA had magnetic resonance imaging at baseline and 2 years later. Cartilage integrity and bone marrow lesions, cysts, and attrition were scored within tibiofemoral subregions. Logistic regression, with generalized estimating equations to account for correlation among multiple subregions within a knee, was used to estimate odds ratios (ORs) for cartilage loss associated with bone marrow lesions, adjusting for age, sex, body mass index, and bone attrition and cysts in the same subregion., Results: Analyzing 1,953 subregions among 177 knees, 90% of subregions had no bone lesions at baseline. Only 0-3% of subregions without cartilage lesions had bone lesions in the same subregion; in contrast, 5-33% of subregions without bone lesions had cartilage lesions. Bone marrow lesions at baseline were associated with cartilage loss in the same subregion at 2 years, adjusting for other types of bone lesions at baseline (adjusted OR 3.74, 95% confidence interval 1.59-8.82)., Conclusion: In subjects with knee OA, bone marrow lesions were rare at early disease stages but predicted subregional cartilage loss after accounting for the presence of other types of bone lesions in the same subregion.