SUMMARY Objective The purpose of this study was to analyze the longitudinal association between physical activity levels and early degenerative cartilage changes in the knee, measured using T2 relaxation times over a period of 4 years in individuals without clinical or radiographic evidence of OA. Design Cartilage T2 was measured at baseline and after 2 and 4 years in 205 subjects aged 45–60 years from the Osteoarthritis Initiative (OAI) incidence and normal cohorts with no knee pain (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score of zero), and a Kellgren Lawrence (KL) score of <2 at baseline. Physical activity was scored using the Physical Activity Scale for the Elderly (PASE) questionnaire, which was obtained yearly over 4 years. The relationship between physical activity and T2 was studied using a mixed model linear regression, including random effects, and adjusted for age, sex, and body mass index (BMI). Results T2 values for all PASE tertiles progressed over the 4-year period. T2 progression was increased in the highest tertile of physical activity compared to the mid-tertile at the medial tibia (MT) (P = 0.041), patella (Pat) (P = 0.019), and average T2 of all knee compartments combined (P = 0.033). Subjects with the lowest 15% PASE scores showed significantly higher T2 progression compared to the mid-level physical activity group at the lateral femur (LF) (P = 0.025), lateral tibia (LT) (P = 0.043), medial femur (MF) (P = 0.044), tibiofemoral compartment (P = 0.017), patellofemoral compartment (P = 0.016), lateral compartments (P = 0.003), and average of all compartments (P = 0.043). Conclusion High and very low PASE scores were associated with greater progression of cartilage T2 measurements in asymptomatic, middle-aged individuals, suggesting accelerated cartilage matrix biochemical degeneration over time.

Objective To determine the effect of weight gain on progression of early knee morphologic abnormalities using magnetic resonance imaging (MRI) in a longitudinal study over 48 months. Design We studied the right knee of 100 subjects from the Osteoarthritis Initiative, selecting subjects aged ≥ 45 with osteoarthritis risk factors who demonstrated weight gain (minimum 5% increase in body mass index, BMI, n=50) or no change in weight (BMI change < 2%, n=50), frequency matched for age, gender, and baseline BMI. Baseline and 48 month knee MRI studies were scored for lesions using a modified whole organ MRI score (WORMS). Logistic regression models were used to compare the differences between the two groups. Results The odds of worsening maximum cartilage (11.3, 95%, CI 3.5–51.4) and meniscal WORMS (4.5, 95% CI 1.4–17.3) were significantly greater in the weight gain group compared to the no change group, in addition to the odds of worsening cartilage defects at the patella and average meniscal WORMS (p<0.05). Odds of worsening average bone marrow edema pattern (BMEP) were significantly greater for the weight gain group compared to the no change cohort (p<0.05). Conclusion Our study demonstrated that weight gain is strongly associated with increased progression of cartilage degeneration in middle-aged individuals with risk factors for osteoarthritis.

HR-pQCT provides a sensitive method with high reader agreement in assessment of structural bone damage in RA. The good correlation of erosion measures with disease duration as well as BME volume suggests that they could become feasible measures of erosions in RA.

The computer-aided, manual and semiquantitative methods presented in this study can be used to evaluate MRI pathologies in RA with excellent reproducibility. Significant correlations with standard RAMRIS were found in the measurements using these methods.

This study demonstrates that HR-pQCT detects more and smaller bone erosions compared to MRI and CR. In addition, 3 T MRI can provide quantitative measurement of BME. Combination of HR-pQCT and MRI modalities may provide powerful tools to evaluate joint inflammation and bone damage in RA.

BMEP regions showed significantly increased bone density and structures as well as perfusion measures, suggesting bone remodeling and active inflammation. Combining MRI and HR-pQCT provides a powerful multimodality approach for understanding BMEP and erosions, and for potentially identifying novel imaging markers for disease progression in RA.

Axial STIR sequences reduce magic angle effects and improve visualization of ankle tendon pathology.