Michael Nevitt

University of California, Davis, Davis, CA, USA

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Publications (40)171.42 Total impact

  • Article: Walking to meet physical activity guidelines in knee osteoarthritis: Is 10,000 steps enough?
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    ABSTRACT: OBJECTIVE: To study if step goals (e.g. walking 10,000 steps/day) approximate meeting 2008 Physical Activity Guidelines for Americans among adults with or at high risk of knee OA. DESIGN: Cross-sectional observational cohort SETTING: Community PARTICIPANTS: People with or at high risk of knee OA INTERVENTIONS: None MAIN OUTCOME MEASURES: Objective physical activity data were collected over 7 consecutive days from people with or at high risk of knee (OA) participating in the Multicenter Osteoarthritis Study. Using activity monitor data, we determined the proportion that 1) walked ≥10,000 steps/day, 2) met the 2008 Physical Activity Guidelines, and 3) achieved both recommendations. RESULTS: Of 1788 subjects studied (age 67 ± 8 yrs, BMI 31 ± 6 kg/m(2), 60% women), 16.7% of men and 12.6% of women walked ≥10,000 steps/day, while 6% of men and 5% of women met the 2008 Physical Activity Guidelines for Americans. Of those walking ≥10,000 steps/day, 16.7% and 26.7% of men and women also met the 2008 Physical Activity Guidelines. CONCLUSIONS: Among this sample of older adults with or at high risk of knee OA, walking ≥10,000 steps/day did not translate into meeting public health guidelines. These findings highlight the disparity between number of steps/day believed to be needed and recommended time-intensity guidelines to achieve positive health benefits.
    Archives of physical medicine and rehabilitation 12/2012; · 2.18 Impact Factor
  • Article: Do radiographic disease and pain account for why people with or at high risk of knee osteoarthritis do not meet physical activity guidelines?
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    ABSTRACT: OBJECTIVE: Knee Osteoarthritis (OA) and pain are assumed to be barriers for meeting physical activity guidelines, but this has not been formally evaluated. The purpose of this study was to determine the proportion of people with and without knee OA and knee pain who met recommended physical activity levels through walking. METHODS: Cross-sectional analysis of community dwelling adults who have or who are at high risk of knee OA from The Multicenter Osteoarthritis Study. Participants wore a StepWatch activity monitor to record steps/day over 7 days. The proportion that met the recommended physical activity levels was determined as those accumulating ≥150 minutes/week at ≥100 steps/minute in bouts lasting ≥10 minutes. These proportions were also determined for those with and without knee OA, as classified by radiograph, and by severity of knee pain. RESULTS: Of the 1788 study participants (age 67 sd 8 yrs, BMI 31 sd 6 kg/m(2) , 60% female), lower overall percentages of participants with radiographic knee OA and knee pain met recommended physical activity levels. However, these differences were not statistically significant between those with and without knee OA; 7.3% and 10.1% of men (p=0.34), and 6.3% and 7.8% of women (p=0.51), respectively, met recommended physical activity levels. Similarly, for those with moderate/severe pain versus no pain, 12.9% and 10.9% of men (p=0.74) and 6.7% and 11.0% (p=0.40) of women met recommended physical activity levels. CONCLUSIONS: Disease and pain have little impact on achieving recommended physical activity levels among people with or at high risk of knee OA. © 2012 American College of Rheumatology.
    Arthritis & Rheumatism 11/2012; · 7.87 Impact Factor
  • Article: Frequency and Spatial Distribution of Cartilage Thickness Change in Knee Osteoarthritis and its Relation to Clinical and Radiographic Covariates - Data from the Osteoarthritis Initiative.
