Ali Guermazi MD, PhD, Presenter: President, Boston Imaging Core Lab, LLC Research Consultant, Merck KgaA Research Consultant, sanofi-aventis Group Research Consultant, TissueGene, Inc

Felix Eckstein MD, Abstract Co-Author: Co-owner, Chondrometrics GmbH Co-founder, Chondrometrics GmbH CEO, Chondrometrics GmbH Consultant, Novartis AG Consultant, Merck KGaA Consultant, sanofi-aventis Group

Daichi Hayashi MBBS, PhD, Abstract Co-Author: Nothing to Disclose

Frank W. Roemer MD, Abstract Co-Author: Vice-President, Boston Imaging Core Lab LLC Shareholder, Boston Imaging Core Lab LLC Research Consultant, Merck KGaA

Jingbo Niu MD, PhD, Abstract Co-Author: Nothing to Disclose

David Tobin Felson MD, MPH, Abstract Co-Author: Consultant, Knee Creations, Ltd

Although several pathological MRI and radiographic features of knee osteoarthritis (OA) have been associated with subsequent structural disease progression, no study has compared these features within the same study. We aimed to determine which of these features are most predictive of quantitative cartilage thickness loss measured by MRI.

196 subjects from the Multicenter OA Study subcohort had baseline and 30-month knee MRIs, quantitative cartilage thickness measurement, and semiquantitative scoring (Whole Organ MRI Score) of cartilage, bone marrow, meniscus, effusion synovitis, and Hoffa synovitis at both time points. Presence of radiographic joint space narrowing (JSN) was noted at baseline. Knees were classified into progressors (those who lost cartilage thickness above thresholds) and non-progressors (those who did not). All MRI predictors were dichotomized into present (score≥2 for cartilage, ≥1 for others) or absent. Differences in baseline scores of ipsicompartmental predictor variables were compared between progressors and non-progressors by logistic regression adjusting for covariates. Odds ratios (OR) and 95%CIs were calculated for medial (MFTC) and lateral femorotibial compartment (LFTC) cartilage loss, respectively. We combined MFTC and LFTC to calculate ORs of ipsicompartmental cartilage loss across compartments using Generalized Estimating Equations.

Of 196 knees (mean age 59.8±6.3, BMI 29.5±4.6), 46 knees had radiographic OA at baseline. Compared to non-progressors (n=149), progressors (n=47) had higher adjusted OR (aOR) for having baseline medial meniscal damage (aOR 2.4 [95%CI 1.2-5.1]), medial meniscal extrusion (aOR 2.5 [1.2-5.3]) and effusion synovitis (aOR 3.2 [1.2-8.2]) in MFTC. In LFTC, baseline JSN (aOR 7.0 [1.8-27.1]), lateral meniscal damage (aOR 8.1 [2.5-26.6]) and lateral meniscal extrusion (aOR 4.1 [1.4-12.5]) predicted cartilage loss. For analysis combining MFTC and LFTC, results were similar to those of LTFC, with baseline compartment specific JSN, meniscal damage and extrusion predicting cartilage loss.

Among MRI and radiographic features, meniscal damage/extrusion and effusion synovitis most strongly predict quantitatively assessed cartilage thickness loss over 30 months.

Knees with meniscal damage and extrusion are likely to have cartilage thickness loss over time in the same FTC and should be a therapeutic target in knee OA.

Guermazi, A, Eckstein, F, Hayashi, D, Roemer, F, Niu, J, Felson, D, Semiquantitative MRI-based Predictors of Quantitative Cartilage Thickness Loss in Knee Osteoarthritis: Data from the MOST Study.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13013420.html