Michel D. Crema MD, Presenter: Shareholder, Boston Imaging Core Lab, LLC

Ali Guermazi MD, Abstract Co-Author: President, Boston Imaging Core Lab, LLC Research Consultant, Merck KGaA Research Consultant, Facet Solutions, Inc Research Consultant, Novartis AG Research Consultant, Genzyme Corporation Research Consultant, Stryker Corporation Research Consultant, AstraZeneca PLC

Michael C. Nevitt PhD, Abstract Co-Author: Nothing to Disclose

David Tobin Felson MD, MPH, Abstract Co-Author: Nothing to Disclose

Monica Dias Marra MD, Abstract Co-Author: Shareholder, Boston Imaging Core Lab, LLC

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

To determine the association of magnetic resonance imaging (MRI) assessment of worsening of 1) cartilage loss, 2) meniscal damage, and 3) meniscal extrusion with both fast and slow radiographic joint space narrowing (JSN) over 30 months.

The Multicenter Osteoarthritis (MOST) Study is an observational study of subjects with or at risk for knee osteoarthritis (OA). Knees with available baseline (BL) and 30-months follow-up (FU) posteroanterior radiographs and MRIs were included. Radiographs were read at BL and FU by two readers who graded joint space using a 0-3 scale including scoring of within-grade progression. MRIs were performed on a 1.0 T extremity system and read using the WORMS system by two musculoskeletal radiologists. In each tibiofemoral compartment, cartilage morphology (0-6 scale), meniscal morphology (0-4), and meniscal extrusion (0-2) were assessed at BL and FU. Compartments with maximum grades of any BL MRI feature were excluded (no progression of features is possible). Slow JSN was defined as an increase of > 0 and < 2 grades from BL to FU, whereas fast JSN was defined as an increase of ≥ 2 grades. For each tibiofemoral compartment separately, we assessed the associations of worsening of cartilage damage, meniscal damage, and meniscal extrusion (predictors) with slow and fast JSN (outcome) using logistic regression. All models included all three MRI predictors.

2284 knees of 1402 subjects were included (women 61.6%, mean age 62.0 ± 7.8, mean body mass index 29.9 ± 4.8). In both compartments, worsening of all MRI features was independently associated with both slow and fast JSN. Progression of cartilage damage had the highest risk for fast JSN, with adjusted odds ratios (OR) of 55.6 (95%CI 13.2, 234.1) medially and 20.0 (95%CI 3.4, 118.0) laterally. Increasing risk of JSN was directly associated with number of worsening MRI features (p for trend <.00001).

Worsening of cartilage loss, meniscal damage, and meniscal extrusion are independent predictors of tibiofemoral JSN in subjects with or at risk for knee OA. Progression of cartilage loss appears to play a major role when fast JSN is seen.

Tibiofemoral JSN is a result of multi-tissue articular degeneration, which needs to be considered in patient treatment and planning of observational studies using radiography as a structural outcome.

Crema, M, Guermazi, A, Nevitt, M, Felson, D, Marra, M, Roemer, F, Worsening of Cartilage Loss and Meniscal Pathology and Its Relationship with Progression of Radiographic Tibiofemoral Joint Space Narrowing in a Large Cohort of Persons with or at Risk for Knee Osteoarthritis: The MOST Study.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034308.html