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    ABSTRACT: OBJECTIVE: Estimate the frequency and spatial location of rapid femorotibial cartilage thinning or thickening in knees with, or at risk of, osteoarthritis and examine their association with clinical and radiographic covariates. DESIGN: Knee cartilage thickness change over 12 months was measured using magnetic resonance imaging in the right knee of 757 Osteoarthritis Initiative (OAI) participants that had radiographic findings of osteophytes or joint space narrowing. Thickness changes in individual knees were classified as having rapid thinning or thickening or no detectable OA-related change when compared to asymptomatic OAI Control cohort knees. RESULTS: Cartilage thinning, found in 18.5% of subjects, was more frequent in knees with OAI calculated Kellgren-Lawrence Grade (cKLG)>2 (p<0.001) and with frequent pain (p=0.047). No link was found between body mass index, sex, and age and cartilage thinning (p>0.15). The percent of knees with thickening was small (4.4%), but greater in knees with frequent pain (p=0.02). Rapid thinning was most common in the central (36.4%) and external (32.1%) subregions of the medial weight-bearing femur. Mean cartilage loss in rapidly thinning subregions ranged from 11.2%/y to 24.6%/y. Knees with cKLG>2, but classified as having no detectable OA-related change had mean cartilage loss rates significantly >0 (0.4%/y to 1.3%/y) in 10 subregions. CONCLUSION: Most observed subregional changes in OA knees were indistinguishable from changes found in an asymptomatic cohort, but a fraction of subregions showed rapid progression. The relative frequency of rapid thinning increases when cKLG>2, a classification closely associated with joint space narrowing and/or frequent knee pain are present.
    Osteoarthritis and Cartilage 10/2012; · 3.90 Impact Factor
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    Dataset: Leg-length inequality is not associated with greater trochanteric pain syndrome
  • Article: How do short-term rates of femorotibial cartilage change compare to long-term changes? Four year follow-up data from the osteoarthritis initiative.
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    ABSTRACT: OBJECTIVE: To compare unbiased estimates of short- vs long-term cartilage loss in osteoarthritic knees. METHOD: 441 knees [216 Kellgren Lawrence (KL) grade 2, 225 KL grade 3] from participants of the Osteoarthritis Initiative were studied over a 4-year period. Femorotibial cartilage thickness was determined using 3 T double echo steady state magnetic resonance imaging, the readers being blinded to time points. Because common measurement time points bias correlations, short-term change (year-1 to year-2: Y1 → Y2) was compared with long-term change (baseline to year-4: BL → Y4), and initial (BL → Y1) with subsequent (Y2 → Y4) observation periods. RESULTS: The mean femorotibial cartilage thickness change (standardized response mean) was -1.2%/-0.8% (-0.42/-0.28) over 1 (BL → Y1/Y1 → Y2), -2.1%/-2.5% (-0.56/-0.55) over 2 (BL → Y2/Y2 → Y4), -3.3% (-0.63) over 3 (Y1 → Y4), and -4.5% (-0.78) over 4 years. Spearman correlations were 0.33 for Y1 → Y2 vs BL → Y4, and 0.17 for BL → Y1 vs Y2 → Y4 change. Percent agreement between knees showing progression during Y1 → Y2 vs BL → Y4 was 59%, and 64% for BL → Y1 vs Y2 → Y4. The area under the receiver operating characteristic curve was 0.66 for using Y1 → Y2 to predict BL → Y4, and 0.59 for using BL → Y1 to predict Y2 → Y4 change. CONCLUSION: Weak to moderate correlations and agreement were observed between individual short- vs long-term cartilage loss, and between initial and subsequent observation periods. Hence, longer observation periods are recommended to achieve robust results on cartilage loss in individual knees. At cohort and subcohort level (e.g., KLG3 vs KLG2 knees), the mean cartilage loss increased almost linearly with the length of the observation period and was constant throughout the study.
    Osteoarthritis and Cartilage 07/2012; 20(11):1250-1257. · 3.90 Impact Factor
  • Article: Obesity and other modifiable factors for physical inactivity measured by accelerometer in adults with knee osteoarthritis: Data from the osteoarthritis initiative (OAI).
