Cross-Sectional Comparison of Extended Anteroposterior and Posteroanterior Fixed Flexion Positioning to Assess Radiographic Osteoarthritis at the Knee: The Johnston County Osteoarthritis Project

University of North Carolina, Chapel Hill, NC 27599-7280, USA.
Arthritis care & research 09/2010; 62(9):1342-5. DOI: 10.1002/acr.20210
Source: PubMed

ABSTRACT To compare values for Kellgren/Lawrence (K/L) scale grade, joint space narrowing (JSN), and osteophytes in anteroposterior (AP) extended and fixed flexion posteroanterior (PA) radiographs obtained during a single clinic visit (the first followup of the Johnston County Osteoarthritis Project).
All films (n = 1,664 bilateral knees) were read by an experienced musculoskeletal radiologist. For each subject, AP and PA fixed flexion films were read in one sitting. K/L scale grades (range 0-4) and JSN and osteophytes (ranges 0-3) were assessed using standard atlases. Descriptive statistics were calculated for demographic and clinical variables. AP and PA fixed flexion results were compared by contingency table methods to obtain frequencies for K/L scale, JSN, and osteophyte grades using percent agreement and kappa coefficients. Results from the right and left knees were similar; data for the right knee are presented.
There was substantial agreement between AP and PA fixed flexion reads for radiographic osteoarthritis, defined as a K/L scale grade ≥ 2 (89% agreement; κ = 0.73, 95% confidence interval 0.69-0.76). Substantial agreement was also seen for tibial osteophytes and medial JSN; slightly lower kappa values were observed for femoral osteophytes and lateral JSN.
The requirements of large observational cohort studies are different than those of clinical trials, and sensitivity is less of an issue because of longer followup times. In cohort studies such as the Johnston County Osteoarthritis Project, there is substantial agreement by K/L scale grade for AP and PA fixed flexion radiographs, allowing incorporation of older films in longitudinal analyses.