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    ABSTRACT: OBJECTIVE: To investigate the public health impact of obesity and other modifiable risk factors related to physical inactivity in adults with knee osteoarthritis (OA). METHODS: The frequency of inactivity as defined by the United States Department of Health and Human Services was assessed from objective accelerometer monitoring of 1089 participants with radiographic knee OA aged 49 to 84 years during the OAI 48 month visit (2008-2010). The relationship between modifiable factors (weight status, dietary fat, fiber, smoking, depressive symptoms, knee function, knee pain, knee confidence) with inactivity was assessed using odds ratios (OR) and attributable fractions (AF) controlling for descriptive factors (age, gender, race, education, live alone, employment, frequent knee symptoms, comorbidity). RESULTS: Almost half (48.9%) of participants with knee OA were inactive. Being overweight (OR=1.8, CI: 1.2, 2.5) or obese (OR=3.9, CI: 2.6, 5.7), inadequate dietary fiber intake (OR =1.6, 95% CI: 1.2, 2.2), severe knee dysfunction (OR=1.9, 95% CI: 1.3, 2.8), and severe pain (OR=1.7, 95% CI: 1.1, 2.5) were significantly related to inactivity, controlling for descriptive factors. Modifiable factors with significant average AFs were being overweight or obese (AF=23.8%, 95% CI: 10.5%, 38.6%) and inadequate dietary fiber (AF=12.1%, 95% CI: 0.1%, 24.5%) controlling for all factors. CONCLUSION: Being obese or overweight, the quality of the diet, severe pain, and severe dysfunction are significantly associated with physical inactivity in adults with knee OA. All components should be considered in designing physical activity interventions that target arthritis populations with low activity levels. © 2012 by the American College of Rheumatology.
    Arthritis care & research. 06/2012;
  • Article: Cartilage thickening in early radiographic human knee osteoarthritis - within-person, between-knee comparison.
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    ABSTRACT: OBJECTIVE: To determine whether the presence of definite osteophytes (in absence of joint space narrowing [JSN]) by radiograph is associated with (subregional) increases in cartilage thickness, in a within-person, between-knee cross-sectional comparison of participants in the Osteoarthritis Initiative (OAI). Based on previous results, external medial (ecMF) and external lateral weight-bearing femoral (ecLF) subregions were selected as primary endpoints. METHODS: Both knees of 61 (of 4798) OAI participants displayed definite tibial or femoral marginal osteophytes and no JSN in one knee, and no signs of radiographic OA in the contra-lateral knee; this being confirmed by an expert central reader. In these participants, cartilage thickness was measured in 16 femorotibial subregions of each knee, based on sagittal DESSwe magnetic resonance images. Location-specific joint space width from fixed flexion radiographs was determined using dedicated software. Location-specific associations of osteophytes with cartilage thickness were evaluated using paired t-tests and mixed effect models. RESULTS: Of the 61 participants, 48% had only medial, 36% only lateral, and 16% bi-compartmental osteophytes. Osteophyte knees had significantly thicker cartilage than contra-lateral non-osteophyte knees in the ecMF (+71±223μm, equivalent to +5.5%, p=0.015) and ecLF (+64±195μm, +4.1%, p=0.013). No significant differences between knees were noted in other subregions, nor in joint space width. Cartilage thickness in ecMF and ecLF was significantly associated with tibial osteophytes in the same (medial or lateral) compartment (p=0.003). CONCLUSION: Knees with early radiographic OA display thicker cartilage than (contra-lateral) knees without radiographic findings of OA, specifically in the external femoral subregions of compartments with marginal osteophytes. © 2012 by the American College of Rheumatology.
    Arthritis care & research. 05/2012;
  • Article: The role of varus and valgus alignment in the initial development of knee cartilage damage by MRI: the MOST study.
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    ABSTRACT: OBJECTIVE: Varus and valgus alignment are associated with progression of knee osteoarthritis, but their role in incident disease is less certain. Radiographic measures of incident knee osteoarthritis may be capturing early progression rather than disease development. The authors tested the hypothesis: in knees with normal cartilage morphology by MRI, varus is associated with incident medial cartilage damage and valgus with incident lateral damage.METHODS: In MOST, a prospective study of persons at risk of or with knee osteoarthritis, baseline full-limb x-rays and baseline and 30-month MRI were acquired. In knees with normal baseline cartilage morphology in all tibiofemoral subregions, logistic regression was used with generalised estimating equations to examine the association between alignment and incident cartilage damage adjusting for age, gender, body mass index, laxity, meniscal tear and extrusion.RESULTS: Of 1881 knees, 293 from 256 persons met the criteria. Varus versus non-varus was associated with incident medial damage (adjusted OR 3.59, 95% CI 1.59 to 8.10), as was varus versus neutral, with evidence of a dose effect (adjusted OR 1.38/1° varus, 95% CI 1.19 to 1.59). The findings held even excluding knees with medial meniscal damage. Valgus was not associated with incident lateral damage. Varus and valgus were associated with a reduced risk of incident lateral and medial damage, respectively.CONCLUSION: In knees with normal cartilage morphology, varus was associated with incident cartilage damage in the medial compartment, and varus and valgus with a reduced risk of incident damage in the less loaded compartment. These results support that varus increases the risk of the initial development of knee osteoarthritis.
    Annals of the rheumatic diseases 05/2012; · 8.11 Impact Factor
  • Article: When it hurts, a positive attitude may help: association of positive affect with daily walking in knee osteoarthritis. Results from a multicenter longitudinal cohort study.
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    ABSTRACT: While depressive symptoms and knee pain are independently known to impede daily walking in older adults, it is unknown whether positive affect promotes daily walking. This study investigated this association among adults with knee osteoarthritis (OA) and examined whether knee pain modified this association. This study is a cross-sectional analysis of the Multicenter Osteoarthritis Study. We included 1,018 participants (mean ± SD age 63.1 ± 7.8 years, 60% women) who had radiographic knee OA and had worn a StepWatch monitor to record their number of steps per day. High and low positive affect and depressive symptoms were based on the Center for Epidemiologic Studies Depression Scale. Knee pain was categorized as present in respondents who reported pain on most days at both a clinic visit and a telephone screening. Compared to respondents with low positive affect (27% of all respondents), those with high positive affect (63%) walked a similar number of steps per day, while those with depressive symptoms (10%) walked less (adjusted β -32.6 [95% confidence interval (95% CI) -458.9, 393.8] and -579.1 [95% CI -1,274.9, 116.7], respectively). There was a statistically significant interaction of positive affect by knee pain (P = 0.0045). Among the respondents with knee pain (39%), those with high positive affect walked significantly more steps per day (adjusted β 711.0 [95% CI 55.1, 1,366.9]) than those with low positive affect. High positive affect was associated with more daily walking among adults with painful knee OA. Positive affect may be an important psychological factor to consider for promoting physical activity among people with painful knee OA.
    Arthritis care & research. 04/2012; 64(9):1312-9.
  • Article: Patterns of compartment involvement in tibiofemoral osteoarthritis in men and women and in whites and African Americans.
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    ABSTRACT: We conducted a cross-sectional study to describe the prevalence of tibiofemoral joint space narrowing (JSN) in medial and lateral compartments and assess whether it differs by sex and ethnic groups, and, if it does, to what extent such a difference is accounted for by knee malalignment. The Multicenter Osteoarthritis Study is an observational study of persons ages 50-79 years with either symptomatic knee osteoarthritis or high risk of disease. Knee radiographs were assessed for JSN in each tibiofemoral compartment. Mechanical axis angle was measured using full-extremity films. We compared the proportion of knees with medial compartment JSN and with lateral JSN between men and women, as well as between whites and African Americans, using a logistic regression model adjusting for covariates (race or sex and body mass index, age, education, and clinic site). We used generalized estimating equations to account for correlation between 2 knees within a person. Of 5,202 knees (2,652 subjects), 1,532 (29.5%) had medial JSN and 427 (8.2%) had lateral JSN. Lateral JSN was more prevalent in the knees of women than in men (odds ratio [OR] 1.9, 95% confidence interval [95% CI] 1.5-2.4) and was also higher in the knees of African Americans than in whites (OR 2.4, 95% CI 1.7-3.3). Further adjustment for malalignment attenuated the OR for sex but not the OR for race. Women and African Americans are more likely to have lateral JSN than men and whites, respectively. Valgus malalignment may contribute to the higher prevalence in women.
    Arthritis care & research. 01/2012; 64(6):847-52.
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    Article: The association of obesity with walking independent of knee pain: the multicenter osteoarthritis study.