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Available from: Todd Schwartz, Jan 08, 2015
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    • "In other chronic diseases and in self-reported arthritis, the poverty rate of one's community has been found to be associated with disease incidence and prevalence independent of a person's level of educational attainment [13-18]. In Canada, two studies have examined associations between provincial or regional context with the prevalence of self-reported arthritis [16,17]. "
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    ABSTRACT: The purpose of this study was to examine data from the Johnston County Osteoarthritis (OA) Project for independent associations of educational attainment, occupation and community poverty with tibiofemoral knee OA. A cross-sectional analysis was conducted on 3,591 individuals (66% Caucasian and 34% African American). Educational attainment (< 12 years or ≥12 years), occupation (non-managerial or not), and Census block group household poverty rate (< 12%, 12 to 25%, > 25%) were examined separately and together in logistic models adjusting for covariates of age, gender, race, body mass index (BMI), smoking, knee injury and occupational activity score. Outcomes were presence of radiographic knee OA (rOA), symptomatic knee OA (sxOA), bilateral rOA and bilateral sxOA. When all three socioeconomic status (SES) variables were analyzed simultaneously, low educational attainment was significantly associated with rOA (odds ratio (OR) = 1.44, 95% confidence interval (CI) 1.20, 1.73), bilateral rOA (OR = 1.43, 95% CI 1.13, 1.81), and sxOA (OR = 1.66, 95% CI 1.34, 2.06), after adjusting for covariates. Independently, living in a community of high household poverty rate was associated with rOA (OR = 1.83, 95% CI 1.43, 2.36), bilateral rOA (OR = 1.56, 95% CI 1.12, 2.16), and sxOA (OR = 1.36, 95% CI 1.00, 1.83). Occupation had no significant independent association beyond educational attainment and community poverty. Both educational attainment and community SES were independently associated with knee OA after adjusting for primary risk factors for knee OA.
    Arthritis research & therapy 10/2011; 13(5):R169. DOI:10.1186/ar3492 · 3.75 Impact Factor
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    ABSTRACT: Although osteoarthritis (OA) commonly involves multiple joints, no widely accepted method for quantifying whole-body OA burden exists. Therefore, our aim was to apply factor analytic methods to radiographic OA (rOA) grades across multiple joint sites, representing both presence and severity, to quantify the burden of rOA. We used cross-sectional data from the Johnston County Osteoarthritis Project. The sample (n = 2092) had a mean age of 65 ± 11 years, body mass index (BMI) 31 ± 7 kg/m2, with 33% men and 34% African Americans. A single expert reader (intra-rater κ = 0.89) provided radiographic grades based on standard atlases for the hands (30 joints, including bilateral distal and proximal interphalangeal [IP], thumb IP, metacarpophalangeal [MCP] and carpometacarpal [CMC] joints), knees (patellofemoral and tibiofemoral, 4 joints), hips (2 joints), and spine (5 levels [L1/2 to L5/S1]). All grades were entered into an exploratory common factor analysis as continuous variables. Stratified factor analyses were used to look for differences by gender, race, age, and cohort subgroups. Four factors were identified as follows: IP/CMC factor (20 joints), MCP factor (8 joints), Knee factor (4 joints), Spine factor (5 levels). These factors had high internal consistency reliability (Cronbach's α range 0.80 to 0.95), were not collapsible into a single factor, and had moderate between-factor correlations (Pearson correlation coefficient r = 0.24 to 0.44). There were no major differences in factor structure when stratified by subgroup. The 4 factors obtained in this analysis indicate that the variables contained within each factor share an underlying cause, but the 4 factors are distinct, suggesting that combining these joint sites into one overall measure is not appropriate. Using such factors to reflect multi-joint rOA in statistical models can reduce the number of variables needed and increase precision.
    Arthritis research & therapy 10/2011; 13(5):R176. DOI:10.1186/ar3501 · 3.75 Impact Factor
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    ABSTRACT: Objective: To determine if supplemental intraarticular α2-macroglobulin (α2 M) has a chondroprotective effect in a rat model of osteoarthritis (OA). Methods: Using Western blotting, mass spectrometry, enzyme-linked immunosorbent assay (ELISA), and immunohistochemistry, α2 M was identified as a potential therapeutic agent through a comparison of α2 M concentrations in serum, synovial fluid (SF), and cartilage from normal subjects and patients with OA. In cultured chondrocytes, the effects of α2 M on interleukin-1 (IL-1)-induced cartilage catabolic enzymes were evaluated by Luminex assay and ELISA. In vivo effects on cartilage degeneration and matrix metalloproteinase 13 (MMP-13) concentration were evaluated in male rats (n = 120) randomized to 1 of 4 treatments: 1) anterior cruciate ligament transection (ACLT) and saline injections, 2) ACLT and 1 IU/kg injections of α2 M, 3) ACLT and 2 IU/kg injections of α2 M, or 4) sham operation and saline injections. Rats were administered intraarticular injections for 6 weeks. The concentration of MMP-13 in SF lavage fluid was measured using ELISA. OA-related gene expression was quantified by real-time quantitative polymerase chain reaction. The extent of OA progression was graded by histologic examination. Results: In both normal subjects and OA patients, α2 M levels were lower in SF as compared to serum, and in OA patients, MMP-13 levels were higher in SF than in serum. In vitro, α2 M inhibited the induction of MMP-13 by IL-1 in a dose-dependent manner in human chondrocytes. In the rat model of ACLT OA, supplemental intraarticular injection of α2 M reduced the concentration of MMP-13 in SF, had a favorable effect on OA-related gene expression, and attenuated OA progression. Conclusion: The plasma protease inhibitor α2 M is not present in sufficient concentrations to inactivate the high concentrations of catabolic factors found in OA SF. Our findings suggest that supplemental intraarticular α2 M provides chondral protection in posttraumatic OA.
    Arthritis and Rheumatology 02/2014; 66(7). DOI:10.1002/art.38576
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