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    ABSTRACT: Practice guidelines recommend addressing obesity for people with knee OA, however, the association of obesity with walking independent of pain is not known. We investigated this association within the Multicenter Osteoarthritis Study, a cohort of older adults who have or are at high risk of knee OA. Subjects wore a StepWatch to record steps taken over 7 days. We measured knee pain from a visual analogue scale and obesity by BMI. We examined the association of obesity with walking using linear regression adjusting for pain and covariates. Of 1788 subjects, the mean steps/day taken was 8872.9 ± 3543.4. Subjects with a BMI ≥35 took 3355 fewer steps per day independent of knee pain compared with those with a BMI ≤25 (95% CI -3899, -2811). BMI accounted for 9.7% of the variability of walking while knee pain accounted for 2.9%. BMI was associated with walking independent of knee pain.
    Journal of obesity 01/2012; 2012:261974.
  • Article: Hand joint space narrowing and osteophytes are associated with magnetic resonance imaging-defined knee cartilage thickness and radiographic knee osteoarthritis: data from the Osteoarthritis Initiative.
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    ABSTRACT: To evaluate whether features of radiographic hand osteoarthritis (OA) are associated with quantitative magnetic resonance imaging (MRI)-defined knee cartilage thickness, radiographic knee OA, and 1-year structural progression. A total of 765 participants in Osteoarthritis Initiative (OAI; 455 women, mean age 62.5 yrs, SD 9.4) obtained hand radiographs (at baseline), knee radiographs (baseline and Year 1), and knee MRI (baseline and Year 1). Hand radiographs were scored for presence of osteophytes and joint space narrowing (JSN). Knee radiographs were scored according to the Kellgren-Lawrence (KL) scale. Cartilage thickness in the medial and lateral femorotibial compartments was measured quantitatively from coronal FLASHwe images. We examined the cross-sectional and longitudinal associations between features of hand OA (total osteophyte and JSN scores) and knee cartilage thickness, 1-year knee cartilage thinning (above smallest detectable change), presence of knee OA (KL grade ≥ 3), and progression of knee OA (KL change ≥ 1) by linear and logistic regression. Both hand OA features were included in a multivariate model (if p ≤ 0.25) adjusted for age, sex, and body mass index (BMI). Hand JSN was associated with reduced knee cartilage thickness (ß = -0.02, 95% CI -0.03, -0.01) in the medial femorotibial compartment, while hand osteophytes were associated with the presence of radiographic knee OA (OR 1.10, 95% CI 1.03-1.18; multivariate models) with both hand OA features as independent variables adjusted for age, sex, and BMI). Radiographic features of hand OA were not associated with 1-year cartilage thinning or radiographic knee OA progression. Our results support a systemic OA susceptibility and possibly different mechanisms for osteophyte formation and cartilage thinning.
    The Journal of Rheumatology 11/2011; 39(1):161-6. · 3.69 Impact Factor
  • Article: Physical activity is associated with magnetic resonance imaging-based knee cartilage T2 measurements in asymptomatic subjects with and those without osteoarthritis risk factors.
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    ABSTRACT: To evaluate the association of exercise and knee-bending activities with magnetic resonance imaging (MRI)-based knee cartilage T2 relaxation times and morphologic abnormalities in asymptomatic subjects from the Osteoarthritis Initiative, with or without osteoarthritis (OA) risk factors. We studied 128 subjects with knee OA risk factors and 33 normal control subjects ages 45-55 years, with a body mass index of 18-27 kg/m(2) and no knee pain. Subjects were categorized according to exercise level, using the leisure activity component of the Physical Activity Scale for the Elderly, and by self-reported frequent knee-bending activities. Two radiologists graded the cartilage of the right knee on MR images, using the Whole-Organ MRI Score (WORMS). Cartilage was segmented, and compartment-specific T2 values were calculated. Differences between the exercise groups and knee-bending groups were determined using multiple linear and logistic regression models. Among subjects with risk factors for knee OA, light exercisers had lower T2 values compared with sedentary and moderate/strenuous exercisers. When the sexes were analyzed separately, female moderate/strenuous exercisers had higher T2 values compared with sedentary individuals and light exercisers. Subjects without risk factors displayed no significant differences in T2 values according to exercise level. However, frequent knee-bending activities were associated with higher T2 values in both subjects with OA risk factors and those without OA risk factors and with more severe cartilage lesions in the group with risk factors. In subjects at risk of knee OA, light exercise was associated with low T2 values, whereas moderate/strenuous exercise in women was associated with high T2 values. Higher T2 values and WORMS grades were also observed in frequent knee-benders, suggesting greater cartilage degeneration in these individuals.
    Arthritis & Rheumatism 05/2011; 63(8):2248-56. · 7.87 Impact Factor
  • Article: Greater rates of cartilage loss in painful knees than in pain-free knees after adjustment for radiographic disease stage: data from the osteoarthritis initiative.
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    ABSTRACT: To investigate whether rates of cartilage loss differ in knees with frequent baseline pain versus those without pain, after adjustment for radiographic osteoarthritis (OA) stage. One knee in each of 718 Osteoarthritis Initiative participants was examined: 310 with calculated Kellgren/Lawrence (K/L) grade 2, 299 with calculated K/L grade 3, and 109 with calculated K/L grade 4. Twelve-month change in (subregional) cartilage thickness was assessed by magnetic resonance imaging. Change in cartilage thickness in the central subregion of the weight-bearing medial femoral condyle and ordered value 1 (OV1) were selected as primary end points. Frequent knee symptoms were defined as pain, aching, or stiffness on most days of at least 1 month during the previous year. The mean 12-month rate of change in cartilage thickness in the central subregion of the medial femoral condyle was -12 μm (standardized response mean [SRM] -0.15) in knees without pain (n = 146), -27 μm (SRM -0.25) in those with infrequent pain (n = 255), and -54 μm (SRM -0.32) in those with frequent pain (n = 317). Rates differed significantly between frequently painful knees and pain-free knees after adjustment for age, sex, body mass index, and calculated K/L grade (P = 0.011, R(2) = 2.6%, partial R(2) for frequent pain = 1.4%). Similar results were found in stratified samples of calculated K/L grade 2/calculated K/L grade 3 knees, and in analyses restricted to knees with consistent pain frequency between baseline and followup. OV1 results showed similar trends but were not significant. Knees with frequent pain display greater rates of medial cartilage loss longitudinally than knees without pain, with or without adjustment or stratification for radiographic disease stage. Enrollment of participants with frequent knee pain in clinical trials can increase the observed rate of structural progression (i.e., cartilage loss) and sensitivity to change.
    Arthritis & Rheumatism 04/2011; 63(8):2257-67. · 7.87 Impact Factor
  • Article: Different thresholds for detecting osteophytes and joint space narrowing exist between the site investigators and the centralized reader in a multicenter knee osteoarthritis study--data from the Osteoarthritis Initiative.
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    ABSTRACT: To evaluate how the reading of knee radiographs by site investigators differs from that by an expert musculoskeletal radiologist who trained and validated them in a multicenter knee osteoarthritis (OA) study. A subset of participants from the Osteoarthritis Initiative progression cohort was studied. Osteophytes and joint space narrowing (JSN) were evaluated using Kellgren-Lawrence (KL) and Osteoarthritis Research Society International (OARSI) grading. Radiographs were read by site investigators, who received training and validation of their competence by an expert musculoskeletal radiologist. Radiographs were re-read by this radiologist, who acted as a central reader. For KL and OARSI grading of osteophytes, discrepancies between two readings were adjudicated by another expert reader. Radiographs from 96 subjects (49 women) and 192 knees (138 KL grade ≥ 2) were included. The site reading showed moderate agreement for KL grading overall (kappa = 0.52) and for KL ≥ 2 (i.e., radiographic diagnosis of "definite OA"; kappa = 0.41). For OARSI grading, the site reading showed substantial agreement for lateral and medial JSN (kappa = 0.65 and 0.71), but only fair agreement for osteophytes (kappa = 0.37). For KL grading, the adjudicator's reading showed substantial agreement with the centralized reading (kappa = 0.62), but only slight agreement with the site reading (kappa = 0.10). Site investigators over-graded osteophytes compared to the central reader and the adjudicator. Different thresholds for scoring of JSN exist even between experts. Our results suggest that research studies using radiographic grading of OA should use a centralized reader for all grading.
    Skeletal Radiology 04/2011; 41(2):179-86. · 1.54 Impact Factor
  • Article: Fluctuation of knee pain and changes in bone marrow lesions, effusions, and synovitis on magnetic resonance imaging.
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    ABSTRACT: Fluctuations in pain in patients with knee osteoarthritis (OA) are common, but risk factors for pain fluctuation are poorly understood. To best identify the structural causes of fluctuations, multiple assessments of pain status and structural lesions are needed. This study was undertaken to determine whether pain resolution is accompanied by diminution of lesions in patients with knee OA. Subjects in the Multicenter Osteoarthritis Study were queried about their knee pain by interview, and knees were assessed by magnetic resonance imaging at the baseline and 15-month and 30-month clinic visits. For those knees in which pain fluctuation was identified over 3 clinic visits, the relationship of bone marrow lesions (BMLs), synovitis, and effusion to frequent knee pain and severity of knee pain was examined using conditional logistic regression analyses. Included in the analysis were 570 subjects with knee OA (651 knees). When the BML score changed from 0 to 1, 2, 3, 4, 5-6, and 7-18 over 2 consecutive clinic visits, the odds ratios (ORs) for frequent knee pain were 1.2, 1.2, 1.5, 2.2, 2.4, and 2.5, respectively (P for trend = 0.006). The corresponding ORs were 1.5, 1.5, and 2.4 when the synovitis score changed from 0 to 1, 2, and 3-6, respectively (P for trend = 0.045). No significant association was found between the effusion score and frequent knee pain. Diminishing size of BMLs was associated with resolution of knee pain (P for trend = 0.007). Similar associations were also observed between these structural lesions and the severity of knee pain. Changes in BMLs and synovitis are associated with fluctuations in knee pain in patients with knee OA. Pain resolution occurs more frequently when BMLs become smaller.
    Arthritis & Rheumatism 03/2011; 63(3):691-9. · 7.87 Impact Factor
  • Article: MRI-based extended ordered values more efficiently differentiate cartilage loss in knees with and without joint space narrowing than region-specific approaches using MRI or radiography--data from the OA initiative.
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    ABSTRACT: The sensitivity to change of quantitative analysis of cartilage in knee osteoarthritis using magnetic resonance imaging (MRI) is compromised by the spatial heterogeneity of cartilage loss. We explore whether extended (medial-lateral) "ordered values" (OVs) are superior to conventional approaches of analyzing subregional cartilage thickness loss and to radiography, in differentiating rates of progression in knees with and without joint space narrowing (JSN). 607 Osteoarthritis Initiative (OAI) participants (308 without and 299 with baseline JSN at baseline) were studied over 12 months. Subregional femorotibial cartilage loss was determined in all knees, and changes in minimum joint space width (mJSW) in a subset of 290 knees. Subregional thickness changes in medial and lateral tibial and femoral cartilages were sorted in ascending order (OV1-16). A Wilcoxon rank-sum test was used to compare rates of change in knees with and without JSN. JSN-knees displayed greater cartilage loss than those without JSN, with minimal P-values of 0.008 for femorotibial subregions, 3.3×10(-4) for medial OV1, and 5.4×10(-7) for extended (medial and lateral) OV1. mJSW measurements (n=290) did not discriminate between longitudinal rates of change in JSN vs no-JSN knees (P=0.386), whereas medial OV1 (P=5.1×10(-4)) and extended OV1 did (P=2.1×10(-5)). Extended OVs showed higher sensitivity to detecting differences in longitudinal rates of cartilage loss in knees with and without baseline JSN than anatomical (sub)regions and radiography. The OV technique also circumvents challenges of selecting particular regions "a priori" in clinical trials and may thus provide a powerful tool in studying risk factors or treatment efficacy in osteoarthritis.
    Osteoarthritis and Cartilage 02/2011; 19(6):689-99. · 3.90 Impact Factor
  • Article: Assessing physical activity in persons with knee osteoarthritis using accelerometers: data from the osteoarthritis initiative.
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    ABSTRACT: Physical activity measured by accelerometers requires basic assumptions to translate the output into meaningful measures. We used accelerometer data from the Osteoarthritis Initiative to investigate in the context of knee osteoarthritis (OA) the following data processing assumptions derived from the general US adult population: nonwear (a period the monitor was removed), based on zero activity exceeding 60 minutes; and a valid day of monitoring, based on wear time evidence exceeding 10 hours. We examined the influence of nonwear thresholds ranging from 20 to 300 minutes of zero activity on mean daily activity minutes (counts>0), mean daily activity counts, and mean daily moderate to vigorous physical activity minutes. The effect of selecting minimums of 8, 10, or 12 wear hours to signify a valid day of monitoring on data retention was examined. Our sample of 3,536 days of accelerometer data from 519 persons with knee OA showed that mean daily activity minutes increased with the nonwear threshold until stabilizing at 463 minutes per day, corresponding to the 90-minute nonwear threshold. Similar patterns were observed for mean daily activity counts. Varying the nonwear threshold had no effect on mean daily moderate to vigorous physical activity minutes. Choosing the 90-minute nonwear threshold and a minimum of 10 wear hours to constitute a valid day provided 94% data retention. Data supported applying the 90-minute nonwear threshold to the knee OA population instead of the 60-minute threshold for the general population, while retaining the 10-hour valid day threshold.
    Arthritis care & research. 12/2010; 62(12):1724-32.
  • Article: Methodologic challenges in studying risk factors for progression of knee osteoarthritis.
    Arthritis care & research. 11/2010; 62(11):1527-32.
  • Article: Varus and valgus alignment and incident and progressive knee osteoarthritis.
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    ABSTRACT: Varus and valgus alignment increase medial and lateral tibiofemoral load. Alignment was associated with tibiofemoral osteoarthritis progression in previous studies; an effect on incident osteoarthritis risk is less certain. This study tested whether alignment influences the risk of incident and progressive radiographic tibiofemoral osteoarthritis. In an observational, longitudinal study of the Multicenter Osteoarthritis Study cohort, full-limb x-rays to measure alignment were acquired at baseline and knee x-rays were acquired at baseline and knee x-rays at baseline and 30 months. Varus alignment was defined as ≤178° and valgus ≥182°. Using logistic regression and generalised estimating equations, the associations of baseline alignment and incident osteoarthritis at 30 months (in knees without baseline osteoarthritis) and alignment and osteoarthritis progression (in knees with osteoarthritis) were examined, adjusting. For age, gender, body mass index, injury, laxity and strength, with neutral knees as referent. 2958 knees (1752 participants) were without osteoarthritis at baseline. Varus (adjusted OR 1.49, 95% CI 1.06 to 2.10) but not valgus alignment was associated with incident osteoarthritis. 1307 knees (950 participants) had osteoarthritis at baseline. Varus alignment was associated with a greater risk of medial osteoarthritis progression (adjusted OR 3.59, 95% CI 2.62 to 4.92) and a reduced risk of lateral progression, and valgus with a greater risk of lateral progression (adjusted OR 4.85, 95% CI 3.17 to 7.42) and a reduced risk of medial progression. Varus but not valgus alignment increased the risk of incident tibiofemoral osteoarthritis. In knees with osteoarthritis, varus and valgus alignment each increased the risk of progression in the biomechanically stressed compartment.
    Annals of the rheumatic diseases 11/2010; 69(11):1940-5. · 8.11 Impact Factor

Institutions

  • 2012
    • University of California, Davis
      • Area of Musculoskeletal Imaging
      Davis, CA, USA
    • Paracelsus Medizinische Privatuniversität
      • Institut für Anatomie und muskuloskelettale Forschung
      Salzburg, Salzburg, Austria
    • Northwestern University
      • Feinberg School of Medicine
      Evanston, IL, USA
  • 2011
    • Diakonhjemmet Hospital (Norway)
      Oslo, Oslo, Norway
  • 2010–2011
    • University of Massachusetts Boston
      • Clinical Epidemiology Research and Training Unit
      Boston, MA, USA
  • 2007–2010
    • University of California, San Francisco
      San Francisco, CA, USA
  • 2009
    • University of Oxford
      Oxford, ENG, United Kingdom
  • 2008–2009
    • University of Iowa
      • Department of Orthopaedics and Rehabilitation
      Iowa City, IA, USA
  • 2007–2009
    • Boston University
      Boston, MA, USA
  • 2006
    • Boston Medical Center
      Boston, MA, USA